mirror of
https://git.tartarus.org/simon/putty.git
synced 2025-01-10 01:48:00 +00:00
aaeecbb4ea
compression. This involves introducing an option to disable Zlib compression (that is, continue to work within the Zlib format but output an uncompressed block) for the duration of a single packet. [originally from svn r982]
3855 lines
123 KiB
C
3855 lines
123 KiB
C
#include <windows.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <assert.h>
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#include "putty.h"
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#include "tree234.h"
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#include "ssh.h"
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#ifndef FALSE
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#define FALSE 0
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#endif
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#ifndef TRUE
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#define TRUE 1
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#endif
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#define logevent(s) { logevent(s); \
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if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
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fprintf(stderr, "%s\n", s); }
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#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
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(s ? sk_close(s), s = NULL : 0), \
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connection_fatal msg )
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#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
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#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
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#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
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#define SSH1_CMSG_USER 4 /* 0x4 */
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#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
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#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
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#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
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#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
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#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
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#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
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#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
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#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
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#define SSH1_SMSG_SUCCESS 14 /* 0xe */
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#define SSH1_SMSG_FAILURE 15 /* 0xf */
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#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
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#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
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#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
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#define SSH1_CMSG_EOF 19 /* 0x13 */
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#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
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#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
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#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
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#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
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#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
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#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
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#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
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#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
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#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
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#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
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#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
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#define SSH1_MSG_IGNORE 32 /* 0x20 */
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#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
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#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
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#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
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#define SSH1_MSG_DEBUG 36 /* 0x24 */
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#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
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#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
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#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
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#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
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#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
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#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
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#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
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#define SSH1_AUTH_TIS 5 /* 0x5 */
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#define SSH1_AUTH_CCARD 16 /* 0x10 */
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#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
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#define SSH2_MSG_IGNORE 2 /* 0x2 */
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#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
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#define SSH2_MSG_DEBUG 4 /* 0x4 */
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#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
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#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
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#define SSH2_MSG_KEXINIT 20 /* 0x14 */
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#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
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#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
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#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
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#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
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#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
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#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
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#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
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#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
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#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
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#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
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#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
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#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
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#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
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#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
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#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
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#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
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#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
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#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
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#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
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#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
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#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
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#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
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#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
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#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
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#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
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#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
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#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
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#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
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#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
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#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
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#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
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#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
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#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
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#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
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#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
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#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
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#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
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#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
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#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
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#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
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#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
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#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
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#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
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#define GET_32BIT(cp) \
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(((unsigned long)(unsigned char)(cp)[0] << 24) | \
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((unsigned long)(unsigned char)(cp)[1] << 16) | \
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((unsigned long)(unsigned char)(cp)[2] << 8) | \
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((unsigned long)(unsigned char)(cp)[3]))
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#define PUT_32BIT(cp, value) { \
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(cp)[0] = (unsigned char)((value) >> 24); \
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(cp)[1] = (unsigned char)((value) >> 16); \
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(cp)[2] = (unsigned char)((value) >> 8); \
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(cp)[3] = (unsigned char)(value); }
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enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
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/* Coroutine mechanics for the sillier bits of the code */
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#define crBegin1 static int crLine = 0;
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#define crBegin2 switch(crLine) { case 0:;
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#define crBegin crBegin1; crBegin2;
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#define crFinish(z) } crLine = 0; return (z)
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#define crFinishV } crLine = 0; return
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#define crReturn(z) \
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do {\
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crLine=__LINE__; return (z); case __LINE__:;\
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} while (0)
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#define crReturnV \
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do {\
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crLine=__LINE__; return; case __LINE__:;\
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} while (0)
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#define crStop(z) do{ crLine = 0; return (z); }while(0)
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#define crStopV do{ crLine = 0; return; }while(0)
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#define crWaitUntil(c) do { crReturn(0); } while (!(c))
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#define crWaitUntilV(c) do { crReturnV; } while (!(c))
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extern char *x11_init (Socket *, char *, void *);
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extern void x11_close (Socket);
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extern void x11_send (Socket , char *, int);
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extern void x11_invent_auth(char *, int, char *, int);
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/*
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* Ciphers for SSH2. We miss out single-DES because it isn't
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* supported; also 3DES and Blowfish are both done differently from
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* SSH1. (3DES uses outer chaining; Blowfish has the opposite
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* endianness and different-sized keys.)
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*/
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const static struct ssh2_ciphers *ciphers[] = {
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&ssh2_aes,
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&ssh2_blowfish,
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&ssh2_3des,
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};
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const static struct ssh_kex *kex_algs[] = {
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#ifdef DO_DIFFIE_HELLMAN_GEX
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&ssh_diffiehellman_gex,
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#endif
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&ssh_diffiehellman };
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const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
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static void nullmac_key(unsigned char *key) { }
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static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
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static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
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const static struct ssh_mac ssh_mac_none = {
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nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
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};
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const static struct ssh_mac *macs[] = {
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&ssh_sha1, &ssh_md5, &ssh_mac_none };
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const static struct ssh_mac *buggymacs[] = {
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&ssh_sha1_buggy, &ssh_md5, &ssh_mac_none };
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static void ssh_comp_none_init(void) { }
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static int ssh_comp_none_block(unsigned char *block, int len,
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unsigned char **outblock, int *outlen) {
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return 0;
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}
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const static struct ssh_compress ssh_comp_none = {
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"none",
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ssh_comp_none_init, ssh_comp_none_block,
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ssh_comp_none_init, ssh_comp_none_block
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};
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extern const struct ssh_compress ssh_zlib;
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const static struct ssh_compress *compressions[] = {
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&ssh_zlib, &ssh_comp_none };
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enum { /* channel types */
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CHAN_MAINSESSION,
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CHAN_X11,
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CHAN_AGENT,
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};
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/*
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* 2-3-4 tree storing channels.
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*/
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struct ssh_channel {
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unsigned remoteid, localid;
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int type;
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int closes;
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struct ssh2_data_channel {
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unsigned char *outbuffer;
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unsigned outbuflen, outbufsize;
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unsigned remwindow, remmaxpkt;
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} v2;
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union {
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struct ssh_agent_channel {
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unsigned char *message;
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unsigned char msglen[4];
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int lensofar, totallen;
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} a;
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struct ssh_x11_channel {
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Socket s;
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} x11;
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} u;
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};
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struct Packet {
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long length;
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int type;
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unsigned char *data;
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unsigned char *body;
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long savedpos;
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long maxlen;
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};
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static SHA_State exhash, exhashbase;
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static Socket s = NULL;
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static unsigned char session_key[32];
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static int ssh1_compressing;
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static int ssh_agentfwd_enabled;
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static int ssh_X11_fwd_enabled;
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static const struct ssh_cipher *cipher = NULL;
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static const struct ssh2_cipher *cscipher = NULL;
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static const struct ssh2_cipher *sccipher = NULL;
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static const struct ssh_mac *csmac = NULL;
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static const struct ssh_mac *scmac = NULL;
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static const struct ssh_compress *cscomp = NULL;
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static const struct ssh_compress *sccomp = NULL;
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static const struct ssh_kex *kex = NULL;
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static const struct ssh_signkey *hostkey = NULL;
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static unsigned char ssh2_session_id[20];
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int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
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static char *savedhost;
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static int savedport;
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static int ssh_send_ok;
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static int ssh_echoing, ssh_editing;
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static tree234 *ssh_channels; /* indexed by local id */
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static struct ssh_channel *mainchan; /* primary session channel */
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static enum {
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SSH_STATE_PREPACKET,
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SSH_STATE_BEFORE_SIZE,
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SSH_STATE_INTERMED,
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SSH_STATE_SESSION,
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SSH_STATE_CLOSED
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} ssh_state = SSH_STATE_PREPACKET;
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static int size_needed = FALSE, eof_needed = FALSE;
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static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
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static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
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static unsigned char *deferred_send_data = NULL;
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static int deferred_len = 0, deferred_size = 0;
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static int ssh_version;
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static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
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static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
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static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
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static void ssh_size(void);
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static void ssh_special (Telnet_Special);
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static void ssh2_try_send(struct ssh_channel *c);
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static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
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static int (*s_rdpkt)(unsigned char **data, int *datalen);
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static struct rdpkt1_state_tag {
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long len, pad, biglen, to_read;
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unsigned long realcrc, gotcrc;
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unsigned char *p;
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int i;
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int chunk;
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} rdpkt1_state;
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static struct rdpkt2_state_tag {
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long len, pad, payload, packetlen, maclen;
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int i;
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int cipherblk;
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unsigned long incoming_sequence;
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} rdpkt2_state;
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static int ssh_channelcmp(void *av, void *bv) {
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struct ssh_channel *a = (struct ssh_channel *)av;
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struct ssh_channel *b = (struct ssh_channel *)bv;
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if (a->localid < b->localid) return -1;
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if (a->localid > b->localid) return +1;
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return 0;
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}
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static int ssh_channelfind(void *av, void *bv) {
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unsigned *a = (unsigned *)av;
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struct ssh_channel *b = (struct ssh_channel *)bv;
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if (*a < b->localid) return -1;
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if (*a > b->localid) return +1;
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return 0;
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}
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static void c_write (char *buf, int len) {
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if ((flags & FLAG_STDERR)) {
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int i;
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for (i = 0; i < len; i++)
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if (buf[i] != '\r')
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fputc(buf[i], stderr);
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return;
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}
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from_backend(1, buf, len);
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}
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static void c_write_str (char *buf) {
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c_write(buf, strlen(buf));
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}
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/*
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* Collect incoming data in the incoming packet buffer.
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* Decipher and verify the packet when it is completely read.
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* Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
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* Update the *data and *datalen variables.
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* Return the additional nr of bytes needed, or 0 when
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* a complete packet is available.
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*/
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static int ssh1_rdpkt(unsigned char **data, int *datalen)
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{
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struct rdpkt1_state_tag *st = &rdpkt1_state;
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crBegin;
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next_packet:
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pktin.type = 0;
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pktin.length = 0;
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for (st->i = st->len = 0; st->i < 4; st->i++) {
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while ((*datalen) == 0)
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crReturn(4-st->i);
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st->len = (st->len << 8) + **data;
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(*data)++, (*datalen)--;
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}
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#ifdef FWHACK
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if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
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st->len = 0x300; /* big enough to carry to end */
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}
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#endif
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st->pad = 8 - (st->len % 8);
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st->biglen = st->len + st->pad;
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pktin.length = st->len - 5;
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if (pktin.maxlen < st->biglen) {
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pktin.maxlen = st->biglen;
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pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
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srealloc(pktin.data, st->biglen+APIEXTRA));
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if (!pktin.data)
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fatalbox("Out of memory");
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}
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st->to_read = st->biglen;
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st->p = pktin.data;
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while (st->to_read > 0) {
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st->chunk = st->to_read;
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while ((*datalen) == 0)
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crReturn(st->to_read);
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if (st->chunk > (*datalen))
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st->chunk = (*datalen);
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memcpy(st->p, *data, st->chunk);
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*data += st->chunk;
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*datalen -= st->chunk;
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st->p += st->chunk;
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st->to_read -= st->chunk;
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}
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if (cipher)
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cipher->decrypt(pktin.data, st->biglen);
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#if 0
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debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
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for (st->i = 0; st->i < st->biglen; st->i++)
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debug((" %02x", (unsigned char)pktin.data[st->i]));
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debug(("\r\n"));
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#endif
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st->realcrc = crc32(pktin.data, st->biglen-4);
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st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
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if (st->gotcrc != st->realcrc) {
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bombout(("Incorrect CRC received on packet"));
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crReturn(0);
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}
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pktin.body = pktin.data + st->pad + 1;
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if (ssh1_compressing) {
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unsigned char *decompblk;
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int decomplen;
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#if 0
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int i;
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debug(("Packet payload pre-decompression:\n"));
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for (i = -1; i < pktin.length; i++)
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debug((" %02x", (unsigned char)pktin.body[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
zlib_decompress_block(pktin.body-1, pktin.length+1,
|
|
&decompblk, &decomplen);
|
|
|
|
if (pktin.maxlen < st->pad + decomplen) {
|
|
pktin.maxlen = st->pad + decomplen;
|
|
pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
|
|
pktin.body = pktin.data + st->pad + 1;
|
|
if (!pktin.data)
|
|
fatalbox("Out of memory");
|
|
}
|
|
|
|
memcpy(pktin.body-1, decompblk, decomplen);
|
|
sfree(decompblk);
|
|
pktin.length = decomplen-1;
|
|
#if 0
|
|
debug(("Packet payload post-decompression:\n"));
|
|
for (i = -1; i < pktin.length; i++)
|
|
debug((" %02x", (unsigned char)pktin.body[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
}
|
|
|
|
if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
|
|
pktin.type == SSH1_SMSG_STDERR_DATA ||
|
|
pktin.type == SSH1_MSG_DEBUG ||
|
|
pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
|
|
pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
|
|
long strlen = GET_32BIT(pktin.body);
|
|
if (strlen + 4 != pktin.length) {
|
|
bombout(("Received data packet with bogus string length"));
|
|
crReturn(0);
|
|
}
|
|
}
|
|
|
|
pktin.type = pktin.body[-1];
|
|
|
|
if (pktin.type == SSH1_MSG_DEBUG) {
|
|
/* log debug message */
|
|
char buf[80];
|
|
int strlen = GET_32BIT(pktin.body);
|
|
strcpy(buf, "Remote: ");
|
|
if (strlen > 70) strlen = 70;
|
|
memcpy(buf+8, pktin.body+4, strlen);
|
|
buf[8+strlen] = '\0';
|
|
logevent(buf);
|
|
goto next_packet;
|
|
} else if (pktin.type == SSH1_MSG_IGNORE) {
|
|
/* do nothing */
|
|
goto next_packet;
|
|
}
|
|
|
|
crFinish(0);
|
|
}
|
|
|
|
static int ssh2_rdpkt(unsigned char **data, int *datalen)
|
|
{
|
|
struct rdpkt2_state_tag *st = &rdpkt2_state;
|
|
|
|
crBegin;
|
|
|
|
next_packet:
|
|
pktin.type = 0;
|
|
pktin.length = 0;
|
|
if (sccipher)
|
|
st->cipherblk = sccipher->blksize;
|
|
else
|
|
st->cipherblk = 8;
|
|
if (st->cipherblk < 8)
|
|
st->cipherblk = 8;
|
|
|
|
if (pktin.maxlen < st->cipherblk) {
|
|
pktin.maxlen = st->cipherblk;
|
|
pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
|
|
srealloc(pktin.data, st->cipherblk+APIEXTRA));
|
|
if (!pktin.data)
|
|
fatalbox("Out of memory");
|
|
}
|
|
|
|
/*
|
|
* Acquire and decrypt the first block of the packet. This will
|
|
* contain the length and padding details.
|
|
*/
|
|
for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
|
|
while ((*datalen) == 0)
|
|
crReturn(st->cipherblk-st->i);
|
|
pktin.data[st->i] = *(*data)++;
|
|
(*datalen)--;
|
|
}
|
|
#ifdef FWHACK
|
|
if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
|
|
/* FIXME */
|
|
}
|
|
#endif
|
|
if (sccipher)
|
|
sccipher->decrypt(pktin.data, st->cipherblk);
|
|
|
|
/*
|
|
* Now get the length and padding figures.
|
|
*/
|
|
st->len = GET_32BIT(pktin.data);
|
|
st->pad = pktin.data[4];
|
|
|
|
/*
|
|
* This enables us to deduce the payload length.
|
|
*/
|
|
st->payload = st->len - st->pad - 1;
|
|
|
|
pktin.length = st->payload + 5;
|
|
|
|
/*
|
|
* So now we can work out the total packet length.
|
|
*/
|
|
st->packetlen = st->len + 4;
|
|
st->maclen = scmac ? scmac->len : 0;
|
|
|
|
/*
|
|
* Adjust memory allocation if packet is too big.
