mirror of
https://git.tartarus.org/simon/putty.git
synced 2025-01-09 09:27:59 +00:00
5d718ef64b
The number of people has been steadily increasing who read our source
code with an editor that thinks tab stops are 4 spaces apart, as
opposed to the traditional tty-derived 8 that the PuTTY code expects.
So I've been wondering for ages about just fixing it, and switching to
a spaces-only policy throughout the code. And I recently found out
about 'git blame -w', which should make this change not too disruptive
for the purposes of source-control archaeology; so perhaps now is the
time.
While I'm at it, I've also taken the opportunity to remove all the
trailing spaces from source lines (on the basis that git dislikes
them, and is the only thing that seems to have a strong opinion one
way or the other).
Apologies to anyone downstream of this code who has complicated patch
sets to rebase past this change. I don't intend it to be needed again.
560 lines
17 KiB
C
560 lines
17 KiB
C
/*
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* Top-level code for SSH server implementation.
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*/
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#include <assert.h>
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#include <stddef.h>
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#include "putty.h"
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#include "ssh.h"
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#include "sshbpp.h"
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#include "sshppl.h"
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#include "sshserver.h"
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#ifndef NO_GSSAPI
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#include "sshgssc.h"
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#include "sshgss.h"
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#endif
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struct Ssh { int dummy; };
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typedef struct server server;
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struct server {
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bufchain in_raw, out_raw;
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IdempotentCallback ic_out_raw;
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bool pending_close;
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bufchain dummy_user_input; /* we never put anything on this */
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PacketLogSettings pls;
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LogContext *logctx;
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struct DataTransferStats stats;
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int remote_bugs;
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Socket *socket;
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Plug plug;
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int conn_throttle_count;
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bool frozen;
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Conf *conf;
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const SshServerConfig *ssc;
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ssh_key *const *hostkeys;
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int nhostkeys;
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RSAKey *hostkey1;
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AuthPolicy *authpolicy;
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LogPolicy *logpolicy;
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const SftpServerVtable *sftpserver_vt;
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Seat seat;
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Ssh ssh;
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struct ssh_version_receiver version_receiver;
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BinaryPacketProtocol *bpp;
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PacketProtocolLayer *base_layer;
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ConnectionLayer *cl;
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#ifndef NO_GSSAPI
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struct ssh_connection_shared_gss_state gss_state;
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#endif
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};
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static void ssh_server_free_callback(void *vsrv);
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static void server_got_ssh_version(struct ssh_version_receiver *rcv,
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int major_version);
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static void server_connect_bpp(server *srv);
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static void server_bpp_output_raw_data_callback(void *vctx);
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void share_activate(ssh_sharing_state *sharestate,
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const char *server_verstring) {}
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void ssh_connshare_provide_connlayer(ssh_sharing_state *sharestate,
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ConnectionLayer *cl) {}
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int share_ndownstreams(ssh_sharing_state *sharestate) { return 0; }
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void share_got_pkt_from_server(ssh_sharing_connstate *cs, int type,
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const void *vpkt, int pktlen) {}
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void share_setup_x11_channel(ssh_sharing_connstate *cs, share_channel *chan,
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unsigned upstream_id, unsigned server_id,
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unsigned server_currwin, unsigned server_maxpkt,
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unsigned client_adjusted_window,
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const char *peer_addr, int peer_port, int endian,
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int protomajor, int protominor,
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const void *initial_data, int initial_len) {}
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Channel *agentf_new(SshChannel *c) { return NULL; }
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bool agent_exists(void) { return false; }
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void ssh_got_exitcode(Ssh *ssh, int exitcode) {}
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void ssh_check_frozen(Ssh *ssh) {}
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mainchan *mainchan_new(
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PacketProtocolLayer *ppl, ConnectionLayer *cl, Conf *conf,
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int term_width, int term_height, int is_simple, SshChannel **sc_out)
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{ return NULL; }
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void mainchan_get_specials(
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mainchan *mc, add_special_fn_t add_special, void *ctx) {}
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void mainchan_special_cmd(mainchan *mc, SessionSpecialCode code, int arg) {}
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void mainchan_terminal_size(mainchan *mc, int width, int height) {}
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/* Seat functions to ensure we don't get choosy about crypto - as the
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* server, it's not up to us to give user warnings */
