From eb87f1a4a96e8b768b021e11ab8372fb4aad7e17 Mon Sep 17 00:00:00 2001
From: Ted Lemon <source@isc.org>
Date: Sat, 13 Feb 1999 19:17:03 +0000
Subject: - Fix a bug in the SIOCGIFCONF interface scanning code.

- Fix a core dump in the interface scanner that crops up on Linux when
  an interface is specified on the command line.
---
 common/dispatch.c | 37 +++++++++++++++----------------------
 1 file changed, 15 insertions(+), 22 deletions(-)

diff --git a/common/dispatch.c b/common/dispatch.c
index 0a383a04..775bada3 100644
--- a/common/dispatch.c
+++ b/common/dispatch.c
@@ -42,7 +42,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: dispatch.c,v 1.47.2.9 1999/02/05 20:23:50 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: dispatch.c,v 1.47.2.10 1999/02/13 19:17:03 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -79,6 +79,7 @@ void discover_interfaces (state)
 	struct shared_network *share;
 	struct sockaddr_in foo;
 	int ir;
+	struct ifreq *tif;
 #ifdef ALIAS_NAMES_PERMUTED
 	char *s;
 #endif
@@ -110,7 +111,7 @@ void discover_interfaces (state)
 	for (i = 0; i < ic.ifc_len;) {
 		struct ifreq *ifp = (struct ifreq *)((caddr_t)ic.ifc_req + i);
 #ifdef HAVE_SA_LEN
-		if (ifp -> ifr_addr.sa_len)
+		if (ifp -> ifr_addr.sa_len > sizeof (struct sockaddr))
 			i += (sizeof ifp -> ifr_name) + ifp -> ifr_addr.sa_len;
 		else
 #endif
@@ -194,7 +195,6 @@ void discover_interfaces (state)
 			   found, keep a pointer to ifreq structure in
 			   which we found it. */
 			if (!tmp -> ifp) {
-				struct ifreq *tif;
 #ifdef HAVE_SA_LEN
 				int len = ((sizeof ifp -> ifr_name) +
 					   ifp -> ifr_addr.sa_len);
@@ -276,7 +276,6 @@ void discover_interfaces (state)
 	if (state == DISCOVER_UNCONFIGURED) {
 		FILE *proc_dev;
 		char buffer [256];
-		struct ifreq *tif;
 		int skip = 2;
 
 		proc_dev = fopen (PROCDEV_DEVICE, "r");
@@ -306,25 +305,10 @@ void discover_interfaces (state)
 				if (!strcmp (tmp -> name, name))
 					break;
 
-			/* If we found one, and it already has an ifreq
-			   structure, nothing more to do.. */
-			if (tmp && tmp -> ifp)
+			/* If we found one, nothing more to do.. */
+			if (tmp)
 				continue;
 
-			/* Make up an ifreq structure. */
-			tif = (struct ifreq *)malloc (sizeof (struct ifreq));
-			if (!tif)
-				error ("no space to remember ifp.");
-			memset (tif, 0, sizeof (struct ifreq));
-			strcpy (tif -> ifr_name, name);
-
-			/* Now, if we just needed the ifreq structure, hook
-			   it in and move on. */
-			if (tmp) {
-				tmp -> ifp = tif;
-				continue;
-			}
-
 			/* Otherwise, allocate one. */
 			tmp = ((struct interface_info *)
 			       dmalloc (sizeof *tmp, "discover_interfaces"));
@@ -334,7 +318,6 @@ void discover_interfaces (state)
 			memset (tmp, 0, sizeof *tmp);
 			strcpy (tmp -> name, name);
 
-			tmp -> ifp = tif;
 			tmp -> flags = ir;
 			tmp -> next = interfaces;
 			interfaces = tmp;
@@ -351,6 +334,16 @@ void discover_interfaces (state)
 		struct sockaddr sa;
 		int b, sk;
 		
+		if (!tmp -> ifp) {
+			/* Make up an ifreq structure. */
+			tif = (struct ifreq *)malloc (sizeof (struct ifreq));
+			if (!tif)
+				error ("no space to remember ifp.");
+			memset (tif, 0, sizeof (struct ifreq));
+			strcpy (tif -> ifr_name, tmp -> name);
+			tmp -> ifp = tif;
+		}
+
 		/* Read the hardware address from this interface. */
 		ifr = *tmp -> ifp;
 		if (ioctl (sock, SIOCGIFHWADDR, &ifr) < 0)
-- 
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