kernel/linux.git/fs/ext4/extents.c, branch v6.4

ext4: fix use-after-free read in ext4_find_extent for bigalloc + inline

2023-04-28T16:56:35+00:00

Syzbot found the following issue: loop0: detected capacity change from 0 to 2048 EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none. ================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931 Read of size 4 at addr ffff888073644750 by task syz-executor420/5067 CPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106 print_address_description+0x74/0x340 mm/kasan/report.c:306 print_report+0x107/0x1f0 mm/kasan/report.c:417 kasan_report+0xcd/0x100 mm/kasan/report.c:517 ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline] ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931 ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809 ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline] ext4_da_map_blocks fs/ext4/inode.c:1806 [inline] ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870 ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098 ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082 generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772 ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285 ext4_file_write_iter+0x1d0/0x18f0 call_write_iter include/linux/fs.h:2186 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x7dc/0xc50 fs/read_write.c:584 ksys_write+0x177/0x2a0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f4b7a9737b9 RSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9 RDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004 RBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Above issue is happens when enable bigalloc and inline data feature. As commit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for bigalloc + inline. But it only resolved issue when has inline data, if inline data has been converted to extent(ext4_da_convert_inline_data_to_extent) before writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However i_data is still store inline data in this scene. Then will trigger UAF when find extent. To resolve above issue, there is need to add judge "ext4_has_inline_data(inode)" in ext4_clu_mapped(). Fixes: 131294c35ed6 ("ext4: fix delayed allocation bug in ext4_clu_mapped for bigalloc + inline") Reported-by: syzbot+bf4bb7731ef73b83a3b4@syzkaller.appspotmail.com Reviewed-by: Jan Kara Reviewed-by: Ye Bin Reviewed-by: Tudor Ambarus Tested-by: Tudor Ambarus Link: https://lore.kernel.org/r/20230406111627.1916759-1-tudor.ambarus@linaro.org Signed-off-by: Theodore Ts'o

ext4: Fix special handling of journalled data from extent zeroing

2023-04-14T23:56:53+00:00

The handling of journalled data in ext4_zero_range() is incomplete. We do not need to commit running transaction but we rather need to checkpoint pages with journalled data. If we don't, journal tail can be advanced beyond transaction containing the journalled data and if we then crash before committing the transaction doing the zeroing we will have inconsistent (too old) data in the file. Make sure file pages with journalled data are properly checkpointed before removing them from the page cache. Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20230329154950.19720-8-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: Drop special handling of journalled data from extent shifting operations

2023-04-14T23:56:53+00:00

Now that filemap_write_and_wait() makes sure pages with journalled data are safely on disk, ext4_collapse_range() and ext4_insert_range() do not need special handling of journalled data. Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20230329154950.19720-7-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: fix inode tree inconsistency caused by ENOMEM

2023-02-19T04:58:28+00:00

If ENOMEM fails when the extent is splitting, we need to restore the length of the split extent. In the ext4_split_extent_at function, only in ext4_ext_create_new_leaf will it alloc memory and change the shape of the extent tree,even if an ENOMEM is returned at this time, the extent tree is still self-consistent, Just restore the split extent lens in the function ext4_split_extent_at. ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf 1)ext4_ext_split ext4_find_extent 2)ext4_ext_grow_indepth ext4_find_extent Signed-off-by: zhanchengbin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230103022812.130603-1-zhanchengbin1@huawei.com Signed-off-by: Theodore Ts'o

ext4: fix delayed allocation bug in ext4_clu_mapped for bigalloc + inline

2022-12-09T02:49:25+00:00

When converting files with inline data to extents, delayed allocations made on a file system created with both the bigalloc and inline options can result in invalid extent status cache content, incorrect reserved cluster counts, kernel memory leaks, and potential kernel panics. With bigalloc, the code that determines whether a block must be delayed allocated searches the extent tree to see if that block maps to a previously allocated cluster. If not, the block is delayed allocated, and otherwise, it isn't. However, if the inline option is also used, and if the file containing the block is marked as able to store data inline, there isn't a valid extent tree associated with the file. The current code in ext4_clu_mapped() calls ext4_find_extent() to search the non-existent tree for a previously allocated cluster anyway, which typically finds nothing, as desired. However, a side effect of the search can be to cache invalid content from the non-existent tree (garbage) in the extent status tree, including bogus entries in the pending reservation tree. To fix this, avoid searching the extent tree when allocating blocks for bigalloc + inline files that are being converted from inline to extent mapped. Signed-off-by: Eric Whitney Link: https://lore.kernel.org/r/20221117152207.2424-1-enwlinux@gmail.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

fs/ext4: replace ternary operator with min()/max() and min_t()

