GUACAMOLE-203: Deal correctly with negative keepalive values.

src/common-ssh/ssh.c

@@ -532,16 +532,20 @@ guac_common_ssh_session* guac_common_ssh_create_session(guac_client* client,
         return NULL;
     }
 
-    /* Configure session keepalive */
-    if (keepalive > 0)
-        libssh2_keepalive_config(common_session->session, 1, keepalive);
-
     /* Warn if keepalive below minimum value */
-    if (keepalive == 1) {
+    if (keepalive < 0) {
+        keepalive = 0;
+        guac_client_log(client, GUAC_LOG_WARNING, "negative keepalive intervals "
+            "are converted to 0, disabling keepalive.");
+    }
+    else if(keepalive == 1) {
         guac_client_log(client, GUAC_LOG_WARNING, "keepalive interval will "
             "be rounded up to minimum value of 2.");
     }
 
+    /* Configure session keepalive */
+    libssh2_keepalive_config(common_session->session, 1, keepalive);
+
     /* Return created session */
     return common_session;
 

src/protocols/rdp/rdp_settings.h

@@ -366,7 +366,7 @@ typedef struct guac_rdp_settings {
      * of 1 is automatically increased to 2 by libssh2 to avoid busy loop corner
      * cases.
      */
-    unsigned sftp_server_alive_interval;
+    int sftp_server_alive_interval;
 #endif
 
     /**

src/protocols/ssh/settings.h

@@ -189,7 +189,7 @@ typedef struct guac_ssh_settings {
     /**
      * The number of seconds between sending server alive messages.
      */
-    unsigned server_alive_interval;
+    int server_alive_interval;
 
 } guac_ssh_settings;
 

src/protocols/vnc/settings.h

@@ -180,7 +180,7 @@ typedef struct guac_vnc_settings {
      * of 1 is automatically increased to 2 by libssh2 to avoid busy loop corner
      * cases.
      */
-    unsigned sftp_server_alive_interval;
+    int sftp_server_alive_interval;
 #endif
 
     /**