[PATCH v5 0/2] firmware_loader: fix uaf in firmware_fallback_sysfs

Anirudh Rayabharam mail at anirudhrb.com
Wed Jul 21 19:00:12 UTC 2021

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


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 v5:
1. Split the patch into two patches as discussed here:

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

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
  firmware_loader: fix use-after-free in firmware_fallback_sysfs

 drivers/base/firmware_loader/fallback.c | 46 ++++++++++++++++++-------
 drivers/base/firmware_loader/firmware.h |  6 +++-
 drivers/base/firmware_loader/main.c     |  2 ++
 3 files changed, 40 insertions(+), 14 deletions(-)


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