From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 EA13DC4338F for ; Thu, 29 Jul 2021 10:32:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB0B26056C for ; Thu, 29 Jul 2021 10:32:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235633AbhG2Kcb (ORCPT ); Thu, 29 Jul 2021 06:32:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:35100 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235309AbhG2Kc1 (ORCPT ); Thu, 29 Jul 2021 06:32:27 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9F256601FF; Thu, 29 Jul 2021 10:32:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627554744; bh=evqS+jYgdy4AaHR+PlFUIfPANh3VC9qSJLUKVyCQu2E=; h=Date:From:To:Subject:References:In-Reply-To:From; b=QtB01bi7tcSTf3qCn/mJiicVJt5X2UEAyOotNQTpfXgGcIwP1UHR9r9GfHd0IDrJh bXvzB/vLtOmLnuInGz2KruvBWSWRdRyT8vwbKuKmwy24gihB8GHp3aqeg4qi1F53Gl kiIpApj/SIs1sisgDYqhm9AYx0qXIb53qdnWPQ1s= Date: Thu, 29 Jul 2021 12:32:21 +0200 From: Greg KH To: Dan Carpenter , Stefan Richter , Luo Likang , security@kernel.org, linux-distros@vs.openwall.org, Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux1394-devel@lists.sourceforge.net Subject: Re: [PATCH] media: firewire: firedtv-avc: fix a buffer overflow in avc_ca_pmt() Message-ID: References: <000001d73031$d5304480$7f90cd80$@nsfocus.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Wed, Apr 14, 2021 at 11:57:59AM +0300, Dan Carpenter wrote: > 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 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 > --- > This hardware isn't super common so there is no embargo. Resending > through normal lists. > > Oh, another thing is the data_length calculation in fdtv_ca_pmt() seems > very suspicous. Reading more than 4 bytes in the loop will lead to > shift wrapping. > > 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..2d6992ac5dd6 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) - 4) > + return -EINVAL; > > return avc_ca_pmt(fdtv, &msg->msg[data_pos], data_length); > } > -- > 2.30.2 > This patch seems to have gotten lost. Any change of it getting applied? thanks, greg k-h