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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 AD515C41621 for ; Tue, 24 Mar 2020 13:33:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 874E02076E for ; Tue, 24 Mar 2020 13:33:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585056814; bh=AL7hoBSzUmkmWDlkQMwp9cp9Ui5kceVTauOdV7/oyJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=im04Gsv0/zWCamZ+J33DFPWyXVceGdx+WSTdJDLum+cpdnAfkZwftX0fLJWtGjl8Y LsLjmZpEFJXpyt8l5nV1KHBtLGN2ikGBfIilW5a/4xQrMshfBraHicJDthDPPyWpCt aYDPV6Tp3iRtLM2mGEHu6du2mmrwKiiEiBJ6KznU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727772AbgCXNNB (ORCPT ); Tue, 24 Mar 2020 09:13:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:58990 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727736AbgCXNM5 (ORCPT ); Tue, 24 Mar 2020 09:12:57 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ECC8F208D6; Tue, 24 Mar 2020 13:12:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585055577; bh=AL7hoBSzUmkmWDlkQMwp9cp9Ui5kceVTauOdV7/oyJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gc1X/JStsTWXQgOB5BCrzmDAQdUHJCy6taxbxde6FP0OKmKP+9zfWFyOQ43h/t0V8 exA0inf3ZvtvuYLc3WLnArc5ehu4fTGQMxr4EXLRMuB57M9MQhwCAWxeKAT+MRptzx kjRLR+jCUr3lTzlJoyev9FQhxxad4S7JijAaN0A0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+e1fe9f44fb8ecf4fb5dd@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 4.19 29/65] ALSA: pcm: oss: Avoid plugin buffer overflow Date: Tue, 24 Mar 2020 14:10:50 +0100 Message-Id: <20200324130800.913385421@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200324130756.679112147@linuxfoundation.org> References: <20200324130756.679112147@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai commit f2ecf903ef06eb1bbbfa969db9889643d487e73a upstream. 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: Greg Kroah-Hartman --- sound/core/oss/pcm_plugin.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- 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_si 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_si 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_siz 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);