On 2017年08月22日 19:00, Nikolay Borisov wrote:
On 22.08.2017 13:57, Nikolay Borisov wrote:
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;
+ }
One more thing - don't we really want to use -EUCLEAN rather than -EIO?
Nice suggestion.
Since it's not really something wrong with IO routine, EUCLEAN is better.
+
+
+ /* 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.
Sounds valid. Considering how many times this item_key_to_cpu() get
called in a large leaf,
micro-optimization counts.
I'll update this in next revision.
Thanks for your review,
Qu
+ /*
+ * 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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