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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 474D7C282CA for ; Wed, 13 Feb 2019 02:52:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11AE521934 for ; Wed, 13 Feb 2019 02:52:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550026377; bh=/bfzr3pbD935cBixdWG+eeuqkmEhXexT/CsAvfbMrO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lH/M48RTLsN8kgXhVIVNpf59tW6F3+W1sf1O15+jfKQPVIOkdBP0TikF1aezADhUg Vuq37Bjcup70gqIs/68ci7ynN/a7846234iODLnaHrubmD9Y2tCI5INh3SiZkhCzyP or50qUW2FAqnmeDXKutcmnnMvwjChiyX44y8H0d8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389611AbfBMCww (ORCPT ); Tue, 12 Feb 2019 21:52:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:41978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388439AbfBMCi1 (ORCPT ); Tue, 12 Feb 2019 21:38:27 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 179E0222C7; Wed, 13 Feb 2019 02:38:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025506; bh=/bfzr3pbD935cBixdWG+eeuqkmEhXexT/CsAvfbMrO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tT+HDnqy2BaRMY+DgnHBJN93G62Af+/Sy6iGfUebdu3w2/MkWE+cxpWbK1o/w4LKr 2/5jLcEbOv5jnobWZFjzRQiBP77nKJZ7YujQc+R/37zhzW9bVCofeTixPY3nEZJ/1D lzjvxK8gkxJbh7bnCn6U1ruhdzb6ByEPdDJKWifc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jia-Ju Bai , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 50/83] isdn: i4l: isdn_tty: Fix some concurrency double-free bugs Date: Tue, 12 Feb 2019 21:36:28 -0500 Message-Id: <20190213023701.20286-50-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190213023701.20286-1-sashal@kernel.org> References: <20190213023701.20286-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jia-Ju Bai [ 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 b730037a0e2d..9cff667b2d24 100644 --- a/drivers/isdn/i4l/isdn_tty.c +++ b/drivers/isdn/i4l/isdn_tty.c @@ -1456,15 +1456,19 @@ 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