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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,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 51A23C43381 for ; Mon, 25 Feb 2019 21:43:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1EAB820652 for ; Mon, 25 Feb 2019 21:43:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130994; bh=wiFuo/dAQgp+VzKIWwCoe207TcTApLD2b7rhMUTcB34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=u+benFeIYPGIWJx8w5bAfZ5/VtrszZOv9NXcxWwAyGBHVInAJ5ALGCPQoMUPhuuwZ YoflrHWmk/vZTU3Gyoe4v98JXHlEJavwXq67mDTVY6aP6+vtHgDFzh1VL8c6mSYjTp W8Lm28lcTmVOkHEkTPlcaNvXiCaHyWXMybTYqUS4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730092AbfBYVnM (ORCPT ); Mon, 25 Feb 2019 16:43:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:37158 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732325AbfBYVbe (ORCPT ); Mon, 25 Feb 2019 16:31:34 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 58078217F5; Mon, 25 Feb 2019 21:31:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130293; bh=wiFuo/dAQgp+VzKIWwCoe207TcTApLD2b7rhMUTcB34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qNzTzarLMQln8nww/0x9XYDHbfc8mMlqgEC3xsnbK0fdamb5//y0ZTpsLdcDaEuKY uChNHEC4wtziWdj3hi8dpvxAymRSgfubto6h0xcOY15E5IVfm51GoxTrRmwW9yBVrP Hp64YgQ4nvntmOTKbcRVr1l4UmoVLF3MYGAJIKtY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jia-Ju Bai , "David S. Miller" , Sasha Levin Subject: [PATCH 4.20 076/183] isdn: i4l: isdn_tty: Fix some concurrency double-free bugs Date: Mon, 25 Feb 2019 22:10:49 +0100 Message-Id: <20190225195107.276849007@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190225195054.748060397@linuxfoundation.org> References: <20190225195054.748060397@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 2ff33d6637393fe9348357285931811b76e1402f ] The functions isdn_tty_tiocmset() and isdn_tty_set_termios() may be concurrently executed. isdn_tty_tiocmset isdn_tty_modem_hup line 719: kfree(info->dtmf_state); line 721: kfree(info->silence_state); line 723: kfree(info->adpcms); line 725: kfree(info->adpcmr); isdn_tty_set_termios isdn_tty_modem_hup line 719: kfree(info->dtmf_state); line 721: kfree(info->silence_state); line 723: kfree(info->adpcms); line 725: kfree(info->adpcmr); Thus, some concurrency double-free bugs may occur. These possible bugs are found by a static tool written by myself and my manual code review. To fix these possible bugs, the mutex lock "modem_info_mutex" used in isdn_tty_tiocmset() is added in isdn_tty_set_termios(). Signed-off-by: Jia-Ju Bai Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/isdn/i4l/isdn_tty.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c index 1b2239c1d5694..dc1cded716c1a 100644 --- a/drivers/isdn/i4l/isdn_tty.c +++ b/drivers/isdn/i4l/isdn_tty.c @@ -1437,15 +1437,19 @@ isdn_tty_set_termios(struct tty_struct *tty, struct ktermios *old_termios) { modem_info *info = (modem_info *) tty->driver_data; + mutex_lock(&modem_info_mutex); if (!old_termios) isdn_tty_change_speed(info); else { if (tty->termios.c_cflag == old_termios->c_cflag && tty->termios.c_ispeed == old_termios->c_ispeed && - tty->termios.c_ospeed == old_termios->c_ospeed) + tty->termios.c_ospeed == old_termios->c_ospeed) { + mutex_unlock(&modem_info_mutex); return; + } isdn_tty_change_speed(info); } + mutex_unlock(&modem_info_mutex); } /* -- 2.19.1