From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 371DF14A633; Thu, 23 May 2024 13:20:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716470409; cv=none; b=ccVlUrM/hz+r1C/sXeDXKoLjv6S7gchiOD9WAuKpCSvZgw7gAdveSwM6KfFQnt3L1B216BG5xHZNiZsawKqHimcU1EH290xBl1zQrlvm07miMQk9jrESmtIYTgvI7+tqul4gyYCRVZ2WFxknBbIgy/XakWZUwMBxlNfmd5Ok2E8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716470409; c=relaxed/simple; bh=jFQpfPzSRYM/6cfIXxhCWe2mpzmn1rJyqLnIZNdzAUA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oZ9Gye5/tpu7NZq70hCWLiYu2RgRDp9WjQ6ToGJ1GcqpQzAKqRmm1tUSFGZ87se9PqFXOUxRrRbHxZD6/hxXXWNgFtTD26mfrEaZw62o6Rkqq3nz8ek6cAg21/ZevHbIwAYduzB4pAtW8y92pSDfMmhs7Xok7i/ZmrNu918JLYQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=v8zSxUdj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="v8zSxUdj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D52CC32786; Thu, 23 May 2024 13:20:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1716470408; bh=jFQpfPzSRYM/6cfIXxhCWe2mpzmn1rJyqLnIZNdzAUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v8zSxUdjvUJ8weyz3/czLcFSq3Bp3oFibJaEwFzabInTJSRSfDumldkPhVMnUo2GQ k/zfe8ictNja4SBtyu/Xrpj4NumxqwAnE8BaelHcSPiZaLwMeY9Tr3PhDYWfRcope4 fw9JbnZI3Qbcndcy7HwrQ1HoEKxQRXkHz+tl+qY4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Guo Xuenan , "Darrick J. Wong" , Leah Rumancik Subject: [PATCH 6.1 26/45] xfs: fix super block buf log item UAF during force shutdown Date: Thu, 23 May 2024 15:13:17 +0200 Message-ID: <20240523130333.483183696@linuxfoundation.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240523130332.496202557@linuxfoundation.org> References: <20240523130332.496202557@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guo Xuenan [ Upstream commit 575689fc0ffa6c4bb4e72fd18e31a6525a6124e0 ] xfs log io error will trigger xlog shut down, and end_io worker call xlog_state_shutdown_callbacks to unpin and release the buf log item. The race condition is that when there are some thread doing transaction commit and happened not to be intercepted by xlog_is_shutdown, then, these log item will be insert into CIL, when unpin and release these buf log item, UAF will occur. BTW, add delay before `xlog_cil_commit` can increase recurrence probability. The following call graph actually encountered this bad situation. fsstress io end worker kworker/0:1H-216 xlog_ioend_work ->xlog_force_shutdown ->xlog_state_shutdown_callbacks ->xlog_cil_process_committed ->xlog_cil_committed ->xfs_trans_committed_bulk ->xfs_trans_apply_sb_deltas ->li_ops->iop_unpin(lip, 1); ->xfs_trans_getsb ->_xfs_trans_bjoin ->xfs_buf_item_init ->if (bip) { return 0;} //relog ->xlog_cil_commit ->xlog_cil_insert_items //insert into CIL ->xfs_buf_ioend_fail(bp); ->xfs_buf_ioend ->xfs_buf_item_done ->xfs_buf_item_relse ->xfs_buf_item_free when cil push worker gather percpu cil and insert super block buf log item into ctx->log_items then uaf occurs. ================================================================== BUG: KASAN: use-after-free in xlog_cil_push_work+0x1c8f/0x22f0 Write of size 8 at addr ffff88801800f3f0 by task kworker/u4:4/105 CPU: 0 PID: 105 Comm: kworker/u4:4 Tainted: G W 6.1.0-rc1-00001-g274115149b42 #136 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: xfs-cil/sda xlog_cil_push_work Call Trace: dump_stack_lvl+0x4d/0x66 print_report+0x171/0x4a6 kasan_report+0xb3/0x130 xlog_cil_push_work+0x1c8f/0x22f0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 Allocated by task 2145: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x54/0x60 kmem_cache_alloc+0x14a/0x510 xfs_buf_item_init+0x160/0x6d0 _xfs_trans_bjoin+0x7f/0x2e0 xfs_trans_getsb+0xb6/0x3f0 xfs_trans_apply_sb_deltas+0x1f/0x8c0 __xfs_trans_commit+0xa25/0xe10 xfs_symlink+0xe23/0x1660 xfs_vn_symlink+0x157/0x280 vfs_symlink+0x491/0x790 do_symlinkat+0x128/0x220 __x64_sys_symlink+0x7a/0x90 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 216: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 __kasan_slab_free+0x105/0x1a0 kmem_cache_free+0xb6/0x460 xfs_buf_ioend+0x1e9/0x11f0 xfs_buf_item_unpin+0x3d6/0x840 xfs_trans_committed_bulk+0x4c2/0x7c0 xlog_cil_committed+0xab6/0xfb0 xlog_cil_process_committed+0x117/0x1e0 xlog_state_shutdown_callbacks+0x208/0x440 xlog_force_shutdown+0x1b3/0x3a0 xlog_ioend_work+0xef/0x1d0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff88801800f388 which belongs to the cache xfs_buf_item of size 272 The buggy address is located 104 bytes inside of 272-byte region [ffff88801800f388, ffff88801800f498) The buggy address belongs to the physical page: page:ffffea0000600380 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801800f208 pfn:0x1800e head:ffffea0000600380 order:1 compound_mapcount:0 compound_pincount:0 flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) raw: 001fffff80010200 ffffea0000699788 ffff88801319db50 ffff88800fb50640 raw: ffff88801800f208 000000000015000a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88801800f280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801800f300: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88801800f380: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801800f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801800f480: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Disabling lock debugging due to kernel taint Signed-off-by: Guo Xuenan Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Leah Rumancik Acked-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_buf_item.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -1018,6 +1018,8 @@ xfs_buf_item_relse( trace_xfs_buf_item_relse(bp, _RET_IP_); ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags)); + if (atomic_read(&bip->bli_refcount)) + return; bp->b_log_item = NULL; xfs_buf_rele(bp); xfs_buf_item_free(bip);