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-rw-r--r--fs/btrfs/tree-checker.c589
1 files changed, 589 insertions, 0 deletions
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
new file mode 100644
index 000000000000..8871286c1a91
--- /dev/null
+++ b/fs/btrfs/tree-checker.c
@@ -0,0 +1,589 @@
+/*
+ * Copyright (C) Qu Wenruo 2017. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program.
+ */
+
+/*
+ * The module is used to catch unexpected/corrupted tree block data.
+ * Such behavior can be caused either by a fuzzed image or bugs.
+ *
+ * The objective is to do leaf/node validation checks when tree block is read
+ * from disk, and check *every* possible member, so other code won't
+ * need to checking them again.
+ *
+ * Due to the potential and unwanted damage, every checker needs to be
+ * carefully reviewed otherwise so it does not prevent mount of valid images.
+ */
+
+#include "ctree.h"
+#include "tree-checker.h"
+#include "disk-io.h"
+#include "compression.h"
+
+/*
+ * Error message should follow the following format:
+ * corrupt <type>: <identifier>, <reason>[, <bad_value>]
+ *
+ * @type: leaf or node
+ * @identifier: the necessary info to locate the leaf/node.
+ * It's recommened to decode key.objecitd/offset if it's
+ * meaningful.
+ * @reason: describe the error
+ * @bad_value: optional, it's recommened to output bad value and its
+ * expected value (range).
+ *
+ * Since comma is used to separate the components, only space is allowed
+ * inside each component.
+ */
+
+/*
+ * Append generic "corrupt leaf/node root=%llu block=%llu slot=%d: " to @fmt.
+ * Allows callers to customize the output.
+ */
+__printf(4, 5)
+__cold
+static void generic_err(const struct btrfs_fs_info *fs_info,
+ const struct extent_buffer *eb, int slot,
+ const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ btrfs_crit(fs_info,
+ "corrupt %s: root=%llu block=%llu slot=%d, %pV",
+ btrfs_header_level(eb) == 0 ? "leaf" : "node",
+ btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot, &vaf);
+ va_end(args);
+}
+
+/*
+ * Customized reporter for extent data item, since its key objectid and
+ * offset has its own meaning.
+ */
+__printf(4, 5)
+__cold
+static void file_extent_err(const struct btrfs_fs_info *fs_info,
+ 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(fs_info,
+ "corrupt %s: root=%llu block=%llu slot=%d ino=%llu file_offset=%llu, %pV",
+ btrfs_header_level(eb) == 0 ? "leaf" : "node",
+ btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot,
+ key.objectid, key.offset, &vaf);
+ va_end(args);
+}
+
+/*
+ * Return 0 if the btrfs_file_extent_##name is aligned to @alignment
+ * Else return 1
+ */
+#define CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, name, alignment) \
+({ \
+ if (!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment))) \
+ file_extent_err((fs_info), (leaf), (slot), \
+ "invalid %s for file extent, have %llu, should be aligned to %u", \
+ (#name), btrfs_file_extent_##name((leaf), (fi)), \
+ (alignment)); \
+ (!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment))); \
+})
+
+static int check_extent_data_item(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf,
+ struct btrfs_key *key, int slot)
+{
+ struct btrfs_file_extent_item *fi;
+ u32 sectorsize = fs_info->sectorsize;
+ u32 item_size = btrfs_item_size_nr(leaf, slot);
+
+ if (!IS_ALIGNED(key->offset, sectorsize)) {
+ file_extent_err(fs_info, leaf, slot,
+"unaligned file_offset for file extent, have %llu should be aligned to %u",
+ key->offset, sectorsize);
+ return -EUCLEAN;
+ }
+
+ fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+
+ if (btrfs_file_extent_type(leaf, fi) > BTRFS_FILE_EXTENT_TYPES) {
+ file_extent_err(fs_info, leaf, slot,
+ "invalid type for file extent, have %u expect range [0, %u]",
+ btrfs_file_extent_type(leaf, fi),
+ BTRFS_FILE_EXTENT_TYPES);
+ 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) {
+ file_extent_err(fs_info, leaf, slot,
+ "invalid compression for file extent, have %u expect range [0, %u]",
+ btrfs_file_extent_compression(leaf, fi),
+ BTRFS_COMPRESS_TYPES);
+ return -EUCLEAN;
+ }
+ if (btrfs_file_extent_encryption(leaf, fi)) {
+ file_extent_err(fs_info, leaf, slot,
+ "invalid encryption for file extent, have %u expect 0",
+ btrfs_file_extent_encryption(leaf, fi));
+ return -EUCLEAN;
+ }
+ if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
+ /* Inline extent must have 0 as key offset */
+ if (key->offset) {
+ file_extent_err(fs_info, leaf, slot,
+ "invalid file_offset for inline file extent, have %llu expect 0",
+ key->offset);
+ 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)) {
+ file_extent_err(fs_info, leaf, slot,
+ "invalid ram_bytes for uncompressed inline extent, have %u expect %llu",
+ item_size, BTRFS_FILE_EXTENT_INLINE_DATA_START +