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static int server_confirm_weak_crypto_primitive(
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Seat *seat, const char *algtype, const char *algname,
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void (*callback)(void *ctx, int result), void *ctx) { return 1; }
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static int server_confirm_weak_cached_hostkey(
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Seat *seat, const char *algname, const char *betteralgs,
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void (*callback)(void *ctx, int result), void *ctx) { return 1; }
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static const SeatVtable server_seat_vt = {
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nullseat_output,
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nullseat_eof,
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nullseat_get_userpass_input,
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nullseat_notify_remote_exit,
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nullseat_connection_fatal,
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nullseat_update_specials_menu,
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nullseat_get_ttymode,
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nullseat_set_busy_status,
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nullseat_verify_ssh_host_key,
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server_confirm_weak_crypto_primitive,
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server_confirm_weak_cached_hostkey,
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nullseat_is_never_utf8,
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nullseat_echoedit_update,
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nullseat_get_x_display,
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nullseat_get_windowid,
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nullseat_get_window_pixel_size,
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nullseat_stripctrl_new,
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nullseat_set_trust_status,
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};
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static void server_socket_log(Plug *plug, int type, SockAddr *addr, int port,
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const char *error_msg, int error_code)
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{
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/* server *srv = container_of(plug, server, plug); */
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/* FIXME */
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}
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static void server_closing(Plug *plug, const char *error_msg, int error_code,
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bool calling_back)
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{
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server *srv = container_of(plug, server, plug);
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if (error_msg) {
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ssh_remote_error(&srv->ssh, "%s", error_msg);
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} else if (srv->bpp) {
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srv->bpp->input_eof = true;
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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}
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static void server_receive(
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Plug *plug, int urgent, const char *data, size_t len)
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{
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server *srv = container_of(plug, server, plug);
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/* Log raw data, if we're in that mode. */
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if (srv->logctx)
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log_packet(srv->logctx, PKT_INCOMING, -1, NULL, data, len,
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0, NULL, NULL, 0, NULL);
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bufchain_add(&srv->in_raw, data, len);
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if (!srv->frozen && srv->bpp)
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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static void server_sent(Plug *plug, size_t bufsize)
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{
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#ifdef FIXME
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server *srv = container_of(plug, server, plug);
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/*
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* If the send backlog on the SSH socket itself clears, we should
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* unthrottle the whole world if it was throttled. Also trigger an
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* extra call to the consumer of the BPP's output, to try to send
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* some more data off its bufchain.
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*/
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if (bufsize < SSH_MAX_BACKLOG) {
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srv_throttle_all(srv, 0, bufsize);
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queue_idempotent_callback(&srv->ic_out_raw);
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}
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#endif
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}
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LogContext *ssh_get_logctx(Ssh *ssh)
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{
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server *srv = container_of(ssh, server, ssh);
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return srv->logctx;
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}
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void ssh_throttle_conn(Ssh *ssh, int adjust)
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{
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server *srv = container_of(ssh, server, ssh);
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int old_count = srv->conn_throttle_count;
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bool frozen;
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srv->conn_throttle_count += adjust;
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assert(srv->conn_throttle_count >= 0);
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if (srv->conn_throttle_count && !old_count) {
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frozen = true;
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} else if (!srv->conn_throttle_count && old_count) {
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frozen = false;
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} else {
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return; /* don't change current frozen state */
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}
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srv->frozen = frozen;
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if (srv->socket) {
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sk_set_frozen(srv->socket, frozen);
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/*
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* Now process any SSH connection data that was stashed in our
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* queue while we were frozen.
