On 06/15/2017 11:57 PM, David Sterba wrote:
On Tue, Jun 06, 2017 at 05:56:59PM +0800, Su Yue wrote:
When reading out name from inode_ref, dir_item, it's possible that
corrupted name_len leads to read beyond boundary.
Since there are already patches for btrfs-progs, this patchset is
for btrfs.

Introduce 'btrfs_is_name_len_valid' to make check name_len with
item boundary.
If read name from dir_item, use 'verify_dir_item' to do more strict
check. Otherwise, use 'btrfs_is_name_len_valid'.

It's unnessary to do check before every read/memcmp_extent_buffer name.
Checking name_len when read name for the first time in the call graph is
enough.

Changlog:
v2:
        1.Change 'btrfs_check_namelen' to 'btrfs_is_namelen_valid'.
        2.Split patches according call graph.
v3:
        1.Add cases about BTRFS_ROOT_REF_KEY and BTRFS_ROOT_BACKREF_KEY.
        2.Add more comments about how/where extent_buffer is to be read
        for the first time.
        3.Change 'namelen' to 'name_len' in function and changelog.

I still see some fstests fail, eg. btrfs/048

trfs/048 30s ...       [18:05:48] [18:06:18] - output mismatch (see 
/root/test/mmtests/work/testdisk/sources/xfstests-git-installed/results//btrfs/048.out.bad)
     --- tests/btrfs/048.out     2017-04-24 16:56:02.268104570 +0200
     +++ 
/root/test/mmtests/work/testdisk/sources/xfstests-git-installed/results//btrfs/048.out.bad
      2017-06-15 18:06:18.996635908 +0200
     @@ -30,22 +30,13 @@
      ERROR: failed to set compression for SCRATCH_MNT/testdir/file1: Invalid 
argument
      ***
      compression=lzo
     -compression=lzo
     -compression=zlib
      ***
     -compression=lzo
     ...

in syslog with several lines

[ 2156.970285] BTRFS critical (device sdb6): invalid dir item name len: 17

and

[ 2157.220219] BTRFS error (device sdb6): error loading props for ino 259 (root 
5): -5

similarly btrfs/059 fails. Have you seen such errors during your testing?


TBH, I just realized I messed up the test because of wrong git operations.
The problem is caused by that btrfs_is_name_len_vallid() does not handle data_len in XATTR_ITEM.
Sorry for my carelessness.


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