2022-11-29T21:10:49+00:00

Fix the following coccicheck warning: fs/ext4/inline.c:183: WARNING opportunity for min(). fs/ext4/extents.c:2631: WARNING opportunity for max(). fs/ext4/extents.c:2632: WARNING opportunity for min(). fs/ext4/extents.c:5559: WARNING opportunity for max(). fs/ext4/super.c:6908: WARNING opportunity for min(). min()/max() and min_t() macro is defined in include/linux/minmax.h. It avoids multiple evaluations of the arguments when non-constant and performs strict type-checking. Reported-by: kernel test robot Suggested-by: Lukas Czerner Signed-off-by: Jiangshan Yi Reviewed-by: Lukas Czerner Link: https://lore.kernel.org/r/20220817025928.612851-1-13667453960@163.com Signed-off-by: Theodore Ts'o

ext4: fix use-after-free in ext4_ext_shift_extents

2022-11-07T17:53:43+00:00

If the starting position of our insert range happens to be in the hole between the two ext4_extent_idx, because the lblk of the ext4_extent in the previous ext4_extent_idx is always less than the start, which leads to the "extent" variable access across the boundary, the following UAF is triggered: ================================================================== BUG: KASAN: use-after-free in ext4_ext_shift_extents+0x257/0x790 Read of size 4 at addr ffff88819807a008 by task fallocate/8010 CPU: 3 PID: 8010 Comm: fallocate Tainted: G E 5.10.0+ #492 Call Trace: dump_stack+0x7d/0xa3 print_address_description.constprop.0+0x1e/0x220 kasan_report.cold+0x67/0x7f ext4_ext_shift_extents+0x257/0x790 ext4_insert_range+0x5b6/0x700 ext4_fallocate+0x39e/0x3d0 vfs_fallocate+0x26f/0x470 ksys_fallocate+0x3a/0x70 __x64_sys_fallocate+0x4f/0x60 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ================================================================== For right shifts, we can divide them into the following situations： 1. When the first ee_block of ext4_extent_idx is greater than or equal to start, make right shifts directly from the first ee_block. 1) If it is greater than start, we need to continue searching in the previous ext4_extent_idx. 2) If it is equal to start, we can exit the loop (iterator=NULL). 2. When the first ee_block of ext4_extent_idx is less than start, then traverse from the last extent to find the first extent whose ee_block is less than start. 1) If extent is still the last extent after traversal, it means that the last ee_block of ext4_extent_idx is less than start, that is, start is located in the hole between idx and (idx+1), so we can exit the loop directly (break) without right shifts. 2) Otherwise, make right shifts at the corresponding position of the found extent, and then exit the loop (iterator=NULL). Fixes: 331573febb6a ("ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate") Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Zhihao Cheng Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20220922120434.1294789-1-libaokun1@huawei.com Signed-off-by: Theodore Ts'o

ext4: factor out ext4_free_ext_path()

2022-10-01T03:46:54+00:00

Factor out ext4_free_ext_path() to free extent path. As after previous patch 'ext4_ext_drop_refs()' is only used in 'extents.c', so make it static. Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220924021211.3831551-3-yebin10@huawei.com Signed-off-by: Theodore Ts'o

ext4: fix bug in extents parsing when eh_entries == 0 and eh_depth > 0

2022-09-22T14:50:54+00:00

When walking through an inode extents, the ext4_ext_binsearch_idx() function assumes that the extent header has been previously validated. However, there are no checks that verify that the number of entries (eh->eh_entries) is non-zero when depth is > 0. And this will lead to problems because the EXT_FIRST_INDEX() and EXT_LAST_INDEX() will return garbage and result in this: [ 135.245946] ------------[ cut here ]------------ [ 135.247579] kernel BUG at fs/ext4/extents.c:2258! [ 135.249045] invalid opcode: 0000 [#1] PREEMPT SMP [ 135.250320] CPU: 2 PID: 238 Comm: tmp118 Not tainted 5.19.0-rc8+ #4 [ 135.252067] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014 [ 135.255065] RIP: 0010:ext4_ext_map_blocks+0xc20/0xcb0 [ 135.256475] Code: [ 135.261433] RSP: 0018:ffffc900005939f8 EFLAGS: 00010246 [ 135.262847] RAX: 0000000000000024 RBX: ffffc90000593b70 RCX: 0000000000000023 [ 135.264765] RDX: ffff8880038e5f10 RSI: 0000000000000003 RDI: ffff8880046e922c [ 135.266670] RBP: ffff8880046e9348 R08: 0000000000000001 R09: ffff888002ca580c [ 135.268576] R10: 0000000000002602 R11: 0000000000000000 R12: 0000000000000024 [ 135.270477] R13: 0000000000000000 R14: 0000000000000024 R15: 0000000000000000 [ 135.272394] FS: 00007fdabdc56740(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 [ 135.274510] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 135.276075] CR2: 00007ffc26bd4f00 CR3: 0000000006261004 CR4: 0000000000170ea0 [ 135.277952] Call Trace: [ 135.278635] [ 135.279247] ? preempt_count_add+0x6d/0xa0 [ 135.280358] ? percpu_counter_add_batch+0x55/0xb0 [ 135.281612] ? _raw_read_unlock+0x18/0x30 [ 135.282704] ext4_map_blocks+0x294/0x5a0 [ 135.283745] ? xa_load+0x6f/0xa0 [ 135.284562] ext4_mpage_readpages+0x3d6/0x770 [ 135.285646] read_pages+0x67/0x1d0 [ 135.286492] ? folio_add_lru+0x51/0x80 [ 135.287441] page_cache_ra_unbounded+0x124/0x170 [ 135.288510] filemap_get_pages+0x23d/0x5a0 [ 135.289457] ? path_openat+0xa72/0xdd0 [ 135.290332] filemap_read+0xbf/0x300 [ 135.291158] ? _raw_spin_lock_irqsave+0x17/0x40 [ 135.292192] new_sync_read+0x103/0x170 [ 135.293014] vfs_read+0x15d/0x180 [ 135.293745] ksys_read+0xa1/0xe0 [ 135.294461] do_syscall_64+0x3c/0x80 [ 135.295284] entry_SYSCALL_64_after_hwframe+0x46/0xb0 This patch simply adds an extra check in __ext4_ext_check(), verifying that eh_entries is not 0 when eh_depth is > 0. Link: https://bugzilla.kernel.org/show_bug.cgi?id=215941 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216283 Cc: Baokun Li Cc: stable@kernel.org Signed-off-by: Luís Henriques Reviewed-by: Jan Kara Reviewed-by: Baokun Li Link: https://lore.kernel.org/r/20220822094235.2690-1-lhenriques@suse.de Signed-off-by: Theodore Ts'o

