From patchwork Mon Dec 28 12:48:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353958 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 9EF6DC433E9 for ; Mon, 28 Dec 2020 12:53:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DA38208B6 for ; Mon, 28 Dec 2020 12:53:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727924AbgL1Mwx (ORCPT ); Mon, 28 Dec 2020 07:52:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:49800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727913AbgL1Mwx (ORCPT ); Mon, 28 Dec 2020 07:52:53 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 967EF229C5; Mon, 28 Dec 2020 12:51:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609159913; bh=IBN4FXt4kUT2e8XoT0yEQUrj7qMsz1qCie4Ktrr0Kto=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gc3GvmnsWTfYGE9Tp94q3uaVAbF+lnAjdReYaibUs+OoL4ou6n5oUHmoMu6gH4hB6 GLYBnlo7SSEauNo+ezMiTx+tuID6WybPVBthiz3/IJtUEeyzNyZMm7c4QEJ744AcMt QYKcFd/uMxW7N70Mz91gds0Ry98t4KpOxNFE/O3c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 4.4 019/132] ALSA: pcm: oss: Fix potential out-of-bounds shift Date: Mon, 28 Dec 2020 13:48:23 +0100 Message-Id: <20201228124847.339806144@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124846.409999325@linuxfoundation.org> References: <20201228124846.409999325@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai commit 175b8d89fe292796811fdee87fa39799a5b6b87a upstream. syzbot spotted a potential out-of-bounds shift in the PCM OSS layer where it calculates the buffer size with the arbitrary shift value given via an ioctl. Add a range check for avoiding the undefined behavior. As the value can be treated by a signed integer, the max shift should be 30. Reported-by: syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/20201209084552.17109-2-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/oss/pcm_oss.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -2000,11 +2000,15 @@ static int snd_pcm_oss_set_subdivide(str static int snd_pcm_oss_set_fragment1(struct snd_pcm_substream *substream, unsigned int val) { struct snd_pcm_runtime *runtime; + int fragshift; runtime = substream->runtime; if (runtime->oss.subdivision || runtime->oss.fragshift) return -EINVAL; - runtime->oss.fragshift = val & 0xffff; + fragshift = val & 0xffff; + if (fragshift >= 31) + return -EINVAL; + runtime->oss.fragshift = fragshift; runtime->oss.maxfrags = (val >> 16) & 0xffff; if (runtime->oss.fragshift < 4) /* < 16 */ runtime->oss.fragshift = 4;