CVS commit: src/sys/opencrypto

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sun May 22 11:29:54 UTC 2022

Modified Files:
        src/sys/opencrypto: cryptodev.c

Log Message:
crypto(4): Fix possible use-after-free in race around detach.

This is extremely unlikely because I don't think we have any drivers
for removable crypto decelerators^Waccelerators...but if we were to
sprout one, and someone ran crypto_dispatch concurrently with
crypto_unregister, cryptodev_cb/mcb would enter with crp->crp_etype =
EAGAIN and with CRYPTO_F_DONE set in crp->crp_flags.  In this case,
cryptodev_cb/mcb would issue crypto_dispatch but -- since nothing
clears CRYPTO_F_DONE -- it would _also_ consider the request done and
notify the ioctl thread of that.

With this change, we return early if crypto_dispatch succeeds.  No
need to consult CRYPTO_F_DONE: if the callback is invoked it's done,
and if we try to redispatch it on EAGAIN but crypto_dispatch fails,
it's done.  (Soon we'll get rid of the possibility of crypto_dispatch
failing synchronously, but not just yet.)

XXX This path could really use some testing!


To generate a diff of this commit:
cvs rdiff -u -r1.115 -r1.116 src/sys/opencrypto/cryptodev.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.