]> asedeno.scripts.mit.edu Git - PuTTY.git/blobdiff - ssh.c
Fix typo in comment.
[PuTTY.git] / ssh.c
diff --git a/ssh.c b/ssh.c
index 5d6514b5ae7829509c8001f435517d1e44061c6f..da43bf0227d6aa3aff2f18ad8c8e2360075e9a8c 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -364,6 +364,7 @@ static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
                             struct Packet *pktin);
 static void ssh2_channel_check_close(struct ssh_channel *c);
 static void ssh_channel_destroy(struct ssh_channel *c);
+static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin);
 
 /*
  * Buffer management constants. There are several of these for
@@ -791,6 +792,7 @@ struct ssh_tag {
     int send_ok;
     int echoing, editing;
 
+    int session_started;
     void *frontend;
 
     int ospeed, ispeed;                       /* temporaries */
@@ -1834,6 +1836,15 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
        }
     }
 
+    /*
+     * RFC 4253 doesn't explicitly say that completely empty packets
+     * with no type byte are forbidden, so treat them as deserving
+     * an SSH_MSG_UNIMPLEMENTED.
+     */
+    if (st->pktin->length <= 5) { /* == 5 we hope, but robustness */
+        ssh2_msg_something_unimplemented(ssh, st->pktin);
+        crStop(NULL);
+    }
     /*
      * pktin->body and pktin->length should identify the semantic
      * content of the packet, excluding the initial type byte.
@@ -3007,6 +3018,10 @@ static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
     }
 
     ssh_fix_verstring(verstring + strlen(protoname));
+#ifdef FUZZING
+    /* FUZZING make PuTTY insecure, so make live use difficult. */
+    verstring[0] = 'I';
+#endif
 
     if (ssh->version == 2) {
        size_t len;
@@ -3056,6 +3071,8 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        crReturn(1);
     }
 
+    ssh->session_started = TRUE;
+
     s->vstrsize = sizeof(protoname) + 16;
     s->vstring = snewn(s->vstrsize, char);
     strcpy(s->vstring, protoname);
@@ -3438,34 +3455,20 @@ static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
                            const char *error_msg, int error_code)
 {
     Ssh ssh = (Ssh) plug;
-    char addrbuf[256], *msg;
 
-    if (ssh->attempting_connshare) {
-        /*
-         * While we're attempting connection sharing, don't loudly log
-         * everything that happens. Real TCP connections need to be
-         * logged when we _start_ trying to connect, because it might
-         * be ages before they respond if something goes wrong; but
-         * connection sharing is local and quick to respond, and it's
-         * sufficient to simply wait and see whether it worked
-         * afterwards.
-         */
-    } else {
-        sk_getaddr(addr, addrbuf, lenof(addrbuf));
-
-        if (type == 0) {
-            if (sk_addr_needs_port(addr)) {
-                msg = dupprintf("Connecting to %s port %d", addrbuf, port);
-            } else {
-                msg = dupprintf("Connecting to %s", addrbuf);
-            }
-        } else {
-            msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
-        }
+    /*
+     * While we're attempting connection sharing, don't loudly log
+     * everything that happens. Real TCP connections need to be logged
+     * when we _start_ trying to connect, because it might be ages
+     * before they respond if something goes wrong; but connection
+     * sharing is local and quick to respond, and it's sufficient to
+     * simply wait and see whether it worked afterwards.
+     */
 
-        logevent(msg);
-        sfree(msg);
-    }
+    if (!ssh->attempting_connshare)
+        backend_socket_log(ssh->frontend, type, addr, port,
+                           error_msg, error_code, ssh->conf,
+                           ssh->session_started);
 }
 
