diff options
| author | Chao Yu <chao@kernel.org> | 2021-12-12 17:16:30 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2022-01-04 13:20:56 -0800 |
| commit | 645a3c40ca3d40cc32b4b5972bf2620f2eb5dba6 (patch) | |
| tree | 5d8010162da753535da40f1e27871a854a6f0048 | |
| parent | a9419b63bf414775e8aeee95d8c4a5e0df690748 (diff) | |
f2fs: fix to do sanity check on last xattr entry in __f2fs_setxattr()
As Wenqing Liu reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215235
- Overview
page fault in f2fs_setxattr() when mount and operate on corrupted image
- Reproduce
tested on kernel 5.16-rc3, 5.15.X under root
1. unzip tmp7.zip
2. ./single.sh f2fs 7
Sometimes need to run the script several times
- Kernel dump
loop0: detected capacity change from 0 to 131072
F2FS-fs (loop0): Found nat_bits in checkpoint
F2FS-fs (loop0): Mounted with checkpoint version = 7548c2ee
BUG: unable to handle page fault for address: ffffe47bc7123f48
RIP: 0010:kfree+0x66/0x320
Call Trace:
__f2fs_setxattr+0x2aa/0xc00 [f2fs]
f2fs_setxattr+0xfa/0x480 [f2fs]
__f2fs_set_acl+0x19b/0x330 [f2fs]
__vfs_removexattr+0x52/0x70
__vfs_removexattr_locked+0xb1/0x140
vfs_removexattr+0x56/0x100
removexattr+0x57/0x80
path_removexattr+0xa3/0xc0
__x64_sys_removexattr+0x17/0x20
do_syscall_64+0x37/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is in __f2fs_setxattr(), we missed to do sanity check on
last xattr entry, result in out-of-bound memory access during updating
inconsistent xattr data of target inode.
After the fix, it can detect such xattr inconsistency as below:
F2FS-fs (loop11): inode (7) has invalid last xattr entry, entry_size: 60676
F2FS-fs (loop11): inode (8) has corrupted xattr
F2FS-fs (loop11): inode (8) has corrupted xattr
F2FS-fs (loop11): inode (8) has invalid last xattr entry, entry_size: 47736
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>
| -rw-r--r-- | fs/f2fs/xattr.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index e348f33bcb2b..797ac505a075 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -684,8 +684,17 @@ static int __f2fs_setxattr(struct inode *inode, int index, } last = here; - while (!IS_XATTR_LAST_ENTRY(last)) + while (!IS_XATTR_LAST_ENTRY(last)) { + if ((void *)(last) + sizeof(__u32) > last_base_addr || + (void *)XATTR_NEXT_ENTRY(last) > last_base_addr) { + f2fs_err(F2FS_I_SB(inode), "inode (%lu) has invalid last xattr entry, entry_size: %zu", + inode->i_ino, ENTRY_SIZE(last)); + set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_FSCK); + error = -EFSCORRUPTED; + goto exit; + } last = XATTR_NEXT_ENTRY(last); + } newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size); |