From: Willy Tarreau <w@1wt.eu>
Date: Wed, 28 Jan 2015 18:03:21 +0000 (+0100)
Subject: MEDIUM: init: continue to enforce SYSTEM_MAXCONN with auto settings if set
X-Git-Tag: v1.6-dev1~162
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=474b96ad41aa76d3b4c343efac7eb20995b3be1e;p=thirdparty%2Fhaproxy.git

MEDIUM: init: continue to enforce SYSTEM_MAXCONN with auto settings if set

Commit d025648 ("MAJOR: init: automatically set maxconn and/or maxsslconn
when possible") resulted in a case where if enough memory is available,
a maxconn value larger than SYSTEM_MAXCONN could be computed, resulting
in possibly overflowing other systems resources (eg: kernel socket buffers,
conntrack entries, etc). Let's bound any automatic maxconn to SYSTEM_MAXCONN
if it is defined. Note that the value is set to DEFAULT_MAXCONN since
SYSTEM_MAXCONN forces DEFAULT_MAXCONN, thus it is not an error.
---

diff --git a/src/haproxy.c b/src/haproxy.c
index 60a0ca26ac..c5ffa0fb95 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -801,7 +801,9 @@ void init(int argc, char **argv)
 	 * handshake once since it is not performed on the two sides at the
 	 * same time (frontend-side is terminated before backend-side begins).
 	 * The SSL stack is supposed to have filled ssl_session_cost and
-	 * ssl_handshake_cost during its initialization.
+	 * ssl_handshake_cost during its initialization. In any case, if
+	 * SYSTEM_MAXCONN is set, we still enforce it as an upper limit for
+	 * maxconn in order to protect the system.
 	 */
 	if (!global.rlimit_memmax) {
 		if (global.maxconn == 0) {
@@ -834,6 +836,10 @@ void init(int argc, char **argv)
 			 global.ssl_handshake_max_cost);       // 1 handshake per connection max
 
 		global.maxconn = round_2dig(global.maxconn);
+#ifdef SYSTEM_MAXCONN
+		if (global.maxconn > DEFAULT_MAXCONN)
+			global.maxconn = DEFAULT_MAXCONN;
+#endif /* SYSTEM_MAXCONN */
 		global.maxsslconn = sides * global.maxconn;
 		if (global.mode & (MODE_VERBOSE|MODE_DEBUG))
 			fprintf(stderr, "Note: setting global.maxconn to %d and global.maxsslconn to %d.\n",
@@ -894,6 +900,10 @@ void init(int argc, char **argv)
 
 		global.maxconn = clearmem / (SESSION_MAX_COST + 2 * global.tune.bufsize);
 		global.maxconn = round_2dig(global.maxconn);
+#ifdef SYSTEM_MAXCONN
+		if (global.maxconn > DEFAULT_MAXCONN)
+			global.maxconn = DEFAULT_MAXCONN;
+#endif /* SYSTEM_MAXCONN */
 
 		if (clearmem <= 0 || !global.maxconn) {
 			Alert("Cannot compute the automatic maxconn because global.maxsslconn is already too "