From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 29 Oct 2020 15:43:35 +0000 (-0400)
Subject: Clean-up: sessiond: silence negative index warning
X-Git-Tag: v2.13.0-rc1~442
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=0e43bcbfbc967868b8b939e378268d6296011886;p=lttng-tools.git

Clean-up: sessiond: silence negative index warning

Coverity warns that `lttng_action_get_type()` can return
a negative index (LTTNG_ACTION_TYPE_UNKNOWN). This scenario
is not reachable, but a check is added to silence the analyzer.

Original report:
  1435955 Negative array index read

  A memory location at a negative offset from the beginning of the array
  will be read, resulting in incorrect values.

  In get_action_name: Negative value used to index an array in a read
  operation (CWE-129)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I5952096a1d29f0d4a3c4350a2a842874d5f3973b
---

diff --git a/src/bin/lttng-sessiond/action-executor.c b/src/bin/lttng-sessiond/action-executor.c
index ca9690743..db16f8049 100644
--- a/src/bin/lttng-sessiond/action-executor.c
+++ b/src/bin/lttng-sessiond/action-executor.c
@@ -104,7 +104,11 @@ static const char *action_type_names[] = {
 
 static const char *get_action_name(const struct lttng_action *action)
 {
-	return action_type_names[lttng_action_get_type(action)];
+	const enum lttng_action_type action_type = lttng_action_get_type(action);
+
+	assert(action_type != LTTNG_ACTION_TYPE_UNKNOWN);
+
+	return action_type_names[action_type];
 }
 
 /* Check if this trigger allowed to interect with a given session. */
@@ -480,12 +484,16 @@ static int action_executor_generic_handler(struct action_executor *executor,
 		const struct action_work_item *work_item,
 		const struct lttng_action *action)
 {
+	const enum lttng_action_type action_type = lttng_action_get_type(action);
+
+	assert(action_type != LTTNG_ACTION_TYPE_UNKNOWN);
+
 	DBG("Executing action `%s` of trigger `%p` action work item %" PRIu64,
 			get_action_name(action),
 			work_item->trigger,
 			work_item->id);
 
-	return action_executors[lttng_action_get_type(action)](
+	return action_executors[action_type](
 			executor, work_item, action);
 }