This is a note to let you know that I've just added the patch titled target/iscsi: avoid NULL dereference in CHAP auth error path to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: target-iscsi-avoid-null-dereference-in-chap-auth-error-path.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ce512d79d0466a604793addb6b769d12ee326822 Mon Sep 17 00:00:00 2001 From: David Disseldorp <ddiss@xxxxxxx> Date: Wed, 13 Dec 2017 18:22:30 +0100 Subject: target/iscsi: avoid NULL dereference in CHAP auth error path From: David Disseldorp <ddiss@xxxxxxx> 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 <elfring@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: David Disseldorp <ddiss@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 4.6+ Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/target/iscsi/iscsi_target_auth.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- 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; Patches currently in stable-queue which might be from ddiss@xxxxxxx are queue-4.15/target-iscsi-avoid-null-dereference-in-chap-auth-error-path.patch