[PATCH v6 0/2] firmware_loader: fix uaf in firmware_fallback_sysfs

[Anirudh Rayabharam]

This series fixes the use after free in firmware_fallback_sysfs reported
by syzbot at:

https://syzkaller.appspot.com/bug?extid=de271708674e2093097b

The first patch does some cleanup of the error codes and documents
them properly. The second patch goes on to actually fix the bug.

Changes in v6:
1. v5 didn't actually remove -EAGAIN. So, fixed that.

Changes in v5:
1. Split the patch into two patches as discussed here:
   https://lore.kernel.org/lkml/20210715232105.am4wsxfclj2ufjdw@garbanzo/

Changes in v4:
Documented the reasons behind the error codes returned from
fw_sysfs_wait_timeout() as suggested by Luis Chamberlain.

Changes in v3:
Modified the patch to incorporate suggestions by Luis Chamberlain in
order to fix the root cause instead of applying a "band-aid" kind of
fix.
https://lore.kernel.org/lkml/20210403013143.GV4332@xxxxxxxxxxxxxxxxxxx/

Changes in v2:
1. Fixed 1 error and 1 warning (in the commit message) reported by
checkpatch.pl. The error was regarding the format for referring to
another commit "commit <sha> ("oneline")". The warning was for line
longer than 75 chars.

Anirudh Rayabharam (2):
  firmware_loader: use -ETIMEDOUT instead of -EAGAIN in
    fw_load_sysfs_fallback
  firmware_loader: fix use-after-free in firmware_fallback_sysfs

 drivers/base/firmware_loader/fallback.c | 44 +++++++++++++++++--------
 drivers/base/firmware_loader/firmware.h |  6 +++-
 drivers/base/firmware_loader/main.c     |  2 ++
 3 files changed, 38 insertions(+), 14 deletions(-)

-- 
2.26.2