4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Qu Wenruo wqu@suse.com
commit ad7b0368f33cffe67fecd302028915926e50ef7e upstream.
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 [bwh: Backported to 4.9: BTRFS_MAX_XATTR_SIZE() takes a root not an fs_info] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/tree-checker.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+)
--- 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"
#define CORRUPT(reason, eb, root, slot) \ btrfs_crit(root->fs_info, \ @@ -176,6 +177,141 @@ static int check_csum_item(struct btrfs_ }
/* + * 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)) { + 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)); + 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. */ static int check_leaf_item(struct btrfs_root *root, @@ -191,6 +327,11 @@ static int check_leaf_item(struct btrfs_ 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; }