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btrfs-progs: check/original: Do extra verification on file extent item

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[BUG]
For certain fuzzed image, `btrfs check` will fail with the following
call trace:

  Checking filesystem on issue_213.raw
  UUID: 99e50868-0bda-4d89-b0e4-7e8560312ef9
  [1/7] checking root items
  [2/7] checking extents
  Program received signal SIGABRT, Aborted.
  0x00007ffff7c88f25 in raise () from /usr/lib/libc.so.6
  (gdb) bt
  #0  0x00007ffff7c88f25 in raise () from /usr/lib/libc.so.6
  #1  0x00007ffff7c72897 in abort () from /usr/lib/libc.so.6
  #2  0x00005555555abc3e in run_next_block (...) at check/main.c:6398
  #3  0x00005555555b0f36 in deal_root_from_list (...) at check/main.c:8408
  #4  0x00005555555b1a3d in check_chunks_and_extents (fs_info=0x5555556a1e30) at check/main.c:8690
  #5  0x00005555555b1e3e in do_check_chunks_and_extents (fs_info=0x5555556a1e30) a
  #6  0x00005555555b5710 in cmd_check (cmd=0x555555696920 <cmd_struct_check>, argc
  #7  0x0000555555568dc7 in cmd_execute (cmd=0x555555696920 <cmd_struct_check>, ar
  #8  0x0000555555569713 in main (argc=2, argv=0x7fffffffde70) at btrfs.c:386

[CAUSE]
This fuzzed images has a corrupted EXTENT_DATA item in data reloc tree:
        item 1 key (256 EXTENT_DATA 256) itemoff 16111 itemsize 12
                generation 0 type 2 (prealloc)
                prealloc data disk byte 16777216 nr 0
                prealloc data offset 0 nr 0

There are several problems with the item:
- Bad item size
  12 is too small.
- Bad key offset
  offset of EXTENT_DATA type key represents file offset, which should
  always be aligned to sector size (4K in this particular case).

[FIX]
Do extra item size and key offset check for original mode, and remove
the abort() call in run_next_block().

And to show off how robust lowmem mode is, lowmem can handle it without
any hiccup.

With this fix, original mode can detect the problem properly:
  Checking filesystem on issue_213.raw
  UUID: 99e50868-0bda-4d89-b0e4-7e8560312ef9
  [1/7] checking root items
  [2/7] checking extents
  ERROR: invalid file extent item size, have 12 expect (21, 16283]
  ERROR: errors found in extent allocation tree or chunk allocation
  [3/7] checking free space cache
  [4/7] checking fs roots
  root 18446744073709551607 root dir 256 error
  root 18446744073709551607 inode 256 errors 62, no orphan item, odd file extent, bad file extent
  ERROR: errors found in fs roots
  found 131072 bytes used, error(s) found
  total csum bytes: 0
  total tree bytes: 131072
  total fs tree bytes: 32768
  total extent tree bytes: 16384
  btree space waste bytes: 124774
  file data blocks allocated: 0
   referenced 0

Issue: #213
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Su Yue <Damenly_Su@gmx.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2019-12-18 09:19:38 +08:00 committed by David Sterba
parent 121b9a2e4c
commit 3dcce48fd7
1 changed files with 32 additions and 2 deletions
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34
check/main.c
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@ -6268,7 +6268,10 @@ static int run_next_block(struct btrfs_root *root,
btree_space_waste += btrfs_leaf_free_space(buf);
for (i = 0; i < nritems; i++) {
struct btrfs_file_extent_item *fi;
unsigned long inline_offset;
inline_offset = offsetof(struct btrfs_file_extent_item,
disk_bytenr);
btrfs_item_key_to_cpu(buf, &key, i);
/*
* Check key type against the leaf owner.
@ -6384,18 +6387,45 @@ static int run_next_block(struct btrfs_root *root,
}
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
/* Check itemsize before we continue */
if (btrfs_item_size_nr(buf, i) < inline_offset) {
ret = -EUCLEAN;
error(
"invalid file extent item size, have %u expect (%lu, %lu]",
btrfs_item_size_nr(buf, i),
inline_offset,
BTRFS_LEAF_DATA_SIZE(fs_info));
continue;
}
fi = btrfs_item_ptr(buf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(buf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
/* Prealloc/regular extent must have fixed item size */
if (btrfs_item_size_nr(buf, i) !=
sizeof(struct btrfs_file_extent_item)) {
ret = -EUCLEAN;
error(
"invalid file extent item size, have %u expect %zu",
btrfs_item_size_nr(buf, i),
sizeof(struct btrfs_file_extent_item));
continue;
}
/* key.offset (file offset) must be aligned */
if (!IS_ALIGNED(key.offset, fs_info->sectorsize)) {
ret = -EUCLEAN;
error(
"invalid file offset, have %llu expect aligned to %u",
key.offset, fs_info->sectorsize);
continue;
}
if (btrfs_file_extent_disk_bytenr(buf, fi) == 0)
continue;
data_bytes_allocated +=
btrfs_file_extent_disk_num_bytes(buf, fi);
if (data_bytes_allocated < root->fs_info->sectorsize)
abort();
data_bytes_referenced +=
btrfs_file_extent_num_bytes(buf, fi);