From patchwork Fri Sep 3 14:02:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 507002 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D09FC433EF for ; Fri, 3 Sep 2021 14:03:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2904061059 for ; Fri, 3 Sep 2021 14:03:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235443AbhICOEz (ORCPT ); Fri, 3 Sep 2021 10:04:55 -0400 Received: from www.linuxtv.org ([130.149.80.248]:51860 "EHLO www.linuxtv.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235169AbhICOEy (ORCPT ); Fri, 3 Sep 2021 10:04:54 -0400 Received: from mchehab by www.linuxtv.org with local (Exim 4.92) (envelope-from ) id 1mM9nE-00BliQ-8I; Fri, 03 Sep 2021 14:03:44 +0000 From: Mauro Carvalho Chehab Date: Fri, 03 Sep 2021 14:02:58 +0000 Subject: [git:media_stage/master] media: firewire: firedtv-avc: fix a buffer overflow in avc_ca_pmt() To: linuxtv-commits@linuxtv.org Cc: Hans Verkuil , Dan Carpenter , stable@vger.kernel.org Mail-followup-to: linux-media@vger.kernel.org Forward-to: linux-media@vger.kernel.org Reply-to: linux-media@vger.kernel.org Message-Id: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is an automatic generated email to let you know that the following patch were queued: Subject: media: firewire: firedtv-avc: fix a buffer overflow in avc_ca_pmt() Author: Dan Carpenter Date: Mon Jun 7 17:23:48 2021 +0200 The bounds checking in avc_ca_pmt() is not strict enough. It should be checking "read_pos + 4" because it's reading 5 bytes. If the "es_info_length" is non-zero then it reads a 6th byte so there needs to be an additional check for that. I also added checks for the "write_pos". I don't think these are required because "read_pos" and "write_pos" are tied together so checking one ought to be enough. But they make the code easier to understand for me. The check on write_pos is: if (write_pos + 4 >= sizeof(c->operand) - 4) { The first "+ 4" is because we're writing 5 bytes and the last " - 4" is to leave space for the CRC. The other problem is that "length" can be invalid. It comes from "data_length" in fdtv_ca_pmt(). Cc: stable@vger.kernel.org Reported-by: Luo Likang Signed-off-by: Dan Carpenter Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab drivers/media/firewire/firedtv-avc.c | 14 +++++++++++--- drivers/media/firewire/firedtv-ci.c | 2 ++ 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/media/firewire/firedtv-avc.c b/drivers/media/firewire/firedtv-avc.c index 2bf9467b917d..71991f8638e6 100644 --- a/drivers/media/firewire/firedtv-avc.c +++ b/drivers/media/firewire/firedtv-avc.c @@ -1165,7 +1165,11 @@ int avc_ca_pmt(struct firedtv *fdtv, char *msg, int length) read_pos += program_info_length; write_pos += program_info_length; } - while (read_pos < length) { + while (read_pos + 4 < length) { + if (write_pos + 4 >= sizeof(c->operand) - 4) { + ret = -EINVAL; + goto out; + } c->operand[write_pos++] = msg[read_pos++]; c->operand[write_pos++] = msg[read_pos++]; c->operand[write_pos++] = msg[read_pos++]; @@ -1177,13 +1181,17 @@ int avc_ca_pmt(struct firedtv *fdtv, char *msg, int length) c->operand[write_pos++] = es_info_length >> 8; c->operand[write_pos++] = es_info_length & 0xff; if (es_info_length > 0) { + if (read_pos >= length) { + ret = -EINVAL; + goto out; + } pmt_cmd_id = msg[read_pos++]; if (pmt_cmd_id != 1 && pmt_cmd_id != 4) dev_err(fdtv->device, "invalid pmt_cmd_id %d at stream level\n", pmt_cmd_id); - if (es_info_length > sizeof(c->operand) - 4 - - write_pos) { + if (es_info_length > sizeof(c->operand) - 4 - write_pos || + es_info_length > length - read_pos) { ret = -EINVAL; goto out; } diff --git a/drivers/media/firewire/firedtv-ci.c b/drivers/media/firewire/firedtv-ci.c index 9363d005e2b6..e0d57e09dab0 100644 --- a/drivers/media/firewire/firedtv-ci.c +++ b/drivers/media/firewire/firedtv-ci.c @@ -134,6 +134,8 @@ static int fdtv_ca_pmt(struct firedtv *fdtv, void *arg) } else { data_length = msg->msg[3]; } + if (data_length > sizeof(msg->msg) - data_pos) + return -EINVAL; return avc_ca_pmt(fdtv, &msg->msg[data_pos], data_length); }