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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 D2699C35242 for ; Sat, 8 Feb 2020 18:32:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8AA120661 for ; Sat, 8 Feb 2020 18:32:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728478AbgBHSca (ORCPT ); Sat, 8 Feb 2020 13:32:30 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34586 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727940AbgBHS3s (ORCPT ); Sat, 8 Feb 2020 13:29:48 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1j0UrO-0003iT-Bz; Sat, 08 Feb 2020 18:29:42 +0000 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1j0UrM-000CWx-Su; Sat, 08 Feb 2020 18:29:40 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , syzbot+f153bde47a62e0b05f83@syzkaller.appspotmail.com, "Takashi Iwai" Date: Sat, 08 Feb 2020 18:21:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 139/148] ALSA: pcm: oss: Avoid potential buffer overflows In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 4cc8d6505ab82db3357613d36e6c58a297f57f7c upstream. syzkaller reported an invalid access in PCM OSS read, and this seems to be an overflow of the internal buffer allocated for a plugin. Since the rate plugin adjusts its transfer size dynamically, the calculation for the chained plugin might be bigger than the given buffer size in some extreme cases, which lead to such an buffer overflow as caught by KASAN. Fix it by limiting the max transfer size properly by checking against the destination size in each plugin transfer callback. Reported-by: syzbot+f153bde47a62e0b05f83@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20191204144824.17801-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- sound/core/oss/linear.c | 2 ++ sound/core/oss/mulaw.c | 2 ++ sound/core/oss/route.c | 2 ++ 3 files changed, 6 insertions(+) --- a/sound/core/oss/linear.c +++ b/sound/core/oss/linear.c @@ -107,6 +107,8 @@ static snd_pcm_sframes_t linear_transfer } } #endif + if (frames > dst_channels[0].frames) + frames = dst_channels[0].frames; convert(plugin, src_channels, dst_channels, frames); return frames; } --- a/sound/core/oss/mulaw.c +++ b/sound/core/oss/mulaw.c @@ -269,6 +269,8 @@ static snd_pcm_sframes_t mulaw_transfer( } } #endif + if (frames > dst_channels[0].frames) + frames = dst_channels[0].frames; data = (struct mulaw_priv *)plugin->extra_data; data->func(plugin, src_channels, dst_channels, frames); return frames; --- a/sound/core/oss/route.c +++ b/sound/core/oss/route.c @@ -57,6 +57,8 @@ static snd_pcm_sframes_t route_transfer( return -ENXIO; if (frames == 0) return 0; + if (frames > dst_channels[0].frames) + frames = dst_channels[0].frames; nsrcs = plugin->src_format.channels; ndsts = plugin->dst_format.channels;