linux/fs/btrfs
Josef Bacik bf53d4687b btrfs: only search for left_info if there is no right_info in try_merge_free_space
In try_to_merge_free_space we attempt to find entries to the left and
right of the entry we are adding to see if they can be merged.  We
search for an entry past our current info (saved into right_info), and
then if right_info exists and it has a rb_prev() we save the rb_prev()
into left_info.

However there's a slight problem in the case that we have a right_info,
but no entry previous to that entry.  At that point we will search for
an entry just before the info we're attempting to insert.  This will
simply find right_info again, and assign it to left_info, making them
both the same pointer.

Now if right_info _can_ be merged with the range we're inserting, we'll
add it to the info and free right_info.  However further down we'll
access left_info, which was right_info, and thus get a use-after-free.

Fix this by only searching for the left entry if we don't find a right
entry at all.

The CVE referenced had a specially crafted file system that could
trigger this use-after-free. However with the tree checker improvements
we no longer trigger the conditions for the UAF.  But the original
conditions still apply, hence this fix.

Reference: CVE-2019-19448
Fixes: 9630308170 ("Btrfs: use hybrid extents+bitmap rb tree for free space")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:07 +02:00
..
tests btrfs: make btrfs_set_extent_delalloc take btrfs_inode 2020-07-27 12:55:35 +02:00
acl.c btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
async-thread.c Btrfs: fix crash during unmount due to race with delayed inode workers 2020-03-23 17:01:51 +01:00
async-thread.h Btrfs: fix crash during unmount due to race with delayed inode workers 2020-03-23 17:01:51 +01:00
backref.c btrfs: fix double free on ulist after backref resolution failure 2020-07-21 21:59:15 +02:00
backref.h btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE 2020-05-25 11:25:35 +02:00
block-group.c btrfs: if we're restriping, use the target restripe profile 2020-07-27 12:55:47 +02:00
block-group.h btrfs: convert block group refcount to refcount_t 2020-07-27 12:55:42 +02:00
block-rsv.c btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE 2020-05-25 11:25:35 +02:00
block-rsv.h btrfs: Remove __ prefix from btrfs_block_rsv_release 2020-03-23 17:01:55 +01:00
btrfs_inode.h btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
check-integrity.c btrfs: check-integrity: remove unnecessary failure messages during memory allocation 2020-07-27 12:55:21 +02:00
check-integrity.h btrfs: remove btrfsic_submit_bh() 2020-03-23 17:01:39 +01:00
compression.c btrfs: remove fail label in check_compressed_csum 2020-07-27 12:55:42 +02:00
compression.h btrfs: make btrfs_submit_compressed_write take btrfs_inode 2020-07-27 12:55:31 +02:00
ctree.c btrfs: add little-endian optimized key helpers 2020-07-27 12:55:24 +02:00
ctree.h btrfs: don't WARN if we abort a transaction with EROFS 2020-07-27 12:55:46 +02:00
delalloc-space.c btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
delalloc-space.h btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
delayed-inode.c btrfs: use nofs allocations for running delayed items 2020-03-25 16:26:00 +01:00
delayed-inode.h btrfs: delayed-inode: Replace zero-length array with flexible-array member 2020-03-23 17:01:53 +01:00
delayed-ref.c btrfs: Remove __ prefix from btrfs_block_rsv_release 2020-03-23 17:01:55 +01:00
delayed-ref.h btrfs: migrate the delayed refs rsv code 2019-07-04 17:26:17 +02:00
dev-replace.c btrfs: sysfs, rename device_link add/remove functions 2020-03-23 17:01:35 +01:00
dev-replace.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dir-item.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
discard.c btrfs: discard: add missing put when grabbing block group from unused list 2020-07-07 16:06:28 +02:00
discard.h btrfs: discard: Use the correct style for SPDX License Identifier 2020-04-20 17:43:42 +02:00
disk-io.c btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT 2020-07-27 12:55:43 +02:00
disk-io.h btrfs: preallocate anon block device at first phase of snapshot creation 2020-07-27 12:55:38 +02:00
export.c btrfs: simplify iget helpers 2020-05-25 11:25:37 +02:00
export.h btrfs: export helpers for subvolume name/id resolution 2020-03-23 17:01:42 +01:00
extent_io.c btrfs: do not set the full sync flag on the inode during page release 2020-07-27 12:55:48 +02:00
extent_io.h btrfs: don't use UAPI types for fiemap callback 2020-07-27 12:55:27 +02:00
extent_map.c Btrfs: fix race between using extent maps and merging them 2020-02-12 17:16:46 +01:00
extent_map.h btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent-io-tree.h btrfs: streamline btrfs_get_io_failure_record logic 2020-07-27 12:55:39 +02:00
extent-tree.c btrfs: avoid possible signal interruption of btrfs_drop_snapshot() on relocation tree 2020-07-27 12:55:45 +02:00
