linux-kernel - [PATCH] KEYS: fix cred refcount leak in request_key_auth

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Date:   Mon, 18 Sep 2017 11:33:31 -0700
From:   Eric Biggers <ebiggers3@...il.com>
To:     keyrings@...r.kernel.org
Cc:     David Howells <dhowells@...hat.com>,
        Michael Halcrow <mhalcrow@...gle.com>,
        linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org, Eric Biggers <ebiggers@...gle.com>
Subject: [PATCH] KEYS: fix cred refcount leak in request_key_auth_new()

From: Eric Biggers <ebiggers@...gle.com>

In request_key_auth_new(), if alloc_key() or key_instantiate_and_link()
were to fail, we would leak a reference to the 'struct cred'.  Currently
this can only happen if alloc_key() fails to to allocate memory.  But it
still should be fixed, as it is a more severe bug waiting to happen.

Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials")
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 security/keys/request_key_auth.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index afe9d22ab361..f2f29f13ecff 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -227,6 +227,7 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
 	key_revoke(authkey);
 	key_put(authkey);
 error_alloc:
+	put_cred(rka->cred);
 	key_put(rka->target_key);
 	key_put(rka->dest_keyring);
 	kfree(rka->callout_info);
-- 
2.14.1.690.gbb1197296e-goog