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btrfs: tree-checker: Add checker for dir item

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Add checker for dir item, for key types DIR_ITEM, DIR_INDEX and
XATTR_ITEM.

This checker does comprehensive checks for:

1) dir_item header and its data size
   Against item boundary and maximum name/xattr length.
   This part is mostly the same as old verify_dir_item().

2) dir_type
   Against maximum file types, and against key type.
   Since XATTR key should only have FT_XATTR dir item, and normal dir
   item type should not have XATTR key.

   The check between key->type and dir_type is newly introduced by this
   patch.

3) name hash
   For XATTR and DIR_ITEM key, key->offset is name hash (crc32c).
   Check the hash of the name against the key to ensure it's correct.

   The name hash check is only found in btrfs-progs before this patch.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Su Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2017-11-08 08:54:25 +08:00 committed by David Sterba
parent 712e36c5f2
commit ad7b0368f3
1 changed files with 141 additions and 0 deletions
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141
fs/btrfs/tree-checker.c
View file

@ -30,6 +30,7 @@
#include "tree-checker.h"
#include "disk-io.h"
#include "compression.h"
#include "hash.h"
/*
* Error message should follow the following format:
@ -222,6 +223,141 @@ static int check_csum_item(struct btrfs_root *root, struct extent_buffer *leaf,
return 0;
}
/*
* Customized reported for dir_item, only important new info is key->objectid,
* which represents inode number
*/
__printf(4, 5)
static void dir_item_err(const struct btrfs_root *root,
const struct extent_buffer *eb, int slot,
const char *fmt, ...)
{
struct btrfs_key key;
struct va_format vaf;
va_list args;
btrfs_item_key_to_cpu(eb, &key, slot);
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
btrfs_crit(root->fs_info,
"corrupt %s: root=%llu block=%llu slot=%d ino=%llu, %pV",
btrfs_header_level(eb) == 0 ? "leaf" : "node", root->objectid,
btrfs_header_bytenr(eb), slot, key.objectid, &vaf);
va_end(args);
}
static int check_dir_item(struct btrfs_root *root,
struct extent_buffer *leaf,
struct btrfs_key *key, int slot)
{
struct btrfs_dir_item *di;
u32 item_size = btrfs_item_size_nr(leaf, slot);
u32 cur = 0;
di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
while (cur < item_size) {
char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];
u32 name_len;
u32 data_len;
u32 max_name_len;
u32 total_size;
u32 name_hash;
u8 dir_type;
/* header itself should not cross item boundary */
if (cur + sizeof(*di) > item_size) {
dir_item_err(root, leaf, slot,
"dir item header crosses item boundary, have %lu boundary %u",
cur + sizeof(*di), item_size);
return -EUCLEAN;
}
/* dir type check */
dir_type = btrfs_dir_type(leaf, di);
if (dir_type >= BTRFS_FT_MAX) {
dir_item_err(root, leaf, slot,
"invalid dir item type, have %u expect [0, %u)",
dir_type, BTRFS_FT_MAX);
return -EUCLEAN;
}
if (key->type == BTRFS_XATTR_ITEM_KEY &&
dir_type != BTRFS_FT_XATTR) {
dir_item_err(root, leaf, slot,
"invalid dir item type for XATTR key, have %u expect %u",
dir_type, BTRFS_FT_XATTR);
return -EUCLEAN;
}
if (dir_type == BTRFS_FT_XATTR &&
key->type != BTRFS_XATTR_ITEM_KEY) {
dir_item_err(root, leaf, slot,
"xattr dir type found for non-XATTR key");
return -EUCLEAN;
}
if (dir_type == BTRFS_FT_XATTR)
max_name_len = XATTR_NAME_MAX;
else
max_name_len = BTRFS_NAME_LEN;
/* Name/data length check */
name_len = btrfs_dir_name_len(leaf, di);
data_len = btrfs_dir_data_len(leaf, di);
if (name_len > max_name_len) {
dir_item_err(root, leaf, slot,
"dir item name len too long, have %u max %u",
name_len, max_name_len);
return -EUCLEAN;
}
if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
dir_item_err(root, leaf, slot,
"dir item name and data len too long, have %u max %u",
name_len + data_len,
BTRFS_MAX_XATTR_SIZE(root->fs_info));
return -EUCLEAN;
}
if (data_len && dir_type != BTRFS_FT_XATTR) {
dir_item_err(root, leaf, slot,
"dir item with invalid data len, have %u expect 0",
data_len);
return -EUCLEAN;
}
total_size = sizeof(*di) + name_len + data_len;
/* header and name/data should not cross item boundary */
if (cur + total_size > item_size) {
dir_item_err(root, leaf, slot,
"dir item data crosses item boundary, have %u boundary %u",
cur + total_size, item_size);
return -EUCLEAN;
}
/*
* Special check for XATTR/DIR_ITEM, as key->offset is name
* hash, should match its name
*/
if (key->type == BTRFS_DIR_ITEM_KEY ||
key->type == BTRFS_XATTR_ITEM_KEY) {
read_extent_buffer(leaf, namebuf,
(unsigned long)(di + 1), name_len);
name_hash = btrfs_name_hash(namebuf, name_len);
if (key->offset != name_hash) {
dir_item_err(root, leaf, slot,
"name hash mismatch with key, have 0x%016x expect 0x%016llx",
name_hash, key->offset);
return -EUCLEAN;
}
}
cur += total_size;
di = (struct btrfs_dir_item *)((void *)di + total_size);
}
return 0;
}
/*
* Common point to switch the item-specific validation.
*/
@ -238,6 +374,11 @@ static int check_leaf_item(struct btrfs_root *root,
case BTRFS_EXTENT_CSUM_KEY:
ret = check_csum_item(root, leaf, key, slot);
break;
case BTRFS_DIR_ITEM_KEY:
case BTRFS_DIR_INDEX_KEY:
case BTRFS_XATTR_ITEM_KEY:
ret = check_dir_item(root, leaf, key, slot);
break;
}
return ret;
}