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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 CCDDBC433DF for ; Tue, 9 Jun 2020 18:11:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B160D20734 for ; Tue, 9 Jun 2020 18:11:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388411AbgFISLg (ORCPT ); Tue, 9 Jun 2020 14:11:36 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41258 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388137AbgFISF5 (ORCPT ); Tue, 9 Jun 2020 14:05:57 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jiidE-0001oJ-NA; Tue, 09 Jun 2020 19:05:52 +0100 Received: from ben by deadeye with local (Exim 4.94) (envelope-from ) id 1jiidE-006VuX-50; Tue, 09 Jun 2020 19:05:52 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Jouni Hogander" , "David Miller" , "Lukas Bulwahn" , "Oliver Hartkopp" , "Wolfgang Grandegger" , "Marc Kleine-Budde" Date: Tue, 09 Jun 2020 19:03:53 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 02/61] can: slcan: Fix use-after-free Read in slcan_open In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.85-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jouni Hogander commit 9ebd796e24008f33f06ebea5a5e6aceb68b51794 upstream. Slcan_open doesn't clean-up device which registration failed from the slcan_devs device list. On next open this list is iterated and freed device is accessed. Fix this by calling slc_free_netdev in error path. Driver/net/can/slcan.c is derived from slip.c. Use-after-free error was identified in slip_open by syzboz. Same bug is in slcan.c. Here is the trace from the Syzbot slip report: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:634 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 sl_sync drivers/net/slip/slip.c:725 [inline] slip_open+0xecd/0x11b7 drivers/net/slip/slip.c:801 tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:469 tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:596 tiocsetd drivers/tty/tty_io.c:2334 [inline] tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2594 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: ed50e1600b44 ("slcan: Fix memory leak in error path") Cc: Wolfgang Grandegger Cc: Marc Kleine-Budde Cc: David Miller Cc: Oliver Hartkopp Cc: Lukas Bulwahn Signed-off-by: Jouni Hogander Acked-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde [bwh: Backported to 3.16: slc_free_netdev() calls free_netdev() here, so delete the direct call to free_netdev()] Signed-off-by: Ben Hutchings --- --- a/drivers/net/can/slcan.c +++ b/drivers/net/can/slcan.c @@ -620,7 +620,7 @@ err_free_chan: sl->tty = NULL; tty->disc_data = NULL; clear_bit(SLF_INUSE, &sl->flags); - free_netdev(sl->dev); + slc_free_netdev(sl->dev); err_exit: rtnl_unlock();