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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 D7CAAC31E5D for ; Mon, 17 Jun 2019 21:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2E6C20657 for ; Mon, 17 Jun 2019 21:36:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560807402; bh=H5s03YtNMgZZCgh2/o5/ZQ9c/DeSnUl0LjC1EaxMO9U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MgHs1GYM82CwETyQF+c9XufWLECR9vuPURkV7CGeb2XWAvWMIUe3gqF4SlvuI6UjH QeFBT/AT+ofkj43SNumtEmjKEqTBFEpRTpqPYDxHLihj/tsg/wzFeBWUGKu5RJsd4Y vduaAauFQwKIYV/Rp9uu+4Vu9IEPK04H9YSDqTGs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728752AbfFQVVH (ORCPT ); Mon, 17 Jun 2019 17:21:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:45486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729267AbfFQVVC (ORCPT ); Mon, 17 Jun 2019 17:21:02 -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 6C92F2089E; Mon, 17 Jun 2019 21:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560806461; bh=H5s03YtNMgZZCgh2/o5/ZQ9c/DeSnUl0LjC1EaxMO9U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PiZh5Zb3xRpqlFb0TW9FL5u7oQJVPc/+7r2RJKS5vSClPS2VxAhgMVMBZsWJtmF8F LQY9s2ikw2w/hifxbxPSvpSfbUkvoFZKkgyiLLLqLCnZwvXv5p/Ky0BP0bVRSdyY/q NRe5io3i9KySkZRcyytkGY4OMKKllJccrW/uJjtk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+e4c8abb920efa77bace9@syzkaller.appspotmail.com, Takashi Iwai , Sasha Levin Subject: [PATCH 5.1 043/115] ALSA: seq: Protect in-kernel ioctl calls with mutex Date: Mon, 17 Jun 2019 23:09:03 +0200 Message-Id: <20190617210802.258998943@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190617210759.929316339@linuxfoundation.org> References: <20190617210759.929316339@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 [ Upstream commit feb689025fbb6f0aa6297d3ddf97de945ea4ad32 ] ALSA OSS sequencer calls the ioctl function indirectly via snd_seq_kernel_client_ctl(). While we already applied the protection against races between the normal ioctls and writes via the client's ioctl_mutex, this code path was left untouched. And this seems to be the cause of still remaining some rare UAF as spontaneously triggered by syzkaller. For the sake of robustness, wrap the ioctl_mutex also for the call via snd_seq_kernel_client_ctl(), too. Reported-by: syzbot+e4c8abb920efa77bace9@syzkaller.appspotmail.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/seq/seq_clientmgr.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index 38e7deab6384..b3280e81bfd1 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -2343,14 +2343,19 @@ int snd_seq_kernel_client_ctl(int clientid, unsigned int cmd, void *arg) { const struct ioctl_handler *handler; struct snd_seq_client *client; + int err; client = clientptr(clientid); if (client == NULL) return -ENXIO; for (handler = ioctl_handlers; handler->cmd > 0; ++handler) { - if (handler->cmd == cmd) - return handler->func(client, arg); + if (handler->cmd == cmd) { + mutex_lock(&client->ioctl_mutex); + err = handler->func(client, arg); + mutex_unlock(&client->ioctl_mutex); + return err; + } } pr_debug("ALSA: seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n", -- 2.20.1