From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49378 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665AbdJXInq (ORCPT ); Tue, 24 Oct 2017 04:43:46 -0400 Subject: Patch "lib/digsig: fix dereference of NULL user_key_payload" has been added to the 4.4-stable tree To: ebiggers@google.com, dhowells@redhat.com, dmitry.kasatkin@intel.com, gregkh@linuxfoundation.org, james.l.morris@oracle.com Cc: , From: Date: Tue, 24 Oct 2017 10:02:13 +0200 Message-ID: <1508832133255206@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled lib/digsig: fix dereference of NULL user_key_payload to the 4.4-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: lib-digsig-fix-dereference-of-null-user_key_payload.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 192cabd6a296cbc57b3d8c05c4c89d87fc102506 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:43:20 -0700 Subject: lib/digsig: fix dereference of NULL user_key_payload From: Eric Biggers commit 192cabd6a296cbc57b3d8c05c4c89d87fc102506 upstream. digsig_verify() requests a user key, then accesses its payload. However, a revoked key has a NULL payload, and we failed to check for this. request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire its semaphore. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. Fixes: 051dbb918c7f ("crypto: digital signature verification support") Reviewed-by: James Morris Cc: Dmitry Kasatkin Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman --- lib/digsig.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/lib/digsig.c +++ b/lib/digsig.c @@ -87,6 +87,12 @@ static int digsig_verify_rsa(struct key down_read(&key->sem); ukp = user_key_payload(key); + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + err = -EKEYREVOKED; + goto err1; + } + if (ukp->datalen < sizeof(*pkh)) goto err1; Patches currently in stable-queue which might be from ebiggers@google.com are queue-4.4/lib-digsig-fix-dereference-of-null-user_key_payload.patch queue-4.4/keys-encrypted-fix-dereference-of-null-user_key_payload.patch queue-4.4/keys-don-t-let-add_key-update-an-uninstantiated-key.patch