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*/
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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}
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void ssh_conn_processed_data(Ssh *ssh)
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{
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/* FIXME: we could add the same check_frozen_state system as we
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* have in ssh.c, but because that was originally added to work
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* around a peculiarity of the GUI event loop, I haven't yet. */
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}
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Conf *make_ssh_server_conf(void)
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{
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Conf *conf = conf_new();
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load_open_settings(NULL, conf);
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/* In Uppity, we support even the legacy des-cbc cipher by
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* default, so that it will be available if the user forces it by
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* overriding the KEXINIT strings. If the user wants it _not_
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* supported, of course, they can override KEXINIT in the other
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* direction. */
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conf_set_bool(conf, CONF_ssh2_des_cbc, true);
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return conf;
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}
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static const PlugVtable ssh_server_plugvt = {
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server_socket_log,
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server_closing,
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server_receive,
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server_sent,
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NULL
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};
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Plug *ssh_server_plug(
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Conf *conf, const SshServerConfig *ssc,
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ssh_key *const *hostkeys, int nhostkeys,
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RSAKey *hostkey1, AuthPolicy *authpolicy, LogPolicy *logpolicy,
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const SftpServerVtable *sftpserver_vt)
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{
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server *srv = snew(server);
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memset(srv, 0, sizeof(server));
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srv->plug.vt = &ssh_server_plugvt;
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srv->conf = conf_copy(conf);
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srv->ssc = ssc;
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srv->logctx = log_init(logpolicy, conf);
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conf_set_bool(srv->conf, CONF_ssh_no_shell, true);
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srv->nhostkeys = nhostkeys;
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srv->hostkeys = hostkeys;
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srv->hostkey1 = hostkey1;
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srv->authpolicy = authpolicy;
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srv->logpolicy = logpolicy;
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srv->sftpserver_vt = sftpserver_vt;
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srv->seat.vt = &server_seat_vt;
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bufchain_init(&srv->in_raw);
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bufchain_init(&srv->out_raw);
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bufchain_init(&srv->dummy_user_input);
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#ifndef NO_GSSAPI
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/* FIXME: replace with sensible */
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srv->gss_state.libs = snew(struct ssh_gss_liblist);
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srv->gss_state.libs->nlibraries = 0;
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#endif
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return &srv->plug;
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}
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void ssh_server_start(Plug *plug, Socket *socket)
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{
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server *srv = container_of(plug, server, plug);
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const char *our_protoversion;
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if (srv->hostkey1 && srv->nhostkeys) {
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our_protoversion = "1.99"; /* offer both SSH-1 and SSH-2 */
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} else if (srv->hostkey1) {
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our_protoversion = "1.5"; /* SSH-1 only */
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} else {
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assert(srv->nhostkeys);
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our_protoversion = "2.0"; /* SSH-2 only */
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}
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srv->socket = socket;
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srv->ic_out_raw.fn = server_bpp_output_raw_data_callback;
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srv->ic_out_raw.ctx = srv;
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srv->version_receiver.got_ssh_version = server_got_ssh_version;
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srv->bpp = ssh_verstring_new(
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srv->conf, srv->logctx, false /* bare_connection */,
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our_protoversion, &srv->version_receiver,