|
|
*/
|
|
if (pktin.maxlen < st->packetlen+st->maclen) {
|
|
pktin.maxlen = st->packetlen+st->maclen;
|
|
pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
|
|
srealloc(pktin.data, pktin.maxlen+APIEXTRA));
|
|
if (!pktin.data)
|
|
fatalbox("Out of memory");
|
|
}
|
|
|
|
/*
|
|
* Read and decrypt the remainder of the packet.
|
|
*/
|
|
for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) {
|
|
while ((*datalen) == 0)
|
|
crReturn(st->packetlen + st->maclen - st->i);
|
|
pktin.data[st->i] = *(*data)++;
|
|
(*datalen)--;
|
|
}
|
|
/* Decrypt everything _except_ the MAC. */
|
|
if (sccipher)
|
|
sccipher->decrypt(pktin.data + st->cipherblk,
|
|
st->packetlen - st->cipherblk);
|
|
|
|
#if 0
|
|
debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
|
|
for (st->i = 0; st->i < st->packetlen; st->i++)
|
|
debug((" %02x", (unsigned char)pktin.data[st->i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
|
|
/*
|
|
* Check the MAC.
|
|
*/
|
|
if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
|
|
bombout(("Incorrect MAC received on packet"));
|
|
crReturn(0);
|
|
}
|
|
st->incoming_sequence++; /* whether or not we MACed */
|
|
|
|
/*
|
|
* Decompress packet payload.
|
|
*/
|
|
{
|
|
unsigned char *newpayload;
|
|
int newlen;
|
|
if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
|
|
&newpayload, &newlen)) {
|
|
if (pktin.maxlen < newlen+5) {
|
|
pktin.maxlen = newlen+5;
|
|
pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
|
|
srealloc(pktin.data, pktin.maxlen+APIEXTRA));
|
|
if (!pktin.data)
|
|
fatalbox("Out of memory");
|
|
}
|
|
pktin.length = 5 + newlen;
|
|
memcpy(pktin.data+5, newpayload, newlen);
|
|
#if 0
|
|
debug(("Post-decompression payload:\r\n"));
|
|
for (st->i = 0; st->i < newlen; st->i++)
|
|
debug((" %02x", (unsigned char)pktin.data[5+st->i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
|
|
sfree(newpayload);
|
|
}
|
|
}
|
|
|
|
pktin.savedpos = 6;
|
|
pktin.type = pktin.data[5];
|
|
|
|
if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
|
|
goto next_packet; /* FIXME: print DEBUG message */
|
|
|
|
crFinish(0);
|
|
}
|
|
|
|
static void ssh1_pktout_size(int len) {
|
|
int pad, biglen;
|
|
|
|
len += 5; /* type and CRC */
|
|
pad = 8 - (len%8);
|
|
biglen = len + pad;
|
|
|
|
pktout.length = len-5;
|
|
if (pktout.maxlen < biglen) {
|
|
pktout.maxlen = biglen;
|
|
#ifdef MSCRYPTOAPI
|
|
/* Allocate enough buffer space for extra block
|
|
* for MS CryptEncrypt() */
|
|
pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
|
|
srealloc(pktout.data, biglen+12));
|
|
#else
|
|
pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
|
|
srealloc(pktout.data, biglen+4));
|
|
#endif
|
|
if (!pktout.data)
|
|
fatalbox("Out of memory");
|
|
}
|
|
pktout.body = pktout.data+4+pad+1;
|
|
}
|
|
|
|
static void s_wrpkt_start(int type, int len) {
|
|
ssh1_pktout_size(len);
|
|
pktout.type = type;
|
|
}
|
|
|
|
static int s_wrpkt_prepare(void) {
|
|
int pad, len, biglen, i;
|
|
unsigned long crc;
|
|
|
|
pktout.body[-1] = pktout.type;
|
|
|
|
if (ssh1_compressing) {
|
|
unsigned char *compblk;
|
|
int complen;
|
|
#if 0
|
|
debug(("Packet payload pre-compression:\n"));
|
|
for (i = -1; i < pktout.length; i++)
|
|
debug((" %02x", (unsigned char)pktout.body[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
zlib_compress_block(pktout.body-1, pktout.length+1,
|
|
&compblk, &complen);
|
|
ssh1_pktout_size(complen-1);
|
|
memcpy(pktout.body-1, compblk, complen);
|
|
sfree(compblk);
|
|
#if 0
|
|
debug(("Packet payload post-compression:\n"));
|
|
for (i = -1; i < pktout.length; i++)
|
|
debug((" %02x", (unsigned char)pktout.body[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
}
|
|
|
|
len = pktout.length + 5; /* type and CRC */
|
|
pad = 8 - (len%8);
|
|
biglen = len + pad;
|
|
|
|
for (i=0; i<pad; i++)
|
|
pktout.data[i+4] = random_byte();
|
|
crc = crc32(pktout.data+4, biglen-4);
|
|
PUT_32BIT(pktout.data+biglen, crc);
|
|
PUT_32BIT(pktout.data, len);
|
|
|
|
#if 0
|
|
debug(("Sending packet len=%d\r\n", biglen+4));
|
|
for (i = 0; i < biglen+4; i++)
|
|
debug((" %02x", (unsigned char)pktout.data[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
if (cipher)
|
|
cipher->encrypt(pktout.data+4, biglen);
|
|
|
|
return biglen+4;
|
|
}
|
|
|
|
static void s_wrpkt(void) {
|
|
int len;
|
|
len = s_wrpkt_prepare();
|
|
sk_write(s, pktout.data, len);
|
|
}
|
|
|
|
static void s_wrpkt_defer(void) {
|
|
int len;
|
|
len = s_wrpkt_prepare();
|
|
if (deferred_len + len > deferred_size) {
|
|
deferred_size = deferred_len + len + 128;
|
|
deferred_send_data = srealloc(deferred_send_data, deferred_size);
|
|
}
|
|
memcpy(deferred_send_data+deferred_len, pktout.data, len);
|
|
deferred_len += len;
|
|
}
|
|
|
|
/*
|
|
* Construct a packet with the specified contents.
|
|
*/
|
|
static void construct_packet(int pkttype, va_list ap1, va_list ap2)
|
|
{
|
|
unsigned char *p, *argp, argchar;
|
|
unsigned long argint;
|
|
int pktlen, argtype, arglen;
|
|
Bignum bn;
|
|
|
|
pktlen = 0;
|
|
while ((argtype = va_arg(ap1, int)) != PKT_END) {
|
|
switch (argtype) {
|
|
case PKT_INT:
|
|
(void) va_arg(ap1, int);
|
|
pktlen += 4;
|
|
break;
|
|
case PKT_CHAR:
|
|
(void) va_arg(ap1, char);
|
|
pktlen++;
|
|
break;
|
|
case PKT_DATA:
|
|
(void) va_arg(ap1, unsigned char *);
|
|
arglen = va_arg(ap1, int);
|
|
pktlen += arglen;
|
|
break;
|
|
case PKT_STR:
|
|
argp = va_arg(ap1, unsigned char *);
|
|
arglen = strlen(argp);
|
|
pktlen += 4 + arglen;
|
|
break;
|
|
case PKT_BIGNUM:
|
|
bn = va_arg(ap1, Bignum);
|
|
pktlen += ssh1_bignum_length(bn);
|
|
break;
|
|
default:
|
|
assert(0);
|
|
}
|
|
}
|
|
|
|
s_wrpkt_start(pkttype, pktlen);
|
|
p = pktout.body;
|
|
|
|
while ((argtype = va_arg(ap2, int)) != PKT_END) {
|
|
switch (argtype) {
|
|
case PKT_INT:
|
|
argint = va_arg(ap2, int);
|
|
PUT_32BIT(p, argint);
|
|
p += 4;
|
|
break;
|
|
case PKT_CHAR:
|
|
argchar = va_arg(ap2, unsigned char);
|
|
*p = argchar;
|
|
p++;
|
|
break;
|
|
case PKT_DATA:
|
|
argp = va_arg(ap2, unsigned char *);
|
|
arglen = va_arg(ap2, int);
|
|
memcpy(p, argp, arglen);
|
|
p += arglen;
|
|
break;
|
|
case PKT_STR:
|
|
argp = va_arg(ap2, unsigned char *);
|
|
arglen = strlen(argp);
|
|
PUT_32BIT(p, arglen);
|
|
memcpy(p + 4, argp, arglen);
|
|
p += 4 + arglen;
|
|
break;
|
|
case PKT_BIGNUM:
|
|
bn = va_arg(ap2, Bignum);
|
|
p += ssh1_write_bignum(p, bn);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void send_packet(int pkttype, ...) {
|
|
va_list ap1, ap2;
|
|
va_start(ap1, pkttype);
|
|
va_start(ap2, pkttype);
|
|
construct_packet(pkttype, ap1, ap2);
|
|
s_wrpkt();
|
|
}
|
|
|
|
static void defer_packet(int pkttype, ...) {
|
|
va_list ap1, ap2;
|
|
va_start(ap1, pkttype);
|
|
va_start(ap2, pkttype);
|
|
construct_packet(pkttype, ap1, ap2);
|
|
s_wrpkt_defer();
|
|
}
|
|
|
|
static int ssh_versioncmp(char *a, char *b) {
|
|
char *ae, *be;
|
|
unsigned long av, bv;
|
|
|
|
av = strtoul(a, &ae, 10);
|
|
bv = strtoul(b, &be, 10);
|
|
if (av != bv) return (av < bv ? -1 : +1);
|
|
if (*ae == '.') ae++;
|
|
if (*be == '.') be++;
|
|
av = strtoul(ae, &ae, 10);
|
|
bv = strtoul(be, &be, 10);
|
|
if (av != bv) return (av < bv ? -1 : +1);
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Utility routines for putting an SSH-protocol `string' and
|
|
* `uint32' into a SHA state.
|
|
*/
|
|
#include <stdio.h>
|
|
static void sha_string(SHA_State *s, void *str, int len) {
|
|
unsigned char lenblk[4];
|
|
PUT_32BIT(lenblk, len);
|
|
SHA_Bytes(s, lenblk, 4);
|
|
SHA_Bytes(s, str, len);
|
|
}
|
|
|
|
static void sha_uint32(SHA_State *s, unsigned i) {
|
|
unsigned char intblk[4];
|
|
PUT_32BIT(intblk, i);
|
|
SHA_Bytes(s, intblk, 4);
|
|
}
|
|
|
|
/*
|
|
* SSH2 packet construction functions.
|
|
*/
|
|
static void ssh2_pkt_ensure(int length) {
|
|
if (pktout.maxlen < length) {
|
|
pktout.maxlen = length + 256;
|
|
pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
|
|
srealloc(pktout.data, pktout.maxlen+APIEXTRA));
|
|
if (!pktout.data)
|
|
fatalbox("Out of memory");
|
|
}
|
|
}
|
|
static void ssh2_pkt_adddata(void *data, int len) {
|
|
pktout.length += len;
|
|
ssh2_pkt_ensure(pktout.length);
|
|
memcpy(pktout.data+pktout.length-len, data, len);
|
|
}
|
|
static void ssh2_pkt_addbyte(unsigned char byte) {
|
|
ssh2_pkt_adddata(&byte, 1);
|
|
}
|
|
static void ssh2_pkt_init(int pkt_type) {
|
|
pktout.length = 5;
|
|
ssh2_pkt_addbyte((unsigned char)pkt_type);
|
|
}
|
|
static void ssh2_pkt_addbool(unsigned char value) {
|
|
ssh2_pkt_adddata(&value, 1);
|
|
}
|
|
static void ssh2_pkt_adduint32(unsigned long value) {
|
|
unsigned char x[4];
|
|
PUT_32BIT(x, value);
|
|
ssh2_pkt_adddata(x, 4);
|
|
}
|
|
static void ssh2_pkt_addstring_start(void) {
|
|
ssh2_pkt_adduint32(0);
|
|
pktout.savedpos = pktout.length;
|
|
}
|
|
static void ssh2_pkt_addstring_str(char *data) {
|
|
ssh2_pkt_adddata(data, strlen(data));
|
|
PUT_32BIT(pktout.data + pktout.savedpos - 4,
|
|
pktout.length - pktout.savedpos);
|
|
}
|
|
static void ssh2_pkt_addstring_data(char *data, int len) {
|
|
ssh2_pkt_adddata(data, len);
|
|
PUT_32BIT(pktout.data + pktout.savedpos - 4,
|
|
pktout.length - pktout.savedpos);
|
|
}
|
|
static void ssh2_pkt_addstring(char *data) {
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_str(data);
|
|
}
|
|
static char *ssh2_mpint_fmt(Bignum b, int *len) {
|
|
unsigned char *p;
|
|
int i, n = (ssh1_bignum_bitcount(b)+7)/8;
|
|
p = smalloc(n + 1);
|
|
if (!p)
|
|
fatalbox("out of memory");
|
|
p[0] = 0;
|
|
for (i = 1; i <= n; i++)
|
|
p[i] = bignum_byte(b, n-i);
|
|
i = 0;
|
|
while (i <= n && p[i] == 0 && (p[i+1] & 0x80) == 0)
|
|
i++;
|
|
memmove(p, p+i, n+1-i);
|
|
*len = n+1-i;
|
|
return p;
|
|
}
|
|
static void ssh2_pkt_addmp(Bignum b) {
|
|
unsigned char *p;
|
|
int len;
|
|
p = ssh2_mpint_fmt(b, &len);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(p, len);
|
|
sfree(p);
|
|
}
|
|
|
|
/*
|
|
* Construct an SSH2 final-form packet: compress it, encrypt it,
|
|
* put the MAC on it. Final packet, ready to be sent, is stored in
|
|
* pktout.data. Total length is returned.
|
|
*/
|
|
static int ssh2_pkt_construct(void) {
|
|
int cipherblk, maclen, padding, i;
|
|
static unsigned long outgoing_sequence = 0;
|
|
|
|
/*
|
|
* Compress packet payload.
|
|
*/
|
|
#if 0
|
|
debug(("Pre-compression payload:\r\n"));
|
|
for (i = 5; i < pktout.length; i++)
|
|
debug((" %02x", (unsigned char)pktout.data[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
{
|
|
unsigned char *newpayload;
|
|
int newlen;
|
|
if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
|
|
&newpayload, &newlen)) {
|
|
pktout.length = 5;
|
|
ssh2_pkt_adddata(newpayload, newlen);
|
|
sfree(newpayload);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Add padding. At least four bytes, and must also bring total
|
|
* length (minus MAC) up to a multiple of the block size.
|
|
*/
|
|
cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
|
|
cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
|
|
padding = 4;
|
|
padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
|
|
maclen = csmac ? csmac->len : 0;
|
|
ssh2_pkt_ensure(pktout.length + padding + maclen);
|
|
pktout.data[4] = padding;
|
|
for (i = 0; i < padding; i++)
|
|
pktout.data[pktout.length + i] = random_byte();
|
|
PUT_32BIT(pktout.data, pktout.length + padding - 4);
|
|
if (csmac)
|
|
csmac->generate(pktout.data, pktout.length + padding,
|
|
outgoing_sequence);
|
|
outgoing_sequence++; /* whether or not we MACed */
|
|
|
|
#if 0
|
|
debug(("Sending packet len=%d\r\n", pktout.length+padding));
|
|
for (i = 0; i < pktout.length+padding; i++)
|
|
debug((" %02x", (unsigned char)pktout.data[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
|
|
if (cscipher)
|
|
cscipher->encrypt(pktout.data, pktout.length + padding);
|
|
|
|
/* Ready-to-send packet starts at pktout.data. We return length. */
|
|
return pktout.length + padding + maclen;
|
|
}
|
|
|
|
/*
|
|
* Construct and send an SSH2 packet immediately.
|
|
*/
|
|
static void ssh2_pkt_send(void) {
|
|
int len = ssh2_pkt_construct();
|
|
sk_write(s, pktout.data, len);
|
|
}
|
|
|
|
/*
|
|
* Construct an SSH2 packet and add it to a deferred data block.
|
|
* Useful for sending multiple packets in a single sk_write() call,
|
|
* to prevent a traffic-analysing listener from being able to work
|
|
* out the length of any particular packet (such as the password
|
|
* packet).
