| Message ID | 25987ba63d6e11a6983bf2c57eb2ac8efe059d8e.1723897285.git.wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: fix a use-after-free bug when hitting errors inside btrfs_submit_chunk() | expand |
Hi Qu,
kernel test robot noticed the following build warnings:
[auto build test WARNING on kdave/for-next]
[also build test WARNING on linus/master v6.11-rc3 next-20240816]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Qu-Wenruo/btrfs-fix-a-use-after-free-bug-when-hitting-errors-inside-btrfs_submit_chunk/20240817-202316
base: https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
patch link: https://lore.kernel.org/r/25987ba63d6e11a6983bf2c57eb2ac8efe059d8e.1723897285.git.wqu%40suse.com
patch subject: [PATCH] btrfs: fix a use-after-free bug when hitting errors inside btrfs_submit_chunk()
config: arc-randconfig-002-20240818 (https://download.01.org/0day-ci/archive/20240818/202408180546.vnwFs9i3-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240818/202408180546.vnwFs9i3-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408180546.vnwFs9i3-lkp@intel.com/
All warnings (new ones prefixed by >>):
fs/btrfs/bio.c: In function 'btrfs_submit_chunk':
>> fs/btrfs/bio.c:671:27: warning: unused variable 'orig_bbio' [-Wunused-variable]
671 | struct btrfs_bio *orig_bbio = bbio;
| ^~~~~~~~~
vim +/orig_bbio +671 fs/btrfs/bio.c
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 666
ae42a154ca89727 Christoph Hellwig 2023-03-07 667 static bool btrfs_submit_chunk(struct btrfs_bio *bbio, int mirror_num)
103c19723c80bf7 Christoph Hellwig 2022-11-15 668 {
d5e4377d505189c Christoph Hellwig 2023-01-21 669 struct btrfs_inode *inode = bbio->inode;
4317ff0056bedfc Qu Wenruo 2023-03-23 670 struct btrfs_fs_info *fs_info = bbio->fs_info;
852eee62d31abd6 Christoph Hellwig 2023-01-21 @671 struct btrfs_bio *orig_bbio = bbio;
ae42a154ca89727 Christoph Hellwig 2023-03-07 672 struct bio *bio = &bbio->bio;
adbe7e388e4239d Anand Jain 2023-04-15 673 u64 logical = bio->bi_iter.bi_sector << SECTOR_SHIFT;
103c19723c80bf7 Christoph Hellwig 2022-11-15 674 u64 length = bio->bi_iter.bi_size;
103c19723c80bf7 Christoph Hellwig 2022-11-15 675 u64 map_length = length;
921603c76246a7f Christoph Hellwig 2022-12-12 676 bool use_append = btrfs_use_zone_append(bbio);
103c19723c80bf7 Christoph Hellwig 2022-11-15 677 struct btrfs_io_context *bioc = NULL;
103c19723c80bf7 Christoph Hellwig 2022-11-15 678 struct btrfs_io_stripe smap;
9ba0004bd95e059 Christoph Hellwig 2023-01-21 679 blk_status_t ret;
9ba0004bd95e059 Christoph Hellwig 2023-01-21 680 int error;
103c19723c80bf7 Christoph Hellwig 2022-11-15 681
31ae7881f9cd502 Johannes Thumshirn 2024-07-31 682 if (!bbio->inode || btrfs_is_data_reloc_root(inode->root))
31ae7881f9cd502 Johannes Thumshirn 2024-07-31 683 smap.rst_search_commit_root = true;
31ae7881f9cd502 Johannes Thumshirn 2024-07-31 684 else
31ae7881f9cd502 Johannes Thumshirn 2024-07-31 685 smap.rst_search_commit_root = false;
9acaa64187f9b4c Johannes Thumshirn 2023-09-14 686
103c19723c80bf7 Christoph Hellwig 2022-11-15 687 btrfs_bio_counter_inc_blocked(fs_info);
cd4efd210edfb34 Christoph Hellwig 2023-05-31 688 error = btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
9fb2acc2fe07f15 Qu Wenruo 2023-09-17 689 &bioc, &smap, &mirror_num);
9ba0004bd95e059 Christoph Hellwig 2023-01-21 690 if (error) {
9ba0004bd95e059 Christoph Hellwig 2023-01-21 691 ret = errno_to_blk_status(error);
