svn commit: r297825 - stable/10/sys/net

[Gleb Smirnoff]

Author: glebius
Date: Mon Apr 11 17:23:47 2016
New Revision: 297825
URL: https://svnweb.freebsd.org/changeset/base/297825

Log:
  Merge r285713 (by zec@) from head:
    Prevent null-pointer dereferencing.

Modified:
  stable/10/sys/net/if.c

Modified: stable/10/sys/net/if.c
==============================================================================
--- stable/10/sys/net/if.c	Mon Apr 11 15:24:59 2016	(r297824)
+++ stable/10/sys/net/if.c	Mon Apr 11 17:23:47 2016	(r297825)
@@ -339,11 +339,12 @@ ifnet_setbyindex(u_short idx, struct ifn
 struct ifaddr *
 ifaddr_byindex(u_short idx)
 {
-	struct ifaddr *ifa;
+	struct ifnet *ifp;
+	struct ifaddr *ifa = NULL;
 
 	IFNET_RLOCK_NOSLEEP();
-	ifa = ifnet_byindex_locked(idx)->if_addr;
-	if (ifa != NULL)
+	ifp = ifnet_byindex_locked(idx);
+	if (ifp != NULL && (ifa = ifp->if_addr) != NULL)
 		ifa_ref(ifa);
 	IFNET_RUNLOCK_NOSLEEP();
 	return (ifa);