[PATCH 5.4 210/411] f2fs: fix to do sanity check on block address in f2fs_do_zero_range()

Greg Kroah-Hartman
2022-06-13T11:26:46Z

From: Chao Yu <chao@kernel.org>

commit 25f8236213a91efdf708b9d77e9e51b6fc3e141c upstream.

As Yanming reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215894

I have encountered a bug in F2FS file system in kernel v5.17.

I have uploaded the system call sequence as case.c, and a fuzzed image can
be found in google net disk

The kernel should enable CONFIG_KASAN=y and CONFIG_KASAN_INLINE=y. You can
reproduce the bug by running the following commands:

kernel BUG at fs/f2fs/segment.c:2291!
Call Trace:
f2fs_invalidate_blocks+0x193/0x2d0
f2fs_fallocate+0x2593/0x4a70
vfs_fallocate+0x2a5/0xac0
ksys_fallocate+0x35/0x70
__x64_sys_fallocate+0x8e/0xf0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae

The root cause is, after image was fuzzed, block mapping info in inode
will be inconsistent with SIT table, so in f2fs_fallocate(), it will cause
panic when updating SIT with invalid blkaddr.

Let's fix the issue by adding sanity check on block address before updating
SIT table with it.

Cc: stable@vger.kernel.org
Reported-by: Ming Yan <yanming@tju.edu.cn>
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/f2fs/file.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1320,11 +1320,19 @@ static int f2fs_do_zero_range(struct dno
ret = -ENOSPC;
break;
}
- if (dn->data_blkaddr != NEW_ADDR) {
- f2fs_invalidate_blocks(sbi, dn->data_blkaddr);
- dn->data_blkaddr = NEW_ADDR;
- f2fs_set_data_blkaddr(dn);
+
+ if (dn->data_blkaddr == NEW_ADDR)
+ continue;
+
+ if (!f2fs_is_valid_blkaddr(sbi, dn->data_blkaddr,
+ DATA_GENERIC_ENHANCE)) {
+ ret = -EFSCORRUPTED;
+ break;
}
+
+ f2fs_invalidate_blocks(sbi, dn->data_blkaddr);
+ dn->data_blkaddr = NEW_ADDR;
+ f2fs_set_data_blkaddr(dn);
}

f2fs_update_extent_cache_range(dn, start, 0, index - start);