ext4: fix bug_on in __es_tree_search

2022-05-24T19:34:17+00:00

Hulk Robot reported a BUG_ON: ================================================================== kernel BUG at fs/ext4/extents_status.c:199! [...] RIP: 0010:ext4_es_end fs/ext4/extents_status.c:199 [inline] RIP: 0010:__es_tree_search+0x1e0/0x260 fs/ext4/extents_status.c:217 [...] Call Trace: ext4_es_cache_extent+0x109/0x340 fs/ext4/extents_status.c:766 ext4_cache_extents+0x239/0x2e0 fs/ext4/extents.c:561 ext4_find_extent+0x6b7/0xa20 fs/ext4/extents.c:964 ext4_ext_map_blocks+0x16b/0x4b70 fs/ext4/extents.c:4384 ext4_map_blocks+0xe26/0x19f0 fs/ext4/inode.c:567 ext4_getblk+0x320/0x4c0 fs/ext4/inode.c:980 ext4_bread+0x2d/0x170 fs/ext4/inode.c:1031 ext4_quota_read+0x248/0x320 fs/ext4/super.c:6257 v2_read_header+0x78/0x110 fs/quota/quota_v2.c:63 v2_check_quota_file+0x76/0x230 fs/quota/quota_v2.c:82 vfs_load_quota_inode+0x5d1/0x1530 fs/quota/dquot.c:2368 dquot_enable+0x28a/0x330 fs/quota/dquot.c:2490 ext4_quota_enable fs/ext4/super.c:6137 [inline] ext4_enable_quotas+0x5d7/0x960 fs/ext4/super.c:6163 ext4_fill_super+0xa7c9/0xdc00 fs/ext4/super.c:4754 mount_bdev+0x2e9/0x3b0 fs/super.c:1158 mount_fs+0x4b/0x1e4 fs/super.c:1261 [...] ================================================================== Above issue may happen as follows: ------------------------------------- ext4_fill_super ext4_enable_quotas ext4_quota_enable ext4_iget __ext4_iget ext4_ext_check_inode ext4_ext_check __ext4_ext_check ext4_valid_extent_entries Check for overlapping extents does't take effect dquot_enable vfs_load_quota_inode v2_check_quota_file v2_read_header ext4_quota_read ext4_bread ext4_getblk ext4_map_blocks ext4_ext_map_blocks ext4_find_extent ext4_cache_extents ext4_es_cache_extent ext4_es_cache_extent __es_tree_search ext4_es_end BUG_ON(es->es_lblk + es->es_len < es->es_lblk) The error ext4 extents is as follows: 0af3 0300 0400 0000 00000000 extent_header 00000000 0100 0000 12000000 extent1 00000000 0100 0000 18000000 extent2 02000000 0400 0000 14000000 extent3 In the ext4_valid_extent_entries function, if prev is 0, no error is returned even if lblock<=prev. This was intended to skip the check on the first extent, but in the error image above, prev=0+1-1=0 when checking the second extent, so even though lblock<=prev, the function does not return an error. As a result, bug_ON occurs in __es_tree_search and the system panics. To solve this problem, we only need to check that: 1. The lblock of the first extent is not less than 0. 2. The lblock of the next extent is not less than the next block of the previous extent. The same applies to extent_idx. Cc: stable@kernel.org Fixes: 5946d089379a ("ext4: check for overlapping extents in ext4_valid_extent_entries()") Reported-by: Hulk Robot Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220518120816.1541863-1-libaokun1@huawei.com Signed-off-by: Theodore Ts'o