From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754943AbbHEWXu (ORCPT ); Wed, 5 Aug 2015 18:23:50 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38350 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754287AbbHEVt7 (ORCPT ); Wed, 5 Aug 2015 17:49:59 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Al Viro , Ben Hutchings , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 012/107] sg_start_req(): make sure that there's not too many elements in iovec Date: Wed, 5 Aug 2015 14:48:04 -0700 Message-Id: <1438811379-384-13-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438811379-384-1-git-send-email-kamal@canonical.com> References: <1438811379-384-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 451a2886b6bf90e2fb378f7c46c655450fb96e81 upstream. unfortunately, allowing an arbitrary 16bit value means a possibility of overflow in the calculation of total number of pages in bio_map_user_iov() - we rely on there being no more than PAGE_SIZE members of sum in the first loop there. If that sum wraps around, we end up allocating too small array of pointers to pages and it's easy to overflow it in the second loop. X-Coverup: TINC (and there's no lumber cartel either) Signed-off-by: Al Viro [bwh: s/MAX_UIOVEC/UIO_MAXIOV/. This was fixed upstream by commit fdc81f45e9f5 ("sg_start_req(): use import_iovec()"), but we don't have that function.] Signed-off-by: Ben Hutchings Reference: CVE-2015-5707 Signed-off-by: Kamal Mostafa --- drivers/scsi/sg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index dbf8e77..9b6e7cb 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1759,6 +1759,9 @@ sg_start_req(Sg_request *srp, unsigned char *cmd) md->from_user = 0; } + if (unlikely(iov_count > UIO_MAXIOV)) + return -EINVAL; + if (iov_count) { int len, size = sizeof(struct sg_iovec) * iov_count; struct iovec *iov; -- 1.9.1