From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933286AbcBIAJN (ORCPT ); Mon, 8 Feb 2016 19:09:13 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59811 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755841AbcBHXyi (ORCPT ); Mon, 8 Feb 2016 18:54:38 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Nicolas Boichat" , "Takashi Iwai" Date: Mon, 08 Feb 2016 23:53:51 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 62/87] ALSA: pcm: Fix snd_pcm_hw_params struct copy in compat mode In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:a11:96ff:fe28:a980 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.77-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Nicolas Boichat commit 43c54b8c7cfe22f868a751ba8a59abf1724160b1 upstream. This reverts one hunk of commit ef44a1ec6eee ("ALSA: sound/core: use memdup_user()"), which replaced a number of kmalloc followed by memcpy with memdup calls. In this case, we are copying from a struct snd_pcm_hw_params32 to a struct snd_pcm_hw_params, but the latter is 4 bytes longer than the 32-bit version, so we need to separate kmalloc and copy calls. This actually leads to an out-of-bounds memory access later on in sound/soc/soc-pcm.c:soc_pcm_hw_params() (detected using KASan). Fixes: ef44a1ec6eee ('ALSA: sound/core: use memdup_user()') Signed-off-by: Nicolas Boichat Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- sound/core/pcm_compat.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/sound/core/pcm_compat.c +++ b/sound/core/pcm_compat.c @@ -235,10 +235,15 @@ static int snd_pcm_ioctl_hw_params_compa if (! (runtime = substream->runtime)) return -ENOTTY; - /* only fifo_size is different, so just copy all */ - data = memdup_user(data32, sizeof(*data32)); - if (IS_ERR(data)) - return PTR_ERR(data); + data = kmalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + /* only fifo_size (RO from userspace) is different, so just copy all */ + if (copy_from_user(data, data32, sizeof(*data32))) { + err = -EFAULT; + goto error; + } if (refine) err = snd_pcm_hw_refine(substream, data);