 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
@@ -3660,10 +3663,8 @@ static const char *connect_to_host(Ssh ssh, const char *host, int port,
          * Try to find host.
          */
         addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
-        logeventf(ssh, "Looking up host \"%s\"%s", host,
-                  (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
-                   (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
-        addr = name_lookup(host, port, realhost, ssh->conf, addressfamily);
+        addr = name_lookup(host, port, realhost, ssh->conf, addressfamily,
+                           ssh->frontend, "SSH connection");
         if ((err = sk_addr_error(addr)) != NULL) {
             sk_addr_free(addr);
             return err;
@@ -4040,6 +4041,9 @@ static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
                                             "rsa", keystr, fingerprint,
                                             ssh_dialog_callback, ssh);
             sfree(keystr);
+#ifdef FUZZING
+           s->dlgret = 1;
+#endif
             if (s->dlgret < 0) {
                 do {
                     crReturn(0);
@@ -5558,7 +5562,7 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
     ssh_pkt_getstring(pktin, &host, &hostsize);
     port = ssh_pkt_getuint32(pktin);
 
-    pf.dhost = dupprintf("%.*s", hostsize, host);
+    pf.dhost = dupprintf("%.*s", hostsize, NULLTOEMPTY(host));
     pf.dport = port;
     pfp = find234(ssh->rportfwds, &pf, NULL);
 
@@ -6041,7 +6045,7 @@ static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
     int msglen;
 
     ssh_pkt_getstring(pktin, &msg, &msglen);
-    logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
+    logeventf(ssh, "Remote debug message: %.*s", msglen, NULLTOEMPTY(msg));
 }
 
 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
@@ -6051,7 +6055,8 @@ static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
     int msglen;
 
     ssh_pkt_getstring(pktin, &msg, &msglen);
-    bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
+    bombout(("Server sent disconnect message:\n\"%.*s\"",
+             msglen, NULLTOEMPTY(msg)));
 }
 
 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
@@ -6477,6 +6482,11 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
        /* List encryption algorithms (client->server then server->client). */
        for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
            warn = FALSE;
+#ifdef FUZZING
+           alg = ssh2_kexinit_addalg(s->kexlists[k], "none");
+           alg->u.cipher.cipher = NULL;
+           alg->u.cipher.warn = warn;
+#endif /* FUZZING */
            for (i = 0; i < s->n_preferred_ciphers; i++) {
                const struct ssh2_ciphers *c = s->preferred_ciphers[i];
                if (!c) warn = TRUE;
@@ -6490,6 +6500,11 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
        }
        /* List MAC algorithms (client->server then server->client). */
        for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
+#ifdef FUZZING
+           alg = ssh2_kexinit_addalg(s->kexlists[j], "none");
+           alg->u.mac.mac = NULL;
+           alg->u.mac.etm = FALSE;
+#endif /* FUZZING */
            for (i = 0; i < s->nmacs; i++) {
                alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
                alg->u.mac.mac = s->maclist[i];
@@ -6762,8 +6777,8 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
         {
             int csbits, scbits;
 
-            csbits = s->cscipher_tobe->real_keybits;
-            scbits = s->sccipher_tobe->real_keybits;
+            csbits = s->cscipher_tobe ? s->cscipher_tobe->real_keybits : 0;
+            scbits = s->sccipher_tobe ? s->sccipher_tobe->real_keybits : 0;
             s->nbits = (csbits > scbits ? csbits : scbits);
         }
         /* The keys only have hlen-bit entropy, since they're based on
@@ -7099,12 +7114,18 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
     dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
 #endif
 
-    if (!s->hkey ||
-       !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
+    if (!s->hkey) {
+       bombout(("Server's host key is invalid"));
+       crStopV;
+    }
+
+    if (!ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
                                 (char *)s->exchange_hash,
                                 ssh->kex->hash->hlen)) {
+#ifndef FUZZING
        bombout(("Server's host key did not match the signature supplied"));
        crStopV;
+#endif
     }
 
