From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Wed, 10 Feb 2021 19:20:34 +0000 (-0500)
Subject: Fix: sessiond: ust-registry: dereference of NULL pointer on allocation failure
X-Git-Tag: v2.13.0-rc1~338
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=70987ead6fdcd00aa3365e3b4d2a6ffd5efd511f

Fix: sessiond: ust-registry: dereference of NULL pointer on allocation failure

Coverity reports:
1445771 Dereference after null check
Either the check against null is unnecessary, or there may be a null pointer dereference.
In ust_registry_channel_add: 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: I3976e0d7b059b47ca233bc9a20585eff2e1290fc
---

diff --git a/src/bin/lttng-sessiond/ust-registry.c b/src/bin/lttng-sessiond/ust-registry.c
index 2e33b9575..1b1e65eba 100644
--- a/src/bin/lttng-sessiond/ust-registry.c
+++ b/src/bin/lttng-sessiond/ust-registry.c
@@ -739,13 +739,16 @@ static void destroy_channel(struct ust_registry_channel *chan, bool notif)
 		}
 	}
 
-	rcu_read_lock();
-	/* Destroy all event associated with this registry. */
-	cds_lfht_for_each_entry(chan->ht->ht, &iter.iter, event, node.node) {
-		/* Delete the node from the ht and free it. */
-		ust_registry_destroy_event(chan, event);
+	if (chan->ht) {
+		rcu_read_lock();
+		/* Destroy all event associated with this registry. */
+		cds_lfht_for_each_entry(
+				chan->ht->ht, &iter.iter, event, node.node) {
+			/* Delete the node from the ht and free it. */
+			ust_registry_destroy_event(chan, event);
+		}
+		rcu_read_unlock();
 	}
-	rcu_read_unlock();
 	call_rcu(&chan->rcu_head, destroy_channel_rcu);
 }