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btrfs: tree-checker: Check leaf chunk item size

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Inspired by btrfs-progs github issue #208, where chunk item in chunk
tree has invalid num_stripes (0).

Although that can already be caught by current btrfs_check_chunk_valid(),
that function doesn't really check item size as it needs to handle chunk
item in super block sys_chunk_array().

This patch will add two extra checks for chunk items in chunk tree:

- Basic chunk item size
  If the item is smaller than btrfs_chunk (which already contains one
  stripe), exit right now as reading num_stripes may even go beyond
  eb boundary.

- Item size check against num_stripes
  If item size doesn't match with calculated chunk size, then either the
  item size or the num_stripes is corrupted. Error out anyway.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2019-12-17 18:58:20 +08:00 committed by David Sterba
parent 0ab575c5df
commit f6d2a5c263
1 changed files with 39 additions and 1 deletions
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40
fs/btrfs/tree-checker.c
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@ -738,6 +738,44 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
return 0;
}
/*
* Enhanced version of chunk item checker.
*
* The common btrfs_check_chunk_valid() doesn't check item size since it needs
* to work on super block sys_chunk_array which doesn't have full item ptr.
*/
static int check_leaf_chunk_item(struct extent_buffer *leaf,
struct btrfs_chunk *chunk,
struct btrfs_key *key, int slot)
{
int num_stripes;
if (btrfs_item_size_nr(leaf, slot) < sizeof(struct btrfs_chunk)) {
chunk_err(leaf, chunk, key->offset,
"invalid chunk item size: have %u expect [%zu, %u)",
btrfs_item_size_nr(leaf, slot),
sizeof(struct btrfs_chunk),
BTRFS_LEAF_DATA_SIZE(leaf->fs_info));
return -EUCLEAN;
}
num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
/* Let btrfs_check_chunk_valid() handle this error type */
if (num_stripes == 0)
goto out;
if (btrfs_chunk_item_size(num_stripes) !=
btrfs_item_size_nr(leaf, slot)) {
chunk_err(leaf, chunk, key->offset,
"invalid chunk item size: have %u expect %lu",
btrfs_item_size_nr(leaf, slot),
btrfs_chunk_item_size(num_stripes));
return -EUCLEAN;
}
out:
return btrfs_check_chunk_valid(leaf, chunk, key->offset);
}
__printf(3, 4)
__cold
static void dev_item_err(const struct extent_buffer *eb, int slot,
@ -1384,7 +1422,7 @@ static int check_leaf_item(struct extent_buffer *leaf,
break;
case BTRFS_CHUNK_ITEM_KEY:
chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
ret = btrfs_check_chunk_valid(leaf, chunk, key->offset);
ret = check_leaf_chunk_item(leaf, chunk, key, slot);
break;
case BTRFS_DEV_ITEM_KEY:
ret = check_dev_item(leaf, key, slot);