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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 19C25C5ACAE for ; Thu, 12 Sep 2019 10:52:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5EA0208C2 for ; Thu, 12 Sep 2019 10:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568285541; bh=FG0wlmvwJ52zKOcfojakrhjRCLZkbsr1odTsy7hLJGg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=eQqbmzjIA8YR174z8w58my+o/rSWlKQalxOlW/gjc2INbRIqhQ2B7HbqNmQzmiRV9 d3jj3Swjqjjdxmve79Qvtk1nefvzcBs+7YlhpT72dJr8vt/T8iLw66gQZ7xJjJk9Lv 2wwMuAjuTQde2oiOrTsg+g2jOTNBhrOiIHqKs34g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731240AbfILKwU (ORCPT ); Thu, 12 Sep 2019 06:52:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:53976 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731218AbfILKwU (ORCPT ); Thu, 12 Sep 2019 06:52:20 -0400 Received: from localhost (unknown [148.69.85.38]) (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 096D820678; Thu, 12 Sep 2019 10:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568285538; bh=FG0wlmvwJ52zKOcfojakrhjRCLZkbsr1odTsy7hLJGg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZneDnPDMVf5jVPIpR5e6lWjHCfdst55bqO0Gaz6OuvH0vXaepUqCWRX5b9xJwsO9x Nj2PPVyaVOxSwSdKE4XoFGI50A0lGd6DRii5auTD38FG34XTbMlF5KKEbOw1mV+7j8 Vn/avwq058NnCjTRA5kOuJJNzlouLlWgJEV148OY= Date: Thu, 12 Sep 2019 06:52:15 -0400 From: Sasha Levin To: Johannes Thumshirn Cc: stable@vger.kernel.org, Linux BTRFS Mailinglist Subject: Re: [PATCH for-4.19.x ] btrfs: correctly validate compression type Message-ID: <20190912105215.GC1546@sasha-vm> References: <20190912100259.7784-1-jthumshirn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190912100259.7784-1-jthumshirn@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Sep 12, 2019 at 12:02:59PM +0200, Johannes Thumshirn wrote: >[ Upstream commit aa53e3bfac7205fb3a8815ac1c937fd6ed01b41e ] > >Nikolay reported the following KASAN splat when running btrfs/048: > >[ 1843.470920] ================================================================== >[ 1843.471971] BUG: KASAN: slab-out-of-bounds in strncmp+0x66/0xb0 >[ 1843.472775] Read of size 1 at addr ffff888111e369e2 by task btrfs/3979 > >[ 1843.473904] CPU: 3 PID: 3979 Comm: btrfs Not tainted 5.2.0-rc3-default #536 >[ 1843.475009] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 >[ 1843.476322] Call Trace: >[ 1843.476674] dump_stack+0x7c/0xbb >[ 1843.477132] ? strncmp+0x66/0xb0 >[ 1843.477587] print_address_description+0x114/0x320 >[ 1843.478256] ? strncmp+0x66/0xb0 >[ 1843.478740] ? strncmp+0x66/0xb0 >[ 1843.479185] __kasan_report+0x14e/0x192 >[ 1843.479759] ? strncmp+0x66/0xb0 >[ 1843.480209] kasan_report+0xe/0x20 >[ 1843.480679] strncmp+0x66/0xb0 >[ 1843.481105] prop_compression_validate+0x24/0x70 >[ 1843.481798] btrfs_xattr_handler_set_prop+0x65/0x160 >[ 1843.482509] __vfs_setxattr+0x71/0x90 >[ 1843.483012] __vfs_setxattr_noperm+0x84/0x130 >[ 1843.483606] vfs_setxattr+0xac/0xb0 >[ 1843.484085] setxattr+0x18c/0x230 >[ 1843.484546] ? vfs_setxattr+0xb0/0xb0 >[ 1843.485048] ? __mod_node_page_state+0x1f/0xa0 >[ 1843.485672] ? _raw_spin_unlock+0x24/0x40 >[ 1843.486233] ? __handle_mm_fault+0x988/0x1290 >[ 1843.486823] ? lock_acquire+0xb4/0x1e0 >[ 1843.487330] ? lock_acquire+0xb4/0x1e0 >[ 1843.487842] ? mnt_want_write_file+0x3c/0x80 >[ 1843.488442] ? debug_lockdep_rcu_enabled+0x22/0x40 >[ 1843.489089] ? rcu_sync_lockdep_assert+0xe/0x70 >[ 1843.489707] ? __sb_start_write+0x158/0x200 >[ 