|
|
*
|
|
* Note that because SSH2 sequence-numbers its packets, this can
|
|
* NOT be used as an m4-style `defer' allowing packets to be
|
|
* constructed in one order and sent in another.
|
|
*/
|
|
static void ssh2_pkt_defer(void) {
|
|
int len = ssh2_pkt_construct();
|
|
if (deferred_len + len > deferred_size) {
|
|
deferred_size = deferred_len + len + 128;
|
|
deferred_send_data = srealloc(deferred_send_data, deferred_size);
|
|
}
|
|
memcpy(deferred_send_data+deferred_len, pktout.data, len);
|
|
deferred_len += len;
|
|
}
|
|
|
|
/*
|
|
* Send the whole deferred data block constructed by
|
|
* ssh2_pkt_defer() or SSH1's defer_packet().
|
|
*/
|
|
static void ssh_pkt_defersend(void) {
|
|
sk_write(s, deferred_send_data, deferred_len);
|
|
deferred_len = deferred_size = 0;
|
|
sfree(deferred_send_data);
|
|
deferred_send_data = NULL;
|
|
}
|
|
|
|
#if 0
|
|
void bndebug(char *string, Bignum b) {
|
|
unsigned char *p;
|
|
int i, len;
|
|
p = ssh2_mpint_fmt(b, &len);
|
|
debug(("%s", string));
|
|
for (i = 0; i < len; i++)
|
|
debug((" %02x", p[i]));
|
|
debug(("\r\n"));
|
|
sfree(p);
|
|
}
|
|
#endif
|
|
|
|
static void sha_mpint(SHA_State *s, Bignum b) {
|
|
unsigned char *p;
|
|
int len;
|
|
p = ssh2_mpint_fmt(b, &len);
|
|
sha_string(s, p, len);
|
|
sfree(p);
|
|
}
|
|
|
|
/*
|
|
* SSH2 packet decode functions.
|
|
*/
|
|
static unsigned long ssh2_pkt_getuint32(void) {
|
|
unsigned long value;
|
|
if (pktin.length - pktin.savedpos < 4)
|
|
return 0; /* arrgh, no way to decline (FIXME?) */
|
|
value = GET_32BIT(pktin.data+pktin.savedpos);
|
|
pktin.savedpos += 4;
|
|
return value;
|
|
}
|
|
static int ssh2_pkt_getbool(void) {
|
|
unsigned long value;
|
|
if (pktin.length - pktin.savedpos < 1)
|
|
return 0; /* arrgh, no way to decline (FIXME?) */
|
|
value = pktin.data[pktin.savedpos] != 0;
|
|
pktin.savedpos++;
|
|
return value;
|
|
}
|
|
static void ssh2_pkt_getstring(char **p, int *length) {
|
|
*p = NULL;
|
|
if (pktin.length - pktin.savedpos < 4)
|
|
return;
|
|
*length = GET_32BIT(pktin.data+pktin.savedpos);
|
|
pktin.savedpos += 4;
|
|
if (pktin.length - pktin.savedpos < *length)
|
|
return;
|
|
*p = pktin.data+pktin.savedpos;
|
|
pktin.savedpos += *length;
|
|
}
|
|
static Bignum ssh2_pkt_getmp(void) {
|
|
char *p;
|
|
int length;
|
|
Bignum b;
|
|
|
|
ssh2_pkt_getstring(&p, &length);
|
|
if (!p)
|
|
return NULL;
|
|
if (p[0] & 0x80) {
|
|
bombout(("internal error: Can't handle negative mpints"));
|
|
return NULL;
|
|
}
|
|
b = bignum_from_bytes(p, length);
|
|
return b;
|
|
}
|
|
|
|
static int do_ssh_init(unsigned char c) {
|
|
static char *vsp;
|
|
static char version[10];
|
|
static char vstring[80];
|
|
static char vlog[sizeof(vstring)+20];
|
|
static int i;
|
|
|
|
crBegin;
|
|
|
|
/* Search for the string "SSH-" in the input. */
|
|
i = 0;
|
|
while (1) {
|
|
static const int transS[] = { 1, 2, 2, 1 };
|
|
static const int transH[] = { 0, 0, 3, 0 };
|
|
static const int transminus[] = { 0, 0, 0, -1 };
|
|
if (c == 'S') i = transS[i];
|
|
else if (c == 'H') i = transH[i];
|
|
else if (c == '-') i = transminus[i];
|
|
else i = 0;
|
|
if (i < 0)
|
|
break;
|
|
crReturn(1); /* get another character */
|
|
}
|
|
|
|
strcpy(vstring, "SSH-");
|
|
vsp = vstring+4;
|
|
i = 0;
|
|
while (1) {
|
|
crReturn(1); /* get another char */
|
|
if (vsp < vstring+sizeof(vstring)-1)
|
|
*vsp++ = c;
|
|
if (i >= 0) {
|
|
if (c == '-') {
|
|
version[i] = '\0';
|
|
i = -1;
|
|
} else if (i < sizeof(version)-1)
|
|
version[i++] = c;
|
|
}
|
|
else if (c == '\n')
|
|
break;
|
|
}
|
|
|
|
ssh_agentfwd_enabled = FALSE;
|
|
rdpkt2_state.incoming_sequence = 0;
|
|
|
|
*vsp = 0;
|
|
sprintf(vlog, "Server version: %s", vstring);
|
|
vlog[strcspn(vlog, "\r\n")] = '\0';
|
|
logevent(vlog);
|
|
|
|
/*
|
|
* Server version "1.99" means we can choose whether we use v1
|
|
* or v2 protocol. Choice is based on cfg.sshprot.
|
|
*/
|
|
if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
|
|
/*
|
|
* This is a v2 server. Begin v2 protocol.
|
|
*/
|
|
char *verstring = "SSH-2.0-PuTTY";
|
|
SHA_Init(&exhashbase);
|
|
/*
|
|
* Hash our version string and their version string.
|
|
*/
|
|
sha_string(&exhashbase, verstring, strlen(verstring));
|
|
sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
|
|
sprintf(vstring, "%s\n", verstring);
|
|
sprintf(vlog, "We claim version: %s", verstring);
|
|
logevent(vlog);
|
|
logevent("Using SSH protocol version 2");
|
|
sk_write(s, vstring, strlen(vstring));
|
|
ssh_protocol = ssh2_protocol;
|
|
ssh_version = 2;
|
|
s_rdpkt = ssh2_rdpkt;
|
|
} else {
|
|
/*
|
|
* This is a v1 server. Begin v1 protocol.
|
|
*/
|
|
sprintf(vstring, "SSH-%s-PuTTY\n",
|
|
(ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
|
|
sprintf(vlog, "We claim version: %s", vstring);
|
|
vlog[strcspn(vlog, "\r\n")] = '\0';
|
|
logevent(vlog);
|
|
logevent("Using SSH protocol version 1");
|
|
sk_write(s, vstring, strlen(vstring));
|
|
ssh_protocol = ssh1_protocol;
|
|
ssh_version = 1;
|
|
s_rdpkt = ssh1_rdpkt;
|
|
}
|
|
ssh_state = SSH_STATE_BEFORE_SIZE;
|
|
|
|
crFinish(0);
|
|
}
|
|
|
|
static void ssh_gotdata(unsigned char *data, int datalen)
|
|
{
|
|
crBegin;
|
|
|
|
/*
|
|
* To begin with, feed the characters one by one to the
|
|
* protocol initialisation / selection function do_ssh_init().
|
|
* When that returns 0, we're done with the initial greeting
|
|
* exchange and can move on to packet discipline.
|
|
*/
|
|
while (1) {
|
|
int ret;
|
|
if (datalen == 0)
|
|
crReturnV; /* more data please */
|
|
ret = do_ssh_init(*data);
|
|
data++; datalen--;
|
|
if (ret == 0)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We emerge from that loop when the initial negotiation is
|
|
* over and we have selected an s_rdpkt function. Now pass
|
|
* everything to s_rdpkt, and then pass the resulting packets
|
|
* to the proper protocol handler.
|
|
*/
|
|
if (datalen == 0)
|
|
crReturnV;
|
|
while (1) {
|
|
while (datalen > 0) {
|
|
if ( s_rdpkt(&data, &datalen) == 0 ) {
|
|
ssh_protocol(NULL, 0, 1);
|
|
if (ssh_state == SSH_STATE_CLOSED) {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
crReturnV;
|
|
}
|
|
crFinishV;
|
|
}
|
|
|
|
static int ssh_receive(Socket skt, int urgent, char *data, int len) {
|
|
if (urgent==3) {
|
|
/* A socket error has occurred. */
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
sk_close(s);
|
|
s = NULL;
|
|
connection_fatal(data);
|
|
return 0;
|
|
} else if (!len) {
|
|
/* Connection has closed. */
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
sk_close(s);
|
|
s = NULL;
|
|
return 0;
|
|
}
|
|
ssh_gotdata (data, len);
|
|
if (ssh_state == SSH_STATE_CLOSED) {
|
|
if (s) {
|
|
sk_close(s);
|
|
s = NULL;
|
|
}
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Connect to specified host and port.
|
|
* Returns an error message, or NULL on success.
|
|
* Also places the canonical host name into `realhost'.
|
|
*/
|
|
static char *connect_to_host(char *host, int port, char **realhost)
|
|
{
|
|
SockAddr addr;
|
|
char *err;
|
|
#ifdef FWHACK
|
|
char *FWhost;
|
|
int FWport;
|
|
#endif
|
|
|
|
savedhost = smalloc(1+strlen(host));
|
|
if (!savedhost)
|
|
fatalbox("Out of memory");
|
|
strcpy(savedhost, host);
|
|
|
|
if (port < 0)
|
|
port = 22; /* default ssh port */
|
|
savedport = port;
|
|
|
|
#ifdef FWHACK
|
|
FWhost = host;
|
|
FWport = port;
|
|
host = FWSTR;
|
|
port = 23;
|
|
#endif
|
|
|
|
/*
|
|
* Try to find host.
|
|
*/
|
|
addr = sk_namelookup(host, realhost);
|
|
if ( (err = sk_addr_error(addr)) )
|
|
return err;
|
|
|
|
#ifdef FWHACK
|
|
*realhost = FWhost;
|
|
#endif
|
|
|
|
/*
|
|
* Open socket.
|
|
*/
|
|
s = sk_new(addr, port, 0, 1, ssh_receive);
|
|
if ( (err = sk_socket_error(s)) )
|
|
return err;
|
|
|
|
#ifdef FWHACK
|
|
sk_write(s, "connect ", 8);
|
|
sk_write(s, FWhost, strlen(FWhost));
|
|
{
|
|
char buf[20];
|
|
sprintf(buf, " %d\n", FWport);
|
|
sk_write(s, buf, strlen(buf));
|
|
}
|
|
#endif
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Handle the key exchange and user authentication phases.
|
|
*/
|
|
static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
|
|
{
|
|
int i, j, len;
|
|
unsigned char *rsabuf, *keystr1, *keystr2;
|
|
unsigned char cookie[8];
|
|
struct RSAKey servkey, hostkey;
|
|
struct MD5Context md5c;
|
|
static unsigned long supported_ciphers_mask, supported_auths_mask;
|
|
static int tried_publickey;
|
|
static unsigned char session_id[16];
|
|
int cipher_type;
|
|
static char username[100];
|
|
|
|
crBegin;
|
|
|
|
if (!ispkt) crWaitUntil(ispkt);
|
|
|
|
if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
|
|
bombout(("Public key packet not received"));
|
|
crReturn(0);
|
|
}
|
|
|
|
logevent("Received public keys");
|
|
|
|
memcpy(cookie, pktin.body, 8);
|
|
|
|
i = makekey(pktin.body+8, &servkey, &keystr1, 0);
|
|
j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
|
|
|
|
/*
|
|
* Log the host key fingerprint.
|
|
*/
|
|
{
|
|
char logmsg[80];
|
|
logevent("Host key fingerprint is:");
|
|
strcpy(logmsg, " ");
|
|
hostkey.comment = NULL;
|
|
rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg),
|
|
&hostkey);
|
|
logevent(logmsg);
|
|
}
|
|
|
|
supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
|
|
supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
|
|
|
|
MD5Init(&md5c);
|
|
MD5Update(&md5c, keystr2, hostkey.bytes);
|
|
MD5Update(&md5c, keystr1, servkey.bytes);
|
|
MD5Update(&md5c, pktin.body, 8);
|
|
MD5Final(session_id, &md5c);
|
|
|
|
for (i=0; i<32; i++)
|
|
session_key[i] = random_byte();
|
|
|
|
len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
|
|
|
|
rsabuf = smalloc(len);
|
|
if (!rsabuf)
|
|
fatalbox("Out of memory");
|
|
|
|
/*
|
|
* Verify the host key.
|
|
*/
|
|
{
|
|
/*
|
|
* First format the key into a string.
|
|
*/
|
|
int len = rsastr_len(&hostkey);
|
|
char fingerprint[100];
|
|
char *keystr = smalloc(len);
|
|
if (!keystr)
|
|
fatalbox("Out of memory");
|
|
rsastr_fmt(keystr, &hostkey);
|
|
rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
|
|
verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
|
|
sfree(keystr);
|
|
}
|
|
|
|
for (i=0; i<32; i++) {
|
|
rsabuf[i] = session_key[i];
|
|
if (i < 16)
|
|
rsabuf[i] ^= session_id[i];
|
|
}
|
|
|
|
if (hostkey.bytes > servkey.bytes) {
|
|
rsaencrypt(rsabuf, 32, &servkey);
|
|
rsaencrypt(rsabuf, servkey.bytes, &hostkey);
|
|
} else {
|
|
rsaencrypt(rsabuf, 32, &hostkey);
|
|
rsaencrypt(rsabuf, hostkey.bytes, &servkey);
|
|
}
|
|
|
|
logevent("Encrypted session key");
|
|
|
|
switch (cfg.cipher) {
|
|
case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; break;
|
|
case CIPHER_DES: cipher_type = SSH_CIPHER_DES; break;
|
|
case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES; break;
|
|
case CIPHER_AES:
|
|
c_write_str("AES not supported in SSH1, falling back to 3DES\r\n");
|
|
cipher_type = SSH_CIPHER_3DES;
|
|
break;
|
|
}
|
|
if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
|
|
c_write_str("Selected cipher not supported, falling back to 3DES\r\n");
|
|
cipher_type = SSH_CIPHER_3DES;
|
|
}
|
|
switch (cipher_type) {
|
|
case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
|
|
case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
|
|
case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
|
|
}
|
|
|
|
send_packet(SSH1_CMSG_SESSION_KEY,
|
|
PKT_CHAR, cipher_type,
|
|
PKT_DATA, cookie, 8,
|
|
PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
|
|
PKT_DATA, rsabuf, len,
|
|
PKT_INT, 0,
|
|
PKT_END);
|
|
|
|
logevent("Trying to enable encryption...");
|
|
|
|
sfree(rsabuf);
|
|
|
|
cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
|
|
cipher_type == SSH_CIPHER_DES ? &ssh_des :
|
|
&ssh_3des;
|
|
cipher->sesskey(session_key);
|
|
|
|
crWaitUntil(ispkt);
|
|
|
|
if (pktin.type != SSH1_SMSG_SUCCESS) {
|
|
bombout(("Encryption not successfully enabled"));
|
|
crReturn(0);
|
|
}
|
|
|
|
logevent("Successfully started encryption");
|
|
|
|
fflush(stdout);
|
|
{
|
|
static int pos = 0;
|
|
static char c;
|
|
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
|
|
c_write_str("login as: ");
|
|
ssh_send_ok = 1;
|
|
while (pos >= 0) {
|
|
crWaitUntil(!ispkt);
|
|
while (inlen--) switch (c = *in++) {
|
|
case 10: case 13:
|
|
username[pos] = 0;
|
|
pos = -1;
|
|
break;
|
|
case 8: case 127:
|
|
if (pos > 0) {
|
|
c_write_str("\b \b");
|
|
pos--;
|
|
}
|
|
break;
|
|
case 21: case 27:
|
|
while (pos > 0) {
|
|
c_write_str("\b \b");
|
|
pos--;
|
|
}
|
|
break;
|
|
case 3: case 4:
|
|
random_save_seed();
|
|
exit(0);
|
|
break;
|
|
default:
|
|
if (((c >= ' ' && c <= '~') ||
|
|
((unsigned char)c >= 160)) && pos < 40) {
|
|
username[pos++] = c;
|
|
c_write(&c, 1);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
c_write_str("\r\n");
|
|
username[strcspn(username, "\n\r")] = '\0';
|
|
} else {
|
|
strncpy(username, cfg.username, 99);
|
|
username[99] = '\0';
|
|
}
|
|
|
|
send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
|
|
{
|
|
char userlog[22+sizeof(username)];
|
|
sprintf(userlog, "Sent username \"%s\"", username);
|
|
logevent(userlog);
|
|
if (flags & FLAG_INTERACTIVE &&
|
|
(!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
|
|
strcat(userlog, "\r\n");
|
|
c_write_str(userlog);
|
|
}
|
|
}
|
|
}
|
|
|
|
crWaitUntil(ispkt);
|
|
|
|
tried_publickey = 0;
|
|
|
|
while (pktin.type == SSH1_SMSG_FAILURE) {
|
|
static char password[100];
|
|
static char prompt[200];
|
|
static int pos;
|
|
static char c;
|
|
static int pwpkt_type;
|
|
/*
|
|
* Show password prompt, having first obtained it via a TIS
|
|
* or CryptoCard exchange if we're doing TIS or CryptoCard
|
|
* authentication.