+ btrfs_file_extent_ram_bytes(leaf, fi));
+ return -EUCLEAN;
+ }
+ return 0;
+ }
+
+ /* Regular or preallocated extent has fixed item size */
+ if (item_size != sizeof(*fi)) {
+ file_extent_err(fs_info, leaf, slot,
+ "invalid item size for reg/prealloc file extent, have %u expect %zu",
+ item_size, sizeof(*fi));
+ return -EUCLEAN;
+ }
+ if (CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, ram_bytes, sectorsize) ||
+ CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, disk_bytenr, sectorsize) ||
+ CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, disk_num_bytes, sectorsize) ||
+ CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, offset, sectorsize) ||
+ CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, num_bytes, sectorsize))
+ return -EUCLEAN;
+ return 0;
+}
+
+static int check_csum_item(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf, struct btrfs_key *key,
+ int slot)
+{
+ u32 sectorsize = fs_info->sectorsize;
+ u32 csumsize = btrfs_super_csum_size(fs_info->super_copy);
+
+ if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) {
+ generic_err(fs_info, leaf, slot,
+ "invalid key objectid for csum item, have %llu expect %llu",
+ key->objectid, BTRFS_EXTENT_CSUM_OBJECTID);
+ return -EUCLEAN;
+ }
+ if (!IS_ALIGNED(key->offset, sectorsize)) {
+ generic_err(fs_info, leaf, slot,
+ "unaligned key offset for csum item, have %llu should be aligned to %u",
+ key->offset, sectorsize);
+ return -EUCLEAN;
+ }
+ if (!IS_ALIGNED(btrfs_item_size_nr(leaf, slot), csumsize)) {
+ generic_err(fs_info, leaf, slot,
+ "unaligned item size for csum item, have %u should be aligned to %u",
+ btrfs_item_size_nr(leaf, slot), csumsize);
+ return -EUCLEAN;
+ }
+ return 0;
+}
+
+/*
+ * Customized reported for dir_item, only important new info is key->objectid,
+ * which represents inode number
+ */
+__printf(4, 5)
+__cold
+static void dir_item_err(const struct btrfs_fs_info *fs_info,
+ 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(fs_info,
+ "corrupt %s: root=%llu block=%llu slot=%d ino=%llu, %pV",
+ btrfs_header_level(eb) == 0 ? "leaf" : "node",
+ btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot,
+ key.objectid, &vaf);
+ va_end(args);
+}
+
+static int check_dir_item(struct btrfs_fs_info *fs_info,
+ 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) {
+ 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(fs_info, leaf, slot,
+ "dir item header crosses item boundary, have %zu 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(fs_info, 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(fs_info, 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(fs_info, 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(fs_info, 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(fs_info)) {
+ dir_item_err(fs_info, leaf, slot,
+ "dir item name and data len too long, have %u max %u",
+ name_len + data_len,
+ BTRFS_MAX_XATTR_SIZE(fs_info));
+ return -EUCLEAN;
+ }
+
+ if (data_len && dir_type != BTRFS_FT_XATTR) {
+ dir_item_err(fs_info, 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(fs_info, 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) {
+ char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];
+
+ 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(fs_info, 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_fs_info *fs_info,
+ 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(fs_info, leaf, key, slot);
+ break;
+ case BTRFS_EXTENT_CSUM_KEY:
+ ret = check_csum_item(fs_info, leaf, key, slot);
+ break;
+ case BTRFS_DIR_ITEM_KEY:
+ case BTRFS_DIR_INDEX_KEY:
+ case BTRFS_XATTR_ITEM_KEY:
+ ret = check_dir_item(fs_info, leaf, key, slot);
+ break;
+ }
+ return ret;
+}
+
+static int check_leaf(struct btrfs_fs_info *fs_info, struct extent_buffer *leaf,
+ bool check_item_data)
+{
+ /* No valid key type is 0, so all key should be larger than this key */
+ struct btrfs_key prev_key = {0, 0, 0};
+ struct btrfs_key key;
+ u32 nritems = btrfs_header_nritems(leaf);
+ int slot;
+
+ /*
+ * Extent buffers from a relocation tree have a owner field that
+ * corresponds to the subvolume tree they are based on. So just from an
+ * extent buffer alone we can not find out what is the id of the
+ * corresponding subvolume tree, so we can not figure out if the extent
+ * buffer corresponds to the root of the relocation tree or not. So
+ * skip this check for relocation trees.
+ */
+ if (nritems == 0 && !btrfs_header_flag(leaf, BTRFS_HEADER_FLAG_RELOC)) {
+ struct btrfs_root *check_root;
+
+ key.objectid = btrfs_header_owner(leaf);
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ check_root = btrfs_get_fs_root(fs_info, &key, false);
+ /*
+ * The only reason we also check NULL here is that during
+ * open_ctree() some roots has not yet been set up.
