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=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 47618C2D0E7 for ; Thu, 26 Mar 2020 23:27:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E37920409 for ; Thu, 26 Mar 2020 23:27:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265266; bh=HZKph1vlL2+lbjT545LdjST3edbD4zKJanui7XS+8/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rN9lvbIMnKhtZ+g79sFaQmI3F+fbpn95NlkUCT8Pn3g+HqVCsJypmOduGJLO0VPbK xSyz7wopRC6dbodAaOYBTvwf3SxMse2YOi1gSWW0RGI6GmB2hiTY+GSZlAp7orKDZr cfgm/PmHPEGPhvPZx0qfUXVKYuzzpePoZLlv0PTQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727943AbgCZX1o (ORCPT ); Thu, 26 Mar 2020 19:27:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:45018 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728060AbgCZXYt (ORCPT ); Thu, 26 Mar 2020 19:24:49 -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 797E320409; Thu, 26 Mar 2020 23:24:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265089; bh=HZKph1vlL2+lbjT545LdjST3edbD4zKJanui7XS+8/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=awNVImfem1FjxMDX6/ArD9J0T/EkPE31LyCBS9kNiWvrkLzlIjCIQqdWuhXXn0IsP KJUEZZLuh2Jn1f1AcKnfmEFJ1NMS0d12xgo5YSuipSwNpRtvlql6itKm5qX39YvWrG TEWdCKYZTxRqb7XlrZtGd33jsZqimch4ZkC9Z+qk= 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 5.4 15/19] ALSA: pcm: oss: Avoid plugin buffer overflow Date: Thu, 26 Mar 2020 19:24:27 -0400 Message-Id: <20200326232431.7816-15-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232431.7816-1-sashal@kernel.org> References: <20200326232431.7816-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 31cb2acf8afcc..9b588c6a6f099 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