From: Aurelien DARRAGON <adarragon@haproxy.com>
Date: Thu, 6 Mar 2025 08:05:23 +0000 (+0100)
Subject: BUG/MINOR: cfgparse/peers: fix inconsistent check for missing peer server
X-Git-Tag: v3.2-dev7~21
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2560ab892f355e958007b287946f787b578d3131;p=thirdparty%2Fhaproxy.git

BUG/MINOR: cfgparse/peers: fix inconsistent check for missing peer server

In the "peers" section parser, right after parse_server() is called, we
used to check whether the curpeers->peers_fe->srv pointer was set or not
to know if parse_server() successfuly added a server to the peers proxy,
server that we can then associate to the new peer.

However the check is wrong, as curpeers->peers_fe->srv points to the
last added server, if a server was successfully added before the
failing one, we cannot detect that the last parse_server() didn't
add a server. This is known to cause bug with bad "peer"/"server"
statements.

To fix the issue, we save a pointer on the last known
curpeers->peers_fe->srv before parse_server() is called, and we then
compare the save with the pointer after parse_server(), if the value
didn't change, then parse_server() didn't add a server. This makes
the check consistent in all situations.

It should be backported to all stable versions.
---

diff --git a/src/cfgparse.c b/src/cfgparse.c
index c99a7339e..bf8d7a6c0 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -835,6 +835,7 @@ int cfg_parse_peers(const char *file, int linenum, char **args, int kwm)
 	}
 	else if (strcmp(args[0], "peer") == 0 ||
 	         strcmp(args[0], "server") == 0) { /* peer or server definition */
+		struct server *prev_srv;
 		int local_peer, peer;
 		int parse_addr = 0;
 
@@ -885,10 +886,13 @@ int cfg_parse_peers(const char *file, int linenum, char **args, int kwm)
 		 * or if we are parsing a "server" line and the current peer is not the local one.
 		 */
 		parse_addr = (peer || !local_peer) ? SRV_PARSE_PARSE_ADDR : 0;
+		prev_srv = curpeers->peers_fe->srv;
 		err_code |= parse_server(file, linenum, args, curpeers->peers_fe, NULL,
 		                         SRV_PARSE_IN_PEER_SECTION|parse_addr|SRV_PARSE_INITIAL_RESOLVE);
-		if (!curpeers->peers_fe->srv) {
-			/* Remove the newly allocated peer. */
+		if (curpeers->peers_fe->srv == prev_srv) {
+			/* parse_server didn't add a server:
+			 * Remove the newly allocated peer.
+			 */
 			if (newpeer != curpeers->local) {
 				struct peer *p;