1 files changed, 43 insertions, 11 deletions

diff --git a/sshconnect.c b/sshconnect.c
index 11008e544..5158416f0 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -50,6 +50,13 @@ extern pid_t proxy_command_pid;
 #define INET6_ADDRSTRLEN 46
 #endif
 
+static sig_atomic_t banner_timedout;
+
+static void banner_alarm_catch (int signum)
+{
+        banner_timedout = 1;
+}
+
 static int show_other_keys(const char *, Key *);
 static void warn_changed_key(Key *);
 
@@ -157,7 +164,7 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
         buffer_free(&command);
 
         /* Set the connection file descriptors. */
-        packet_set_connection(pout[0], pin[1]);
+        packet_set_connection(pout[0], pin[1], options.setuptimeout);
 
         /* Indicate OK return */
         return 0;
@@ -422,7 +429,7 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
                 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
 
         /* Set the connection. */
-        packet_set_connection(sock, sock);
+        packet_set_connection(sock, sock, options.setuptimeout);
 
         return 0;
 }
@@ -439,24 +446,41 @@ ssh_exchange_identification(void)
         int connection_in = packet_get_connection_in();
         int connection_out = packet_get_connection_out();
         int minor1 = PROTOCOL_MINOR_1;
+        struct sigaction sa, osa;
 
-        /* Read other side\'s version identification. */
+        /* Read other side's version identification.
+         * If SetupTimeOut has been set, give up after
+         * the specified amount of time
+         */
+        if(options.setuptimeout > 0){
+                memset(&sa, 0, sizeof(sa));
+                sa.sa_handler = banner_alarm_catch;
+                /*throw away any pending alarms, since we'd block otherwise*/
+                alarm(0);
+                sigaction(SIGALRM, &sa, &osa);
+                alarm(options.setuptimeout);
+        }
         for (;;) {
-                for (i = 0; i < sizeof(buf) - 1; i++) {
-                        int len = atomicio(read, connection_in, &buf[i], 1);
-                        if (len < 0)
+                for (i = 0; i < sizeof(buf) - 1; ) {
+                        int len = read(connection_in, &buf[i], 1);
+                        if (banner_timedout)
+                                fatal("ssh_exchange_identification: Timeout waiting for version information.");
+                        if (len < 0) {
+                                if (errno == EINTR)
+                                        continue;
                                 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
+                        }
                         if (len != 1)
                                 fatal("ssh_exchange_identification: Connection closed by remote host");
-                        if (buf[i] == '\r') {
-                                buf[i] = '\n';
-                                buf[i + 1] = 0;
-                                continue;               /**XXX wait for \n */
-                        }
                         if (buf[i] == '\n') {
                                 buf[i + 1] = 0;
                                 break;
                         }
+                        if (buf[i] == '\r') {
+                                buf[i] = '\n';
+                                buf[i + 1] = 0;         /**XXX wait for \n */
+                        }
+                        i++;
                 }
                 buf[sizeof(buf) - 1] = 0;
                 if (strncmp(buf, "SSH-", 4) == 0)
@@ -465,6 +489,14 @@ ssh_exchange_identification(void)
         }
         server_version_string = xstrdup(buf);
 
+        /* If SetupTimeOut has been set, unset the alarm now, and
+         * put the correct handler for SIGALRM back.
+         */
+        if (options.setuptimeout > 0) {
+                alarm(0);
+                sigaction(SIGALRM,&osa,NULL);
+        }
+
         /*
          * Check that the versions match.  In future this might accept
          * several versions and set appropriate flags to handle them.