4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Qu Wenruo quwenruo.btrfs@gmx.com
commit 40c3c40947324d9f40bf47830c92c59a9bbadf4a upstream.
Add extra checks for item with EXTENT_DATA type. This checks the following thing:
0) Key offset All key offsets must be aligned to sectorsize. Inline extent must have 0 for key offset.
1) Item size Uncompressed inline file extent size must match item size. (Compressed inline file extent has no information 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 strict check in the context of btrfs_item for EXTENT_DATA.
Signed-off-by: Qu Wenruo quwenruo.btrfs@gmx.com Reviewed-by: Nikolay Borisov nborisov@suse.com Reviewed-by: David Sterba dsterba@suse.com [ switch to BTRFS_FILE_EXTENT_TYPES, similar to what BTRFS_COMPRESS_TYPES does ] Signed-off-by: David Sterba dsterba@suse.com [bwh: Backported to 4.9: Use root->sectorsize instead of root->fs_info->sectorsize] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/disk-io.c | 103 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/btrfs_tree.h | 1 2 files changed, 104 insertions(+)
--- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -544,6 +544,100 @@ static int check_tree_block_fsid(struct 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, + struct btrfs_key *key, int slot) +{ + struct btrfs_file_extent_item *fi; + u32 sectorsize = root->sectorsize; + u32 item_size = btrfs_item_size_nr(leaf, slot); + + if (!IS_ALIGNED(key->offset, sectorsize)) { + CORRUPT("unaligned key offset for file extent", + leaf, root, slot); + return -EUCLEAN; + } + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + + if (btrfs_file_extent_type(leaf, fi) > BTRFS_FILE_EXTENT_TYPES) { + CORRUPT("invalid file extent type", leaf, root, slot); + return -EUCLEAN; + } + + /* + * Support for new compression/encrption must introduce incompat flag, + * and must be caught in open_ctree(). + */ + if (btrfs_file_extent_compression(leaf, fi) > BTRFS_COMPRESS_TYPES) { + CORRUPT("invalid file extent compression", leaf, root, slot); + return -EUCLEAN; + } + if (btrfs_file_extent_encryption(leaf, fi)) { + CORRUPT("invalid file extent encryption", leaf, root, slot); + return -EUCLEAN; + } + if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) { + /* Inline extent must have 0 as key offset */ + if (key->offset) { + CORRUPT("inline extent has non-zero key offset", + leaf, root, slot); + return -EUCLEAN; + } + + /* Compressed inline extent has no on-disk size, skip it */ + if (btrfs_file_extent_compression(leaf, fi) != + BTRFS_COMPRESS_NONE) + return 0; + + /* Uncompressed 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 -EUCLEAN; + } + 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 -EUCLEAN; + } + 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 -EUCLEAN; + } + + return 0; +} + +/* + * Common point to switch the item-specific validation. + */ +static int check_leaf_item(struct btrfs_root *root, + struct extent_buffer *leaf, + struct btrfs_key *key, int slot) +{ + int ret = 0; + + switch (key->type) { + case BTRFS_EXTENT_DATA_KEY: + ret = check_extent_data_item(root, leaf, key, slot); + break; + } + return ret; +} + static noinline int check_leaf(struct btrfs_root *root, struct extent_buffer *leaf) { @@ -599,9 +693,13 @@ static noinline int check_leaf(struct bt * 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 checks 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);
@@ -644,6 +742,11 @@ static noinline int check_leaf(struct bt return -EUCLEAN; }
+ /* Check if the item size and content meet other criteria */ + ret = check_leaf_item(root, leaf, &key, slot); + if (ret < 0) + return ret; + prev_key.objectid = key.objectid; prev_key.type = key.type; prev_key.offset = key.offset; --- a/include/uapi/linux/btrfs_tree.h +++ b/include/uapi/linux/btrfs_tree.h @@ -730,6 +730,7 @@ 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_TYPES 2
struct btrfs_file_extent_item { /*