     s->keystr = ssh->hostkey->fmtkey(s->hkey);
@@ -7129,6 +7150,9 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
                                             ssh->hostkey->keytype, s->keystr,
                                             s->fingerprint,
                                             ssh_dialog_callback, ssh);
+#ifdef FUZZING
+           s->dlgret = 1;
+#endif
             if (s->dlgret < 0) {
                 do {
                     crReturnV;
@@ -7161,8 +7185,10 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
          * the one we saw before.
          */
         if (strcmp(ssh->hostkey_str, s->keystr)) {
+#ifndef FUZZING
             bombout(("Host key was different in repeat key exchange"));
             crStopV;
+#endif
         }
         sfree(s->keystr);
     }
@@ -7196,13 +7222,14 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
     if (ssh->cs_cipher_ctx)
        ssh->cscipher->free_context(ssh->cs_cipher_ctx);
     ssh->cscipher = s->cscipher_tobe;
-    ssh->cs_cipher_ctx = ssh->cscipher->make_context();
+    if (ssh->cscipher) ssh->cs_cipher_ctx = ssh->cscipher->make_context();
 
     if (ssh->cs_mac_ctx)
        ssh->csmac->free_context(ssh->cs_mac_ctx);
     ssh->csmac = s->csmac_tobe;
     ssh->csmac_etm = s->csmac_etm_tobe;
-    ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
+    if (ssh->csmac)
+        ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
 
     if (ssh->cs_comp_ctx)
        ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
@@ -7213,7 +7240,7 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
      * Set IVs on client-to-server keys. Here we use the exchange
      * hash from the _first_ key exchange.
      */
-    {
+    if (ssh->cscipher) {
        unsigned char *key;
 
        key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
@@ -7227,6 +7254,9 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
        ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
         smemclr(key, ssh->cscipher->blksize);
         sfree(key);
+    }
+    if (ssh->csmac) {
+       unsigned char *key;
 
        key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
                          ssh->csmac->keylen);
@@ -7235,12 +7265,14 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
         sfree(key);
     }
 
-    logeventf(ssh, "Initialised %.200s client->server encryption",
-             ssh->cscipher->text_name);
-    logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
-             ssh->csmac->text_name,
-              ssh->csmac_etm ? " (in ETM mode)" : "",
-              ssh->cscipher->required_mac ? " (required by cipher)" : "");
+    if (ssh->cscipher)
+       logeventf(ssh, "Initialised %.200s client->server encryption",
+                 ssh->cscipher->text_name);
+    if (ssh->csmac)
+       logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
+                 ssh->csmac->text_name,
+                 ssh->csmac_etm ? " (in ETM mode)" : "",
+                 ssh->cscipher->required_mac ? " (required by cipher)" : "");
     if (ssh->cscomp->text_name)
        logeventf(ssh, "Initialised %s compression",
                  ssh->cscomp->text_name);
@@ -7268,14 +7300,18 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
      */
     if (ssh->sc_cipher_ctx)
        ssh->sccipher->free_context(ssh->sc_cipher_ctx);
-    ssh->sccipher = s->sccipher_tobe;
-    ssh->sc_cipher_ctx = ssh->sccipher->make_context();
+    if (s->sccipher_tobe) {
+       ssh->sccipher = s->sccipher_tobe;
+       ssh->sc_cipher_ctx = ssh->sccipher->make_context();
+    }
 
     if (ssh->sc_mac_ctx)
        ssh->scmac->free_context(ssh->sc_mac_ctx);
-    ssh->scmac = s->scmac_tobe;
-    ssh->scmac_etm = s->scmac_etm_tobe;
-    ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
+    if (s->scmac_tobe) {
+       ssh->scmac = s->scmac_tobe;
+       ssh->scmac_etm = s->scmac_etm_tobe;
+       ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
+    }
 
     if (ssh->sc_comp_ctx)
        ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
@@ -7286,7 +7322,7 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
      * Set IVs on server-to-client keys. Here we use the exchange
      * hash from the _first_ key exchange.
      */
-    {
+    if (ssh->sccipher) {
        unsigned char *key;
 
        key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
@@ -7300,6 +7336,9 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
        ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
         smemclr(key, ssh->sccipher->blksize);
         sfree(key);
+    }
+    if (ssh->scmac) {
+       unsigned char *key;
 
