From a5795fd38ee8194451ba3f281f075301a3696ce2 Mon Sep 17 00:00:00 2001
From: James Morris <james.morris@microsoft.com>
Date: Wed, 16 Jan 2019 15:41:11 -0800
Subject: [PATCH] LSM: Check for NULL cred-security on free
Git-commit: a5795fd38ee8194451ba3f281f075301a3696ce2
Patch-mainline: v5.0-rc3
References: bsc#1051510
From: Casey Schaufler <casey@schaufler-ca.com>
Check that the cred security blob has been set before trying
to clean it up. There is a case during credential initialization
that could result in this.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Reported-by: syzbot+69ca07954461f189e808@syzkaller.appspotmail.com
Acked-by: Takashi Iwai <tiwai@suse.de>
---
security/security.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/security/security.c b/security/security.c
index f1b8d2587639..55bc49027ba9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1027,6 +1027,13 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp)
void security_cred_free(struct cred *cred)
{
+ /*
+ * There is a failure case in prepare_creds() that
+ * may result in a call here with ->security being NULL.
+ */
+ if (unlikely(cred->security == NULL))
+ return;
+
call_void_hook(cred_free, cred);
}
--
2.16.4