[src/trunk]: src/sys/netinet - Handle realloc failure without leaking memory

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

details:   https://anonhg.NetBSD.org/src/rev/c32a2954ecba
branches:  trunk
changeset: 509773:c32a2954ecba
user:      christos <christos%NetBSD.org@localhost>
date:      Sat May 12 19:21:57 2001 +0000

description:
- Handle realloc failure without leaking memory
  (reported by: grendel%heorot.stanford.edu@localhost (Ted U)
- Don't cast malloc/realloc/calloc return values because they hide LP64 bugs.
- Don't destroy the whole array when realloc fails
- Use calloc in all cases (malloc was used inconsistently).
- Avoid duplicating code.

Reviewed by: ross

diffstat:

 sys/netinet/ip_fil.c |  46 ++++++++++++++++++----------------------------
 1 files changed, 18 insertions(+), 28 deletions(-)

diffs (75 lines):

diff -r 8afd3ae0da57 -r c32a2954ecba sys/netinet/ip_fil.c
--- a/sys/netinet/ip_fil.c      Sat May 12 19:18:57 2001 +0000
+++ b/sys/netinet/ip_fil.c      Sat May 12 19:21:57 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ip_fil.c,v 1.66 2001/03/26 06:13:12 mike Exp $ */
+/*     $NetBSD: ip_fil.c,v 1.67 2001/05/12 19:21:57 christos Exp $     */
 
 /*
  * Copyright (C) 1993-2000 by Darren Reed.
@@ -9,7 +9,7 @@
  */
 #if !defined(lint)
 #if defined(__NetBSD__)
-static const char rcsid[] = "$NetBSD: ip_fil.c,v 1.66 2001/03/26 06:13:12 mike Exp $";
+static const char rcsid[] = "$NetBSD: ip_fil.c,v 1.67 2001/05/12 19:21:57 christos Exp $";
 #else
 static const char sccsid[] = "@(#)ip_fil.c     2.41 6/5/96 (C) 1993-2000 Darren Reed";
 static const char rcsid[] = "@(#)Id: ip_fil.c,v 2.42.2.17 2000/10/19 15:39:42 darrenr Exp";
@@ -1706,6 +1706,8 @@
 int v;
 {
        struct ifnet *ifp, **ifa;
+       size_t len;
+
 # if (defined(NetBSD) && (NetBSD <= 1991011) && (NetBSD >= 199606)) || \
        (defined(OpenBSD) && (OpenBSD >= 199603))
        for (ifa = ifneta; ifa && (ifp = *ifa); ifa++) {
@@ -1722,33 +1724,21 @@
        }
 # endif
 
-       if (!ifneta) {
-               ifneta = (struct ifnet **)malloc(sizeof(ifp) * 2);
-               if (!ifneta)
-                       return NULL;
-               ifneta[1] = NULL;
-               ifneta[0] = (struct ifnet *)calloc(1, sizeof(*ifp));
-               if (!ifneta[0]) {
-                       free(ifneta);
-                       return NULL;
-               }
-               nifs = 1;
-       } else {
-               nifs++;
-               ifneta = (struct ifnet **)realloc(ifneta,
-                                                 (nifs + 1) * sizeof(*ifa));
-               if (!ifneta) {
-                       nifs = 0;
-                       return NULL;
-               }
-               ifneta[nifs] = NULL;
-               ifneta[nifs - 1] = (struct ifnet *)malloc(sizeof(*ifp));
-               if (!ifneta[nifs - 1]) {
-                       nifs--;
-                       return NULL;
-               }
+       len = (nifs + 2) * sizeof(*ifa);
+       ifa = ifneta == NULL ? malloc(len) : realloc(ifneta, len);
+
+       if (ifa == NULL)
+               return NULL;
+
+       ifp = ifa[nifs] = calloc(1, sizeof(*ifp));
+       if (ifa[nifs] == NULL) {
+               if (nifs == 0)
+                       free(ifa);
+               return NULL;
        }
-       ifp = ifneta[nifs - 1];
+
+       ifneta = ifa;
+       ifneta[++nifs] = NULL;
 
 # if (defined(NetBSD) && (NetBSD <= 1991011) && (NetBSD >= 199606)) || \
        (defined(OpenBSD) && (OpenBSD >= 199603))