diff options
author | Qu Wenruo <wqu@suse.com> | 2018-07-03 12:10:05 +0300 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2018-08-06 14:12:41 +0300 |
commit | fce466eab7ac6baa9d2dcd88abcf945be3d4a089 (patch) | |
tree | b1dfc302a5c93cf38ab82bf11cdabc2b47dc9f91 | |
parent | 6d8ff4e4584cd84093b751671351c8103ead551d (diff) |
btrfs: tree-checker: Verify block_group_item
A crafted image with invalid block group items could make free space cache
code to cause panic.
We could detect such invalid block group item by checking:
1) Item size
Known fixed value.
2) Block group size (key.offset)
We have an upper limit on block group item (10G)
3) Chunk objectid
Known fixed value.
4) Type
Only 4 valid type values, DATA, METADATA, SYSTEM and DATA|METADATA.
No more than 1 bit set for profile type.
5) Used space
No more than the block group size.
This should allow btrfs to detect and refuse to mount the crafted image.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=199849
Reported-by: Xu Wen <wen.xu@gatech.edu>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r-- | fs/btrfs/tree-checker.c | 100 | ||||
-rw-r--r-- | fs/btrfs/volumes.c | 2 | ||||
-rw-r--r-- | fs/btrfs/volumes.h | 2 |
3 files changed, 103 insertions, 1 deletions
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 8d40e7dd8c30..3bade2ad39e8 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -19,6 +19,7 @@ #include "tree-checker.h" #include "disk-io.h" #include "compression.h" +#include "volumes.h" /* * Error message should follow the following format: @@ -353,6 +354,102 @@ static int check_dir_item(struct btrfs_fs_info *fs_info, return 0; } +__printf(4, 5) +__cold +static void block_group_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 bg_start=%llu bg_len=%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); +} + +static int check_block_group_item(struct btrfs_fs_info *fs_info, + struct extent_buffer *leaf, + struct btrfs_key *key, int slot) +{ + struct btrfs_block_group_item bgi; + u32 item_size = btrfs_item_size_nr(leaf, slot); + u64 flags; + u64 type; + + /* + * Here we don't really care about alignment since extent allocator can + * handle it. We care more about the size, as if one block group is + * larger than maximum size, it's must be some obvious corruption. + */ + if (key->offset > BTRFS_MAX_DATA_CHUNK_SIZE || key->offset == 0) { + block_group_err(fs_info, leaf, slot, + "invalid block group size, have %llu expect (0, %llu]", + key->offset, BTRFS_MAX_DATA_CHUNK_SIZE); + return -EUCLEAN; + } + + if (item_size != sizeof(bgi)) { + block_group_err(fs_info, leaf, slot, + "invalid item size, have %u expect %zu", + item_size, sizeof(bgi)); + return -EUCLEAN; + } + + read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot), + sizeof(bgi)); + if (btrfs_block_group_chunk_objectid(&bgi) != + BTRFS_FIRST_CHUNK_TREE_OBJECTID) { + block_group_err(fs_info, leaf, slot, + "invalid block group chunk objectid, have %llu expect %llu", + btrfs_block_group_chunk_objectid(&bgi), + BTRFS_FIRST_CHUNK_TREE_OBJECTID); + return -EUCLEAN; + } + + if (btrfs_block_group_used(&bgi) > key->offset) { + block_group_err(fs_info, leaf, slot, + "invalid block group used, have %llu expect [0, %llu)", + btrfs_block_group_used(&bgi), key->offset); + return -EUCLEAN; + } + + flags = btrfs_block_group_flags(&bgi); + if (hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) > 1) { + block_group_err(fs_info, leaf, slot, +"invalid profile flags, have 0x%llx (%lu bits set) expect no more than 1 bit set", + flags & BTRFS_BLOCK_GROUP_PROFILE_MASK, + hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)); + return -EUCLEAN; + } + + type = flags & BTRFS_BLOCK_GROUP_TYPE_MASK; + if (type != BTRFS_BLOCK_GROUP_DATA && + type != BTRFS_BLOCK_GROUP_METADATA && + type != BTRFS_BLOCK_GROUP_SYSTEM && + type != (BTRFS_BLOCK_GROUP_METADATA | + BTRFS_BLOCK_GROUP_DATA)) { + block_group_err(fs_info, leaf, slot, +"invalid type, have 0x%llx (%lu bits set) expect either 0x%llx, 0x%llx, 0x%llu or 0x%llx", + type, hweight64(type), + BTRFS_BLOCK_GROUP_DATA, BTRFS_BLOCK_GROUP_METADATA, + BTRFS_BLOCK_GROUP_SYSTEM, + BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA); + return -EUCLEAN; + } + return 0; +} + /* * Common point to switch the item-specific validation. */ @@ -374,6 +471,9 @@ static int check_leaf_item(struct btrfs_fs_info *fs_info, case BTRFS_XATTR_ITEM_KEY: ret = check_dir_item(fs_info, leaf, key, slot); break; + case BTRFS_BLOCK_GROUP_ITEM_KEY: + ret = check_block_group_item(fs_info, leaf, key, slot); + break; } return ret; } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index fe497937933f..256e57eec8ec 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4692,7 +4692,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, if (type & BTRFS_BLOCK_GROUP_DATA) { max_stripe_size = SZ_1G; - max_chunk_size = 10 * max_stripe_size; + max_chunk_size = BTRFS_MAX_DATA_CHUNK_SIZE; if (!devs_max) devs_max = BTRFS_MAX_DEVS(info); } else if (type & BTRFS_BLOCK_GROUP_METADATA) { diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index df2d8bdf8c9a..275c31c730cf 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -11,6 +11,8 @@ #include <linux/btrfs.h> #include "async-thread.h" +#define BTRFS_MAX_DATA_CHUNK_SIZE (10ULL * SZ_1G) + extern struct mutex uuid_mutex; #define BTRFS_STRIPE_LEN SZ_64K |