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| author | Chao Yu <chao@kernel.org> | 2021-12-06 17:44:19 +0300 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2021-12-11 02:48:32 +0300 |
| commit | 9056d6489f5a41cfbb67f719d2c0ce61ead72d9f (patch) | |
| tree | 7c1b99b5ad53113aa9ae9cec8203a4c4dbc5119b /fs/f2fs | |
| parent | 766c663933bec1068a6041f05bf31d39606bc2e8 (diff) | |
| download | linux-9056d6489f5a41cfbb67f719d2c0ce61ead72d9f.tar.xz | |
f2fs: fix to do sanity check on inode type during garbage collection
As report by Wenqing Liu in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215231
- Overview
kernel NULL pointer dereference triggered in folio_mark_dirty() when mount and operate on a crafted f2fs image
- Reproduce
tested on kernel 5.16-rc3, 5.15.X under root
1. mkdir mnt
2. mount -t f2fs tmp1.img mnt
3. touch tmp
4. cp tmp mnt
F2FS-fs (loop0): sanity_check_inode: inode (ino=49) extent info [5942, 4294180864, 4] is incorrect, run fsck to fix
F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=31340049, run fsck to fix.
BUG: kernel NULL pointer dereference, address: 0000000000000000
folio_mark_dirty+0x33/0x50
move_data_page+0x2dd/0x460 [f2fs]
do_garbage_collect+0xc18/0x16a0 [f2fs]
f2fs_gc+0x1d3/0xd90 [f2fs]
f2fs_balance_fs+0x13a/0x570 [f2fs]
f2fs_create+0x285/0x840 [f2fs]
path_openat+0xe6d/0x1040
do_filp_open+0xc5/0x140
do_sys_openat2+0x23a/0x310
do_sys_open+0x57/0x80
The root cause is for special file: e.g. character, block, fifo or socket file,
f2fs doesn't assign address space operations pointer array for mapping->a_ops field,
so, in a fuzzed image, SSA table indicates a data block belong to special file, when
f2fs tries to migrate that block, it causes NULL pointer access once move_data_page()
calls a_ops->set_dirty_page().
Cc: stable@vger.kernel.org
Reported-by: Wenqing Liu <wenqingliu0120@gmail.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
| -rw-r--r-- | fs/f2fs/gc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index a946ce0ead34..e0bdc4361a9b 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1457,7 +1457,8 @@ next_step: if (phase == 3) { inode = f2fs_iget(sb, dni.ino); - if (IS_ERR(inode) || is_bad_inode(inode)) + if (IS_ERR(inode) || is_bad_inode(inode) || + special_file(inode->i_mode)) continue; if (!down_write_trylock( |