[PATCHSET,0/3] xfs: fix name/value buffer lifetime errrors

Message

Darrick J. Wong May 18, 2022, 6:55 p.m. UTC

Hi all,

As part of kicking the tires on the new logged extended attributes
(LARP) code, I observed a crash in the xattr intent log item relogging
function.  A quick code inspection led to me noticing that the logging
code repeatedly allocates and frees space for the name and value
buffers, which is unnecessary.  Replace all that with a shared
refcounted buffer to hold the name and the value across all the log
items involved in the transaction, and as long as is necessary for the
log to process all work.

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

kernel git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=attr-intent-uaf-fixes-5.19
---
 fs/xfs/libxfs/xfs_attr.h |    8 +
 fs/xfs/xfs_attr_item.c   |  296 +++++++++++++++++++++++++++-------------------
 fs/xfs/xfs_attr_item.h   |   13 +-
 3 files changed, 191 insertions(+), 126 deletions(-)