On 22.08.2017 10:37, Qu Wenruo wrote:
> Add extra checker for item with EXTENT_DATA type.
> This checks the following thing:
> 1) Item size
> Plain text inline file extent size must match item size.
> (compressed inline file extent has no info about its on-disk size)
> Regular/preallocated file extent size must be a fixed value.
>
> 2) Every member of regular file extent item
> Including alignment for bytenr and offset, possible value for
> compression/encryption/type.
>
> 3) Type/compression/encode must be one of the valid values.
>
> This should be the most comprehensive and restrict check in the context
> of btrfs_item for EXTENT_DATA.
>
> Signed-off-by: Qu Wenruo <quwenruo.btrfs@xxxxxxx>
> ---
> fs/btrfs/disk-io.c | 88 +++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/btrfs_tree.h | 1 +
> 2 files changed, 89 insertions(+)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 59ee7b959bf0..557f9a520e2a 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -549,6 +549,83 @@ static int check_tree_block_fsid(struct btrfs_fs_info *fs_info,
> btrfs_header_level(eb) == 0 ? "leaf" : "node", \
> reason, btrfs_header_bytenr(eb), root->objectid, slot)
>
> +static int check_extent_data_item(struct btrfs_root *root,
> + struct extent_buffer *leaf, int slot)
> +{
> + struct btrfs_file_extent_item *fi;
> + u32 sectorsize = root->fs_info->sectorsize;
> + u32 item_size = btrfs_item_size_nr(leaf, slot);
> +
> + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
> +
> + if (btrfs_file_extent_type(leaf, fi) >= BTRFS_FILE_EXTENT_LAST_TYPE) {
> + CORRUPT("invalid file extent type", leaf, root, slot);
> + return -EIO;
> + }
> + if (btrfs_file_extent_compression(leaf, fi) >= BTRFS_COMPRESS_LAST) {
> + CORRUPT("invalid file extent compression", leaf, root, slot);
> + return -EIO;
> + }
> + if (btrfs_file_extent_encryption(leaf, fi)) {
> + CORRUPT("invalid file extent encryption", leaf, root, slot);
> + return -EIO;
> + }
> + if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
> + if (btrfs_file_extent_compression(leaf, fi) !=
> + BTRFS_COMPRESS_NONE)
> + return 0;
> + /* Plaintext inline extent size must match item size */
> + if (item_size != BTRFS_FILE_EXTENT_INLINE_DATA_START +
> + btrfs_file_extent_ram_bytes(leaf, fi)) {
> + CORRUPT("plaintext inline extent has invalid size",
> + leaf, root, slot);
> + return -EIO;
> + }
> + return 0;
> + }
> +
> +
> + /* regular or preallocated extent has fixed item size */
> + if (item_size != sizeof(*fi)) {
> + CORRUPT(
> + "regluar or preallocated extent data item size is invalid",
> + leaf, root, slot);
> + return -EIO;
> + }
> + if (!IS_ALIGNED(btrfs_file_extent_ram_bytes(leaf, fi), sectorsize) ||
> + !IS_ALIGNED(btrfs_file_extent_disk_bytenr(leaf, fi), sectorsize) ||
> + !IS_ALIGNED(btrfs_file_extent_disk_num_bytes(leaf, fi),
> + sectorsize) ||
> + !IS_ALIGNED(btrfs_file_extent_offset(leaf, fi), sectorsize) ||
> + !IS_ALIGNED(btrfs_file_extent_num_bytes(leaf, fi), sectorsize)) {
> + CORRUPT(
> + "regular or preallocated extent data item has unaligned value",
> + leaf, root, slot);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int check_leaf_item(struct btrfs_root *root,
> + struct extent_buffer *leaf, int slot)
> +{
> + struct btrfs_key key;
> + int ret = 0;
> +
> + btrfs_item_key_to_cpu(leaf, &key, slot);
nit: We already have the key in the proper format in the caller of this
function. Why not just pass in the type as an argument and save a
redundant call for every item in a leaf? Perhaps it's a
microoptimisation but for very densely populated trees the miniature
cost might build up.
> + /*
> + * Considering how overcrowded the code will be inside the switch,
> + * complex verification is better to moved its own function.
> + */
> + switch (key.type) {
> + case BTRFS_EXTENT_DATA_KEY:
> + ret = check_extent_data_item(root, leaf, slot);
> + break;
> + }
> + return ret;
> +}
> +
> static noinline int check_leaf(struct btrfs_root *root,
> struct extent_buffer *leaf)
> {
> @@ -605,9 +682,13 @@ static noinline int check_leaf(struct btrfs_root *root,
> * 1) key order
> * 2) item offset and size
> * No overlap, no hole, all inside the leaf.
> + * 3) item content
> + * If possible, do comprehensive sanity check.
> + * NOTE: All check must only rely on the item data itself.
> */
> for (slot = 0; slot < nritems; slot++) {
> u32 item_end_expected;
> + int ret;
>
> btrfs_item_key_to_cpu(leaf, &key, slot);
>
> @@ -650,6 +731,13 @@ static noinline int check_leaf(struct btrfs_root *root,
> return -EIO;
> }
>
> + /*
> + * Check if the item size and content meets other limitation
> + */
> + ret = check_leaf_item(root, leaf, slot);
> + if (ret < 0)
> + return ret;
> +
> prev_key.objectid = key.objectid;
> prev_key.type = key.type;
> prev_key.offset = key.offset;
> diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
> index 10689e1fdf11..3aadbb74a024 100644
> --- a/include/uapi/linux/btrfs_tree.h
> +++ b/include/uapi/linux/btrfs_tree.h
> @@ -732,6 +732,7 @@ struct btrfs_balance_item {
> #define BTRFS_FILE_EXTENT_INLINE 0
> #define BTRFS_FILE_EXTENT_REG 1
> #define BTRFS_FILE_EXTENT_PREALLOC 2
> +#define BTRFS_FILE_EXTENT_LAST_TYPE 3
>
> struct btrfs_file_extent_item {
> /*
>
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