[PATCH -next] smack: fix a missing-check bug in smack_sb_eat_lsm_opts()

[Chen Zhou]

In smack_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul().
It returns NULL when fails, add check for it.

Signed-off-by: Chen Zhou <chenzhou10 at huawei.com>
---
 security/smack/smack_lsm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 2862fc3..9ec30f3 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -731,6 +731,8 @@ static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
 		token = match_opt_prefix(from, len, &arg);
 		if (token != Opt_error) {
 			arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
+			if (!arg)
+				return -ENOMEM;
 			rc = smack_add_opt(token, arg, mnt_opts);
 			if (unlikely(rc)) {
 				kfree(arg);
-- 
2.7.4