[src/trunk]: src/sys/netipsec Fix locking: it is fine if the lock is already ...

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

details:   https://anonhg.NetBSD.org/src/rev/52573456231b
branches:  trunk
changeset: 997189:52573456231b
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Feb 26 06:52:34 2019 +0000

description:
Fix locking: it is fine if the lock is already key_so_mtx, this can happen
in socketpair. In that case don't take it.

Ok ozaki-r@

Reported-by: syzbot+901e2e5edaaaed21c069%syzkaller.appspotmail.com@localhost

diffstat:

 sys/netipsec/keysock.c |  14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diffs (35 lines):

diff -r e1dd5ae94c62 -r 52573456231b sys/netipsec/keysock.c
--- a/sys/netipsec/keysock.c    Tue Feb 26 06:28:43 2019 +0000
+++ b/sys/netipsec/keysock.c    Tue Feb 26 06:52:34 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: keysock.c,v 1.68 2019/01/27 02:08:48 pgoyette Exp $    */
+/*     $NetBSD: keysock.c,v 1.69 2019/02/26 06:52:34 maxv Exp $        */
 /*     $FreeBSD: keysock.c,v 1.3.2.1 2003/01/24 05:11:36 sam Exp $     */
 /*     $KAME: keysock.c,v 1.25 2001/08/13 20:07:41 itojun Exp $        */
 
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: keysock.c,v 1.68 2019/01/27 02:08:48 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: keysock.c,v 1.69 2019/02/26 06:52:34 maxv Exp $");
 
 /* This code has derived from sys/net/rtsock.c on FreeBSD2.2.5 */
 
@@ -383,10 +383,12 @@
 
        s = splsoftnet();
 
-       KASSERT(so->so_lock == NULL);
-       mutex_obj_hold(key_so_mtx);
-       so->so_lock = key_so_mtx;
-       solock(so);
+       if (so->so_lock != key_so_mtx) {
+               KASSERT(so->so_lock == NULL);
+               mutex_obj_hold(key_so_mtx);
+               so->so_lock = key_so_mtx;
+               solock(so);
+       }
 
        error = raw_attach(so, proto, &key_rawcb);
        if (error) {