log: prevent stack smashing

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/log.c b/src/lxc/log.c
index 6ca315bd6a6257c68ca5af4ef67cfa1779609e0b..a99b4c8f04c57e4a0ba1429ec316e46f9d6f3c58 100644 (file)
--- a/src/lxc/log.c
+++ b/src/lxc/log.c
@@ -297,7 +297,8 @@ static int log_append_logfile(const struct lxc_log_appender *appender,
 
        if ((size_t)n < (sizeof(buffer) - 1))
                n += vsnprintf(buffer + n, sizeof(buffer) - n, event->fmt, *event->vap);
-       else
+
+       if ((size_t)n >= sizeof(buffer))
                n = sizeof(buffer) - 1;
 
        buffer[n] = '\n';