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Date:   Thu, 30 May 2019 11:53:10 +0800
From:   Gen Zhang <blackgod016574@gmail.com>
To:     paul@paul-moore.com, tony.luck@intel.com, sds@tycho.nsa.gov,
        eparis@parisplace.org
Cc:     selinux@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org
Subject: [PATCH] hooks: fix a missing-check bug in selinux_sb_eat_lsm_opts()
Message-ID: <20190530035310.GA9127@zhanggen-UX430UQ>
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In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
returns NULL when fails. So 'arg' should be checked.

Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
---
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3ec702c..5a9e959 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
 						*q++ = c;
 				}
 				arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
+				if (!arg)
+					return 0;
 			}
 			rc = selinux_add_opt(token, arg, mnt_opts);
 			if (unlikely(rc)) {