[src/trunk]: src/sys/kern Fix a NULL pointer dereference after a loooong disc...

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

details:   https://anonhg.NetBSD.org/src/rev/d333e29174f4
branches:  trunk
changeset: 796852:d333e29174f4
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Jun 22 18:32:27 2014 +0000

description:
Fix a NULL pointer dereference after a loooong discussion with dholland@,
hannken@, blymn@ and martin@.

This bug would panic the system when veriexec is set to the VERIEXEC_LOCKDOWN
mode (only settable from root).

diffstat:

 sys/kern/vfs_vnops.c |  25 +++++++++++++++++++++----
 1 files changed, 21 insertions(+), 4 deletions(-)

diffs (46 lines):

diff -r 7f92192fb12f -r d333e29174f4 sys/kern/vfs_vnops.c
--- a/sys/kern/vfs_vnops.c      Sun Jun 22 17:36:42 2014 +0000
+++ b/sys/kern/vfs_vnops.c      Sun Jun 22 18:32:27 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_vnops.c,v 1.189 2014/02/27 16:51:38 hannken Exp $  */
+/*     $NetBSD: vfs_vnops.c,v 1.190 2014/06/22 18:32:27 maxv Exp $     */
 
 /*-
  * Copyright (c) 2009 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.189 2014/02/27 16:51:38 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.190 2014/06/22 18:32:27 maxv Exp $");
 
 #include "veriexec.h"
 
@@ -171,8 +171,25 @@
 
 #if NVERIEXEC > 0
        error = veriexec_openchk(l, ndp->ni_vp, pathstring, fmode);
-       if (error)
-               goto bad;
+       if (error) {
+               /* We have to release the locks ourselves */
+               if (fmode & O_CREAT) {
+                       if (vp == NULL) {
+                               vput(ndp->ni_dvp);
+                       } else {
+                               VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd);
+                               if (ndp->ni_dvp == ndp->ni_vp)
+                                       vrele(ndp->ni_dvp);
+                               else
+                                       vput(ndp->ni_dvp);
+                               ndp->ni_dvp = NULL;
+                               vput(vp);
+                       }
+               } else {
+                       vput(vp);
+               }
+               goto out;
+       }
 #endif /* NVERIEXEC > 0 */
 
        if (fmode & O_CREAT) {