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true, "Uppity");
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server_connect_bpp(srv);
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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static void ssh_server_free_callback(void *vsrv)
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{
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server *srv = (server *)vsrv;
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logeventf(srv->logctx, "freeing server instance");
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bufchain_clear(&srv->in_raw);
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bufchain_clear(&srv->out_raw);
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bufchain_clear(&srv->dummy_user_input);
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if (srv->socket)
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sk_close(srv->socket);
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if (srv->base_layer)
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ssh_ppl_free(srv->base_layer);
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if (srv->bpp)
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ssh_bpp_free(srv->bpp);
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delete_callbacks_for_context(srv);
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conf_free(srv->conf);
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log_free(srv->logctx);
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#ifndef NO_GSSAPI
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sfree(srv->gss_state.libs); /* FIXME: replace with sensible */
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#endif
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LogPolicy *lp = srv->logpolicy;
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sfree(srv);
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server_instance_terminated(lp);
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}
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static void server_connect_bpp(server *srv)
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{
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srv->bpp->ssh = &srv->ssh;
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srv->bpp->in_raw = &srv->in_raw;
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srv->bpp->out_raw = &srv->out_raw;
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bufchain_set_callback(srv->bpp->out_raw, &srv->ic_out_raw);
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srv->bpp->pls = &srv->pls;
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srv->bpp->logctx = srv->logctx;
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srv->bpp->remote_bugs = srv->remote_bugs;
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/* Servers don't really have a notion of 'unexpected' connection
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* closure. The client is free to close if it likes. */
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srv->bpp->expect_close = true;
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}
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static void server_connect_ppl(server *srv, PacketProtocolLayer *ppl)
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{
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ppl->bpp = srv->bpp;
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ppl->user_input = &srv->dummy_user_input;
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ppl->logctx = srv->logctx;
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ppl->ssh = &srv->ssh;
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ppl->seat = &srv->seat;
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ppl->remote_bugs = srv->remote_bugs;
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}
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static void server_bpp_output_raw_data_callback(void *vctx)
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{
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server *srv = (server *)vctx;
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if (!srv->socket)
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return;
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while (bufchain_size(&srv->out_raw) > 0) {
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size_t backlog;
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ptrlen data = bufchain_prefix(&srv->out_raw);
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if (srv->logctx)
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log_packet(srv->logctx, PKT_OUTGOING, -1, NULL, data.ptr, data.len,
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0, NULL, NULL, 0, NULL);
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backlog = sk_write(srv->socket, data.ptr, data.len);
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bufchain_consume(&srv->out_raw, data.len);
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if (backlog > SSH_MAX_BACKLOG) {
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#ifdef FIXME
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ssh_throttle_all(ssh, 1, backlog);
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#endif
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return;
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}
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}
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if (srv->pending_close) {
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sk_close(srv->socket);
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srv->socket = NULL;
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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}
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static void server_shutdown_internal(server *srv)
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{
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/*
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* We only need to free the base PPL, which will free the others
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* (if any) transitively.
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*/
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if (srv->base_layer) {
