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 35261C282C4 for ; Wed, 13 Feb 2019 02:42:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2B81222C1 for ; Wed, 13 Feb 2019 02:42:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025757; bh=u9W1CarKLeoCOo524XgXUxG4UFkYEXwIi0w8kxn1GZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qZ/aCMh4VnE8/P7ORCiRrk5nxcFjTdSi1Sldyo5R4nlE6+CtFycbR+xAVARZ3QnA2 v2KZdjZD4eei76elsuVo0fr2lBsDv9Vk5dDsXEQ6IjoCJsVMDKON+7QB4NqzWfeddc cX4Au2zR2iyebq2YoE5WKM2fhnYm69WVY5TBDKcc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387934AbfBMCmc (ORCPT ); Tue, 12 Feb 2019 21:42:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:45612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389397AbfBMCl5 (ORCPT ); Tue, 12 Feb 2019 21:41:57 -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 84E222175B; Wed, 13 Feb 2019 02:41:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025716; bh=u9W1CarKLeoCOo524XgXUxG4UFkYEXwIi0w8kxn1GZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PS0+SE1JpHLEIwkKgnuxk7iLP+jUDVR8Lsnt1WJSKfEy7uykYiyBkMYqvkiTr8QKL a247tuO90FkL9pFguXBU6cM9JwANIIWKbCaV83Z3iRpwa1RZ0b/TQnH5vhNW82FKI4 c1qegF/ZLEQRsMpSmp13dB8kkOpdJs42NG+V+hz8= 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 3.18 11/14] isdn: i4l: isdn_tty: Fix some concurrency double-free bugs Date: Tue, 12 Feb 2019 21:41:35 -0500 Message-Id: <20190213024139.22268-11-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190213024139.22268-1-sashal@kernel.org> References: <20190213024139.22268-1-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 bc912611fe09..b166354b8042 100644 --- a/drivers/isdn/i4l/isdn_tty.c +++ b/drivers/isdn/i4l/isdn_tty.c @@ -1459,15 +1459,19 @@ 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