9ba0004bd95e059 Christoph Hellwig 2023-01-21 692 goto fail;
103c19723c80bf7 Christoph Hellwig 2022-11-15 693 }
103c19723c80bf7 Christoph Hellwig 2022-11-15 694
852eee62d31abd6 Christoph Hellwig 2023-01-21 695 map_length = min(map_length, length);
d5e4377d505189c Christoph Hellwig 2023-01-21 696 if (use_append)
d5e4377d505189c Christoph Hellwig 2023-01-21 697 map_length = min(map_length, fs_info->max_zone_append_size);
d5e4377d505189c Christoph Hellwig 2023-01-21 698
103c19723c80bf7 Christoph Hellwig 2022-11-15 699 if (map_length < length) {
2cef0c79bb81d8b Christoph Hellwig 2023-03-07 700 bbio = btrfs_split_bio(fs_info, bbio, map_length, use_append);
2cef0c79bb81d8b Christoph Hellwig 2023-03-07 701 bio = &bbio->bio;
103c19723c80bf7 Christoph Hellwig 2022-11-15 702 }
103c19723c80bf7 Christoph Hellwig 2022-11-15 703
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 704 /*
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 705 * Save the iter for the end_io handler and preload the checksums for
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 706 * data reads.
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 707 */
fbe960877b6f434 Christoph Hellwig 2023-05-31 708 if (bio_op(bio) == REQ_OP_READ && is_data_bbio(bbio)) {
0d3acb25e70d5f5 Christoph Hellwig 2023-01-21 709 bbio->saved_iter = bio->bi_iter;
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 710 ret = btrfs_lookup_bio_sums(bbio);
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 711 if (ret)
852eee62d31abd6 Christoph Hellwig 2023-01-21 712 goto fail_put_bio;
1c2b3ee3b0ec4bc Christoph Hellwig 2023-01-21 713 }
7276aa7d38255b4 Christoph Hellwig 2023-01-21 714
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 715 if (btrfs_op(bio) == BTRFS_MAP_WRITE) {
d5e4377d505189c Christoph Hellwig 2023-01-21 716 if (use_append) {
d5e4377d505189c Christoph Hellwig 2023-01-21 717 bio->bi_opf &= ~REQ_OP_WRITE;
d5e4377d505189c Christoph Hellwig 2023-01-21 718 bio->bi_opf |= REQ_OP_ZONE_APPEND;
69ccf3f4244abc5 Christoph Hellwig 2023-01-21 719 }
69ccf3f4244abc5 Christoph Hellwig 2023-01-21 720
02c372e1f016e51 Johannes Thumshirn 2023-09-14 721 if (is_data_bbio(bbio) && bioc &&
02c372e1f016e51 Johannes Thumshirn 2023-09-14 722 btrfs_need_stripe_tree_update(bioc->fs_info, bioc->map_type)) {
02c372e1f016e51 Johannes Thumshirn 2023-09-14 723 /*
02c372e1f016e51 Johannes Thumshirn 2023-09-14 724 * No locking for the list update, as we only add to
02c372e1f016e51 Johannes Thumshirn 2023-09-14 725 * the list in the I/O submission path, and list
02c372e1f016e51 Johannes Thumshirn 2023-09-14 726 * iteration only happens in the completion path, which
02c372e1f016e51 Johannes Thumshirn 2023-09-14 727 * can't happen until after the last submission.
02c372e1f016e51 Johannes Thumshirn 2023-09-14 728 */
02c372e1f016e51 Johannes Thumshirn 2023-09-14 729 btrfs_get_bioc(bioc);
02c372e1f016e51 Johannes Thumshirn 2023-09-14 730 list_add_tail(&bioc->rst_ordered_entry, &bbio->ordered->bioc_list);
02c372e1f016e51 Johannes Thumshirn 2023-09-14 731 }
02c372e1f016e51 Johannes Thumshirn 2023-09-14 732
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 733 /*
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 734 * Csum items for reloc roots have already been cloned at this
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 735 * point, so they are handled as part of the no-checksum case.
