On 6.11.2017 11:20, Qu Wenruo wrote:
> Add checker for dir item, for key types DIR_ITEM, DIR_INDEX and
> XATTR_ITEM.
>
> This checker does comprehensive check 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 (crc32).
> Check the hash of name against key to ensure it's correct.
>
> The name hash check is only found in btrfs-progs before this patch.
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> ---
> fs/btrfs/tree-checker.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 141 insertions(+)
>
> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
> index a4c2517fa2a1..9644c9616f95 100644
> --- a/fs/btrfs/tree-checker.c
> +++ b/fs/btrfs/tree-checker.c
> @@ -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 expect (%u, %u]",
> + cur + sizeof(*di), cur, 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 expect (0, %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 expect (0, %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 expect (%lu, %u]",
> + cur + total_size, cur + sizeof(*di), 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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