+ */
+ if (!IS_ERR_OR_NULL(check_root)) {
+ struct extent_buffer *eb;
+
+ eb = btrfs_root_node(check_root);
+ /* if leaf is the root, then it's fine */
+ if (leaf != eb) {
+ generic_err(fs_info, leaf, 0,
+ "invalid nritems, have %u should not be 0 for non-root leaf",
+ nritems);
+ free_extent_buffer(eb);
+ return -EUCLEAN;
+ }
+ free_extent_buffer(eb);
+ }
+ return 0;
+ }
+
+ if (nritems == 0)
+ return 0;
+
+ /*
+ * Check the following things to make sure this is a good leaf, and
+ * leaf users won't need to bother with similar sanity checks:
+ *
+ * 1) key ordering
+ * 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);
+
+ /* Make sure the keys are in the right order */
+ if (btrfs_comp_cpu_keys(&prev_key, &key) >= 0) {
+ generic_err(fs_info, leaf, slot,
+ "bad key order, prev (%llu %u %llu) current (%llu %u %llu)",
+ prev_key.objectid, prev_key.type,
+ prev_key.offset, key.objectid, key.type,
+ key.offset);
+ return -EUCLEAN;
+ }
+
+ /*
+ * Make sure the offset and ends are right, remember that the
+ * item data starts at the end of the leaf and grows towards the
+ * front.
+ */
+ if (slot == 0)
+ item_end_expected = BTRFS_LEAF_DATA_SIZE(fs_info);
+ else
+ item_end_expected = btrfs_item_offset_nr(leaf,
+ slot - 1);
+ if (btrfs_item_end_nr(leaf, slot) != item_end_expected) {
+ generic_err(fs_info, leaf, slot,
+ "unexpected item end, have %u expect %u",
+ btrfs_item_end_nr(leaf, slot),
+ item_end_expected);
+ return -EUCLEAN;
+ }
+
+ /*
+ * Check to make sure that we don't point outside of the leaf,
+ * just in case all the items are consistent to each other, but
+ * all point outside of the leaf.
+ */
+ if (btrfs_item_end_nr(leaf, slot) >
+ BTRFS_LEAF_DATA_SIZE(fs_info)) {
+ generic_err(fs_info, leaf, slot,
+ "slot end outside of leaf, have %u expect range [0, %u]",
+ btrfs_item_end_nr(leaf, slot),
+ BTRFS_LEAF_DATA_SIZE(fs_info));
+ return -EUCLEAN;
+ }
+
+ /* Also check if the item pointer overlaps with btrfs item. */
+ if (btrfs_item_nr_offset(slot) + sizeof(struct btrfs_item) >
+ btrfs_item_ptr_offset(leaf, slot)) {
+ generic_err(fs_info, leaf, slot,
+ "slot overlaps with its data, item end %lu data start %lu",
+ btrfs_item_nr_offset(slot) +
+ sizeof(struct btrfs_item),
+ btrfs_item_ptr_offset(leaf, slot));
+ return -EUCLEAN;
+ }
+
+ if (check_item_data) {
+ /*
+ * Check if the item size and content meet other
+ * criteria
+ */
+ ret = check_leaf_item(fs_info, leaf, &key, slot);
+ if (ret < 0)
+ return ret;
+ }
+
+ prev_key.objectid = key.objectid;
+ prev_key.type = key.type;
+ prev_key.offset = key.offset;
+ }
+
+ return 0;
+}
+
+int btrfs_check_leaf_full(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf)
+{
+ return check_leaf(fs_info, leaf, true);
+}
+
+int btrfs_check_leaf_relaxed(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf)
+{
+ return check_leaf(fs_info, leaf, false);
+}
+
+int btrfs_check_node(struct btrfs_fs_info *fs_info, struct extent_buffer *node)
+{
+ unsigned long nr = btrfs_header_nritems(node);
+ struct btrfs_key key, next_key;
+ int slot;
+ u64 bytenr;
+ int ret = 0;
+
+ if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(fs_info)) {
+ btrfs_crit(fs_info,
+"corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]",
+ btrfs_header_owner(node), node->start,
+ nr == 0 ? "small" : "large", nr,
+ BTRFS_NODEPTRS_PER_BLOCK(fs_info));
+ return -EUCLEAN;
+ }
+
+ for (slot = 0; slot < nr - 1; slot++) {
+ bytenr = btrfs_node_blockptr(node, slot);
+ btrfs_node_key_to_cpu(node, &key, slot);
+ btrfs_node_key_to_cpu(node, &next_key, slot + 1);
+
+ if (!bytenr) {
+ generic_err(fs_info, node, slot,
+ "invalid NULL node pointer");
+ ret = -EUCLEAN;
+ goto out;
+ }
+ if (!IS_ALIGNED(bytenr, fs_info->sectorsize)) {
+ generic_err(fs_info, node, slot,
+ "unaligned pointer, have %llu should be aligned to %u",
+ bytenr, fs_info->sectorsize);
+ ret = -EUCLEAN;
+ goto out;
+ }
+
+ if (btrfs_comp_cpu_keys(&key, &next_key) >= 0) {
+ generic_err(fs_info, node, slot,
+ "bad key order, current (%llu %u %llu) next (%llu %u %llu)",
+ key.objectid, key.type, key.offset,
+ next_key.objectid, next_key.type,
+ next_key.offset);
+ ret = -EUCLEAN;
+ goto out;
+ }
+ }
+out:
+ return ret;
+}
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