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,URIBL_BLOCKED,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 D1B0DC2BA15 for ; Wed, 1 Apr 2020 16:35:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9538720857 for ; Wed, 1 Apr 2020 16:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585758903; bh=AL7hoBSzUmkmWDlkQMwp9cp9Ui5kceVTauOdV7/oyJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nsfQT1mE7jnBqLSTO2WDp6sdawXIar/0lJuC+pflH5KQH7kltPbswp/RnXyQVB2+3 89xhZ5GAUjevgmVuFWyU5ttpfVfIJE1TPPPHO7dc9fAMvupxgQzPuGsrcj76pp63N9 HaQcL8zzNi5+gWRrLbdo4p52yCFD0u2gVGi0zXrQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388703AbgDAQfC (ORCPT ); Wed, 1 Apr 2020 12:35:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:33684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387470AbgDAQfA (ORCPT ); Wed, 1 Apr 2020 12:35:00 -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 9EE1820658; Wed, 1 Apr 2020 16:34:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585758900; bh=AL7hoBSzUmkmWDlkQMwp9cp9Ui5kceVTauOdV7/oyJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0htzdNIOC+BnhGKekAPBtMOuOhF/dhlRqYRi4yCvggrTCXAK84j8CKUpXZyn6a53q o4P6/eIIuri3Ibv5bezINfwlFyBJ9r80T3ejRReStLoms3Z6mjlilhjronEdPj/+hn LZ3l+3Lif6Kdsiv7PMqUSdSlZVdzyLqX7jHqm5dU= 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 4.9 016/102] ALSA: pcm: oss: Avoid plugin buffer overflow Date: Wed, 1 Apr 2020 18:17:19 +0200 Message-Id: <20200401161535.218243378@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200401161530.451355388@linuxfoundation.org> References: <20200401161530.451355388@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 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);