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authorChris Mason <clm@fb.com>2015-10-13 14:06:48 -0400
committerChris Mason <clm@fb.com>2015-10-26 19:38:28 -0700
commit2849a854224487bc578b73b64422c3cb3ef93ff5 (patch)
treececc18105ff992cc0ec13283b28ae6f2c038dd5a /fs/btrfs/backref.c
parent849ef9286f30c88113906dc35f44a499c0cb385d (diff)
btrfs: fix use after free iterating extrefs
The code for btrfs inode-resolve has never worked properly for files with enough hard links to trigger extrefs. It was trying to get the leaf out of a path after freeing the path: btrfs_release_path(path); leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, slot); The fix here is to use the extent buffer we cloned just a little higher up to avoid deadlocks caused by using the leaf in the path. Signed-off-by: Chris Mason <clm@fb.com> cc: stable@vger.kernel.org # v3.7+ cc: Mark Fasheh <mfasheh@suse.de> Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/backref.c')
-rw-r--r--fs/btrfs/backref.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 2adc152a32e3..6dcdb2ec9211 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1834,7 +1834,6 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
int found = 0;
struct extent_buffer *eb;
struct btrfs_inode_extref *extref;
- struct extent_buffer *leaf;
u32 item_size;
u32 cur_offset;
unsigned long ptr;
@@ -1862,9 +1861,8 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
btrfs_release_path(path);
- leaf = path->nodes[0];
- item_size = btrfs_item_size_nr(leaf, slot);
- ptr = btrfs_item_ptr_offset(leaf, slot);
+ item_size = btrfs_item_size_nr(eb, slot);
+ ptr = btrfs_item_ptr_offset(eb, slot);
cur_offset = 0;
while (cur_offset < item_size) {
@@ -1878,7 +1876,7 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
if (ret)
break;
- cur_offset += btrfs_inode_extref_name_len(leaf, extref);
+ cur_offset += btrfs_inode_extref_name_len(eb, extref);
cur_offset += sizeof(*extref);
}
btrfs_tree_read_unlock_blocking(eb);