net_ssh: Fix IP address extraction on failed connect.

When clients fail to negotiate an SSH session (usually
spam connections), the underlying socket file descriptor
was -1 by the time we tried to log it. In fact, we already
have the IP address available to us in a buffer from the
start of the session, so just use that directly for
generating the event, rather than trying to query it
again when it's no longer available to us.

nets/net_ssh.c

@@ -218,8 +218,12 @@ static int save_remote_ip(ssh_session session, struct bbs_node *node, char *buf,
 	socklen_t socklen = sizeof(tmp);
 
 	sfd = ssh_get_fd(session); /* Get fd of the connection */
+	if (sfd < 0) {
+		bbs_error("No file descriptor available for SSH session\n");
+		return -1;
+	}
 	if (getpeername(sfd, &tmp, &socklen)) {
-		bbs_error("getpeername: %s\n", strerror(errno));
+		bbs_error("getpeername(%d): %s\n", sfd, strerror(errno));
 		return -1;
 	}
 
@@ -277,16 +281,15 @@ static void auth_fail(ssh_session session, const char *username)
 	bbs_event_broadcast(&event);
 }
 
-static void request_fail(ssh_session session, enum bbs_event_type type)
+static void request_fail(const char *ip, enum bbs_event_type type)
 {
 	struct bbs_event event;
 
 	/* Don't have a node, so need to dispatch manually */
 	memset(&event, 0, sizeof(event));
 	event.type = type;
-	if (!save_remote_ip(session, NULL, event.ipaddr, sizeof(event.ipaddr))) {
-		bbs_event_broadcast(&event);
-	}
+	safe_strncpy(event.ipaddr, ip, sizeof(event.ipaddr));
+	bbs_event_broadcast(&event);
 }
 
 #ifdef ALLOW_ANON_AUTH
@@ -731,8 +734,10 @@ static void handle_session(ssh_event event, ssh_session session)
 	 * The timeout above is to address that. */
 
 	if (ssh_handle_key_exchange(session) != SSH_OK) {
-		bbs_error("%s\n", ssh_get_error(session));
-		request_fail(session, EVENT_NODE_ENCRYPTION_FAILED);
+		/* This isn't our fault, it's the clients, and since this is typical of
+		 * spammy connections, log it as a debug message. */
+		bbs_debug(1, "Fatal key exchange error: %s\n", ssh_get_error(session));
+		request_fail(ipaddr, EVENT_NODE_ENCRYPTION_FAILED);
 		return;
 	}
 	if (ssh_event_add_session(event, session) != SSH_OK) {
@@ -751,9 +756,9 @@ static void handle_session(ssh_event event, ssh_session session)
 
 		if (ssh_event_dopoll(event, 100) == SSH_ERROR) {
 			/* If client disconnects during login stage, this could happen.
-			 * Hence, it's a warning, not an error, as it's not our fault. */
-			bbs_warning("%s\n", ssh_get_error(session));
-			request_fail(session, EVENT_NODE_BAD_REQUEST);
+			 * Hence, it's not an error, as it's not our fault. */
+			bbs_debug(1, "%s\n", ssh_get_error(session));
+			request_fail(ipaddr, EVENT_NODE_BAD_REQUEST);
 			return;
 		}
 	}