From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Mon, 5 Jul 2021 18:16:00 +0000 (-0400)
Subject: Fix: lttng: add-trigger: null dereference on MI initialization error
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=1e0b19a257a7fe8307103757def955010cb5a03e

Fix: lttng: add-trigger: null dereference on MI initialization error

Failures to create an MI writer instance will result in a dereference of
the MI writer when attempting to close the command's output element.

1457842 Dereference after null check

Either the check against null is unnecessary, or there may be a null
pointer dereference.

In cmd_add_trigger: Pointer is checked against null but then
dereferenced anyway (CWE-476)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I98b844d2f1c7abd43bd42ee472759de57b34484e
---

diff --git a/src/bin/lttng/commands/add_trigger.c b/src/bin/lttng/commands/add_trigger.c
index e4111eba0..00f8f47e3 100644
--- a/src/bin/lttng/commands/add_trigger.c
+++ b/src/bin/lttng/commands/add_trigger.c
@@ -2428,7 +2428,7 @@ error:
 
 end:
 	/* Mi closing. */
-	if (lttng_opt_mi) {
+	if (lttng_opt_mi && mi_writer) {
 		int mi_ret;
 
 		/* Close output element. */