svn commit: r251725 - head/sys/kern

[Lawrence Stewart]

Author: lstewart
Date: Fri Jun 14 02:25:40 2013
New Revision: 251725
URL: http://svnweb.freebsd.org/changeset/base/251725

Log:
  Fix a potential NULL-pointer dereference that would trigger if the hhook
  registration site did not provide storage for a copy of the hhook_head struct.
  
  MFC after:	3 days

Modified:
  head/sys/kern/kern_hhook.c

Modified: head/sys/kern/kern_hhook.c
==============================================================================
--- head/sys/kern/kern_hhook.c	Fri Jun 14 02:21:32 2013	(r251724)
+++ head/sys/kern/kern_hhook.c	Fri Jun 14 02:25:40 2013	(r251725)
@@ -264,9 +264,10 @@ hhook_head_register(int32_t hhook_type, 
 	STAILQ_INIT(&tmphhh->hhh_hooks);
 	HHH_LOCK_INIT(tmphhh);
 
-	if (hhh != NULL)
+	if (hhh != NULL) {
 		refcount_init(&tmphhh->hhh_refcount, 1);
-	else
+		*hhh = tmphhh;
+	} else
 		refcount_init(&tmphhh->hhh_refcount, 0);
 
 	if (flags & HHOOK_HEADISINVNET) {
@@ -278,8 +279,6 @@ hhook_head_register(int32_t hhook_type, 
 		/* XXXLAS: Add tmphhh to the non-virtualised list. */
 	}
 
-	*hhh = tmphhh;
-
 	return (0);
 }