|
|
*/
|
|
pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
|
|
if (agent_exists()) {
|
|
/*
|
|
* Attempt RSA authentication using Pageant.
|
|
*/
|
|
static unsigned char request[5], *response, *p;
|
|
static int responselen;
|
|
static int i, nkeys;
|
|
static int authed = FALSE;
|
|
void *r;
|
|
|
|
logevent("Pageant is running. Requesting keys.");
|
|
|
|
/* Request the keys held by the agent. */
|
|
PUT_32BIT(request, 1);
|
|
request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
|
|
agent_query(request, 5, &r, &responselen);
|
|
response = (unsigned char *)r;
|
|
if (response) {
|
|
p = response + 5;
|
|
nkeys = GET_32BIT(p); p += 4;
|
|
{ char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
|
|
logevent(buf); }
|
|
for (i = 0; i < nkeys; i++) {
|
|
static struct RSAKey key;
|
|
static Bignum challenge;
|
|
static char *commentp;
|
|
static int commentlen;
|
|
|
|
{ char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
|
|
logevent(buf); }
|
|
p += 4;
|
|
p += ssh1_read_bignum(p, &key.exponent);
|
|
p += ssh1_read_bignum(p, &key.modulus);
|
|
commentlen = GET_32BIT(p); p += 4;
|
|
commentp = p; p += commentlen;
|
|
send_packet(SSH1_CMSG_AUTH_RSA,
|
|
PKT_BIGNUM, key.modulus, PKT_END);
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
|
|
logevent("Key refused");
|
|
continue;
|
|
}
|
|
logevent("Received RSA challenge");
|
|
ssh1_read_bignum(pktin.body, &challenge);
|
|
{
|
|
char *agentreq, *q, *ret;
|
|
int len, retlen;
|
|
len = 1 + 4; /* message type, bit count */
|
|
len += ssh1_bignum_length(key.exponent);
|
|
len += ssh1_bignum_length(key.modulus);
|
|
len += ssh1_bignum_length(challenge);
|
|
len += 16; /* session id */
|
|
len += 4; /* response format */
|
|
agentreq = smalloc(4 + len);
|
|
PUT_32BIT(agentreq, len);
|
|
q = agentreq + 4;
|
|
*q++ = SSH1_AGENTC_RSA_CHALLENGE;
|
|
PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
|
|
q += 4;
|
|
q += ssh1_write_bignum(q, key.exponent);
|
|
q += ssh1_write_bignum(q, key.modulus);
|
|
q += ssh1_write_bignum(q, challenge);
|
|
memcpy(q, session_id, 16); q += 16;
|
|
PUT_32BIT(q, 1); /* response format */
|
|
agent_query(agentreq, len+4, &ret, &retlen);
|
|
sfree(agentreq);
|
|
if (ret) {
|
|
if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
|
|
logevent("Sending Pageant's response");
|
|
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
|
|
PKT_DATA, ret+5, 16, PKT_END);
|
|
sfree(ret);
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type == SSH1_SMSG_SUCCESS) {
|
|
logevent("Pageant's response accepted");
|
|
if (flags & FLAG_VERBOSE) {
|
|
c_write_str("Authenticated using RSA key \"");
|
|
c_write(commentp, commentlen);
|
|
c_write_str("\" from agent\r\n");
|
|
}
|
|
authed = TRUE;
|
|
} else
|
|
logevent("Pageant's response not accepted");
|
|
} else {
|
|
logevent("Pageant failed to answer challenge");
|
|
sfree(ret);
|
|
}
|
|
} else {
|
|
logevent("No reply received from Pageant");
|
|
}
|
|
}
|
|
freebn(key.exponent);
|
|
freebn(key.modulus);
|
|
freebn(challenge);
|
|
if (authed)
|
|
break;
|
|
}
|
|
}
|
|
if (authed)
|
|
break;
|
|
}
|
|
if (*cfg.keyfile && !tried_publickey)
|
|
pwpkt_type = SSH1_CMSG_AUTH_RSA;
|
|
|
|
if (pktin.type == SSH1_SMSG_FAILURE &&
|
|
cfg.try_tis_auth &&
|
|
(supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
|
|
pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
|
|
logevent("Requested TIS authentication");
|
|
send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
|
|
logevent("TIS authentication declined");
|
|
if (flags & FLAG_INTERACTIVE)
|
|
c_write_str("TIS authentication refused.\r\n");
|
|
} else {
|
|
int challengelen = ((pktin.body[0] << 24) |
|
|
(pktin.body[1] << 16) |
|
|
(pktin.body[2] << 8) |
|
|
(pktin.body[3]));
|
|
logevent("Received TIS challenge");
|
|
if (challengelen > sizeof(prompt)-1)
|
|
challengelen = sizeof(prompt)-1; /* prevent overrun */
|
|
memcpy(prompt, pktin.body+4, challengelen);
|
|
prompt[challengelen] = '\0';
|
|
}
|
|
}
|
|
if (pktin.type == SSH1_SMSG_FAILURE &&
|
|
cfg.try_tis_auth &&
|
|
(supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
|
|
pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
|
|
logevent("Requested CryptoCard authentication");
|
|
send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
|
|
logevent("CryptoCard authentication declined");
|
|
c_write_str("CryptoCard authentication refused.\r\n");
|
|
} else {
|
|
int challengelen = ((pktin.body[0] << 24) |
|
|
(pktin.body[1] << 16) |
|
|
(pktin.body[2] << 8) |
|
|
(pktin.body[3]));
|
|
logevent("Received CryptoCard challenge");
|
|
if (challengelen > sizeof(prompt)-1)
|
|
challengelen = sizeof(prompt)-1; /* prevent overrun */
|
|
memcpy(prompt, pktin.body+4, challengelen);
|
|
strncpy(prompt + challengelen, "\r\nResponse : ",
|
|
sizeof(prompt)-challengelen);
|
|
prompt[sizeof(prompt)-1] = '\0';
|
|
}
|
|
}
|
|
if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
|
|
sprintf(prompt, "%.90s@%.90s's password: ",
|
|
username, savedhost);
|
|
}
|
|
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
|
|
char *comment = NULL;
|
|
if (flags & FLAG_VERBOSE)
|
|
c_write_str("Trying public key authentication.\r\n");
|
|
if (!rsakey_encrypted(cfg.keyfile, &comment)) {
|
|
if (flags & FLAG_VERBOSE)
|
|
c_write_str("No passphrase required.\r\n");
|
|
goto tryauth;
|
|
}
|
|
sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
|
|
sfree(comment);
|
|
}
|
|
|
|
if (ssh_get_password) {
|
|
if (!ssh_get_password(prompt, password, sizeof(password))) {
|
|
/*
|
|
* get_password failed to get a password (for
|
|
* example because one was supplied on the command
|
|
* line which has already failed to work).
|
|
* Terminate.
|
|
*/
|
|
logevent("No more passwords to try");
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
crReturn(1);
|
|
}
|
|
} else {
|
|
c_write_str(prompt);
|
|
pos = 0;
|
|
ssh_send_ok = 1;
|
|
while (pos >= 0) {
|
|
crWaitUntil(!ispkt);
|
|
while (inlen--) switch (c = *in++) {
|
|
case 10: case 13:
|
|
password[pos] = 0;
|
|
pos = -1;
|
|
break;
|
|
case 8: case 127:
|
|
if (pos > 0)
|
|
pos--;
|
|
break;
|
|
case 21: case 27:
|
|
pos = 0;
|
|
break;
|
|
case 3: case 4:
|
|
random_save_seed();
|
|
exit(0);
|
|
break;
|
|
default:
|
|
if (((c >= ' ' && c <= '~') ||
|
|
((unsigned char)c >= 160)) && pos < sizeof(password))
|
|
password[pos++] = c;
|
|
break;
|
|
}
|
|
}
|
|
c_write_str("\r\n");
|
|
}
|
|
|
|
tryauth:
|
|
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
|
|
/*
|
|
* Try public key authentication with the specified
|
|
* key file.
|
|
*/
|
|
static struct RSAKey pubkey;
|
|
static Bignum challenge, response;
|
|
static int i;
|
|
static unsigned char buffer[32];
|
|
|
|
tried_publickey = 1;
|
|
i = loadrsakey(cfg.keyfile, &pubkey, password);
|
|
if (i == 0) {
|
|
c_write_str("Couldn't load public key from ");
|
|
c_write_str(cfg.keyfile);
|
|
c_write_str(".\r\n");
|
|
continue; /* go and try password */
|
|
}
|
|
if (i == -1) {
|
|
c_write_str("Wrong passphrase.\r\n");
|
|
tried_publickey = 0;
|
|
continue; /* try again */
|
|
}
|
|
|
|
/*
|
|
* Send a public key attempt.
|
|
*/
|
|
send_packet(SSH1_CMSG_AUTH_RSA,
|
|
PKT_BIGNUM, pubkey.modulus, PKT_END);
|
|
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
c_write_str("Server refused our public key.\r\n");
|
|
continue; /* go and try password */
|
|
}
|
|
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
|
|
bombout(("Bizarre response to offer of public key"));
|
|
crReturn(0);
|
|
}
|
|
ssh1_read_bignum(pktin.body, &challenge);
|
|
response = rsadecrypt(challenge, &pubkey);
|
|
freebn(pubkey.private_exponent); /* burn the evidence */
|
|
|
|
for (i = 0; i < 32; i++) {
|
|
buffer[i] = bignum_byte(response, 31-i);
|
|
}
|
|
|
|
MD5Init(&md5c);
|
|
MD5Update(&md5c, buffer, 32);
|
|
MD5Update(&md5c, session_id, 16);
|
|
MD5Final(buffer, &md5c);
|
|
|
|
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
|
|
PKT_DATA, buffer, 16, PKT_END);
|
|
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
if (flags & FLAG_VERBOSE)
|
|
c_write_str("Failed to authenticate with our public key.\r\n");
|
|
continue; /* go and try password */
|
|
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
|
|
bombout(("Bizarre response to RSA authentication response"));
|
|
crReturn(0);
|
|
}
|
|
|
|
break; /* we're through! */
|
|
} else {
|
|
if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
|
|
/*
|
|
* Defence against traffic analysis: we send a
|
|
* whole bunch of packets containing strings of
|
|
* different lengths. One of these strings is the
|
|
* password, in a SSH1_CMSG_AUTH_PASSWORD packet.
|
|
* The others are all random data in
|
|
* SSH1_MSG_IGNORE packets. This way a passive
|
|
* listener can't tell which is the password, and
|
|
* hence can't deduce the password length.
|
|
*
|
|
* Anybody with a password length greater than 16
|
|
* bytes is going to have enough entropy in their
|
|
* password that a listener won't find it _that_
|
|
* much help to know how long it is. So what we'll
|
|
* do is:
|
|
*
|
|
* - if password length < 16, we send 15 packets
|
|
* containing string lengths 1 through 15
|
|
*
|
|
* - otherwise, we let N be the nearest multiple
|
|
* of 8 below the password length, and send 8
|
|
* packets containing string lengths N through
|
|
* N+7. This won't obscure the order of
|
|
* magnitude of the password length, but it will
|
|
* introduce a bit of extra uncertainty.