        key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
                          ssh->scmac->keylen);
@@ -7307,12 +7346,14 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
         smemclr(key, ssh->scmac->keylen);
         sfree(key);
     }
-    logeventf(ssh, "Initialised %.200s server->client encryption",
-             ssh->sccipher->text_name);
-    logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
-             ssh->scmac->text_name,
-              ssh->scmac_etm ? " (in ETM mode)" : "",
-              ssh->sccipher->required_mac ? " (required by cipher)" : "");
+    if (ssh->sccipher)
+       logeventf(ssh, "Initialised %.200s server->client encryption",
+                 ssh->sccipher->text_name);
+    if (ssh->scmac)
+       logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
+                 ssh->scmac->text_name,
+                 ssh->scmac_etm ? " (in ETM mode)" : "",
+                 ssh->sccipher->required_mac ? " (required by cipher)" : "");
     if (ssh->sccomp->text_name)
        logeventf(ssh, "Initialised %s decompression",
                  ssh->sccomp->text_name);
@@ -8224,7 +8265,8 @@ static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
             reason_code = 0; /* ensure reasons[reason_code] in range */
         ssh_pkt_getstring(pktin, &reason_string, &reason_length);
         logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
-                  reasons[reason_code], reason_length, reason_string);
+                  reasons[reason_code], reason_length,
+                  NULLTOEMPTY(reason_string));
 
         pfd_close(c->u.pfd.pf);
     } else if (c->type == CHAN_ZOMBIE) {
@@ -8520,9 +8562,7 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
        char *addrstr;
 
        ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
-       addrstr = snewn(peeraddrlen+1, char);
-       memcpy(addrstr, peeraddr, peeraddrlen);
-       addrstr[peeraddrlen] = '\0';
+       addrstr = dupprintf("%.*s", peeraddrlen, NULLTOEMPTY(peeraddr));
        peerport = ssh_pkt_getuint32(pktin);
 
        logeventf(ssh, "Received X11 connect request from %s:%d",
@@ -8557,13 +8597,14 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
        char *shost;
        int shostlen;
        ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
-        pf.shost = dupprintf("%.*s", shostlen, shost);
+        pf.shost = dupprintf("%.*s", shostlen, NULLTOEMPTY(shost));
        pf.sport = ssh_pkt_getuint32(pktin);
        ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
        peerport = ssh_pkt_getuint32(pktin);
        realpf = find234(ssh->rportfwds, &pf, NULL);
        logeventf(ssh, "Received remote port %s:%d open request "
-                 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
+                 "from %.*s:%d", pf.shost, pf.sport,
+                  peeraddrlen, NULLTOEMPTY(peeraddr), peerport);
         sfree(pf.shost);
 
        if (realpf == NULL) {
@@ -10227,7 +10268,7 @@ static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
                    s->cur_prompt->to_server = TRUE;
                    s->cur_prompt->name = dupstr("New SSH password");
                    s->cur_prompt->instruction =
-                       dupprintf("%.*s", prompt_len, prompt);
+                       dupprintf("%.*s", prompt_len, NULLTOEMPTY(prompt));
                    s->cur_prompt->instr_reqd = TRUE;
                    /*
                     * There's no explicit requirement in the protocol
@@ -10665,13 +10706,13 @@ static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
     logevent(buf);
     sfree(buf);
     buf = dupprintf("Disconnection message text: %.*s",
-                   msglen, msg);
+                   msglen, NULLTOEMPTY(msg));
     logevent(buf);
     bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
             reason,
             (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
             ssh2_disconnect_reasons[reason] : "unknown",
-            msglen, msg));
+            msglen, NULLTOEMPTY(msg)));
     sfree(buf);
 }
 
@@ -10685,7 +10726,7 @@ static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
     ssh2_pkt_getbool(pktin);
     ssh_pkt_getstring(pktin, &msg, &msglen);
 
-    logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
+    logeventf(ssh, "Remote debug message: %.*s", msglen, NULLTOEMPTY(msg));
 }
 
 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
@@ -10962,6 +11003,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->X11_fwd_enabled = FALSE;
     ssh->connshare = NULL;
     ssh->attempting_connshare = FALSE;
+    ssh->session_started = FALSE;
 
     *backend_handle = ssh;