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679fa90dfe
sshbpp.h now defines a classoid that encapsulates both directions of an SSH binary packet protocol - that is, a system for reading a bufchain of incoming data and turning it into a stream of PktIn, and another system for taking a PktOut and turning it into data on an outgoing bufchain. The state structure in each of those files contains everything that used to be in the 'rdpkt2_state' structure and its friends, and also quite a lot of bits and pieces like cipher and MAC states that used to live in the main Ssh structure. One minor effect of this layer separation is that I've had to extend the packet dispatch table by one, because the BPP layer can no longer directly trigger sending of SSH_MSG_UNIMPLEMENTED for a message too short to have a type byte. Instead, I extend the PktIn type field to use an out-of-range value to encode that, and the easiest way to make that trigger an UNIMPLEMENTED message is to have the dispatch table contain an entry for it. (That's a system that may come in useful again - I was also wondering about inventing a fake type code to indicate network EOF, so that that could be propagated through the layers and be handled by whichever one currently knew best how to respond.) I've also moved the packet-censoring code into its own pair of files, partly because I was going to want to do that anyway sooner or later, and mostly because it's called from the BPP code, and the SSH-2 version in particular has to be called from both the main SSH-2 BPP and the bare unencrypted protocol used for connection sharing. While I was at it, I took the opportunity to merge the outgoing and incoming censor functions, so that the parts that were common between them (e.g. CHANNEL_DATA messages look the same in both directions) didn't need to be repeated.
77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/*
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* Packet-censoring code for SSH-1, used to identify sensitive fields
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* like passwords so that the logging system can avoid writing them
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* into log files.
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*/
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#include <assert.h>
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#include "putty.h"
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#include "ssh.h"
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int ssh1_censor_packet(
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const PacketLogSettings *pls, int type, int sender_is_client,
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ptrlen pkt, logblank_t *blanks)
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{
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int nblanks = 0;
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ptrlen str;
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BinarySource src[1];
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BinarySource_BARE_INIT(src, pkt.ptr, pkt.len);
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if (pls->omit_data &&
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(type == SSH1_SMSG_STDOUT_DATA ||
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type == SSH1_SMSG_STDERR_DATA ||
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type == SSH1_CMSG_STDIN_DATA ||
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type == SSH1_MSG_CHANNEL_DATA)) {
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/* "Session data" packets - omit the data string. */
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if (type == SSH1_MSG_CHANNEL_DATA)
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get_uint32(src); /* skip channel id */
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str = get_string(src);
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if (!get_err(src)) {
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assert(nblanks < MAX_BLANKS);
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blanks[nblanks].offset = src->pos - str.len;
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blanks[nblanks].type = PKTLOG_OMIT;
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blanks[nblanks].len = str.len;
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nblanks++;
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}
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}
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if (sender_is_client && pls->omit_passwords) {
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if (type == SSH1_CMSG_AUTH_PASSWORD ||
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type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
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type == SSH1_CMSG_AUTH_CCARD_RESPONSE) {
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/* If this is a password or similar packet, blank the
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* password(s). */
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assert(nblanks < MAX_BLANKS);
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blanks[nblanks].offset = 0;
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blanks[nblanks].len = pkt.len;
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blanks[nblanks].type = PKTLOG_BLANK;
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nblanks++;
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} else if (type == SSH1_CMSG_X11_REQUEST_FORWARDING) {
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/*
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* If this is an X forwarding request packet, blank the
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* fake auth data.
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*
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* Note that while we blank the X authentication data
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* here, we don't take any special action to blank the
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* start of an X11 channel, so using MIT-MAGIC-COOKIE-1
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* and actually opening an X connection without having
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* session blanking enabled is likely to leak your cookie
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* into the log.
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*/
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get_string(src); /* skip protocol name */
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str = get_string(src);
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if (!get_err(src)) {
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assert(nblanks < MAX_BLANKS);
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blanks[nblanks].offset = src->pos - str.len;
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blanks[nblanks].type = PKTLOG_BLANK;
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blanks[nblanks].len = str.len;
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nblanks++;
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}
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}
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}
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return nblanks;
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}
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