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 <yangerkun@xxxxxxxxxx> >> --- >> 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
