From: Felix Abecassis <fabecassis@nvidia.com>
Date: Wed, 29 Nov 2017 04:27:39 +0000 (-0800)
Subject: log: fix infinite loop with multiple lxc.log.syslog keys
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=46efc0880c27a18465b986fd74d34115da69ad32;p=thirdparty%2Flxc.git

log: fix infinite loop with multiple lxc.log.syslog keys

This caused the linked list of appenders to loop on itself, creating
an infinite logging loop in `__lxc_log_append`.

Signed-off-by: Felix Abecassis <fabecassis@nvidia.com>
---

diff --git a/src/lxc/log.c b/src/lxc/log.c
index 351b191fb..b62aeb8d2 100644
--- a/src/lxc/log.c
+++ b/src/lxc/log.c
@@ -533,6 +533,17 @@ extern int lxc_log_syslog(int facility)
 		lxc_log_category_lxc.appender = &log_appender_syslog;
 		return 0;
 	}
+
+	appender = lxc_log_category_lxc.appender;
+	/* Check if syslog was already added, to avoid creating a loop */
+	while (appender) {
+		if (appender == &log_appender_syslog) {
+			/* not an error: openlog re-opened the connection */
+			return 0;
+		}
+		appender = appender->next;
+	}
+
 	appender = lxc_log_category_lxc.appender;
 	while (appender->next != NULL)
 		appender = appender->next;