From:   Bernard Zhao <bernard@vivo.com>
To:     Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        Eric Paris <eparis@parisplace.org>, selinux@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Bernard Zhao <bernard@vivo.com>
Subject: [PATCH v2] security/selinux: fix potential memleak in error branch
Date:   Sun,  5 Dec 2021 23:18:59 -0800
Message-Id: <20211206071859.324729-1-bernard@vivo.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?956iDOQ+CzxyE2jt078wHwCq9RpdG5iWzN93krxO2xVZrB2Sn1ysl7OZu3gQ?=
 =?us-ascii?Q?kKSwuRemZ8DvfQg/gZnmrsjRMdKA1rDiviKJsRVywqWovL3yMGgJtdpqEcT8?=
 =?us-ascii?Q?jPxal3d3yqdd8p50Lpf98Ld2N3UW5FulU/W21Ryg+SCMv1RCbKv4W8dFsrPP?=
 =?us-ascii?Q?AOm2DZnAO8IDBk64b7NrRpoAhLLy2mwuT6ASjg1UN0y3bmMsCJN20QyfhDR5?=
 =?us-ascii?Q?WFb8W3YMKYTcfnClUgCoC5MEGef9Iyu1wxB1KjKoCx+TOtR82uDlyUIr+DuB?=
 =?us-ascii?Q?ojRrveIjR9UMhfgE4AVVumLWfJ3u6zc+tUY2e2CpKbxZl3lAdGb0J+DZeYwh?=
 =?us-ascii?Q?ILGAb52UyUjarCAxh224tFvNnCUqObEj0wfaXjsnuG+4zWImql5Jp0KnT+Fe?=
 =?us-ascii?Q?9x7zCVpKrLxOBJaq1IG+csWjiRQhx6k86ztC7DWvK+6xr3skJnNUPTDRnZwc?=
 =?us-ascii?Q?fyggVvZPV5T4joM9WXL6wYYLAUzcWBMH2yHijQJJSV45cgjQ/flllM5NBUlA?=
 =?us-ascii?Q?bM0kuoJHyTS1WmZaQ/KEnxzNZ5dlIiPFrqgYG6EdejNT8bujp6b1S88SLvN/?=
 =?us-ascii?Q?KxCyNYv1Oef6GZshMUkGAs3CVJ9t9PcHIzOiCyQ1KFedsuUTwBTSfxHNTYwH?=
 =?us-ascii?Q?x+mQoBhoSmVUd2TR0o8ZsFQwXbDIVCWolZ/IDR15CjY63Ny7/BS5/S70vj0r?=
 =?us-ascii?Q?9+iUCK8IHs/TzmYecYB8qHBiQL0TN+7peNGzwVbwlDttB+NJGNSShOcuGZZx?=
 =?us-ascii?Q?1W9ebCuY/Fj1q39w9eAGPwR63SobQMajCto5qH5+1uIqUucVPfXOIxhorm4K?=
 =?us-ascii?Q?Hz734QxaPsdZMN6qZpD0J/KiGgspTOUx4Zza0WkYM3tsRy4G1ziyidnOUPuC?=
 =?us-ascii?Q?cWqFK3aCFd8RRnfFzJUo7V54eeZvQlKrrywZwuXhGntUJt0b3VSJG3cticIE?=
 =?us-ascii?Q?j39iXRxPaPn6V5nFdhxuyUx5+IWikMelO4e6EY1OpFf76NpIWsmiYKeCa09L?=
 =?us-ascii?Q?H2y+b62Kk58k+2JkPHpa+has3F27p+DUI+zVyuhUI0UQODdTUhA5+pQ219Hv?=
 =?us-ascii?Q?qcimcQzlF1+O3W2dH88Xma3TMa4/hjqhKCtv4r3GGiLfGuOeyYBWUNuJAtCc?=
 =?us-ascii?Q?zUUx/Ul0lcUp92hsJgLxKAQsM1vTZgQB9DEKW/SOFRu52dIOLTnhMm8ua6s/?=
 =?us-ascii?Q?mSqiqsefcHCF+pY+OFZGTdCmMjiXeRXdalzypV5GORrjFRCJ8jl4CtlG56pn?=
 =?us-ascii?Q?LSBtQDRAUOqVuPAoNEzn1j5Jj01pHjBO48pk+XTMdaDJ3f0h+FRygldBmYPc?=
 =?us-ascii?Q?oaUW+bcYDrhnKPo7IMbbA7TI7gUcaNijdNtRwhF7TpKJLsZoboqf3yBrvzM2?=
 =?us-ascii?Q?+zDv7VkkwVd8m1HolS+5JPOT+r6jNiNB06LHeILHBrw95ihwgkh5SpwBR7S0?=
 =?us-ascii?Q?ot3qJ4h+TY0QH7U9GdYpC/76c4/KMyHeCv1h1ZCAhpZrR0RlJn9bmzJ+8QhW?=
 =?us-ascii?Q?KiCZiOlbZxwnNFKUvwIUvasTWIPW6I4C7+iSN87m8sLRrS+PvGdUhgzDXq45?=
 =?us-ascii?Q?kKY7S7H54wxVZBIDG6oPCexaR6PjbXU+vItuXNkYhuec0R3cdwdJWWO1qRig?=
 =?us-ascii?Q?O2HKMF/kW306Ck+ec+AHBa0=3D?=
X-OriginatorOrg: vivo.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 3ae4228b-aa81-42c8-f0e3-08d9b888b24a
X-MS-Exchange-CrossTenant-AuthSource: PSAPR06MB4021.apcprd06.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Dec 2021 07:19:09.8454
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 923e42dc-48d5-4cbe-b582-1a797a6412ed
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: MwnkPKSh79mXb+D9VaWfHWNwpNrGvbNkkjfAZp3FstwDJ2/UFgqTf3TaClqhAK/xZAVkfH+fnndqxNehWvwtxQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PS2PR06MB3303
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

This patch try to fix potential memleak in error branch.

Signed-off-by: Bernard Zhao <bernard@vivo.com>
---
 security/selinux/hooks.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 62d30c0a30c2..8dc140399a23 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -983,18 +983,22 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 static int selinux_add_opt(int token, const char *s, void **mnt_opts)
 {
 	struct selinux_mnt_opts *opts = *mnt_opts;
+	bool is_alloc_opts = false;
 
 	if (token == Opt_seclabel)	/* eaten and completely ignored */
 		return 0;
 
+	if (!s)
+		return -ENOMEM;
+
 	if (!opts) {
 		opts = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
 		if (!opts)
 			return -ENOMEM;
 		*mnt_opts = opts;
+		is_alloc_opts = true;
 	}
-	if (!s)
-		return -ENOMEM;
+
 	switch (token) {
 	case Opt_context:
 		if (opts->context || opts->defcontext)
@@ -1019,6 +1023,8 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
 	}
 	return 0;
 Einval:
+	if (is_alloc_opts)
+		kfree(opts);
 	pr_warn(SEL_MOUNT_FAIL_MSG);
 	return -EINVAL;
 }
-- 
2.33.1