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 736 */
4317ff0056bedfc Qu Wenruo 2023-03-23 737 if (inode && !(inode->flags & BTRFS_INODE_NODATASUM) &&
169aaaf2e0be615 Qu Wenruo 2024-06-14 738 !test_bit(BTRFS_FS_STATE_NO_DATA_CSUMS, &fs_info->fs_state) &&
d5e4377d505189c Christoph Hellwig 2023-01-21 739 !btrfs_is_data_reloc_root(inode->root)) {
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 740 if (should_async_write(bbio) &&
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 741 btrfs_wq_submit_bio(bbio, bioc, &smap, mirror_num))
852eee62d31abd6 Christoph Hellwig 2023-01-21 742 goto done;
103c19723c80bf7 Christoph Hellwig 2022-11-15 743
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 744 ret = btrfs_bio_csum(bbio);
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 745 if (ret)
852eee62d31abd6 Christoph Hellwig 2023-01-21 746 goto fail_put_bio;
cebae292e0c32a2 Johannes Thumshirn 2024-06-07 747 } else if (use_append ||
cebae292e0c32a2 Johannes Thumshirn 2024-06-07 748 (btrfs_is_zoned(fs_info) && inode &&
cebae292e0c32a2 Johannes Thumshirn 2024-06-07 749 inode->flags & BTRFS_INODE_NODATASUM)) {
cbfce4c7fbde23c Christoph Hellwig 2023-05-24 750 ret = btrfs_alloc_dummy_sum(bbio);
cbfce4c7fbde23c Christoph Hellwig 2023-05-24 751 if (ret)
cbfce4c7fbde23c Christoph Hellwig 2023-05-24 752 goto fail_put_bio;
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 753 }
103c19723c80bf7 Christoph Hellwig 2022-11-15 754 }
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 755
f8a53bb58ec7e21 Christoph Hellwig 2023-01-21 756 __btrfs_submit_bio(bio, bioc, &smap, mirror_num);
852eee62d31abd6 Christoph Hellwig 2023-01-21 757 done:
852eee62d31abd6 Christoph Hellwig 2023-01-21 758 return map_length == length;
9ba0004bd95e059 Christoph Hellwig 2023-01-21 759
852eee62d31abd6 Christoph Hellwig 2023-01-21 760 fail_put_bio:
852eee62d31abd6 Christoph Hellwig 2023-01-21 761 if (map_length < length)
ec63b84d4611b2f Christoph Hellwig 2023-05-31 762 btrfs_cleanup_bio(bbio);
9ba0004bd95e059 Christoph Hellwig 2023-01-21 763 fail:
9ba0004bd95e059 Christoph Hellwig 2023-01-21 764 btrfs_bio_counter_dec(fs_info);
75f0d5c40c2c2f5 Qu Wenruo 2024-08-17 765 bbio->bio.bi_status = ret;
75f0d5c40c2c2f5 Qu Wenruo 2024-08-17 766 btrfs_orig_bbio_end_io(bbio);
852eee62d31abd6 Christoph Hellwig 2023-01-21 767 /* Do not submit another chunk */
852eee62d31abd6 Christoph Hellwig 2023-01-21 768 return true;
852eee62d31abd6 Christoph Hellwig 2023-01-21 769 }
852eee62d31abd6 Christoph Hellwig 2023-01-21 770
diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c index 0ef70fce85ff..4a0e97a56475 100644 --- a/fs/btrfs/bio.c +++ b/fs/btrfs/bio.c @@ -762,7 +762,8 @@ static bool btrfs_submit_chunk(struct btrfs_bio *bbio, int mirror_num) btrfs_cleanup_bio(bbio); fail: btrfs_bio_counter_dec(fs_info); - btrfs_bio_end_io(orig_bbio, ret); + bbio->bio.bi_status = ret; + btrfs_orig_bbio_end_io(bbio); /* Do not submit another chunk */ return true; }
