From 4cbb9fdf133cc5a5dcb1ac7153791792976c62c9 Mon Sep 17 00:00:00 2001 From: David Disseldorp Date: Wed, 13 Dec 2017 18:22:30 +0100 Subject: target/iscsi: avoid NULL dereference in CHAP auth error path commit ce512d79d0466a604793addb6b769d12ee326822 upstream. 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 Signed-off-by: David Disseldorp Cc: stable@vger.kernel.org # 4.6+ Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/iscsi/iscsi_target_auth.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/target/iscsi') diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c index f9bc8ec6fb6b..9518ffd8b8ba 100644 --- a/drivers/target/iscsi/iscsi_target_auth.c +++ b/drivers/target/iscsi/iscsi_target_auth.c @@ -421,7 +421,8 @@ 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; -- cgit v1.2.3