check-that-external-xattr-value-block-is-zero

   1 ext4: Check that external xattr value block is zero
   2
   3 From: Jan Kara <jack@suse.cz>
   4
   5 Currently we don't support xattrs with values stored out of line. Check
   6 for that in ext4_xattr_check_names() to make sure we never work with
   7 such xattrs since not all the code counts with that resulting is possible
   8 weird corruption issues.
   9
  10 Signed-off-by: Jan Kara <jack@suse.cz>
  11 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  12 ---
  13  fs/ext4/xattr.c | 2 ++
  14  1 file changed, 2 insertions(+)
  15
  16 diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
  17 index 22d2ebcd1f09..f845cb7c6623 100644
  18 --- a/fs/ext4/xattr.c
  19 +++ b/fs/ext4/xattr.c
  20 @@ -199,6 +199,8 @@ ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
  21         }
  22
  23         while (!IS_LAST_ENTRY(entry)) {
  24 +               if (entry->e_value_block != 0)
  25 +                       return -EFSCORRUPTED;
  26                 if (entry->e_value_size != 0 &&
  27                     (value_start + le16_to_cpu(entry->e_value_offs) <
  28                      (void *)e + sizeof(__u32) ||
  29 --
  30 2.6.6
  31
  32