|
|
*/
|
|
int bottom, top, pwlen, i;
|
|
char *randomstr;
|
|
|
|
pwlen = strlen(password);
|
|
if (pwlen < 16) {
|
|
bottom = 1;
|
|
top = 15;
|
|
} else {
|
|
bottom = pwlen &~ 7;
|
|
top = bottom + 7;
|
|
}
|
|
|
|
assert(pwlen >= bottom && pwlen <= top);
|
|
|
|
randomstr = smalloc(top+1);
|
|
|
|
for (i = bottom; i <= top; i++) {
|
|
if (i == pwlen)
|
|
defer_packet(pwpkt_type, PKT_STR, password, PKT_END);
|
|
else {
|
|
for (j = 0; j < i; j++) {
|
|
do {
|
|
randomstr[j] = random_byte();
|
|
} while (randomstr[j] == '\0');
|
|
}
|
|
randomstr[i] = '\0';
|
|
defer_packet(SSH1_MSG_IGNORE,
|
|
PKT_STR, randomstr, PKT_END);
|
|
}
|
|
}
|
|
ssh_pkt_defersend();
|
|
} else {
|
|
send_packet(pwpkt_type, PKT_STR, password, PKT_END);
|
|
}
|
|
}
|
|
logevent("Sent password");
|
|
memset(password, 0, strlen(password));
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
if (flags & FLAG_VERBOSE)
|
|
c_write_str("Access denied\r\n");
|
|
logevent("Authentication refused");
|
|
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
|
|
logevent("Received disconnect request");
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
crReturn(1);
|
|
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
|
|
bombout(("Strange packet received, type %d", pktin.type));
|
|
crReturn(0);
|
|
}
|
|
}
|
|
|
|
logevent("Authentication successful");
|
|
|
|
crFinish(1);
|
|
}
|
|
|
|
void sshfwd_close(struct ssh_channel *c) {
|
|
if (c) {
|
|
if (ssh_version == 1) {
|
|
send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END);
|
|
} else {
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
|
|
ssh2_pkt_adduint32(c->remoteid);
|
|
ssh2_pkt_send();
|
|
}
|
|
c->closes = 1;
|
|
if (c->type == CHAN_X11) {
|
|
c->u.x11.s = NULL;
|
|
logevent("X11 connection terminated");
|
|
}
|
|
}
|
|
}
|
|
|
|
void sshfwd_write(struct ssh_channel *c, char *buf, int len) {
|
|
if (ssh_version == 1) {
|
|
send_packet(SSH1_MSG_CHANNEL_DATA,
|
|
PKT_INT, c->remoteid,
|
|
PKT_INT, len,
|
|
PKT_DATA, buf, len,
|
|
PKT_END);
|
|
} else {
|
|
ssh2_add_channel_data(c, buf, len);
|
|
ssh2_try_send(c);
|
|
}
|
|
}
|
|
|
|
static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
|
|
crBegin;
|
|
|
|
random_init();
|
|
|
|
while (!do_ssh1_login(in, inlen, ispkt)) {
|
|
crReturnV;
|
|
}
|
|
if (ssh_state == SSH_STATE_CLOSED)
|
|
crReturnV;
|
|
|
|
if (cfg.agentfwd && agent_exists()) {
|
|
logevent("Requesting agent forwarding");
|
|
send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
|
|
do { crReturnV; } while (!ispkt);
|
|
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
|
|
bombout(("Protocol confusion"));
|
|
crReturnV;
|
|
} else if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
logevent("Agent forwarding refused");
|
|
} else {
|
|
logevent("Agent forwarding enabled");
|
|
ssh_agentfwd_enabled = TRUE;
|
|
}
|
|
}
|
|
|
|
if (cfg.x11_forward) {
|
|
char proto[20], data[64];
|
|
logevent("Requesting X11 forwarding");
|
|
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
|
|
send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
|
|
PKT_STR, proto, PKT_STR, data,
|
|
PKT_INT, 0,
|
|
PKT_END);
|
|
do { crReturnV; } while (!ispkt);
|
|
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
|
|
bombout(("Protocol confusion"));
|
|
crReturnV;
|
|
} else if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
logevent("X11 forwarding refused");
|
|
} else {
|
|
logevent("X11 forwarding enabled");
|
|
ssh_X11_fwd_enabled = TRUE;
|
|
}
|
|
}
|
|
|
|
if (!cfg.nopty) {
|
|
send_packet(SSH1_CMSG_REQUEST_PTY,
|
|
PKT_STR, cfg.termtype,
|
|
PKT_INT, rows, PKT_INT, cols,
|
|
PKT_INT, 0, PKT_INT, 0,
|
|
PKT_CHAR, 0,
|
|
PKT_END);
|
|
ssh_state = SSH_STATE_INTERMED;
|
|
do { crReturnV; } while (!ispkt);
|
|
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
|
|
bombout(("Protocol confusion"));
|
|
crReturnV;
|
|
} else if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
c_write_str("Server refused to allocate pty\r\n");
|
|
ssh_editing = ssh_echoing = 1;
|
|
}
|
|
logevent("Allocated pty");
|
|
} else {
|
|
ssh_editing = ssh_echoing = 1;
|
|
}
|
|
|
|
if (cfg.compression) {
|
|
send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
|
|
do { crReturnV; } while (!ispkt);
|
|
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
|
|
bombout(("Protocol confusion"));
|
|
crReturnV;
|
|
} else if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
c_write_str("Server refused to compress\r\n");
|
|
}
|
|
logevent("Started compression");
|
|
ssh1_compressing = TRUE;
|
|
zlib_compress_init();
|
|
zlib_decompress_init();
|
|
}
|
|
|
|
if (*cfg.remote_cmd)
|
|
send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
|
|
else
|
|
send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
|
|
logevent("Started session");
|
|
|
|
ssh_state = SSH_STATE_SESSION;
|
|
if (size_needed)
|
|
ssh_size();
|
|
if (eof_needed)
|
|
ssh_special(TS_EOF);
|
|
|
|
ldisc_send(NULL, 0); /* cause ldisc to notice changes */
|
|
ssh_send_ok = 1;
|
|
ssh_channels = newtree234(ssh_channelcmp);
|
|
while (1) {
|
|
crReturnV;
|
|
if (ispkt) {
|
|
if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
|
|
pktin.type == SSH1_SMSG_STDERR_DATA) {
|
|
long len = GET_32BIT(pktin.body);
|
|
from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
|
|
pktin.body+4, len);
|
|
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
logevent("Received disconnect request");
|
|
crReturnV;
|
|
} else if (pktin.type == SSH1_SMSG_X11_OPEN) {
|
|
/* Remote side is trying to open a channel to talk to our
|
|
* X-Server. Give them back a local channel number. */
|
|
unsigned i;
|
|
struct ssh_channel *c, *d;
|
|
enum234 e;
|
|
|
|
logevent("Received X11 connect request");
|
|
/* Refuse if X11 forwarding is disabled. */
|
|
if (!ssh_X11_fwd_enabled) {
|
|
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
|
|
PKT_INT, GET_32BIT(pktin.body),
|
|
PKT_END);
|
|
logevent("Rejected X11 connect request");
|
|
} else {
|
|
c = smalloc(sizeof(struct ssh_channel));
|
|
|
|
if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
|
|
logevent("opening X11 forward connection failed");
|
|
sfree(c);
|
|
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
|
|
PKT_INT, GET_32BIT(pktin.body),
|
|
PKT_END);
|
|
} else {
|
|
logevent("opening X11 forward connection succeeded");
|
|
for (i=1, d = first234(ssh_channels, &e); d; d = next234(&e)) {
|
|
if (d->localid > i)
|
|
break; /* found a free number */
|
|
i = d->localid + 1;
|
|
}
|
|
c->remoteid = GET_32BIT(pktin.body);
|
|
c->localid = i;
|
|
c->closes = 0;
|
|
c->type = CHAN_X11; /* identify channel type */
|
|
add234(ssh_channels, c);
|
|
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
|
|
PKT_INT, c->remoteid, PKT_INT, c->localid,
|
|
PKT_END);
|
|
logevent("Opened X11 forward channel");
|
|
}
|
|
}
|
|
} else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
|
|
/* Remote side is trying to open a channel to talk to our
|
|
* agent. Give them back a local channel number. */
|
|
unsigned i;
|
|
struct ssh_channel *c;
|
|
enum234 e;
|
|
|
|
/* Refuse if agent forwarding is disabled. */
|
|
if (!ssh_agentfwd_enabled) {
|
|
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
|
|
PKT_INT, GET_32BIT(pktin.body),
|
|
PKT_END);
|
|
} else {
|
|
i = 1;
|
|
for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
|
|
if (c->localid > i)
|
|
break; /* found a free number */
|
|
i = c->localid + 1;
|
|
}
|
|
c = smalloc(sizeof(struct ssh_channel));
|
|
c->remoteid = GET_32BIT(pktin.body);
|
|
c->localid = i;
|
|
c->closes = 0;
|
|
c->type = CHAN_AGENT; /* identify channel type */
|
|
c->u.a.lensofar = 0;
|
|
add234(ssh_channels, c);
|
|
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
|
|
PKT_INT, c->remoteid, PKT_INT, c->localid,
|
|
PKT_END);
|
|
}
|
|
} else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
|
|
pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
|
|
/* Remote side closes a channel. */
|
|
unsigned i = GET_32BIT(pktin.body);
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (c) {
|
|
int closetype;
|
|
closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
|
|
send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
|
|
if ((c->closes == 0) && (c->type == CHAN_X11)) {
|
|
logevent("X11 connection closed");
|
|
assert(c->u.x11.s != NULL);
|
|
x11_close(c->u.x11.s);
|
|
c->u.x11.s = NULL;
|
|
}
|
|
c->closes |= closetype;
|
|
if (c->closes == 3) {
|
|
del234(ssh_channels, c);
|
|
sfree(c);
|
|
}
|
|
}
|
|
} else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
|
|
/* Data sent down one of our channels. */
|
|
int i = GET_32BIT(pktin.body);
|
|
int len = GET_32BIT(pktin.body+4);
|
|
unsigned char *p = pktin.body+8;
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (c) {
|
|
switch(c->type) {
|
|
case CHAN_X11:
|
|
x11_send(c->u.x11.s, p, len);
|
|
break;
|
|
case CHAN_AGENT:
|
|
/* Data for an agent message. Buffer it. */
|
|
while (len > 0) {
|
|
if (c->u.a.lensofar < 4) {
|
|
int l = min(4 - c->u.a.lensofar, len);
|
|
memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
|
|
p += l; len -= l; c->u.a.lensofar += l;
|
|
}
|
|
if (c->u.a.lensofar == 4) {
|
|
c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
|
|
c->u.a.message = smalloc(c->u.a.totallen);
|
|
memcpy(c->u.a.message, c->u.a.msglen, 4);
|
|
}
|
|
if (c->u.a.lensofar >= 4 && len > 0) {
|
|
int l = min(c->u.a.totallen - c->u.a.lensofar, len);
|
|
memcpy(c->u.a.message + c->u.a.lensofar, p, l);
|
|
p += l; len -= l; c->u.a.lensofar += l;
|
|
}
|
|
if (c->u.a.lensofar == c->u.a.totallen) {
|
|
void *reply, *sentreply;
|
|
int replylen;
|
|
agent_query(c->u.a.message, c->u.a.totallen,
|
|
&reply, &replylen);
|
|
if (reply)
|
|
sentreply = reply;
|
|
else {
|
|
/* Fake SSH_AGENT_FAILURE. */
|
|
sentreply = "\0\0\0\1\5";
|
|
replylen = 5;
|
|
}
|
|
send_packet(SSH1_MSG_CHANNEL_DATA,
|
|
PKT_INT, c->remoteid,
|
|
PKT_INT, replylen,
|
|
PKT_DATA, sentreply, replylen,
|
|
PKT_END);
|
|
if (reply)
|
|
sfree(reply);
|
|
sfree(c->u.a.message);
|
|
c->u.a.lensofar = 0;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
} else if (pktin.type == SSH1_SMSG_SUCCESS) {
|
|
/* may be from EXEC_SHELL on some servers */
|
|
} else if (pktin.type == SSH1_SMSG_FAILURE) {
|
|
/* may be from EXEC_SHELL on some servers
|
|
* if no pty is available or in other odd cases. Ignore */
|
|
} else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
|
|
send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
|
|
} else {
|
|
bombout(("Strange packet received: type %d", pktin.type));
|
|
crReturnV;
|
|
}
|
|
} else {
|
|
while (inlen > 0) {
|
|
int len = min(inlen, 512);
|
|
send_packet(SSH1_CMSG_STDIN_DATA,
|
|
PKT_INT, len, PKT_DATA, in, len, PKT_END);
|
|
in += len;
|
|
inlen -= len;
|
|
}
|
|
}
|
|
}
|
|
|
|
crFinishV;
|
|
}
|
|
|
|
/*
|
|
* Utility routine for decoding comma-separated strings in KEXINIT.
|
|
*/
|
|
static int in_commasep_string(char *needle, char *haystack, int haylen) {
|
|
int needlen = strlen(needle);
|
|
while (1) {
|
|
/*
|
|
* Is it at the start of the string?
|
|
*/
|
|
if (haylen >= needlen && /* haystack is long enough */
|
|
!memcmp(needle, haystack, needlen) && /* initial match */
|
|
(haylen == needlen || haystack[needlen] == ',')
|
|
/* either , or EOS follows */
|
|
)
|
|
return 1;
|
|
/*
|
|
* If not, search for the next comma and resume after that.
|
|
* If no comma found, terminate.
|
|
*/
|
|
while (haylen > 0 && *haystack != ',')
|
|
haylen--, haystack++;
|
|
if (haylen == 0)
|
|
return 0;
|
|
haylen--, haystack++; /* skip over comma itself */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* SSH2 key creation method.
|
|
*/
|
|
static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace) {
|
|
SHA_State s;
|
|
/* First 20 bytes. */
|
|
SHA_Init(&s);
|
|
sha_mpint(&s, K);
|
|
SHA_Bytes(&s, H, 20);
|
|
SHA_Bytes(&s, &chr, 1);
|
|
SHA_Bytes(&s, sessid, 20);
|
|
SHA_Final(&s, keyspace);
|
|
/* Next 20 bytes. */
|
|
SHA_Init(&s);
|
|
sha_mpint(&s, K);
|
|
SHA_Bytes(&s, H, 20);
|
|
SHA_Bytes(&s, keyspace, 20);
|
|
SHA_Final(&s, keyspace+20);
|
|
}
|
|
|
|
/*
|
|
* Handle the SSH2 transport layer.
|
|
*/
|
|
static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
|
|
{
|
|
static int i, j, len, nbits;
|
|
static char *str;
|
|
static Bignum p, g, e, f, K;
|
|
static int kex_init_value, kex_reply_value;
|
|
static const struct ssh_mac **maclist;
|
|
static int nmacs;
|
|
static const struct ssh2_cipher *cscipher_tobe = NULL;
|
|
static const struct ssh2_cipher *sccipher_tobe = NULL;
|
|
static const struct ssh_mac *csmac_tobe = NULL;
|
|
static const struct ssh_mac *scmac_tobe = NULL;
|
|
static const struct ssh_compress *cscomp_tobe = NULL;
|
|
static const struct ssh_compress *sccomp_tobe = NULL;
|
|
static char *hostkeydata, *sigdata, *keystr, *fingerprint;
|
|
static int hostkeylen, siglen;
|
|
static void *hkey; /* actual host key */
|
|
static unsigned char exchange_hash[20];
|
|
static unsigned char keyspace[40];
|
|
static const struct ssh2_ciphers *preferred_cipher;
|
|
static const struct ssh_compress *preferred_comp;
|
|
static int first_kex;
|
|
|
|
crBegin;
|
|
random_init();
|
|
first_kex = 1;
|
|
|
|
/*
|
|
* Set up the preferred cipher and compression.
|
|
*/
|
|
if (cfg.cipher == CIPHER_BLOWFISH) {
|
|
preferred_cipher = &ssh2_blowfish;
|
|
} else if (cfg.cipher == CIPHER_DES) {
|
|
logevent("Single DES not supported in SSH2; using 3DES");
|
|
preferred_cipher = &ssh2_3des;
|
|
} else if (cfg.cipher == CIPHER_3DES) {
|
|
preferred_cipher = &ssh2_3des;
|
|
} else if (cfg.cipher == CIPHER_AES) {
|
|
preferred_cipher = &ssh2_aes;
|
|
} else {
|
|
/* Shouldn't happen, but we do want to initialise to _something_. */
|
|
preferred_cipher = &ssh2_3des;
|
|
}
|
|
if (cfg.compression)
|
|
preferred_comp = &ssh_zlib;
|
|
else
|
|
preferred_comp = &ssh_comp_none;
|
|
|
|
/*
|
|
* Be prepared to work around the buggy MAC problem.
|
|
*/
|
|
if (cfg.buggymac)
|
|
maclist = buggymacs, nmacs = lenof(buggymacs);
|
|
else
|
|
maclist = macs, nmacs = lenof(macs);
|
|
|
|
begin_key_exchange:
|
|
/*
|
|
* Construct and send our key exchange packet.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_KEXINIT);
|
|
for (i = 0; i < 16; i++)
|
|
ssh2_pkt_addbyte((unsigned char)random_byte());
|
|
/* List key exchange algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < lenof(kex_algs); i++) {
|
|
ssh2_pkt_addstring_str(kex_algs[i]->name);
|
|
if (i < lenof(kex_algs)-1)
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
/* List server host key algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < lenof(hostkey_algs); i++) {
|
|
ssh2_pkt_addstring_str(hostkey_algs[i]->name);
|
|
if (i < lenof(hostkey_algs)-1)
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
/* List client->server encryption algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < lenof(ciphers)+1; i++) {
|
|
const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
|
|
for (j = 0; j < c->nciphers; j++) {
|
|
ssh2_pkt_addstring_str(c->list[j]->name);
|
|
if (i < lenof(ciphers) || j < c->nciphers-1)
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
}
|
|
/* List server->client encryption algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < lenof(ciphers)+1; i++) {
|
|
const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
|
|
for (j = 0; j < c->nciphers; j++) {
|
|
ssh2_pkt_addstring_str(c->list[j]->name);
|
|
if (i < lenof(ciphers) || j < c->nciphers-1)
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
}
|
|
/* List client->server MAC algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < nmacs; i++) {
|
|
ssh2_pkt_addstring_str(maclist[i]->name);
|
|
if (i < nmacs-1)
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
/* List server->client MAC algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < nmacs; i++) {
|
|
ssh2_pkt_addstring_str(maclist[i]->name);
|
|
if (i < nmacs-1)
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
/* List client->server compression algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < lenof(compressions)+1; i++) {
|
|
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
|
|
ssh2_pkt_addstring_str(c->name);
|
|
if (i < lenof(compressions))
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
/* List server->client compression algorithms. */
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < lenof(compressions)+1; i++) {
|
|
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
|
|
ssh2_pkt_addstring_str(c->name);
|
|
if (i < lenof(compressions))
|
|
ssh2_pkt_addstring_str(",");
|
|
}
|
|
/* List client->server languages. Empty list. */
|
|
ssh2_pkt_addstring_start();
|
|
/* List server->client languages. Empty list. */
|
|
ssh2_pkt_addstring_start();
|
|
/* First KEX packet does _not_ follow, because we're not that brave. */
|
|
ssh2_pkt_addbool(FALSE);
|
|
/* Reserved. */
|
|
ssh2_pkt_adduint32(0);
|
|
|
|
exhash = exhashbase;
|
|
sha_string(&exhash, pktout.data+5, pktout.length-5);
|
|
|
|
ssh2_pkt_send();
|
|
|
|
if (!ispkt) crWaitUntil(ispkt);
|
|
sha_string(&exhash, pktin.data+5, pktin.length-5);
|
|
|
|
/*
|
|
* Now examine the other side's KEXINIT to see what we're up
|
|
* to.
