X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=ssh.c;h=1f8a214b6a07e165872d4e83cfecd8af7517ac21;hb=5471539a6738484b48fb938c88dce547a3e4b299;hp=4979268f130b9c05a0d972306ec86cec869ac726;hpb=43be90e287996e1be6f92f5a426475df25c16e10;p=PuTTY.git

diff --git a/ssh.c b/ssh.c
index 4979268f..1f8a214b 100644
--- 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
@@ -1834,6 +1835,15 @@ 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.
@@ -3549,35 +3559,20 @@ static void ssh_sent(Plug plug, int bufsize)
 	ssh_throttle_all(ssh, 0, bufsize);
 }
 
-/*
- * Connect to specified host and port.
- * Returns an error message, or NULL on success.
- * Also places the canonical host name into `realhost'. It must be
- * freed by the caller.
- */
-static const char *connect_to_host(Ssh ssh, const char *host, int port,
-				   char **realhost, int nodelay, int keepalive)
+static void ssh_hostport_setup(const char *host, int port, Conf *conf,
+                               char **savedhost, int *savedport,
+                               char **loghost_ret)
 {
-    static const struct plug_function_table fn_table = {
-	ssh_socket_log,
-	ssh_closing,
-	ssh_receive,
-	ssh_sent,
-	NULL
-    };
+    char *loghost = conf_get_str(conf, CONF_loghost);
+    if (loghost_ret)
+        *loghost_ret = loghost;
 
-    SockAddr addr;
-    const char *err;
-    char *loghost;
-    int addressfamily, sshprot;
-    
-    loghost = conf_get_str(ssh->conf, CONF_loghost);
     if (*loghost) {
 	char *tmphost;
         char *colon;
 
         tmphost = dupstr(loghost);
-	ssh->savedport = 22;	       /* default ssh port */
+	*savedport = 22;	       /* default ssh port */
 
 	/*
 	 * A colon suffix on the hostname string also lets us affect
@@ -3588,17 +3583,58 @@ static const char *connect_to_host(Ssh ssh, const char *host, int port,
 	if (colon && colon == host_strchr(tmphost, ':')) {
 	    *colon++ = '\0';
 	    if (*colon)
-		ssh->savedport = atoi(colon);
+		*savedport = atoi(colon);
 	}
 
-        ssh->savedhost = host_strduptrim(tmphost);
+        *savedhost = host_strduptrim(tmphost);
         sfree(tmphost);
     } else {
-	ssh->savedhost = host_strduptrim(host);
+	*savedhost = host_strduptrim(host);
 	if (port < 0)
 	    port = 22;		       /* default ssh port */
-	ssh->savedport = port;
+	*savedport = port;
     }
+}
+
+static int ssh_test_for_upstream(const char *host, int port, Conf *conf)
+{
+    char *savedhost;
+    int savedport;
+    int ret;
+
+    random_ref(); /* platform may need this to determine share socket name */
+    ssh_hostport_setup(host, port, conf, &savedhost, &savedport, NULL);
+    ret = ssh_share_test_for_upstream(savedhost, savedport, conf);
+    sfree(savedhost);
+    random_unref();
+
+    return ret;
+}
+
+/*
+ * Connect to specified host and port.
+ * Returns an error message, or NULL on success.
+ * Also places the canonical host name into `realhost'. It must be
+ * freed by the caller.
+ */
+static const char *connect_to_host(Ssh ssh, const char *host, int port,
+				   char **realhost, int nodelay, int keepalive)
+{
+    static const struct plug_function_table fn_table = {
+	ssh_socket_log,
+	ssh_closing,
+	ssh_receive,
+	ssh_sent,
+	NULL
+    };
+
+    SockAddr addr;
+    const char *err;
+    char *loghost;
+    int addressfamily, sshprot;
+
+    ssh_hostport_setup(host, port, ssh->conf,
+                       &ssh->savedhost, &ssh->savedport, &loghost);
 
     ssh->fn = &fn_table;               /* make 'ssh' usable as a Plug */
 
@@ -6568,6 +6604,24 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
 		bombout(("KEXINIT packet was incomplete"));
 		crStopV;
 	    }
+
+            /* If we've already selected a cipher which requires a
+             * particular MAC, then just select that, and don't even
+             * bother looking through the server's KEXINIT string for
+             * MACs. */
+            if (i == KEXLIST_CSMAC && s->cscipher_tobe &&
+                s->cscipher_tobe->required_mac) {
+                s->csmac_tobe = s->cscipher_tobe->required_mac;
+                s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
+                goto matched;
+            }
+            if (i == KEXLIST_SCMAC && s->sccipher_tobe &&
+                s->sccipher_tobe->required_mac) {
+                s->scmac_tobe = s->sccipher_tobe->required_mac;
+                s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
+                goto matched;
+            }
+
 	    for (j = 0; j < MAXKEXLIST; j++) {
 		struct kexinit_algorithm *alg = &s->kexlists[i][j];
 		if (alg->name == NULL) break;
@@ -6613,16 +6667,6 @@ static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
 	  matched:;
 	}
 
-        /* If the cipher over-rides the mac, then pick it */
-        if (s->cscipher_tobe && s->cscipher_tobe->required_mac) {
-            s->csmac_tobe = s->cscipher_tobe->required_mac;
-	    s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
-        }
-        if (s->sccipher_tobe && s->sccipher_tobe->required_mac) {
-            s->scmac_tobe = s->sccipher_tobe->required_mac;
-	    s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
-        }
-
 	if (s->pending_compression) {
 	    logevent("Server supports delayed compression; "
 		     "will try this later");
@@ -11626,6 +11670,7 @@ Backend ssh_backend = {
     ssh_provide_logctx,
     ssh_unthrottle,
     ssh_cfg_info,
+    ssh_test_for_upstream,
     "ssh",
     PROT_SSH,
     22