1843.490278] ? mnt_want_write_file+0x3c/0x80 >[ 1843.490855] ? __mnt_want_write+0x98/0xe0 >[ 1843.491397] __x64_sys_fsetxattr+0xba/0xe0 >[ 1843.492201] ? trace_hardirqs_off_thunk+0x1a/0x1c >[ 1843.493201] do_syscall_64+0x6c/0x230 >[ 1843.493988] entry_SYSCALL_64_after_hwframe+0x49/0xbe >[ 1843.495041] RIP: 0033:0x7fa7a8a7707a >[ 1843.495819] Code: 48 8b 0d 21 de 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 be 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ee dd 2b 00 f7 d8 64 89 01 48 >[ 1843.499203] RSP: 002b:00007ffcb73bca38 EFLAGS: 00000202 ORIG_RAX: 00000000000000be >[ 1843.500210] RAX: ffffffffffffffda RBX: 00007ffcb73bda9d RCX: 00007fa7a8a7707a >[ 1843.501170] RDX: 00007ffcb73bda9d RSI: 00000000006dc050 RDI: 0000000000000003 >[ 1843.502152] RBP: 00000000006dc050 R08: 0000000000000000 R09: 0000000000000000 >[ 1843.503109] R10: 0000000000000002 R11: 0000000000000202 R12: 00007ffcb73bda91 >[ 1843.504055] R13: 0000000000000003 R14: 00007ffcb73bda82 R15: ffffffffffffffff > >[ 1843.505268] Allocated by task 3979: >[ 1843.505771] save_stack+0x19/0x80 >[ 1843.506211] __kasan_kmalloc.constprop.5+0xa0/0xd0 >[ 1843.506836] setxattr+0xeb/0x230 >[ 1843.507264] __x64_sys_fsetxattr+0xba/0xe0 >[ 1843.507886] do_syscall_64+0x6c/0x230 >[ 1843.508429] entry_SYSCALL_64_after_hwframe+0x49/0xbe > >[ 1843.509558] Freed by task 0: >[ 1843.510188] (stack is not available) > >[ 1843.511309] The buggy address belongs to the object at ffff888111e369e0 > which belongs to the cache kmalloc-8 of size 8 >[ 1843.514095] The buggy address is located 2 bytes inside of > 8-byte region [ffff888111e369e0, ffff888111e369e8) >[ 1843.516524] The buggy address belongs to the page: >[ 1843.517561] page:ffff88813f478d80 refcount:1 mapcount:0 mapping:ffff88811940c300 index:0xffff888111e373b8 compound_mapcount: 0 >[ 1843.519993] flags: 0x4404000010200(slab|head) >[ 1843.520951] raw: 0004404000010200 ffff88813f48b008 ffff888119403d50 ffff88811940c300 >[ 1843.522616] raw: ffff888111e373b8 000000000016000f 00000001ffffffff 0000000000000000 >[ 1843.524281] page dumped because: kasan: bad access detected > >[ 1843.525936] Memory state around the buggy address: >[ 1843.526975] ffff888111e36880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >[ 1843.528479] ffff888111e36900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >[ 1843.530138] >ffff888111e36980: fc fc fc fc fc fc fc fc fc fc fc fc 02 fc fc fc >[ 1843.531877] ^ >[ 1843.533287] ffff888111e36a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >[ 1843.534874] ffff888111e36a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >[ 1843.536468] ================================================================== > >This is caused by supplying a too short compression value ('lz') in the >test-case and comparing it to 'lzo' with strncmp() and a length of 3. >strncmp() read past the 'lz' when looking for the 'o' and thus caused an >out-of-bounds read. > >Introduce a new check 'btrfs_compress_is_valid_type()' which not only >checks the user-supplied value against known compression types, but also >employs checks for too short values. > >Reported-by: Nikolay Borisov >Fixes: 272e5326c783 ("btrfs: prop: fix vanished compression property after failed set") >CC: stable@vger.kernel.org # 5.1+ >Reviewed-by: Nikolay Borisov >Signed-off-by: Johannes Thumshirn >Reviewed-by: David Sterba >Signed-off-by: David Sterba It's already sitting in the queue, thank you :) -- Thanks, Sasha