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| author | Chao Yu <yuchao0@huawei.com> | 2020-09-29 09:23:34 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2020-09-29 02:12:41 -0700 |
| commit | 3a22e9ac71585bcb7667e44641f1bbb25295f0ce (patch) | |
| tree | e621db6662c394d653f2fe3266db0625f779e54e /fs | |
| parent | 6a257471fa42c8c9c04a875cd3a2a22db148e0f0 (diff) | |
f2fs: fix to do sanity check on segment/section count
As syzbot reported:
BUG: KASAN: slab-out-of-bounds in init_min_max_mtime fs/f2fs/segment.c:4710 [inline]
BUG: KASAN: slab-out-of-bounds in f2fs_build_segment_manager+0x9302/0xa6d0 fs/f2fs/segment.c:4792
Read of size 8 at addr ffff8880a1b934a8 by task syz-executor682/6878
CPU: 1 PID: 6878 Comm: syz-executor682 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
init_min_max_mtime fs/f2fs/segment.c:4710 [inline]
f2fs_build_segment_manager+0x9302/0xa6d0 fs/f2fs/segment.c:4792
f2fs_fill_super+0x381a/0x6e80 fs/f2fs/super.c:3633
mount_bdev+0x32e/0x3f0 fs/super.c:1417
legacy_get_tree+0x105/0x220 fs/fs_context.c:592
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x1387/0x20a0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount fs/namespace.c:3390 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3390
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The root cause is: if segs_per_sec is larger than one, and segment count
in last section is less than segs_per_sec, we will suffer out-of-boundary
memory access on sit_i->sentries[] in init_min_max_mtime().
Fix this by adding sanity check among segment count, section count and
segs_per_sec value in sanity_check_raw_super().
Reported-by: syzbot+481a3ffab50fed41dcc0@syzkaller.appspotmail.com
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/f2fs/super.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 484601717786..adc98c12ed53 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2833,6 +2833,12 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi, return -EFSCORRUPTED; } + if (segment_count_main != total_sections * segs_per_sec) { + f2fs_info(sbi, "Invalid segment/section count (%u != %u * %u)", + segment_count_main, total_sections, segs_per_sec); + return -EFSCORRUPTED; + } + if ((segment_count / segs_per_sec) < total_sections) { f2fs_info(sbi, "Small segment_count (%u < %u * %u)", segment_count, segs_per_sec, total_sections); |