linux-kernel - [PATCH 5.15 048/132] selinux: fix bad cleanup on error in hashtab

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Date:   Mon, 23 May 2022 19:04:17 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Wander Lairson Costa <wander@...hat.com>,
        Ondrej Mosnacek <omosnace@...hat.com>,
        Paul Moore <paul@...l-moore.com>
Subject: [PATCH 5.15 048/132] selinux: fix bad cleanup on error in hashtab_duplicate()

From: Ondrej Mosnacek <omosnace@...hat.com>

commit 6254bd3db316c9ccb3b05caa8b438be63245466f upstream.

The code attempts to free the 'new' pointer using kmem_cache_free(),
which is wrong because this function isn't responsible of freeing it.
Instead, the function should free new->htable and clear the contents of
*new (to prevent double-free).

Cc: stable@...r.kernel.org
Fixes: c7c556f1e81b ("selinux: refactor changing booleans")
Reported-by: Wander Lairson Costa <wander@...hat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@...hat.com>
Signed-off-by: Paul Moore <paul@...l-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 security/selinux/ss/hashtab.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/security/selinux/ss/hashtab.c
+++ b/security/selinux/ss/hashtab.c
@@ -178,7 +178,8 @@ int hashtab_duplicate(struct hashtab *ne
 			kmem_cache_free(hashtab_node_cachep, cur);
 		}
 	}
-	kmem_cache_free(hashtab_node_cachep, new);
+	kfree(new->htable);
+	memset(new, 0, sizeof(*new));
 	return -ENOMEM;
 }