From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-564561-1519835445-2-444777070694651523 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519835445; b=M/S4tf/MAn8L9K9x1D7RwT73zyAiU0XC01hMxSjWs42b/T5 sCCbtai4KmazAQ9VpG4yl3+utTFfEpeugHHSqRIWc+laxlPk1TSJ0GcghUNuLGkp CNxEC1HCoVSHwkJfFTCyIx3KvPnNTZvozcOCo+oauvy34J0k3X2kLc9tR4vFvQal 0oXDjHqdDSUegSdhujxxGOXeDoG7OqcnD/IOyXl8HHiSoEYPy+xpsE+bt8PDHDg1 KfukclccahUC32OEdKrVhAtrIMu5Xms7HKQoJBpY/GB9zYjkd9+ImQb5ZC8f8FfM WGzbSybbCGiDjPeWV4KEJXT2Dpw/t1c9bQfwAqQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1519835445; bh=Sa+ICi0zGMD19VtYg1X f17OsNRFR+RxK2xnp3J7RASw=; b=DHhrcZirPgQQ+PH+hF3R0XK6HmxfDx+EhRt GA+pfVwxYgl9/fbyHGajU5RvOBxdXnr+Xx278QDjO3+wG5P4gj4JdAE6t+Kyb5HQ JkGZ1mYrj9vAqBTKK6pDPidyjuJLd/NoqtAmmZCg5TCYicpPUUsmBh/UW/nT/+CK j1rjGsRYF+On9DlkvwGsX1g5ULyQlgVPvO5WlCXYukjgsLXnDt+S8giU9GhCmuZl rgcBaqccjGnO/AktszEexgkXrPjeLuZOwEJQ+++WxyJYfXJWyp0ncQr7SDmH84lf z0NjlGeInNc4VJTbRJaUEjciruW61bfTvQcn5U7QKx/QrMJGHlA== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934763AbeB1QPK (ORCPT ); Wed, 28 Feb 2018 11:15:10 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35155 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934746AbeB1QPI (ORCPT ); Wed, 28 Feb 2018 11:15:08 -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, "Takashi Iwai" Date: Wed, 28 Feb 2018 15:20:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 113/254] ALSA: rawmidi: Avoid racy info ioctl via ctl device In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.16.55-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit c1cfd9025cc394fd137a01159d74335c5ac978ce upstream. The rawmidi also allows to obtaining the information via ioctl of ctl API. It means that user can issue an ioctl to the rawmidi device even when it's being removed as long as the control device is present. Although the code has some protection via the global register_mutex, its range is limited to the search of the corresponding rawmidi object, and the mutex is already unlocked at accessing the rawmidi object. This may lead to a use-after-free. For avoiding it, this patch widens the application of register_mutex to the whole snd_rawmidi_info_select() function. We have another mutex per rawmidi object, but this operation isn't very hot path, so it shouldn't matter from the performance POV. Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- sound/core/rawmidi.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -589,15 +589,14 @@ static int snd_rawmidi_info_user(struct return 0; } -int snd_rawmidi_info_select(struct snd_card *card, struct snd_rawmidi_info *info) +static int __snd_rawmidi_info_select(struct snd_card *card, + struct snd_rawmidi_info *info) { struct snd_rawmidi *rmidi; struct snd_rawmidi_str *pstr; struct snd_rawmidi_substream *substream; - mutex_lock(®ister_mutex); rmidi = snd_rawmidi_search(card, info->device); - mutex_unlock(®ister_mutex); if (!rmidi) return -ENXIO; if (info->stream < 0 || info->stream > 1) @@ -613,6 +612,16 @@ int snd_rawmidi_info_select(struct snd_c } return -ENXIO; } + +int snd_rawmidi_info_select(struct snd_card *card, struct snd_rawmidi_info *info) +{ + int ret; + + mutex_lock(®ister_mutex); + ret = __snd_rawmidi_info_select(card, info); + mutex_unlock(®ister_mutex); + return ret; +} EXPORT_SYMBOL(snd_rawmidi_info_select); static int snd_rawmidi_info_select_user(struct snd_card *card,