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ssh_ppl_free(srv->base_layer);
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srv->base_layer = NULL;
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}
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srv->cl = NULL;
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}
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static void server_initiate_connection_close(server *srv)
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{
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/* Wind up everything above the BPP. */
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server_shutdown_internal(srv);
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/* Force any remaining queued SSH packets through the BPP, and
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* schedule closing the network socket after they go out. */
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ssh_bpp_handle_output(srv->bpp);
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srv->pending_close = true;
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queue_idempotent_callback(&srv->ic_out_raw);
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/* Now we expect the other end to close the connection too in
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* response, so arrange that we'll receive notification of that
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* via ssh_remote_eof. */
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srv->bpp->expect_close = true;
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}
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#define GET_FORMATTED_MSG(fmt) \
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char *msg; \
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va_list ap; \
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va_start(ap, fmt); \
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msg = dupvprintf(fmt, ap); \
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va_end(ap);
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#define LOG_FORMATTED_MSG(logctx, fmt) do \
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{ \
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va_list ap; \
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va_start(ap, fmt); \
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logeventvf(logctx, fmt, ap); \
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va_end(ap); \
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} while (0)
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void ssh_remote_error(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_remote_eof(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_proto_error(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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if (srv->base_layer) {
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GET_FORMATTED_MSG(fmt);
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ssh_bpp_queue_disconnect(srv->bpp, msg,
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SSH2_DISCONNECT_PROTOCOL_ERROR);
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server_initiate_connection_close(srv);
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logeventf(srv->logctx, "Protocol error: %s", msg);
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sfree(msg);
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}
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}
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void ssh_sw_abort(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_user_close(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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static void server_got_ssh_version(struct ssh_version_receiver *rcv,
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int major_version)
|
|
{
|
|
server *srv = container_of(rcv, server, version_receiver);
|
|
BinaryPacketProtocol *old_bpp;
|
|
PacketProtocolLayer *connection_layer;
|
|
|
|
old_bpp = srv->bpp;
|
|
srv->remote_bugs = ssh_verstring_get_bugs(old_bpp);
|
|
|
|
if (major_version == 2) {
|
|
PacketProtocolLayer *userauth_layer, *transport_child_layer;
|
|
|
|
srv->bpp = ssh2_bpp_new(srv->logctx, &srv->stats, true);
|
|
server_connect_bpp(srv);
|
|
|
|
connection_layer = ssh2_connection_new(
|
|
&srv->ssh, NULL, false, srv->conf,
|
|
ssh_verstring_get_local(old_bpp), &srv->cl);
|
|
ssh2connection_server_configure(connection_layer,
|
|
srv->sftpserver_vt, srv->ssc);
|
|
server_connect_ppl(srv, connection_layer);
|
|
|
|
if (conf_get_bool(srv->conf, CONF_ssh_no_userauth)) {
|
|
userauth_layer = NULL;
|
|
transport_child_layer = connection_layer;
|
|
} else {
|
|
userauth_layer = ssh2_userauth_server_new(
|
|
connection_layer, srv->authpolicy, srv->ssc);
|
|
server_connect_ppl(srv, userauth_layer);
|
|
transport_child_layer = userauth_layer;
|
|
}
|
|
|
|
srv->base_layer = ssh2_transport_new(
|
|
srv->conf, NULL, 0, NULL,
|
|
ssh_verstring_get_remote(old_bpp),
|
|
ssh_verstring_get_local(old_bpp),
|
|
#ifndef NO_GSSAPI
|
|
&srv->gss_state,
|
|
#else
|
|
NULL,
|
|
#endif
|
|
&srv->stats, transport_child_layer, srv->ssc);
|
|
ssh2_transport_provide_hostkeys(
|
|
srv->base_layer, srv->hostkeys, srv->nhostkeys);
|
|
if (userauth_layer)
|
|
ssh2_userauth_server_set_transport_layer(
|
|
userauth_layer, srv->base_layer);
|
|
server_connect_ppl(srv, srv->base_layer);
|
|
|
|
} else {
|
|
srv->bpp = ssh1_bpp_new(srv->logctx);
|
|
server_connect_bpp(srv);
|
|
|
|
connection_layer = ssh1_connection_new(&srv->ssh, srv->conf, &srv->cl);
|
|
ssh1connection_server_configure(connection_layer, srv->ssc);
|
|
server_connect_ppl(srv, connection_layer);
|
|
|
|
srv->base_layer = ssh1_login_server_new(
|
|
connection_layer, srv->hostkey1, srv->authpolicy, srv->ssc);
|
|
server_connect_ppl(srv, srv->base_layer);
|
|
}
|
|
|
|
/* Connect the base layer - whichever it is - to the BPP, and set
|
|
* up its selfptr. */
|
|
srv->base_layer->selfptr = &srv->base_layer;
|
|
ssh_ppl_setup_queues(srv->base_layer, &srv->bpp->in_pq, &srv->bpp->out_pq);
|
|
|
|
#ifdef FIXME // we probably will want one of these, in the end
|
|
srv->pinger = pinger_new(srv->conf, &srv->backend);
|
|
#endif
|
|
|
|
queue_idempotent_callback(&srv->bpp->ic_in_raw);
|
|
ssh_ppl_process_queue(srv->base_layer);
|
|
|
|
ssh_bpp_free(old_bpp);
|
|
}
|