|
|
*/
|
|
if (pktin.type != SSH2_MSG_KEXINIT) {
|
|
bombout(("expected key exchange packet from server"));
|
|
crReturn(0);
|
|
}
|
|
kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
|
|
csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
|
|
pktin.savedpos += 16; /* skip garbage cookie */
|
|
ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
|
|
for (i = 0; i < lenof(kex_algs); i++) {
|
|
if (in_commasep_string(kex_algs[i]->name, str, len)) {
|
|
kex = kex_algs[i];
|
|
break;
|
|
}
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* host key algorithms */
|
|
for (i = 0; i < lenof(hostkey_algs); i++) {
|
|
if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
|
|
hostkey = hostkey_algs[i];
|
|
break;
|
|
}
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* client->server cipher */
|
|
for (i = 0; i < lenof(ciphers)+1; i++) {
|
|
const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
|
|
for (j = 0; j < c->nciphers; j++) {
|
|
if (in_commasep_string(c->list[j]->name, str, len)) {
|
|
cscipher_tobe = c->list[j];
|
|
break;
|
|
}
|
|
}
|
|
if (cscipher_tobe)
|
|
break;
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* server->client cipher */
|
|
for (i = 0; i < lenof(ciphers)+1; i++) {
|
|
const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
|
|
for (j = 0; j < c->nciphers; j++) {
|
|
if (in_commasep_string(c->list[j]->name, str, len)) {
|
|
sccipher_tobe = c->list[j];
|
|
break;
|
|
}
|
|
}
|
|
if (sccipher_tobe)
|
|
break;
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* client->server mac */
|
|
for (i = 0; i < nmacs; i++) {
|
|
if (in_commasep_string(maclist[i]->name, str, len)) {
|
|
csmac_tobe = maclist[i];
|
|
break;
|
|
}
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* server->client mac */
|
|
for (i = 0; i < nmacs; i++) {
|
|
if (in_commasep_string(maclist[i]->name, str, len)) {
|
|
scmac_tobe = maclist[i];
|
|
break;
|
|
}
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* client->server compression */
|
|
for (i = 0; i < lenof(compressions)+1; i++) {
|
|
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
|
|
if (in_commasep_string(c->name, str, len)) {
|
|
cscomp_tobe = c;
|
|
break;
|
|
}
|
|
}
|
|
ssh2_pkt_getstring(&str, &len); /* server->client compression */
|
|
for (i = 0; i < lenof(compressions)+1; i++) {
|
|
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
|
|
if (in_commasep_string(c->name, str, len)) {
|
|
sccomp_tobe = c;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we're doing Diffie-Hellman group exchange, start by
|
|
* requesting a group.
|
|
*/
|
|
if (kex == &ssh_diffiehellman_gex) {
|
|
int csbits, scbits;
|
|
|
|
logevent("Doing Diffie-Hellman group exchange");
|
|
/*
|
|
* Work out number of bits. We start with the maximum key
|
|
* length of either cipher...
|
|
*/
|
|
csbits = cscipher_tobe->keylen;
|
|
scbits = sccipher_tobe->keylen;
|
|
nbits = (csbits > scbits ? csbits : scbits);
|
|
/* The keys only have 160-bit entropy, since they're based on
|
|
* a SHA-1 hash. So cap the key size at 160 bits. */
|
|
if (nbits > 160) nbits = 160;
|
|
/*
|
|
* ... and then work out how big a DH group we will need to
|
|
* allow that much data.
|
|
*/
|
|
nbits = 512 << ((nbits-1) / 64);
|
|
ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
|
|
ssh2_pkt_adduint32(nbits);
|
|
ssh2_pkt_send();
|
|
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
|
|
bombout(("expected key exchange group packet from server"));
|
|
crReturn(0);
|
|
}
|
|
p = ssh2_pkt_getmp();
|
|
g = ssh2_pkt_getmp();
|
|
dh_setup_group(p, g);
|
|
kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
|
|
kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
|
|
} else {
|
|
dh_setup_group1();
|
|
kex_init_value = SSH2_MSG_KEXDH_INIT;
|
|
kex_reply_value = SSH2_MSG_KEXDH_REPLY;
|
|
}
|
|
|
|
logevent("Doing Diffie-Hellman key exchange");
|
|
/*
|
|
* Now generate and send e for Diffie-Hellman.
|
|
*/
|
|
e = dh_create_e();
|
|
ssh2_pkt_init(kex_init_value);
|
|
ssh2_pkt_addmp(e);
|
|
ssh2_pkt_send();
|
|
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type != kex_reply_value) {
|
|
bombout(("expected key exchange reply packet from server"));
|
|
crReturn(0);
|
|
}
|
|
ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
|
|
f = ssh2_pkt_getmp();
|
|
ssh2_pkt_getstring(&sigdata, &siglen);
|
|
|
|
K = dh_find_K(f);
|
|
|
|
sha_string(&exhash, hostkeydata, hostkeylen);
|
|
if (kex == &ssh_diffiehellman_gex) {
|
|
sha_uint32(&exhash, nbits);
|
|
sha_mpint(&exhash, p);
|
|
sha_mpint(&exhash, g);
|
|
}
|
|
sha_mpint(&exhash, e);
|
|
sha_mpint(&exhash, f);
|
|
sha_mpint(&exhash, K);
|
|
SHA_Final(&exhash, exchange_hash);
|
|
|
|
dh_cleanup();
|
|
|
|
#if 0
|
|
debug(("Exchange hash is:\r\n"));
|
|
for (i = 0; i < 20; i++)
|
|
debug((" %02x", exchange_hash[i]));
|
|
debug(("\r\n"));
|
|
#endif
|
|
|
|
hkey = hostkey->newkey(hostkeydata, hostkeylen);
|
|
if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
|
|
bombout(("Server failed host key check"));
|
|
crReturn(0);
|
|
}
|
|
|
|
/*
|
|
* Expect SSH2_MSG_NEWKEYS from server.
|
|
*/
|
|
crWaitUntil(ispkt);
|
|
if (pktin.type != SSH2_MSG_NEWKEYS) {
|
|
bombout(("expected new-keys packet from server"));
|
|
crReturn(0);
|
|
}
|
|
|
|
/*
|
|
* Authenticate remote host: verify host key. (We've already
|
|
* checked the signature of the exchange hash.)
|
|
*/
|
|
keystr = hostkey->fmtkey(hkey);
|
|
fingerprint = hostkey->fingerprint(hkey);
|
|
verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
|
|
keystr, fingerprint);
|
|
if (first_kex) { /* don't bother logging this in rekeys */
|
|
logevent("Host key fingerprint is:");
|
|
logevent(fingerprint);
|
|
}
|
|
sfree(fingerprint);
|
|
sfree(keystr);
|
|
hostkey->freekey(hkey);
|
|
|
|
/*
|
|
* Send SSH2_MSG_NEWKEYS.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_NEWKEYS);
|
|
ssh2_pkt_send();
|
|
|
|
/*
|
|
* Create and initialise session keys.
|
|
*/
|
|
cscipher = cscipher_tobe;
|
|
sccipher = sccipher_tobe;
|
|
csmac = csmac_tobe;
|
|
scmac = scmac_tobe;
|
|
cscomp = cscomp_tobe;
|
|
sccomp = sccomp_tobe;
|
|
cscomp->compress_init();
|
|
sccomp->decompress_init();
|
|
/*
|
|
* Set IVs after keys. Here we use the exchange hash from the
|
|
* _first_ key exchange.
|
|
*/
|
|
if (first_kex)
|
|
memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
|
|
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
|
|
cscipher->setcskey(keyspace);
|
|
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
|
|
sccipher->setsckey(keyspace);
|
|
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
|
|
cscipher->setcsiv(keyspace);
|
|
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
|
|
sccipher->setsciv(keyspace);
|
|
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
|
|
csmac->setcskey(keyspace);
|
|
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
|
|
scmac->setsckey(keyspace);
|
|
|
|
/*
|
|
* If this is the first key exchange phase, we must pass the
|
|
* SSH2_MSG_NEWKEYS packet to the next layer, not because it
|
|
* wants to see it but because it will need time to initialise
|
|
* itself before it sees an actual packet. In subsequent key
|
|
* exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
|
|
* it would only confuse the layer above.
|
|
*/
|
|
if (!first_kex) {
|
|
crReturn(0);
|
|
}
|
|
first_kex = 0;
|
|
|
|
/*
|
|
* Now we're encrypting. Begin returning 1 to the protocol main
|
|
* function so that other things can run on top of the
|
|
* transport. If we ever see a KEXINIT, we must go back to the
|
|
* start.
|
|
*/
|
|
while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
|
|
crReturn(1);
|
|
}
|
|
logevent("Server initiated key re-exchange");
|
|
goto begin_key_exchange;
|
|
|
|
crFinish(1);
|
|
}
|
|
|
|
/*
|
|
* Add data to an SSH2 channel output buffer.
|
|
*/
|
|
static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len) {
|
|
if (c->v2.outbufsize <
|
|
c->v2.outbuflen + len) {
|
|
c->v2.outbufsize =
|
|
c->v2.outbuflen + len + 1024;
|
|
c->v2.outbuffer = srealloc(c->v2.outbuffer,
|
|
c->v2.outbufsize);
|
|
}
|
|
memcpy(c->v2.outbuffer + c->v2.outbuflen,
|
|
buf, len);
|
|
c->v2.outbuflen += len;
|
|
}
|
|
|
|
/*
|
|
* Attempt to send data on an SSH2 channel.
|
|
*/
|
|
static void ssh2_try_send(struct ssh_channel *c) {
|
|
while (c->v2.remwindow > 0 &&
|
|
c->v2.outbuflen > 0) {
|
|
unsigned len = c->v2.remwindow;
|
|
if (len > c->v2.outbuflen)
|
|
len = c->v2.outbuflen;
|
|
if (len > c->v2.remmaxpkt)
|
|
len = c->v2.remmaxpkt;
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
|
|
ssh2_pkt_adduint32(c->remoteid);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(c->v2.outbuffer, len);
|
|
ssh2_pkt_send();
|
|
c->v2.outbuflen -= len;
|
|
memmove(c->v2.outbuffer, c->v2.outbuffer+len,
|
|
c->v2.outbuflen);
|
|
c->v2.remwindow -= len;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Handle the SSH2 userauth and connection layers.
|
|
*/
|
|
static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
|
|
{
|
|
static unsigned long remote_winsize;
|
|
static unsigned long remote_maxpkt;
|
|
static enum {
|
|
AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, AUTH_PASSWORD
|
|
} method;
|
|
static enum {
|
|
AUTH_TYPE_NONE,
|
|
AUTH_TYPE_PUBLICKEY,
|
|
AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
|
|
AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
|
|
AUTH_TYPE_PASSWORD
|
|
} type;
|
|
static int gotit, need_pw, can_pubkey, can_passwd;
|
|
static int tried_pubkey_config, tried_agent;
|
|
static int we_are_in;
|
|
static char username[100];
|
|
static char pwprompt[200];
|
|
static char password[100];
|
|
|
|
crBegin;
|
|
|
|
/*
|
|
* Request userauth protocol, and await a response to it.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
|
|
ssh2_pkt_addstring("ssh-userauth");
|
|
ssh2_pkt_send();
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
|
|
bombout(("Server refused user authentication protocol"));
|
|
crReturnV;
|
|
}
|
|
|
|
/*
|
|
* We repeat this whole loop, including the username prompt,
|
|
* until we manage a successful authentication. If the user
|
|
* types the wrong _password_, they are sent back to the
|
|
* beginning to try another username. (If they specify a
|
|
* username in the config, they are never asked, even if they
|
|
* do give a wrong password.)
|
|
*
|
|
* I think this best serves the needs of
|
|
*
|
|
* - the people who have no configuration, no keys, and just
|
|
* want to try repeated (username,password) pairs until they
|
|
* type both correctly
|
|
*
|
|
* - people who have keys and configuration but occasionally
|
|
* need to fall back to passwords
|
|
*
|
|
* - people with a key held in Pageant, who might not have
|
|
* logged in to a particular machine before; so they want to
|
|
* type a username, and then _either_ their key will be
|
|
* accepted, _or_ they will type a password. If they mistype
|
|
* the username they will want to be able to get back and
|
|
* retype it!
|
|
*/
|
|
do {
|
|
static int pos;
|
|
static char c;
|
|
|
|
/*
|
|
* Get a username.
|
|
*/
|
|
pos = 0;
|
|
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
|
|
c_write_str("login as: ");
|
|
ssh_send_ok = 1;
|
|
while (pos >= 0) {
|
|
crWaitUntilV(!ispkt);
|
|
while (inlen--) switch (c = *in++) {
|
|
case 10: case 13:
|
|
username[pos] = 0;
|
|
pos = -1;
|
|
break;
|
|
case 8: case 127:
|
|
if (pos > 0) {
|
|
c_write_str("\b \b");
|
|
pos--;
|
|
}
|
|
break;
|
|
case 21: case 27:
|
|
while (pos > 0) {
|
|
c_write_str("\b \b");
|
|
pos--;
|
|
}
|
|
break;
|
|
case 3: case 4:
|
|
random_save_seed();
|
|
exit(0);
|
|
break;
|
|
default:
|
|
if (((c >= ' ' && c <= '~') ||
|
|
((unsigned char)c >= 160)) && pos < 40) {
|
|
username[pos++] = c;
|
|
c_write(&c, 1);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
c_write_str("\r\n");
|
|
username[strcspn(username, "\n\r")] = '\0';
|
|
} else {
|
|
char stuff[200];
|
|
strncpy(username, cfg.username, 99);
|
|
username[99] = '\0';
|
|
if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
|
|
sprintf(stuff, "Using username \"%s\".\r\n", username);
|
|
c_write_str(stuff);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send an authentication request using method "none": (a)
|
|
* just in case it succeeds, and (b) so that we know what
|
|
* authentication methods we can usefully try next.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection"); /* service requested */
|
|
ssh2_pkt_addstring("none"); /* method */
|
|
ssh2_pkt_send();
|
|
type = AUTH_TYPE_NONE;
|
|
gotit = FALSE;
|
|
we_are_in = FALSE;
|
|
|
|
tried_pubkey_config = FALSE;
|
|
tried_agent = FALSE;
|
|
|
|
while (1) {
|
|
/*
|
|
* Wait for the result of the last authentication request.
|
|
*/
|
|
if (!gotit)
|
|
crWaitUntilV(ispkt);
|
|
while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
|
|
/* FIXME: should support this */
|
|
crWaitUntilV(ispkt);
|
|
}
|
|
if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
|
|
logevent("Access granted");
|
|
we_are_in = TRUE;
|
|
break;
|
|
}
|
|
|
|
if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
|
|
bombout(("Strange packet received during authentication: type %d",
|
|
pktin.type));
|
|
}
|
|
|
|
gotit = FALSE;
|
|
|
|
/*
|
|
* OK, we're now sitting on a USERAUTH_FAILURE message, so
|
|
* we can look at the string in it and know what we can
|
|
* helpfully try next.
|
|
*/
|
|
{
|
|
char *methods;
|
|
int methlen;
|
|
ssh2_pkt_getstring(&methods, &methlen);
|
|
if (!ssh2_pkt_getbool()) {
|
|
/*
|
|
* We have received an unequivocal Access
|
|
* Denied. This can translate to a variety of
|
|
* messages:
|
|
*
|
|
* - if we'd just tried "none" authentication,
|
|
* it's not worth printing anything at all
|
|
*
|
|
* - if we'd just tried a public key _offer_,
|
|
* the message should be "Server refused our
|
|
* key" (or no message at all if the key
|
|
* came from Pageant)
|
|
*
|
|
* - if we'd just tried anything else, the
|
|
* message really should be "Access denied".
