From: Pavel Begunkov <[email protected]>
To: yangerkun <[email protected]>,
[email protected], [email protected]
Cc: [email protected], [email protected],
[email protected]
Subject: Re: [PATCH] block: reexpand iov_iter after read/write
Date: Tue, 6 Apr 2021 12:04:49 +0100 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 06/04/2021 02:28, yangerkun wrote:
> Ping...
It wasn't forgotten, but wouln't have worked because of
other reasons. With these two already queued, that's a
different story.
https://git.kernel.dk/cgit/linux-block/commit/?h=io_uring-5.12&id=07204f21577a1d882f0259590c3553fe6a476381
https://git.kernel.dk/cgit/linux-block/commit/?h=io_uring-5.12&id=230d50d448acb6639991440913299e50cacf1daf
Can you re-confirm, that the bug is still there (should be)
and your patch fixes it?
>
> 在 2021/4/1 15:18, yangerkun 写道:
>> 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 <[email protected]>
>> ---
>> 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);
>>
--
Pavel Begunkov
next prev parent reply other threads:[~2021-04-06 11:09 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 7:18 [PATCH] block: reexpand iov_iter after read/write yangerkun
2021-04-06 1:28 ` yangerkun
2021-04-06 11:04 ` Pavel Begunkov [this message]
2021-04-07 14:16 ` yangerkun
2021-04-09 14:49 ` Pavel Begunkov
2021-04-15 17:37 ` Pavel Begunkov
2021-04-15 17:39 ` Pavel Begunkov
2021-04-28 6:16 ` yangerkun
2021-04-30 12:57 ` Pavel Begunkov
2021-04-30 14:35 ` Al Viro
2021-05-06 16:57 ` Pavel Begunkov
2021-05-06 17:17 ` Al Viro
2021-05-06 17:19 ` Jens Axboe
2021-05-06 18:55 ` Al Viro
2021-05-06 19:15 ` Jens Axboe
2021-05-06 21:08 ` Al Viro
2021-05-06 21:17 ` Matthew Wilcox
2021-05-07 14:59 ` Jens Axboe
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