From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Wed, 29 Aug 2018 21:06:48 +0000 (-0400)
Subject: Fix: possible null dereference on communication error
X-Git-Tag: v2.11.0-rc1~36
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=d9f484bc6f074842bc4ac3eab0127fe3aaa10909;p=lttng-tools.git

Fix: possible null dereference on communication error

lttng_ctl_ask_sessiond_fds_varlen() can return a positive
error code and NULL buffers if the sessiond uses a command
return code that is already negative.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index eff08df80..f503fd1cb 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -1959,6 +1959,11 @@ int lttng_list_events(struct lttng_handle *handle,
 		goto end;
 	}
 
+	if (!cmd_header) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
 	/* Set number of events and free command header */
 	nb_events = cmd_header->nb_events;
 	if (nb_events > INT_MAX) {