f2fs: fix to do sanity check on block address in f2fs_do_zero_range()

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>

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index eae2e79080724f1b158ab8798ca9971279ea63ba..e4cf8b7b23aa4bbcb54d7c03a5ec36a79aaf1522 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1438,11 +1438,19 @@ static int f2fs_do_zero_range(struct dnode_of_data *dn, pgoff_t start,
                        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);