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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 73727C2D0E8 for ; Thu, 26 Mar 2020 23:26:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A70920409 for ; Thu, 26 Mar 2020 23:26:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265189; bh=W0Nkmr1pxbEzsY8D6fArEYRWcqQZNP6Afga//UVAqKg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=csbuTUNaBBCtJvOFn8S/JtwSscEUz96syL4c4kTp70U/XF/bcflqUUCSc+/UDH9nZ jCMuC3x6EnlHgS9sZXNmDprvxo6AD+2o5JuYSOwmTE0+RDCNqQZQTSE1uhvUDULfzG oyTB4pzx9H261wl9HsaAaIoR7U8+FMme8JGuVENM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728066AbgCZX0Z (ORCPT ); Thu, 26 Mar 2020 19:26:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:46290 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727722AbgCZXZX (ORCPT ); Thu, 26 Mar 2020 19:25:23 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5F40F2082D; Thu, 26 Mar 2020 23:25:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265123; bh=W0Nkmr1pxbEzsY8D6fArEYRWcqQZNP6Afga//UVAqKg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GwK6BAXiHZfGIPv2xx9MbO/Z0dua/kECw5gtC7evPFhGqm7erhMgKRslhe55MNpmB ZfSYwSmax4hJNSZ2aNbmNCtz7DwLW2vsiepTQ8k2Z8nNwqe8POoHE4lEfulNEB57vf Mx2vtMO2VuYPtroXrbcxqQsQy98GaCKHWv55gVzw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takashi Iwai , syzbot+e1fe9f44fb8ecf4fb5dd@syzkaller.appspotmail.com, Sasha Levin , alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 4.14 08/10] ALSA: pcm: oss: Avoid plugin buffer overflow Date: Thu, 26 Mar 2020 19:25:11 -0400 Message-Id: <20200326232513.8212-8-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232513.8212-1-sashal@kernel.org> References: <20200326232513.8212-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai [ Upstream commit f2ecf903ef06eb1bbbfa969db9889643d487e73a ] Each OSS PCM plugins allocate its internal buffer per pre-calculation of the max buffer size through the chain of plugins (calling src_frames and dst_frames callbacks). This works for most plugins, but the rate plugin might behave incorrectly. The calculation in the rate plugin involves with the fractional position, i.e. it may vary depending on the input position. Since the buffer size pre-calculation is always done with the offset zero, it may return a shorter size than it might be; this may result in the out-of-bound access as spotted by fuzzer. This patch addresses those possible buffer overflow accesses by simply setting the upper limit per the given buffer size for each plugin before src_frames() and after dst_frames() calls. Reported-by: syzbot+e1fe9f44fb8ecf4fb5dd@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/000000000000b25ea005a02bcf21@google.com Link: https://lore.kernel.org/r/20200309082148.19855-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/oss/pcm_plugin.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/sound/core/oss/pcm_plugin.c b/sound/core/oss/pcm_plugin.c index b8ab46b8298de..6583eb411f82a 100644 --- a/sound/core/oss/pcm_plugin.c +++ b/sound/core/oss/pcm_plugin.c @@ -209,6 +209,8 @@ snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_p if (stream == SNDRV_PCM_STREAM_PLAYBACK) { plugin = snd_pcm_plug_last(plug); while (plugin && drv_frames > 0) { + if (drv_frames > plugin->buf_frames) + drv_frames = plugin->buf_frames; plugin_prev = plugin->prev; if (plugin->src_frames) drv_frames = plugin->src_frames(plugin, drv_frames); @@ -220,6 +222,8 @@ snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_p plugin_next = plugin->next; if (plugin->dst_frames) drv_frames = plugin->dst_frames(plugin, drv_frames); + if (drv_frames > plugin->buf_frames) + drv_frames = plugin->buf_frames; plugin = plugin_next; } } else @@ -248,11 +252,15 @@ snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pc if (frames < 0) return frames; } + if (frames > plugin->buf_frames) + frames = plugin->buf_frames; plugin = plugin_next; } } else if (stream == SNDRV_PCM_STREAM_CAPTURE) { plugin = snd_pcm_plug_last(plug); while (plugin) { + if (frames > plugin->buf_frames) + frames = plugin->buf_frames; plugin_prev = plugin->prev; if (plugin->src_frames) { frames = plugin->src_frames(plugin, frames); -- 2.20.1