[BUG] There is an internal report that KASAN is reporting use-after-free, with the following backtrace: ================================================================== BUG: KASAN: slab-use-after-free in btrfs_check_read_bio+0xa68/0xb70 [btrfs] Read of size 4 at addr ffff8881117cec28 by task kworker/u16:2/45 CPU: 1 UID: 0 PID: 45 Comm: kworker/u16:2 Not tainted 6.11.0-rc2-next-20240805-default+ #76 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 Workqueue: btrfs-endio btrfs_end_bio_work [btrfs] Call Trace: <TASK> dump_stack_lvl+0x61/0x80 print_address_description.constprop.0+0x5e/0x2f0 print_report+0x118/0x216 kasan_report+0x11d/0x1f0 btrfs_check_read_bio+0xa68/0xb70 [btrfs] process_one_work+0xce0/0x12a0 worker_thread+0x717/0x1250 kthread+0x2e3/0x3c0 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x11/0x20 </TASK> Allocated by task 20917: kasan_save_stack+0x37/0x60 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x7d/0x80 kmem_cache_alloc_noprof+0x16e/0x3e0 mempool_alloc_noprof+0x12e/0x310 bio_alloc_bioset+0x3f0/0x7a0 btrfs_bio_alloc+0x2e/0x50 [btrfs] submit_extent_page+0x4d1/0xdb0 [btrfs] btrfs_do_readpage+0x8b4/0x12a0 [btrfs] btrfs_readahead+0x29a/0x430 [btrfs] read_pages+0x1a7/0xc60 page_cache_ra_unbounded+0x2ad/0x560 filemap_get_pages+0x629/0xa20 filemap_read+0x335/0xbf0 vfs_read+0x790/0xcb0 ksys_read+0xfd/0x1d0 do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Freed by task 20917: kasan_save_stack+0x37/0x60 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x50 __kasan_slab_free+0x4b/0x60 kmem_cache_free+0x214/0x5d0 bio_free+0xed/0x180 end_bbio_data_read+0x1cc/0x580 [btrfs] btrfs_submit_chunk+0x98d/0x1880 [btrfs] btrfs_submit_bio+0x33/0x70 [btrfs] submit_one_bio+0xd4/0x130 [btrfs] submit_extent_page+0x3ea/0xdb0 [btrfs] btrfs_do_readpage+0x8b4/0x12a0 [btrfs] btrfs_readahead+0x29a/0x430 [btrfs] read_pages+0x1a7/0xc60 page_cache_ra_unbounded+0x2ad/0x560 filemap_get_pages+0x629/0xa20 filemap_read+0x335/0xbf0 vfs_read+0x790/0xcb0 ksys_read+0xfd/0x1d0 do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [CAUSE] Although I can not reproduce the error, the report itself is good enough to pin down the cause. The call trace is the regular endio workqueue context, but the free-by-task trace is showing that during btrfs_submit_chunk() we already hit a critical error, and is calling btrfs_bio_end_io() to error out. And the original endio function called bio_put() to free the whole bio. This means a double freeing thus causing use-after-free, e.g: 1. Enter btrfs_submit_bio() with a read bio The read bio length is 128K, crossing two 64K stripes. 2. The first run of btrfs_submit_chunk() 2.1 Call btrfs_map_block(), which returns 64K 2.2 Call btrfs_split_bio() Now there are two bios, one referring to the first 64K, the other referring to the second 64K. 2.3 The first half is submitted. 3. The second run of btrfs_submit_chunk() 3.1 Call btrfs_map_block(), which by somehow failed Now we call btrfs_bio_end_io() to handle the error 3.2 btrfs_bio_end_io() calls the original endio function Which is end_bbio_data_read(), and it calls bio_put() for the original bio. Now the original bio is freed. 4. The submitted first 64K bio finished Now we call into btrfs_check_read_bio() and tries to advance the bio iter. But since the original bio (thus its iter) is already freed, we trigger the above use-after free. And even if the memory is not poisoned/corrupted, we will later call the original endio function, causing a double freeing. [FIX] Instead of calling btrfs_bio_end_io(), call btrfs_orig_bbio_end_io(), which has the extra check on split bios and do the proper refcounting for cloned bios. Reported-by: David Sterba <dsterba@suse.cz> Fixes: 852eee62d31a ("btrfs: allow btrfs_submit_bio to split bios") Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/bio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)