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=-8.7 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=unavailable 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 84254C31E45 for ; Thu, 13 Jun 2019 16:24:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59ACF20644 for ; Thu, 13 Jun 2019 16:24:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560443069; bh=01JgqLU+q/jditVF0XnE6iIetBdTeaxf7YEBoD9AiAg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ggOZBymZkPKzx1h9o7WfoykoO0KU8iqoFNStnWfWD/kSSF5Az0pkjzKVNaBUgzMZv fbU5Ye4v1o3/AoN7x0wW5LTYP/zjJxa4QpLoqArnc2PmzUD68Tka/OyRJnua6WwdDQ RaPgEMBlQUpNdIG5m32QoaWDiRPEMuui89yDLTNs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391806AbfFMQYZ (ORCPT ); Thu, 13 Jun 2019 12:24:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:54618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730998AbfFMIhP (ORCPT ); Thu, 13 Jun 2019 04:37:15 -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 F2A4220851; Thu, 13 Jun 2019 08:37:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560415034; bh=01JgqLU+q/jditVF0XnE6iIetBdTeaxf7YEBoD9AiAg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eX4NWguhGPmp13Bg2zpyUchZM2MIOiSwTATH0CP6i6bURb5zN1jQAf3CmJZ/czOtc 6o45FiXsUCTY9U/itTs3uQBERr46GN+fWHUWyICYw9QPNJkDQw2nZhsvB4fRUFn14C PN3P8ACUgNtl+BvLtRuhvZz+/KMhWp8abWR5LTTk= 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 61/81] ALSA: seq: Protect in-kernel ioctl calls with mutex Date: Thu, 13 Jun 2019 10:33:44 +0200 Message-Id: <20190613075653.581995283@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190613075649.074682929@linuxfoundation.org> References: <20190613075649.074682929@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