From bbcec789dda02598fb88133febb556b58a04c704 Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@suse.de>
Date: Wed, 13 Dec 2017 18:22:30 +0100
Subject: [PATCH] target/iscsi: avoid NULL dereference in CHAP auth error path
References: bsc#1117165
Git-commit: ce512d79d0466a604793addb6b769d12ee326822
Patch-mainline: v4.16-rc1
If chap_server_compute_md5() fails early, e.g. via CHAP_N mismatch, then
crypto_free_shash() is called with a NULL pointer which gets
dereferenced in crypto_shash_tfm().
Fixes: 69110e3cedbb ("iscsi-target: Use shash and ahash")
Suggested-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: David Disseldorp <ddiss@suse.de>
Cc: stable@vger.kernel.org # 4.6+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/target/iscsi/iscsi_target_auth.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c
index 49d60adc0837..4e680d753941 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -410,7 +410,8 @@ static int chap_server_compute_md5(
auth_ret = 0;
out:
kzfree(desc);
- crypto_free_shash(tfm);
+ if (tfm)
+ crypto_free_shash(tfm);
kfree(challenge);
kfree(challenge_binhex);
return auth_ret;
--
2.13.7