[src/trunk]: src/sys/opencrypto opencrypto: Assert session id is valid in cry...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ccc5175a3b9d
branches:  trunk
changeset: 366344:ccc5175a3b9d
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun May 22 11:40:54 2022 +0000

description:
opencrypto: Assert session id is valid in crypto_freesession.

This gives us the opportunity to detect usage mistakes like
use-after-free.

Exception: Continue to silently ignore sid=0.

diffstat:

 sys/opencrypto/crypto.c |  11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)

diffs (33 lines):

diff -r 702936bac200 -r ccc5175a3b9d sys/opencrypto/crypto.c
--- a/sys/opencrypto/crypto.c   Sun May 22 11:40:46 2022 +0000
+++ b/sys/opencrypto/crypto.c   Sun May 22 11:40:54 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: crypto.c,v 1.129 2022/05/22 11:40:29 riastradh Exp $ */
+/*     $NetBSD: crypto.c,v 1.130 2022/05/22 11:40:54 riastradh Exp $ */
 /*     $FreeBSD: src/sys/opencrypto/crypto.c,v 1.4.2.5 2003/02/26 00:14:05 sam Exp $   */
 /*     $OpenBSD: crypto.c,v 1.41 2002/07/17 23:52:38 art Exp $ */
 
@@ -53,7 +53,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: crypto.c,v 1.129 2022/05/22 11:40:29 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: crypto.c,v 1.130 2022/05/22 11:40:54 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/reboot.h>
@@ -870,11 +870,10 @@
 
        /* Determine two IDs. */
        cap = crypto_checkdriver_lock(CRYPTO_SESID2HID(sid));
-       if (cap == NULL)        /* XXX should assert; need to audit callers */
-               return;
+       KASSERTMSG(cap != NULL, "sid=%"PRIx64, sid);
 
-       if (cap->cc_sessions)
-               (cap->cc_sessions)--;
+       KASSERT(cap->cc_sessions > 0);
+       cap->cc_sessions--;
 
        /* Call the driver cleanup routine, if available. */
        if (cap->cc_freesession)