X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/blobdiff_plain/4ed34d251770cb8dd7f13217976d1dec9452b5e6..babac7bd70fda1ec0c9810c8f4ccf08cfa1e31fb:/ssh.c diff --git a/ssh.c b/ssh.c index 119cd4fe..9f27e3a9 100644 --- a/ssh.c +++ b/ssh.c @@ -235,18 +235,6 @@ extern void pfd_override_throttle(Socket s, int enable); #define SSH_MAX_BACKLOG 32768 #define OUR_V2_WINSIZE 16384 -/* - * Ciphers for SSH2. We miss out single-DES because it isn't - * supported; also 3DES and Blowfish are both done differently from - * SSH1. (3DES uses outer chaining; Blowfish has the opposite - * endianness and different-sized keys.) - */ -const static struct ssh2_ciphers *ciphers[] = { - &ssh2_aes, - &ssh2_blowfish, - &ssh2_3des, -}; - const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman_gex, &ssh_diffiehellman @@ -1659,7 +1647,7 @@ static void ssh_sent(Plug plug, int bufsize) * Also places the canonical host name into `realhost'. It must be * freed by the caller. */ -static char *connect_to_host(char *host, int port, char **realhost) +static char *connect_to_host(char *host, int port, char **realhost, int nodelay) { static struct plug_function_table fn_table = { ssh_closing, @@ -1716,7 +1704,7 @@ static char *connect_to_host(char *host, int port, char **realhost) sprintf(buf, "Connecting to %.100s port %d", addrbuf, port); logevent(buf); } - s = sk_new(addr, port, 0, 1, &fn_table_ptr); + s = sk_new(addr, port, 0, 1, nodelay, &fn_table_ptr); if ((err = sk_socket_error(s))) return err; @@ -2912,6 +2900,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) if (c && c->type == CHAN_SOCKDATA_DORMANT) { c->remoteid = localid; c->type = CHAN_SOCKDATA; + c->v.v1.throttling = 0; pfd_confirm(c->u.pfd.s); } @@ -3154,6 +3143,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) static int n_preferred_ciphers; static const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX]; static const struct ssh_compress *preferred_comp; + static int cipherstr_started; static int first_kex; crBegin; @@ -3171,7 +3161,10 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) n_preferred_ciphers++; break; case CIPHER_DES: - /* Not supported in SSH2; silently drop */ + if (cfg.ssh2_des_cbc) { + preferred_ciphers[n_preferred_ciphers] = &ssh2_des; + n_preferred_ciphers++; + } break; case CIPHER_3DES: preferred_ciphers[n_preferred_ciphers] = &ssh2_3des; @@ -3231,24 +3224,28 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) } /* List client->server encryption algorithms. */ ssh2_pkt_addstring_start(); + cipherstr_started = 0; for (i = 0; i < n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = preferred_ciphers[i]; if (!c) continue; /* warning flag */ for (j = 0; j < c->nciphers; j++) { - ssh2_pkt_addstring_str(c->list[j]->name); - if (i < n_preferred_ciphers || j < c->nciphers - 1) + if (cipherstr_started) ssh2_pkt_addstring_str(","); + ssh2_pkt_addstring_str(c->list[j]->name); + cipherstr_started = 1; } } /* List server->client encryption algorithms. */ ssh2_pkt_addstring_start(); + cipherstr_started = 0; for (i = 0; i < n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = preferred_ciphers[i]; if (!c) continue; /* warning flag */ for (j = 0; j < c->nciphers; j++) { - ssh2_pkt_addstring_str(c->list[j]->name); - if (i < n_preferred_ciphers || j < c->nciphers - 1) + if (cipherstr_started) ssh2_pkt_addstring_str(","); + ssh2_pkt_addstring_str(c->list[j]->name); + cipherstr_started = 1; } } /* List client->server MAC algorithms. */ @@ -3352,6 +3349,11 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) break; } } + if (!cscipher_tobe) { + bombout(("Couldn't agree a client-to-server cipher (available: %s)", str)); + crReturn(0); + } + ssh2_pkt_getstring(&str, &len); /* server->client cipher */ warn = 0; for (i = 0; i < n_preferred_ciphers; i++) { @@ -3372,6 +3374,11 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) break; } } + if (!sccipher_tobe) { + bombout(("Couldn't agree a server-to-client cipher (available: %s)", str)); + crReturn(0); + } + ssh2_pkt_getstring(&str, &len); /* client->server mac */ for (i = 0; i < nmacs; i++) { if (in_commasep_string(maclist[i]->name, str, len)) { @@ -3499,15 +3506,6 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) } /* - * 