[PATCH v1] selinux/ss/services.c: check the return value of audit_log_start() in security_sid_mls_copy()

[lily]

The function audit_log_start() can fail, so its return value should be
checked against NULL. 

Signed-off-by: Li Zhong <floridsleeves@xxxxxxxxx>
---
 security/selinux/ss/services.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index fe5fcf571c56..41d4c4ed93b7 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -3271,6 +3271,9 @@ int security_sid_mls_copy(struct selinux_state *state,
 				ab = audit_log_start(audit_context(),
 						     GFP_ATOMIC,
 						     AUDIT_SELINUX_ERR);
+				if (!ab)
+					goto out_unlock;
+
 				audit_log_format(ab,
 						 "op=security_sid_mls_copy invalid_context=");
 				/* don't record NUL with untrusted strings */
-- 
2.25.1