|
|
*
|
|
* Additionally, if we'd just tried password
|
|
* authentication, we should break out of this
|
|
* whole loop so as to go back to the username
|
|
* prompt.
|
|
*/
|
|
if (type == AUTH_TYPE_NONE) {
|
|
/* do nothing */
|
|
} else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
|
|
type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
|
|
if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
|
|
c_write_str("Server refused our key\r\n");
|
|
logevent("Server refused public key");
|
|
} else {
|
|
c_write_str("Access denied\r\n");
|
|
logevent("Access denied");
|
|
if (type == AUTH_TYPE_PASSWORD) {
|
|
we_are_in = FALSE;
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
c_write_str("Further authentication required\r\n");
|
|
logevent("Further authentication required");
|
|
}
|
|
|
|
can_pubkey = in_commasep_string("publickey", methods, methlen);
|
|
can_passwd = in_commasep_string("password", methods, methlen);
|
|
}
|
|
|
|
method = 0;
|
|
|
|
if (!method && can_pubkey && agent_exists && !tried_agent) {
|
|
/*
|
|
* Attempt public-key authentication using Pageant.
|
|
*/
|
|
static unsigned char request[5], *response, *p;
|
|
static int responselen;
|
|
static int i, nkeys;
|
|
static int authed = FALSE;
|
|
void *r;
|
|
|
|
tried_agent = TRUE;
|
|
|
|
logevent("Pageant is running. Requesting keys.");
|
|
|
|
/* Request the keys held by the agent. */
|
|
PUT_32BIT(request, 1);
|
|
request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
|
|
agent_query(request, 5, &r, &responselen);
|
|
response = (unsigned char *)r;
|
|
if (response) {
|
|
p = response + 5;
|
|
nkeys = GET_32BIT(p); p += 4;
|
|
{ char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
|
|
logevent(buf); }
|
|
for (i = 0; i < nkeys; i++) {
|
|
static char *pkblob, *alg, *commentp;
|
|
static int pklen, alglen, commentlen;
|
|
static int siglen, retlen, len;
|
|
static char *q, *agentreq, *ret;
|
|
|
|
{ char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
|
|
logevent(buf); }
|
|
pklen = GET_32BIT(p); p += 4;
|
|
pkblob = p; p += pklen;
|
|
alglen = GET_32BIT(pkblob);
|
|
alg = pkblob + 4;
|
|
commentlen = GET_32BIT(p); p += 4;
|
|
commentp = p; p += commentlen;
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection");/* service requested */
|
|
ssh2_pkt_addstring("publickey");/* method */
|
|
ssh2_pkt_addbool(FALSE); /* no signature included */
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(alg, alglen);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(pkblob, pklen);
|
|
ssh2_pkt_send();
|
|
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
|
|
logevent("Key refused");
|
|
continue;
|
|
}
|
|
|
|
c_write_str("Authenticating with public key \"");
|
|
c_write(commentp, commentlen);
|
|
c_write_str("\" from agent\r\n");
|
|
|
|
/*
|
|
* Server is willing to accept the key.
|
|
* Construct a SIGN_REQUEST.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection"); /* service requested */
|
|
ssh2_pkt_addstring("publickey"); /* method */
|
|
ssh2_pkt_addbool(TRUE);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(alg, alglen);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(pkblob, pklen);
|
|
|
|
siglen = pktout.length - 5 + 4 + 20;
|
|
len = 1; /* message type */
|
|
len += 4 + pklen; /* key blob */
|
|
len += 4 + siglen; /* data to sign */
|
|
len += 4; /* flags */
|
|
agentreq = smalloc(4 + len);
|
|
PUT_32BIT(agentreq, len);
|
|
q = agentreq + 4;
|
|
*q++ = SSH2_AGENTC_SIGN_REQUEST;
|
|
PUT_32BIT(q, pklen); q += 4;
|
|
memcpy(q, pkblob, pklen); q += pklen;
|
|
PUT_32BIT(q, siglen); q += 4;
|
|
/* Now the data to be signed... */
|
|
PUT_32BIT(q, 20); q += 4;
|
|
memcpy(q, ssh2_session_id, 20); q += 20;
|
|
memcpy(q, pktout.data+5, pktout.length-5);
|
|
q += pktout.length-5;
|
|
/* And finally the (zero) flags word. */
|
|
PUT_32BIT(q, 0);
|
|
agent_query(agentreq, len+4, &ret, &retlen);
|
|
sfree(agentreq);
|
|
if (ret) {
|
|
if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
|
|
logevent("Sending Pageant's response");
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(ret+9, GET_32BIT(ret+5));
|
|
ssh2_pkt_send();
|
|
authed = TRUE;
|
|
break;
|
|
} else {
|
|
logevent("Pageant failed to answer challenge");
|
|
sfree(ret);
|
|
}
|
|
}
|
|
}
|
|
if (authed)
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (!method && can_pubkey && *cfg.keyfile && !tried_pubkey_config) {
|
|
unsigned char *pub_blob;
|
|
char *algorithm, *comment;
|
|
int pub_blob_len;
|
|
|
|
tried_pubkey_config = TRUE;
|
|
|
|
/*
|
|
* Try the public key supplied in the configuration.
|
|
*
|
|
* First, offer the public blob to see if the server is
|
|
* willing to accept it.
|
|
*/
|
|
pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
|
|
&pub_blob_len);
|
|
if (pub_blob) {
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection"); /* service requested */
|
|
ssh2_pkt_addstring("publickey");/* method */
|
|
ssh2_pkt_addbool(FALSE); /* no signature included */
|
|
ssh2_pkt_addstring(algorithm);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
|
|
ssh2_pkt_send();
|
|
logevent("Offered public key"); /* FIXME */
|
|
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
|
|
gotit = TRUE;
|
|
type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
|
|
continue; /* key refused; give up on it */
|
|
}
|
|
|
|
logevent("Offer of public key accepted");
|
|
/*
|
|
* Actually attempt a serious authentication using
|
|
* the key.
|
|
*/
|
|
if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
|
|
sprintf(pwprompt, "Passphrase for key \"%.100s\": ", comment);
|
|
need_pw = TRUE;
|
|
} else {
|
|
need_pw = FALSE;
|
|
}
|
|
c_write_str("Authenticating with public key \"");
|
|
c_write_str(comment);
|
|
c_write_str("\"\r\n");
|
|
method = AUTH_PUBLICKEY_FILE;
|
|
}
|
|
}
|
|
|
|
if (!method && can_passwd) {
|
|
method = AUTH_PASSWORD;
|
|
sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost);
|
|
need_pw = TRUE;
|
|
}
|
|
|
|
if (need_pw) {
|
|
if (ssh_get_password) {
|
|
if (!ssh_get_password(pwprompt, password, sizeof(password))) {
|
|
/*
|
|
* get_password failed to get a password (for
|
|
* example because one was supplied on the command
|
|
* line which has already failed to work).
|
|
* Terminate.
|
|
*/
|
|
logevent("No more passwords to try");
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
crReturnV;
|
|
}
|
|
} else {
|
|
static int pos = 0;
|
|
static char c;
|
|
|
|
c_write_str(pwprompt);
|
|
ssh_send_ok = 1;
|
|
|
|
pos = 0;
|
|
while (pos >= 0) {
|
|
crWaitUntilV(!ispkt);
|
|
while (inlen--) switch (c = *in++) {
|
|
case 10: case 13:
|
|
password[pos] = 0;
|
|
pos = -1;
|
|
break;
|
|
case 8: case 127:
|
|
if (pos > 0)
|
|
pos--;
|
|
break;
|
|
case 21: case 27:
|
|
pos = 0;
|
|
break;
|
|
case 3: case 4:
|
|
random_save_seed();
|
|
exit(0);
|
|
break;
|
|
default:
|
|
if (((c >= ' ' && c <= '~') ||
|
|
((unsigned char)c >= 160)) && pos < 40)
|
|
password[pos++] = c;
|
|
break;
|
|
}
|
|
}
|
|
c_write_str("\r\n");
|
|
}
|
|
}
|
|
|
|
if (method == AUTH_PUBLICKEY_FILE) {
|
|
/*
|
|
* We have our passphrase. Now try the actual authentication.
|
|
*/
|
|
struct ssh2_userkey *key;
|
|
|
|
key = ssh2_load_userkey(cfg.keyfile, password);
|
|
if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
|
|
if (key == SSH2_WRONG_PASSPHRASE) {
|
|
c_write_str("Wrong passphrase\r\n");
|
|
tried_pubkey_config = FALSE;
|
|
} else {
|
|
c_write_str("Unable to load private key\r\n");
|
|
tried_pubkey_config = TRUE;
|
|
}
|
|
/* Send a spurious AUTH_NONE to return to the top. */
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection"); /* service requested */
|
|
ssh2_pkt_addstring("none"); /* method */
|
|
ssh2_pkt_send();
|
|
type = AUTH_TYPE_NONE;
|
|
} else {
|
|
unsigned char *blob, *sigdata;
|
|
int blob_len, sigdata_len;
|
|
|
|
/*
|
|
* We have loaded the private key and the server
|
|
* has announced that it's willing to accept it.
|
|
* Hallelujah. Generate a signature and send it.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection"); /* service requested */
|
|
ssh2_pkt_addstring("publickey"); /* method */
|
|
ssh2_pkt_addbool(TRUE);
|
|
ssh2_pkt_addstring(key->alg->name);
|
|
blob = key->alg->public_blob(key->data, &blob_len);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(blob, blob_len);
|
|
sfree(blob);
|
|
|
|
/*
|
|
* The data to be signed is:
|
|
*
|
|
* string session-id
|
|
*
|
|
* followed by everything so far placed in the
|
|
* outgoing packet.
|
|
*/
|
|
sigdata_len = pktout.length - 5 + 4 + 20;
|
|
sigdata = smalloc(sigdata_len);
|
|
PUT_32BIT(sigdata, 20);
|
|
memcpy(sigdata+4, ssh2_session_id, 20);
|
|
memcpy(sigdata+24, pktout.data+5, pktout.length-5);
|
|
blob = key->alg->sign(key->data, sigdata, sigdata_len, &blob_len);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data(blob, blob_len);
|
|
sfree(blob);
|
|
sfree(sigdata);
|
|
|
|
ssh2_pkt_send();
|
|
type = AUTH_TYPE_PUBLICKEY;
|
|
}
|
|
} else if (method == AUTH_PASSWORD) {
|
|
/*
|
|
* We send the password packet lumped tightly together with
|
|
* an SSH_MSG_IGNORE packet. The IGNORE packet contains a
|
|
* string long enough to make the total length of the two
|
|
* packets constant. This should ensure that a passive
|
|
* listener doing traffic analyis can't work out the length
|
|
* of the password.
|
|
*
|
|
* For this to work, we need an assumption about the
|
|
* maximum length of the password packet. I think 256 is
|
|
* pretty conservative. Anyone using a password longer than
|
|
* that probably doesn't have much to worry about from
|
|
* people who find out how long their password is!
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
|
|
ssh2_pkt_addstring(username);
|
|
ssh2_pkt_addstring("ssh-connection"); /* service requested */
|
|
ssh2_pkt_addstring("password");
|
|
ssh2_pkt_addbool(FALSE);
|
|
ssh2_pkt_addstring(password);
|
|
ssh2_pkt_defer();
|
|
/*
|
|
* We'll include a string that's an exact multiple of the
|
|
* cipher block size. If the cipher is NULL for some
|
|
* reason, we don't do this trick at all because we gain
|
|
* nothing by it.
|
|
*/
|
|
if (cscipher) {
|
|
int stringlen, i;
|
|
|
|
stringlen = (256 - deferred_len);
|
|
stringlen += cscipher->blksize - 1;
|
|
stringlen -= (stringlen % cscipher->blksize);
|
|
if (cscomp) {
|
|
/*
|
|
* Temporarily disable actual compression,
|
|
* so we can guarantee to get this string
|
|
* exactly the length we want it. The
|
|
* compression-disabling routine should
|
|
* return an integer indicating how many
|
|
* bytes we should adjust our string length
|
|
* by.
|
|
*/
|
|
stringlen -= cscomp->disable_compression();
|
|
}
|
|
ssh2_pkt_init(SSH2_MSG_IGNORE);
|
|
ssh2_pkt_addstring_start();
|
|
for (i = 0; i < stringlen; i++) {
|
|
char c = (char)random_byte();
|
|
ssh2_pkt_addstring_data(&c, 1);
|
|
}
|
|
ssh2_pkt_defer();
|
|
}
|
|
ssh_pkt_defersend();
|
|
logevent("Sent password");
|
|
type = AUTH_TYPE_PASSWORD;
|
|
} else {
|
|
c_write_str("No supported authentication methods left to try!\r\n");
|
|
logevent("No supported authentications offered. Disconnecting");
|
|
ssh2_pkt_init(SSH2_MSG_DISCONNECT);
|
|
ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
|
|
ssh2_pkt_addstring("No supported authentication methods available");
|
|
ssh2_pkt_addstring("en"); /* language tag */
|
|
ssh2_pkt_send();
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
crReturnV;
|
|
}
|
|
}
|
|
} while (!we_are_in);
|
|
|
|
/*
|
|
* Now we're authenticated for the connection protocol. The
|
|
* connection protocol will automatically have started at this
|
|
* point; there's no need to send SERVICE_REQUEST.
|
|
*/
|
|
|
|
/*
|
|
* So now create a channel with a session in it.
|
|
*/
|
|
mainchan = smalloc(sizeof(struct ssh_channel));
|
|
mainchan->localid = 100; /* as good as any */
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
|
|
ssh2_pkt_addstring("session");
|
|
ssh2_pkt_adduint32(mainchan->localid);
|
|
ssh2_pkt_adduint32(0x8000UL); /* our window size */
|
|
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
|
|
ssh2_pkt_send();
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
|
|
bombout(("Server refused to open a session"));
|
|
crReturnV;
|
|
/* FIXME: error data comes back in FAILURE packet */
|
|
}
|
|
if (ssh2_pkt_getuint32() != mainchan->localid) {
|
|
bombout(("Server's channel confirmation cited wrong channel"));
|
|
crReturnV;
|
|
}
|
|
mainchan->remoteid = ssh2_pkt_getuint32();
|
|
mainchan->type = CHAN_MAINSESSION;
|
|
mainchan->closes = 0;
|
|
mainchan->v2.remwindow = ssh2_pkt_getuint32();
|
|
mainchan->v2.remmaxpkt = ssh2_pkt_getuint32();
|
|
mainchan->v2.outbuffer = NULL;
|
|
mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0;
|
|
ssh_channels = newtree234(ssh_channelcmp);
|
|
add234(ssh_channels, mainchan);
|
|
logevent("Opened channel for session");
|
|
|
|
/*
|
|
* Potentially enable X11 forwarding.
|
|
*/
|
|
if (cfg.x11_forward) {
|
|
char proto[20], data[64];
|
|
logevent("Requesting X11 forwarding");
|
|
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
|
|
ssh2_pkt_adduint32(mainchan->remoteid);
|
|
ssh2_pkt_addstring("x11-req");
|
|
ssh2_pkt_addbool(1); /* want reply */
|
|
ssh2_pkt_addbool(0); /* many connections */
|
|
ssh2_pkt_addstring(proto);
|
|
ssh2_pkt_addstring(data);
|
|
ssh2_pkt_adduint32(0); /* screen number */
|
|
ssh2_pkt_send();
|
|
|
|
do {
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
c->v2.remwindow += ssh2_pkt_getuint32();
|
|
}
|
|
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
|
|
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
|
|
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
|
|
bombout(("Server got confused by X11 forwarding request"));
|
|
crReturnV;
|
|
}
|
|
logevent("X11 forwarding refused");
|
|
} else {
|
|
logevent("X11 forwarding enabled");
|
|
ssh_X11_fwd_enabled = TRUE;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Potentially enable agent forwarding.