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.) */ @@ -3530,6 +3528,15 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) ssh2_pkt_send(); /* + * Expect SSH2_MSG_NEWKEYS from server. + */ + crWaitUntil(ispkt); + if (pktin.type != SSH2_MSG_NEWKEYS) { + bombout(("expected new-keys packet from server")); + crReturn(0); + } + + /* * Create and initialise session keys. */ cscipher = cscipher_tobe; @@ -3705,6 +3712,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) * the username they will want to be able to get back and * retype it! */ + username[0] = '\0'; do { static int pos; static char c; @@ -3713,7 +3721,13 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) * Get a username. */ pos = 0; - if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { + if (*username && !cfg.change_username) { + /* + * We got a username last time round this loop, and + * with change_username turned off we don't try to get + * it again. + */ + } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { if (ssh_get_line) { if (!ssh_get_line("login as: ", username, sizeof(username), FALSE)) { @@ -3900,7 +3914,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) in_commasep_string("publickey", methods, methlen); can_passwd = in_commasep_string("password", methods, methlen); - can_keyb_inter = + can_keyb_inter = cfg.try_ki_auth && in_commasep_string("keyboard-interactive", methods, methlen); } @@ -4145,6 +4159,8 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_getstring(&prompt, &prompt_len); strncpy(pwprompt, prompt, sizeof(pwprompt)); + pwprompt[prompt_len < sizeof(pwprompt) ? + prompt_len : sizeof(pwprompt)-1] = '\0'; need_pw = TRUE; echo = ssh2_pkt_getbool(); @@ -4796,8 +4812,6 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) 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; @@ -4857,12 +4871,25 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) * See if that was the last channel left open. */ if (count234(ssh_channels) == 0) { +#if 0 + /* + * We used to send SSH_MSG_DISCONNECT here, + * because I'd believed that _every_ conforming + * SSH2 connection had to end with a disconnect + * being sent by at least one side; apparently + * I was wrong and it's perfectly OK to + * unceremoniously slam the connection shut + * when you're done, and indeed OpenSSH feels + * this is more polite than sending a + * DISCONNECT. So now we don't. + */ 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(); +#endif ssh_state = SSH_STATE_CLOSED; crReturnV; } @@ -4916,6 +4943,46 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) del234(ssh_channels, c); sfree(c); + } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { + unsigned localid; + char *type; + int typelen, want_reply; + struct ssh_channel *c; + + localid = ssh2_pkt_getuint32(); + ssh2_pkt_getstring(&type, &typelen); + want_reply = ssh2_pkt_getbool(); + + /* + * First, check that the channel exists. Otherwise, + * we can instantly disconnect with a rude message. + */ + c = find234(ssh_channels, &localid, ssh_channelfind); + if (!c) { + char buf[80]; + sprintf(buf, "Received channel request for nonexistent" + " channel %d", localid); + logevent(buf); + ssh2_pkt_init(SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(buf); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); + connection_fatal(buf); + ssh_state = SSH_STATE_CLOSED; + crReturnV; + } + + /* + * We don't recognise any form of channel request, + * so we now either ignore the request or respond + * with CHANNEL_FAILURE, depending on want_reply. + */ + if (want_reply) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_FAILURE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) { char *type; int typelen; @@ -5059,7 +5126,7 @@ static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) * * Returns an error message, or NULL on success. */ -static char *ssh_init(char *host, int port, char **realhost) +static char *ssh_init(char *host, int port, char **realhost, int nodelay) { char *p; @@ -5075,7 +5142,7 @@ static char *ssh_init(char *host, int port, char **realhost) ssh_overall_bufsize = 0; ssh_fallback_cmd = 0; - p = connect_to_host(host, port, realhost); + p = connect_to_host(host, port, realhost, nodelay); if (p != NULL) return p;