From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59688 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932084AbdJWM5A (ORCPT ); Mon, 23 Oct 2017 08:57:00 -0400 Subject: Patch "KEYS: encrypted: fix dereference of NULL user_key_payload" has been added to the 4.13-stable tree To: ebiggers@google.com, dhowells@redhat.com, gregkh@linuxfoundation.org, james.l.morris@oracle.com, safford@us.ibm.com, zohar@linux.vnet.ibm.com Cc: , From: Date: Mon, 23 Oct 2017 14:56:35 +0200 Message-ID: <1508763395524@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 KEYS: encrypted: fix dereference of NULL user_key_payload to the 4.13-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: keys-encrypted-fix-dereference-of-null-user_key_payload.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 13923d0865ca96312197962522e88bc0aedccd74 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:37:49 -0700 Subject: KEYS: encrypted: fix dereference of NULL user_key_payload From: Eric Biggers commit 13923d0865ca96312197962522e88bc0aedccd74 upstream. A key of type "encrypted" references a "master key" which is used to encrypt and decrypt the encrypted key's payload. However, when we accessed the master key's payload, we failed to handle the case where the master key has been revoked, which sets the payload pointer to NULL. Note that 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. This was an issue for master keys of type "user" only. Master keys can also be of type "trusted", but those cannot be revoked. Fixes: 7e70cb497850 ("keys: add new key-type encrypted") Reviewed-by: James Morris Cc: Mimi Zohar Cc: David Safford Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman --- security/keys/encrypted-keys/encrypted.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -309,6 +309,13 @@ static struct key *request_user_key(cons down_read(&ukey->sem); upayload = user_key_payload_locked(ukey); + if (!upayload) { + /* key was revoked before we acquired its semaphore */ + up_read(&ukey->sem); + key_put(ukey); + ukey = ERR_PTR(-EKEYREVOKED); + goto error; + } *master_key = upayload->data; *master_keylen = upayload->datalen; error: Patches currently in stable-queue which might be from ebiggers@google.com are queue-4.13/keys-encrypted-fix-dereference-of-null-user_key_payload.patch