tree 0be1f9d825fd7ce8ad50ad1d81bb90179249064e
parent 5be9ad1e4287e1742fd8d253267c86446441bdaf
author Jens Axboe <axboe@kernel.dk> 1613163774 -0700
committer Jens Axboe <axboe@kernel.dk> 1613163774 -0700

io-wq: clear out worker ->fs and ->files

By default, kernel threads have init_fs and init_files assigned. In the
past, this has triggered security problems, as commands that don't ask
for (and hence don't get assigned) fs/files from the originating task
can then attempt path resolution etc with access to parts of the system
they should not be able to.

Rather than add checks in the fs code for misuse, just set these to
NULL. If we do attempt to use them, then the resulting code will oops
rather than provide access to something that it should not permit.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>