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 AB739C31E5C for ; Mon, 17 Jun 2019 21:28:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7674621734 for ; Mon, 17 Jun 2019 21:28:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560806934; bh=01JgqLU+q/jditVF0XnE6iIetBdTeaxf7YEBoD9AiAg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ugu/1DEVyjN1t7Hzt4fGpf7+jwrGChwgs7+OdFx31NhM6+/JHm8d5uZugmMO05Oe/ +Iv8A5+5mQfYYJ+AKAiQVPNLvvwuTU0NY38KT0GHEE6wGdpuDS1TJk59bAulpjIUBX tqTnAcy26IT0pKfjhxLfVfZNjiifKHv7qvX3zpLQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730619AbfFQV2x (ORCPT ); Mon, 17 Jun 2019 17:28:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:55950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729031AbfFQV2t (ORCPT ); Mon, 17 Jun 2019 17:28:49 -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 34097204FD; Mon, 17 Jun 2019 21:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560806928; bh=01JgqLU+q/jditVF0XnE6iIetBdTeaxf7YEBoD9AiAg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YMxFLr+Gh/T3nvyFie3z1ngr0niiAbj8mK2n2/SfyOTDG+Zb1t3T3KpbfHFZRXjjE BvsE9jmyh7UUykoBmztOwBJhdSPS0GSGASJA+Vuj8OzuqF2XH5gT5U0FL7Ro9W/2pT Bta/TGe9RDMwXNPRXSFnbruSCOin4i8uuoFOrytg= 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 4.14 23/53] ALSA: seq: Protect in-kernel ioctl calls with mutex Date: Mon, 17 Jun 2019 23:10:06 +0200 Message-Id: <20190617210749.935047820@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190617210745.104187490@linuxfoundation.org> References: <20190617210745.104187490@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 3bcd7a2f0394..692631bd4a35 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -2348,14 +2348,19 @@ 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