file-item.c btrfs: make btrfs_csum_one_bio takae btrfs_inode 2020-07-27 12:55:26 +02:00
file.c btrfs: make btrfs_check_data_free_space take btrfs_inode 2020-07-27 12:55:36 +02:00
free-space-cache.c btrfs: only search for left_info if there is no right_info in try_merge_free_space 2020-08-10 18:58:07 +02:00
free-space-cache.h btrfs: let btrfs_return_cluster_to_free_space() return void 2020-07-27 12:55:21 +02:00
free-space-tree.c btrfs: move the root freeing stuff into btrfs_put_root 2020-03-23 17:01:59 +01:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c btrfs: Make btrfs_find_name_in_ext_backref return struct btrfs_inode_extref 2019-09-09 14:59:16 +02:00
inode-map.c btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
inode-map.h
inode.c btrfs: inode: fix NULL pointer dereference if inode doesn't need compression 2020-08-10 18:57:59 +02:00
ioctl.c btrfs: add missing check for nocow and compression inode flags 2020-07-27 12:55:44 +02:00
Kconfig Revert "btrfs: switch to iomap_dio_rw() for dio" 2020-06-14 01:19:02 +02:00
locking.c btrfs: add missing annotation for btrfs_tree_lock() 2020-05-25 11:25:16 +02:00
locking.h btrfs: Implement DREW lock 2020-03-23 17:01:43 +01:00
lzo.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
Makefile Btrfs: move all reflink implementation code into its own file 2020-03-23 17:01:54 +01:00
misc.h btrfs: rename tree_entry to rb_simple_node and export it 2020-05-25 11:25:19 +02:00
ordered-data.c btrfs: make btrfs_add_ordered_extent_dio take btrfs_inode 2020-07-27 12:55:34 +02:00
ordered-data.h btrfs: make btrfs_add_ordered_extent_dio take btrfs_inode 2020-07-27 12:55:34 +02:00
orphan.c
print-tree.c btrfs: Remove unneeded semicolon 2020-01-20 16:40:55 +01:00
print-tree.h
props.c btrfs: simplify iget helpers 2020-05-25 11:25:37 +02:00
props.h btrfs: delete unused function btrfs_set_prop_trans 2019-04-29 19:02:54 +02:00
qgroup.c btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT 2020-07-27 12:55:43 +02:00
qgroup.h btrfs: qgroup: export qgroups in sysfs 2020-07-27 12:55:37 +02:00
raid56.c btrfs: raid56: remove out label in __raid56_parity_recover 2020-07-27 12:55:44 +02:00
raid56.h btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes 2019-07-01 13:34:58 +02:00
rcu-string.h btrfs: rcu-string: Replace zero-length array with flexible-array member 2020-03-23 17:01:53 +01:00
reada.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
ref-verify.c btrfs: ref-verify: fix memory leak in add_block_entry 2020-07-27 12:55:43 +02:00
ref-verify.h btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod() 2019-04-29 19:02:49 +02:00
reflink.c btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
reflink.h Btrfs: move all reflink implementation code into its own file 2020-03-23 17:01:54 +01:00
relocation.c btrfs: relocation: review the call sites which can be interrupted by signal 2020-07-27 12:55:45 +02:00
root-tree.c btrfs: simplify root lookup by id 2020-05-25 11:25:36 +02:00
scrub.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2020-07-27 12:55:46 +02:00
send.c for-5.8-tag 2020-06-02 19:59:25 -07:00
send.h
space-info.c btrfs: fix lockdep splat from btrfs_dump_space_info 2020-07-27 12:55:47 +02:00
space-info.h btrfs: improve global reserve stealing logic 2020-05-25 11:25:22 +02:00
struct-funcs.c btrfs: update documentation of set/get helpers 2020-05-25 11:25:35 +02:00
super.c btrfs: open-code remount flag setting in btrfs_remount 2020-07-27 12:55:47 +02:00
sysfs.c btrfs: sysfs: use NOFS for device creation 2020-07-27 12:55:46 +02:00
sysfs.h btrfs: qgroup: export qgroups in sysfs 2020-07-27 12:55:37 +02:00
transaction.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2020-07-27 12:55:46 +02:00
transaction.h btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT 2020-07-27 12:55:43 +02:00
tree-checker.c btrfs: tree-checker: remove duplicate definition of 'inode_item_err' 2020-05-25 11:25:23 +02:00
tree-checker.h btrfs: get fs_info from eb in btrfs_check_chunk_valid 2019-04-29 19:02:39 +02:00
tree-defrag.c btrfs: remove unused btrfs_root::defrag_trans_start 2020-07-27 12:55:28 +02:00
tree-log.c btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
tree-log.h btrfs: get fs_info from trans in btrfs_set_log_full_commit 2019-04-29 19:02:41 +02:00
ulist.c
ulist.h
uuid-tree.c btrfs: simplify root lookup by id 2020-05-25 11:25:36 +02:00
volumes.c btrfs: move the chunk_mutex in btrfs_read_chunk_tree 2020-07-27 12:55:46 +02:00
volumes.h btrfs: record btrfs_device directly in btrfs_io_bio 2020-07-27 12:55:40 +02:00
xattr.c Btrfs: fix failure to persist compression property xattr deletion on fsync 2019-06-17 16:37:17 +02:00
xattr.h btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
zlib.c btrfs: use larger zlib buffer for s390 hardware compression 2020-01-31 10:30:40 -08:00
zstd.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00