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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 25D13C43461 for ; Thu, 1 Apr 2021 07:11:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C97CA610CF for ; Thu, 1 Apr 2021 07:11:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233529AbhDAHKg (ORCPT ); Thu, 1 Apr 2021 03:10:36 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:15842 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233406AbhDAHKW (ORCPT ); Thu, 1 Apr 2021 03:10:22 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4F9vR00ZTPz93pF; Thu, 1 Apr 2021 15:08:12 +0800 (CST) Received: from code-website.localdomain (10.175.127.227) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.498.0; Thu, 1 Apr 2021 15:10:10 +0800 From: yangerkun To: , , CC: , , , Subject: [PATCH] block: reexpand iov_iter after read/write Date: Thu, 1 Apr 2021 15:18:07 +0800 Message-ID: <20210401071807.3328235-1-yangerkun@huawei.com> X-Mailer: git-send-email 2.25.4 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org We get a bug: BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x11c/0x404 lib/iov_iter.c:1139 Read of size 8 at addr ffff0000d3fb11f8 by task CPU: 0 PID: 12582 Comm: syz-executor.2 Not tainted 5.10.0-00843-g352c8610ccd2 #2 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x2d0 arch/arm64/kernel/stacktrace.c:132 show_stack+0x28/0x34 arch/arm64/kernel/stacktrace.c:196 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x110/0x164 lib/dump_stack.c:118 print_address_description+0x78/0x5c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report+0x148/0x1e4 mm/kasan/report.c:562 check_memory_region_inline mm/kasan/generic.c:183 [inline] __asan_load8+0xb4/0xbc mm/kasan/generic.c:252 iov_iter_revert+0x11c/0x404 lib/iov_iter.c:1139 io_read fs/io_uring.c:3421 [inline] io_issue_sqe+0x2344/0x2d64 fs/io_uring.c:5943 __io_queue_sqe+0x19c/0x520 fs/io_uring.c:6260 io_queue_sqe+0x2a4/0x590 fs/io_uring.c:6326 io_submit_sqe fs/io_uring.c:6395 [inline] io_submit_sqes+0x4c0/0xa04 fs/io_uring.c:6624 __do_sys_io_uring_enter fs/io_uring.c:9013 [inline] __se_sys_io_uring_enter fs/io_uring.c:8960 [inline] __arm64_sys_io_uring_enter+0x190/0x708 fs/io_uring.c:8960 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:227 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Allocated by task 12570: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0xdc/0x120 mm/kasan/common.c:461 kasan_kmalloc+0xc/0x14 mm/kasan/common.c:475 __kmalloc+0x23c/0x334 mm/slub.c:3970 kmalloc include/linux/slab.h:557 [inline] __io_alloc_async_data+0x68/0x9c fs/io_uring.c:3210 io_setup_async_rw fs/io_uring.c:3229 [inline] io_read fs/io_uring.c:3436 [inline] io_issue_sqe+0x2954/0x2d64 fs/io_uring.c:5943 __io_queue_sqe+0x19c/0x520 fs/io_uring.c:6260 io_queue_sqe+0x2a4/0x590 fs/io_uring.c:6326 io_submit_sqe fs/io_uring.c:6395 [inline] io_submit_sqes+0x4c0/0xa04 fs/io_uring.c:6624 __do_sys_io_uring_enter fs/io_uring.c:9013 [inline] __se_sys_io_uring_enter fs/io_uring.c:8960 [inline] __arm64_sys_io_uring_enter+0x190/0x708 fs/io_uring.c:8960 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:227 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Freed by task 12570: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x38/0x6c mm/kasan/common.c:56 kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:355 __kasan_slab_free+0x124/0x150 mm/kasan/common.c:422 kasan_slab_free+0x10/0x1c mm/kasan/common.c:431 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook mm/slub.c:1577 [inline] slab_free mm/slub.c:3142 [inline] kfree+0x104/0x38c mm/slub.c:4124 io_dismantle_req fs/io_uring.c:1855 [inline] __io_free_req+0x70/0x254 fs/io_uring.c:1867 io_put_req_find_next fs/io_uring.c:2173 [inline] __io_queue_sqe+0x1fc/0x520 fs/io_uring.c:6279 __io_req_task_submit+0x154/0x21c fs/io_uring.c:2051 io_req_task_submit+0x2c/0x44 fs/io_uring.c:2063 task_work_run+0xdc/0x128 kernel/task_work.c:151 get_signal+0x6f8/0x980 kernel/signal.c:2562 do_signal+0x108/0x3a4 arch/arm64/kernel/signal.c:658 do_notify_resume+0xbc/0x25c arch/arm64/kernel/signal.c:722 work_pending+0xc/0x180 blkdev_read_iter can truncate iov_iter's count since the count + pos may exceed the size of the blkdev. This will confuse io_read that we have consume the iovec. And once we do the iov_iter_revert in io_read, we will trigger the slab-out-of-bounds. Fix it by reexpand the count with size has been truncated. blkdev_write_iter can trigger the problem too. Signed-off-by: yangerkun --- fs/block_dev.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index 92ed7d5df677..788e1014576f 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1680,6 +1680,7 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) struct inode *bd_inode = bdev_file_inode(file); loff_t size = i_size_read(bd_inode); struct blk_plug plug; + size_t shorted = 0; ssize_t ret; if (bdev_read_only(I_BDEV(bd_inode))) @@ -1697,12 +1698,17 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) return -EOPNOTSUPP; - iov_iter_truncate(from, size - iocb->ki_pos); + size -= iocb->ki_pos; + if (iov_iter_count(from) > size) { + shorted = iov_iter_count(from) - size; + iov_iter_truncate(from, size); + } blk_start_plug(&plug); ret = __generic_file_write_iter(iocb, from); if (ret > 0) ret = generic_write_sync(iocb, ret); + iov_iter_reexpand(from, iov_iter_count(from) + shorted); blk_finish_plug(&plug); return ret; } @@ -1714,13 +1720,21 @@ ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) struct inode *bd_inode = bdev_file_inode(file); loff_t size = i_size_read(bd_inode); loff_t pos = iocb->ki_pos; + size_t shorted = 0; + ssize_t ret; if (pos >= size) return 0; size -= pos; - iov_iter_truncate(to, size); - return generic_file_read_iter(iocb, to); + if (iov_iter_count(to) > size) { + shorted = iov_iter_count(to) - size; + iov_iter_truncate(to, size); + } + + ret = generic_file_read_iter(iocb, to); + iov_iter_reexpand(to, iov_iter_count(to) + shorted); + return ret; } EXPORT_SYMBOL_GPL(blkdev_read_iter); -- 2.25.4