Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754656AbaGULCH (ORCPT ); Mon, 21 Jul 2014 07:02:07 -0400 Received: from smtp.ispras.ru ([83.149.199.79]:48017 "EHLO smtp.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754350AbaGULCE (ORCPT ); Mon, 21 Jul 2014 07:02:04 -0400 X-Greylist: delayed 359 seconds by postgrey-1.27 at vger.kernel.org; Mon, 21 Jul 2014 07:02:04 EDT Message-ID: <53CCF1EC.30008@ispras.ru> Date: Mon, 21 Jul 2014 14:56:44 +0400 From: Andrey Tsyvarev User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Jaegeuk Kim CC: linux-f2fs-devel@lists.sourceforge.net, linux-kernel , Alexey Khoroshilov Subject: f2fs: Possible use-after-free when umount filesystem References: <52F320FC.50803@ispras.ru> <534BC29B.3020408@ispras.ru> In-Reply-To: <534BC29B.3020408@ispras.ru> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Using memory error detector reveals the following use-after-free error in 3.15.0: AddressSanitizer: heap-use-after-free in f2fs_evict_inode Read of size 8 by thread T22279: [] f2fs_evict_inode+0x102/0x2e0 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/f2fs.h:584 [] evict+0x15f/0x290 /home/tester/linux-sources/linux-kasan/fs/inode.c:550 [< inlined >] iput+0x196/0x280 iput_final /home/tester/linux-sources/linux-kasan/fs/inode.c:1418 [] iput+0x196/0x280 /home/tester/linux-sources/linux-kasan/fs/inode.c:1436 [] f2fs_put_super+0xd6/0x170 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/super.c:434 [] generic_shutdown_super+0xc5/0x1b0 /home/tester/linux-sources/linux-kasan/fs/super.c:406 [] kill_block_super+0x4d/0xb0 /home/tester/linux-sources/linux-kasan/fs/super.c:1019 [] deactivate_locked_super+0x66/0x80 /home/tester/linux-sources/linux-kasan/fs/super.c:284 [] deactivate_super+0x68/0x80 /home/tester/linux-sources/linux-kasan/fs/super.c:307 [] mntput_no_expire+0x198/0x250 /home/tester/linux-sources/linux-kasan/fs/namespace.c:986 (discriminator 3) [< inlined >] SyS_umount+0xe9/0x1a0 SYSC_umount /home/tester/linux-sources/linux-kasan/fs/namespace.c:1424 [] SyS_umount+0xe9/0x1a0 /home/tester/linux-sources/linux-kasan/fs/namespace.c:1392 [] system_call_fastpath+0x16/0x1b /home/tester/linux-sources/linux-kasan/arch/x86/kernel/entry_64.S:426 Freed by thread T3: [] f2fs_i_callback+0x27/0x30 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/super.c:408 [< inlined >] rcu_process_callbacks+0x2d6/0x930 __rcu_reclaim /home/tester/linux-sources/linux-kasan/kernel/rcu/rcu.h:114 [< inlined >] rcu_process_callbacks+0x2d6/0x930 rcu_do_batch /home/tester/linux-sources/linux-kasan/kernel/rcu/tree.c:2242 [< inlined >] rcu_process_callbacks+0x2d6/0x930 invoke_rcu_callbacks /home/tester/linux-sources/linux-kasan/kernel/rcu/tree.c:2499 [< inlined >] rcu_process_callbacks+0x2d6/0x930 __rcu_process_callbacks /home/tester/linux-sources/linux-kasan/kernel/rcu/tree.c:2466 [] rcu_process_callbacks+0x2d6/0x930 /home/tester/linux-sources/linux-kasan/kernel/rcu/tree.c:2483 [] __do_softirq+0x142/0x380 /home/tester/linux-sources/linux-kasan/kernel/softirq.c:269 [] run_ksoftirqd+0x30/0x50 /home/tester/linux-sources/linux-kasan/kernel/softirq.c:658 [] smpboot_thread_fn+0x197/0x280 /home/tester/linux-sources/linux-kasan/kernel/smpboot.c:160 [] kthread+0x148/0x160 /home/tester/linux-sources/linux-kasan/kernel/kthread.c:207 [] ret_from_fork+0x7c/0xb0 /home/tester/linux-sources/linux-kasan/arch/x86/kernel/entry_64.S:351 Allocated by thread T22276: [] f2fs_alloc_inode+0x2d/0x170 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/super.c:356 [] alloc_inode+0x2d/0xe0 /home/tester/linux-sources/linux-kasan/fs/inode.c:208 [] iget_locked+0x10a/0x230 /home/tester/linux-sources/linux-kasan/fs/inode.c:1085 [] f2fs_iget+0x35/0xa80 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/inode.c:129 [] f2fs_fill_super+0xb53/0xff0 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/super.c:1021 [] mount_bdev+0x1de/0x240 /home/tester/linux-sources/linux-kasan/fs/super.c:992 [] f2fs_mount+0x10/0x20 [f2fs] /home/tester/linux-sources/linux-kasan/fs/f2fs/super.c:1127 [] mount_fs+0x55/0x220 /home/tester/linux-sources/linux-kasan/fs/super.c:1095 [] vfs_kern_mount+0x66/0x200 /home/tester/linux-sources/linux-kasan/fs/namespace.c:851 [< inlined >] do_mount+0x2b4/0x1120 do_new_mount /home/tester/linux-sources/linux-kasan/fs/namespace.c:2129 [] do_mount+0x2b4/0x1120 /home/tester/linux-sources/linux-kasan/fs/namespace.c:2453 [< inlined >] SyS_mount+0xb2/0x110 SYSC_mount /home/tester/linux-sources/linux-kasan/fs/namespace.c:2647 [] SyS_mount+0xb2/0x110 /home/tester/linux-sources/linux-kasan/fs/namespace.c:2620 [] system_call_fastpath+0x16/0x1b /home/tester/linux-sources/linux-kasan/arch/x86/kernel/entry_64.S:426 The buggy address ffff8800587866c8 is located 48 bytes inside of 680-byte region [ffff880058786698, ffff880058786940) Memory state around the buggy address: ffff880058786100: ffffffff ffffffff ffffffff ffffffff ffff880058786200: ffffffff ffffffff ffffffrr rrrrrrrr ffff880058786300: rrrrrrrr rrffffff ffffffff ffffffff ffff880058786400: ffffffff ffffffff ffffffff ffffffff ffff880058786500: ffffffff ffffffff ffffffff fffffffr >ffff880058786600: rrrrrrrr rrrrrrrr rrrfffff ffffffff ^ ffff880058786700: ffffffff ffffffff ffffffff ffffffff ffff880058786800: ffffffff ffffffff ffffffff ffffffff ffff880058786900: ffffffff rrrrrrrr rrrrrrrr rrrr.... ffff880058786a00: ........ ........ ........ ........ ffff880058786b00: ........ ........ ........ ........ Legend: f - 8 freed bytes r - 8 redzone bytes . - 8 allocated bytes x=1..7 - x allocated bytes + (8-x) redzone bytes Investigation shows, that f2fs_evict_inode, when called for 'meta_inode', uses invalidate_mapping_pages() for 'node_inode'. But 'node_inode' is deleted before 'meta_inode' in f2fs_put_super via iput(). It seems that in common usage scenario this use-after-free is benign, because 'node_inode' remains partially valid data even after kmem_cache_free(). But things may change if, while 'meta_inode' is evicted in one f2fs filesystem, another (mounted) f2fs filesystem requests inode from cache, and formely 'node_inode' of the first filesystem is returned. Found by Linux File System Verification project (linuxtesting.org). -- Best regards, Andrey Tsyvarev Linux Verification Center, ISPRAS web:http://linuxtesting.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/