We need to check the return value of match_token() for Opt_err before
doing anything with it.
[ Not only did the old "-1" value for Opt_err cause problems for the
__test_and_set_bit(), as fixed in commit 94c13f66e1 ("security:
don't use a negative Opt_err token index"), but accessing
"args[0].from" is invalid for the Opt_err case, as pointed out by Eric
later. - Linus ]
Reported-by: syzbot+a22e0dc07567662c50bc@syzkaller.appspotmail.com
Fixes: 00d60fd3b9 ("KEYS: Provide keyctls to drive the new key type ops for asymmetric keys [ver #2]")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: stable@kernel.org # 4.20
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
57b0e31453