|
|
*/
|
|
if (cfg.agentfwd && agent_exists()) {
|
|
char proto[20], data[64];
|
|
logevent("Requesting OpenSSH-style agent forwarding");
|
|
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
|
|
ssh2_pkt_adduint32(mainchan->remoteid);
|
|
ssh2_pkt_addstring("auth-agent-req@openssh.com");
|
|
ssh2_pkt_addbool(1); /* want reply */
|
|
ssh2_pkt_send();
|
|
|
|
do {
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
c->v2.remwindow += ssh2_pkt_getuint32();
|
|
}
|
|
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
|
|
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
|
|
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
|
|
bombout(("Server got confused by agent forwarding request"));
|
|
crReturnV;
|
|
}
|
|
logevent("Agent forwarding refused");
|
|
} else {
|
|
logevent("Agent forwarding enabled");
|
|
ssh_agentfwd_enabled = TRUE;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Now allocate a pty for the session.
|
|
*/
|
|
if (!cfg.nopty) {
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
|
|
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
|
|
ssh2_pkt_addstring("pty-req");
|
|
ssh2_pkt_addbool(1); /* want reply */
|
|
ssh2_pkt_addstring(cfg.termtype);
|
|
ssh2_pkt_adduint32(cols);
|
|
ssh2_pkt_adduint32(rows);
|
|
ssh2_pkt_adduint32(0); /* pixel width */
|
|
ssh2_pkt_adduint32(0); /* pixel height */
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
|
|
ssh2_pkt_send();
|
|
ssh_state = SSH_STATE_INTERMED;
|
|
|
|
do {
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
c->v2.remwindow += ssh2_pkt_getuint32();
|
|
}
|
|
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
|
|
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
|
|
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
|
|
bombout(("Server got confused by pty request"));
|
|
crReturnV;
|
|
}
|
|
c_write_str("Server refused to allocate pty\r\n");
|
|
ssh_editing = ssh_echoing = 1;
|
|
} else {
|
|
logevent("Allocated pty");
|
|
}
|
|
} else {
|
|
ssh_editing = ssh_echoing = 1;
|
|
}
|
|
|
|
/*
|
|
* Start a shell or a remote command.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
|
|
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
|
|
if (cfg.ssh_subsys) {
|
|
ssh2_pkt_addstring("subsystem");
|
|
ssh2_pkt_addbool(1); /* want reply */
|
|
ssh2_pkt_addstring(cfg.remote_cmd);
|
|
} else if (*cfg.remote_cmd) {
|
|
ssh2_pkt_addstring("exec");
|
|
ssh2_pkt_addbool(1); /* want reply */
|
|
ssh2_pkt_addstring(cfg.remote_cmd);
|
|
} else {
|
|
ssh2_pkt_addstring("shell");
|
|
ssh2_pkt_addbool(1); /* want reply */
|
|
}
|
|
ssh2_pkt_send();
|
|
do {
|
|
crWaitUntilV(ispkt);
|
|
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
c->v2.remwindow += ssh2_pkt_getuint32();
|
|
}
|
|
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
|
|
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
|
|
bombout(("Server got confused by shell/command request"));
|
|
crReturnV;
|
|
}
|
|
bombout(("Server refused to start a shell/command"));
|
|
crReturnV;
|
|
} else {
|
|
logevent("Started a shell/command");
|
|
}
|
|
|
|
ssh_state = SSH_STATE_SESSION;
|
|
if (size_needed)
|
|
ssh_size();
|
|
if (eof_needed)
|
|
ssh_special(TS_EOF);
|
|
|
|
/*
|
|
* Transfer data!
|
|
*/
|
|
ldisc_send(NULL, 0); /* cause ldisc to notice changes */
|
|
ssh_send_ok = 1;
|
|
while (1) {
|
|
static int try_send;
|
|
crReturnV;
|
|
try_send = FALSE;
|
|
if (ispkt) {
|
|
if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
|
|
pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
|
|
char *data;
|
|
int length;
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
|
|
ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
|
|
continue; /* extended but not stderr */
|
|
ssh2_pkt_getstring(&data, &length);
|
|
if (data) {
|
|
switch (c->type) {
|
|
case CHAN_MAINSESSION:
|
|
from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
|
|
data, length);
|
|
break;
|
|
case CHAN_X11:
|
|
x11_send(c->u.x11.s, data, length);
|
|
break;
|
|
case CHAN_AGENT:
|
|
while (length > 0) {
|
|
if (c->u.a.lensofar < 4) {
|
|
int l = min(4 - c->u.a.lensofar, length);
|
|
memcpy(c->u.a.msglen + c->u.a.lensofar, data, l);
|
|
data += l; length -= l; c->u.a.lensofar += l;
|
|
}
|
|
if (c->u.a.lensofar == 4) {
|
|
c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
|
|
c->u.a.message = smalloc(c->u.a.totallen);
|
|
memcpy(c->u.a.message, c->u.a.msglen, 4);
|
|
}
|
|
if (c->u.a.lensofar >= 4 && length > 0) {
|
|
int l = min(c->u.a.totallen - c->u.a.lensofar,
|
|
length);
|
|
memcpy(c->u.a.message + c->u.a.lensofar, data, l);
|
|
data += l; length -= l; c->u.a.lensofar += l;
|
|
}
|
|
if (c->u.a.lensofar == c->u.a.totallen) {
|
|
void *reply, *sentreply;
|
|
int replylen;
|
|
agent_query(c->u.a.message, c->u.a.totallen,
|
|
&reply, &replylen);
|
|
if (reply)
|
|
sentreply = reply;
|
|
else {
|
|
/* Fake SSH_AGENT_FAILURE. */
|
|
sentreply = "\0\0\0\1\5";
|
|
replylen = 5;
|
|
}
|
|
ssh2_add_channel_data(c, sentreply, replylen);
|
|
try_send = TRUE;
|
|
if (reply)
|
|
sfree(reply);
|
|
sfree(c->u.a.message);
|
|
c->u.a.lensofar = 0;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
/*
|
|
* Enlarge the window again at the remote
|
|
* side, just in case it ever runs down and
|
|
* they fail to send us any more data.
|
|
*/
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
ssh2_pkt_adduint32(c->remoteid);
|
|
ssh2_pkt_adduint32(length);
|
|
ssh2_pkt_send();
|
|
}
|
|
} else if (pktin.type == SSH2_MSG_DISCONNECT) {
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
logevent("Received disconnect message");
|
|
crReturnV;
|
|
} else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
|
|
continue; /* exit status et al; ignore (FIXME?) */
|
|
} else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
|
|
if (c->type == CHAN_X11) {
|
|
/*
|
|
* Remote EOF on an X11 channel means we should
|
|
* wrap up and close the channel ourselves.
|
|
*/
|
|
x11_close(c->u.x11.s);
|
|
sshfwd_close(c);
|
|
} else if (c->type == CHAN_AGENT) {
|
|
sshfwd_close(c);
|
|
}
|
|
} else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
enum234 e;
|
|
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
if (c->closes == 0) {
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
|
|
ssh2_pkt_adduint32(c->remoteid);
|
|
ssh2_pkt_send();
|
|
}
|
|
/* Do pre-close processing on the channel. */
|
|
switch (c->type) {
|
|
case CHAN_MAINSESSION:
|
|
break; /* nothing to see here, move along */
|
|
case CHAN_X11:
|
|
break;
|
|
case CHAN_AGENT:
|
|
break;
|
|
}
|
|
del234(ssh_channels, c);
|
|
sfree(c->v2.outbuffer);
|
|
sfree(c);
|
|
|
|
/*
|
|
* See if that was the last channel left open.
|
|
*/
|
|
c = first234(ssh_channels, &e);
|
|
if (!c) {
|
|
logevent("All channels closed. Disconnecting");
|
|
ssh2_pkt_init(SSH2_MSG_DISCONNECT);
|
|
ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
|
|
ssh2_pkt_addstring("All open channels closed");
|
|
ssh2_pkt_addstring("en"); /* language tag */
|
|
ssh2_pkt_send();
|
|
ssh_state = SSH_STATE_CLOSED;
|
|
crReturnV;
|
|
}
|
|
continue; /* remote sends close; ignore (FIXME) */
|
|
} else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
|
|
unsigned i = ssh2_pkt_getuint32();
|
|
struct ssh_channel *c;
|
|
c = find234(ssh_channels, &i, ssh_channelfind);
|
|
if (!c)
|
|
continue; /* nonexistent channel */
|
|
mainchan->v2.remwindow += ssh2_pkt_getuint32();
|
|
try_send = TRUE;
|
|
} else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
|
|
char *type;
|
|
int typelen;
|
|
char *error = NULL;
|
|
struct ssh_channel *c;
|
|
ssh2_pkt_getstring(&type, &typelen);
|
|
c = smalloc(sizeof(struct ssh_channel));
|
|
|
|
if (typelen == 3 && !memcmp(type, "x11", 3)) {
|
|
if (!ssh_X11_fwd_enabled)
|
|
error = "X11 forwarding is not enabled";
|
|
else if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
|
|
error = "Unable to open an X11 connection";
|
|
} else {
|
|
c->type = CHAN_X11;
|
|
}
|
|
} else if (typelen == 22 &&
|
|
!memcmp(type, "auth-agent@openssh.com", 3)) {
|
|
if (!ssh_agentfwd_enabled)
|
|
error = "Agent forwarding is not enabled";
|
|
else {
|
|
c->type = CHAN_AGENT; /* identify channel type */
|
|
c->u.a.lensofar = 0;
|
|
}
|
|
} else {
|
|
error = "Unsupported channel type requested";
|
|
}
|
|
|
|
c->remoteid = ssh2_pkt_getuint32();
|
|
if (error) {
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
|
|
ssh2_pkt_adduint32(c->remoteid);
|
|
ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
|
|
ssh2_pkt_addstring(error);
|
|
ssh2_pkt_addstring("en"); /* language tag */
|
|
ssh2_pkt_send();
|
|
sfree(c);
|
|
} else {
|
|
struct ssh_channel *d;
|
|
unsigned i;
|
|
enum234 e;
|
|
|
|
for (i=1, d = first234(ssh_channels, &e); d;
|
|
d = next234(&e)) {
|
|
if (d->localid > i)
|
|
break; /* found a free number */
|
|
i = d->localid + 1;
|
|
}
|
|
c->localid = i;
|
|
c->closes = 0;
|
|
c->v2.remwindow = ssh2_pkt_getuint32();
|
|
c->v2.remmaxpkt = ssh2_pkt_getuint32();
|
|
c->v2.outbuffer = NULL;
|
|
c->v2.outbuflen = c->v2.outbufsize = 0;
|
|
add234(ssh_channels, c);
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
ssh2_pkt_adduint32(c->remoteid);
|
|
ssh2_pkt_adduint32(c->localid);
|
|
ssh2_pkt_adduint32(0x8000UL); /* our window size */
|
|
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
|
|
ssh2_pkt_send();
|
|
}
|
|
} else {
|
|
bombout(("Strange packet received: type %d", pktin.type));
|
|
crReturnV;
|
|
}
|
|
} else {
|
|
/*
|
|
* We have spare data. Add it to the channel buffer.
|
|
*/
|
|
ssh2_add_channel_data(mainchan, in, inlen);
|
|
try_send = TRUE;
|
|
}
|
|
if (try_send) {
|
|
enum234 e;
|
|
struct ssh_channel *c;
|
|
/*
|
|
* Try to send data on all channels if we can.
|
|
*/
|
|
for (c = first234(ssh_channels, &e); c; c = next234(&e))
|
|
ssh2_try_send(c);
|
|
}
|
|
}
|
|
|
|
crFinishV;
|
|
}
|
|
|
|
/*
|
|
* Handle the top-level SSH2 protocol.
|
|
*/
|
|
static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
|
|
{
|
|
if (do_ssh2_transport(in, inlen, ispkt) == 0)
|
|
return;
|
|
do_ssh2_authconn(in, inlen, ispkt);
|
|
}
|
|
|
|
/*
|
|
* Called to set up the connection.
|
|
*
|
|
* Returns an error message, or NULL on success.
|
|
*/
|
|
static char *ssh_init (char *host, int port, char **realhost) {
|
|
char *p;
|
|
|
|
#ifdef MSCRYPTOAPI
|
|
if(crypto_startup() == 0)
|
|
return "Microsoft high encryption pack not installed!";
|
|
#endif
|
|
|
|
ssh_send_ok = 0;
|
|
ssh_editing = 0;
|
|
ssh_echoing = 0;
|
|
|
|
p = connect_to_host(host, port, realhost);
|
|
if (p != NULL)
|
|
return p;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Called to send data down the Telnet connection.
|
|
*/
|
|
static void ssh_send (char *buf, int len) {
|
|
if (s == NULL || ssh_protocol == NULL)
|
|
return;
|
|
|
|
ssh_protocol(buf, len, 0);
|
|
}
|
|
|
|
/*
|
|
* Called to set the size of the window from SSH's POV.
|
|
*/
|
|
static void ssh_size(void) {
|
|
switch (ssh_state) {
|
|
case SSH_STATE_BEFORE_SIZE:
|
|
case SSH_STATE_PREPACKET:
|
|
case SSH_STATE_CLOSED:
|
|
break; /* do nothing */
|
|
case SSH_STATE_INTERMED:
|
|
size_needed = TRUE; /* buffer for later */
|
|
break;
|
|
case SSH_STATE_SESSION:
|
|
if (!cfg.nopty) {
|
|
if (ssh_version == 1) {
|
|
send_packet(SSH1_CMSG_WINDOW_SIZE,
|
|
PKT_INT, rows, PKT_INT, cols,
|
|
PKT_INT, 0, PKT_INT, 0, PKT_END);
|
|
} else {
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
|
|
ssh2_pkt_adduint32(mainchan->remoteid);
|
|
ssh2_pkt_addstring("window-change");
|
|
ssh2_pkt_addbool(0);
|
|
ssh2_pkt_adduint32(cols);
|
|
ssh2_pkt_adduint32(rows);
|
|
ssh2_pkt_adduint32(0);
|
|
ssh2_pkt_adduint32(0);
|
|
ssh2_pkt_send();
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send Telnet special codes. TS_EOF is useful for `plink', so you
|
|
* can send an EOF and collect resulting output (e.g. `plink
|
|
* hostname sort').
|
|
*/
|
|
static void ssh_special (Telnet_Special code) {
|
|
if (code == TS_EOF) {
|
|
if (ssh_state != SSH_STATE_SESSION) {
|
|
/*
|
|
* Buffer the EOF in case we are pre-SESSION, so we can
|
|
* send it as soon as we reach SESSION.
|
|
*/
|
|
if (code == TS_EOF)
|
|
eof_needed = TRUE;
|
|
return;
|
|
}
|
|
if (ssh_version == 1) {
|
|
send_packet(SSH1_CMSG_EOF, PKT_END);
|
|
} else {
|
|
ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
|
|
ssh2_pkt_adduint32(mainchan->remoteid);
|
|
ssh2_pkt_send();
|
|
}
|
|
logevent("Sent EOF message");
|
|
} else if (code == TS_PING) {
|
|
if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET)
|
|
return;
|
|
if (ssh_version == 1) {
|
|
send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
|
|
} else {
|
|
ssh2_pkt_init(SSH2_MSG_IGNORE);
|
|
ssh2_pkt_addstring_start();
|
|
ssh2_pkt_send();
|
|
}
|
|
} else {
|
|
/* do nothing */
|
|
}
|
|
}
|
|
|
|
static Socket ssh_socket(void) { return s; }
|
|
|
|
static int ssh_sendok(void) { return ssh_send_ok; }
|
|
|
|
static int ssh_ldisc(int option) {
|
|
if (option == LD_ECHO) return ssh_echoing;
|
|
if (option == LD_EDIT) return ssh_editing;
|
|
return FALSE;
|
|
}
|
|
|
|
Backend ssh_backend = {
|
|
ssh_init,
|
|
ssh_send,
|
|
ssh_size,
|
|
ssh_special,
|
|
ssh_socket,
|
|
ssh_sendok,
|
|
ssh_ldisc,
|
|
22
|
|
};
|