Commit ad7b0368 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: tree-checker: Add checker for dir item 



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: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarSu Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 712e36c5

fs/btrfs/tree-checker.c

+141 −0
Original line number Diff line number Diff line
@@ -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;

}

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