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ARCHIVE: Core 'Security Digest' - Archives (1990 - 1991)
DOCUMENT: Core 'Security Digest' V1 #4 1990-07-17 (1 file, 1918 bytes)
SOURCE: http://securitydigest.org/exec/display?f=core/archive/104.txt&t=text/plain
NOTICE: securitydigest.org recognises the rights of all third-party works.
START OF DOCUMENT
Date: Tue Jul 17 15:08:42 PDT 1990
Subject: Core Security Digest V1 #4
Core Security Digest Volume 1 Issue 4
subject(s):
More recent patch to ypserv
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------------------------------------------------------------------------
Date: Wed, 11 Jul 90 23:42:25 EST
From: uunet!cs.purdue.edu!trinkle
Subject: More recent patch to ypserv
Here is a more recent patch for ypserv that fixes a problem with
using a netmask of 255.255.255.255. Unfortunately inet_addr() returns
a -1 to indicate an error AND a -1 for a legitimate value of all 1's.
====================== ypserv securenets patch ======================
RCS file: RCS/ypserv.c,v
retrieving revision 1.1
diff -c -r1.1 ypserv.c
*** /tmp/,RCSt1017343 Wed Apr 4 09:03:54 1990
--- ypserv.c Tue Apr 3 13:46:50 1990
***************
*** 121,127
pmap_unset(YPPROG, YPVERS);
pmap_unset(YPPROG, YPOLDVERS);
ypget_command_line_args(argc, argv);
!
if (silent) {
pid = fork();
--- 121,127 -----
pmap_unset(YPPROG, YPVERS);
pmap_unset(YPPROG, YPOLDVERS);
ypget_command_line_args(argc, argv);
! get_secure_nets();
if (silent) {
pid = fork();
RCS file: RCS/ypserv_map.c,v
retrieving revision 1.1
diff -c -r1.1 ypserv_map.c
*** /tmp/,RCSt1017368 Wed Apr 4 09:03:59 1990
--- ypserv_map.c Tue Apr 3 14:51:31 1990
***************
*** 232,237
return (TRUE);
}
caller = svc_getcaller(transp);
if ((caller->sin_family == AF_INET) &&
(ntohs(caller->sin_port)) < IPPORT_RESERVED) {
return (TRUE);
--- 232,239 -----
return (TRUE);
}
caller = svc_getcaller(transp);
+ if (!(check_secure_net(caller)))
+ return(FALSE);
if ((caller->sin_family == AF_INET) &&
(ntohs(caller->sin_port)) < IPPORT_RESERVED) {
return (TRUE);
*** /tmp/,RCSt1017375 Thu Apr 12 10:10:04 1990
--- ypserv_net_secure.c Thu Apr 5 16:18:59 1990
***************
*** 0 ****
--- 1,99 ----
+ /*
+ * Author:
+ * Richard Watterson
+ * Purdue University
+ * Department of Computer Sciences
+ * April 3, 1990
+ */
+
+ #include <sys/types.h>
+ #include <sys/socket.h>
+ #include <netinet/in.h>
+ #include <arpa/inet.h>
+ #include <stdio.h>
+ #include <syslog.h>
+ #define ACCFILE "/var/yp/securenets"
+ #define MAXLINE 128
+ struct seclist {
+ u_long mask;
+ u_long net;
+ struct seclist *next;
+ };
+ static struct seclist *slist ;
+ static int nofile = 0;
+ get_secure_nets()
+ {
+ FILE *fp;
+ char strung[MAXLINE],nmask[MAXLINE],net[MAXLINE];
+ unsigned long maskin, netin;
+ struct seclist *tmp1,*tmp2;
+ int line = 0;
+ if (fp = fopen(ACCFILE,"r")) {
+ tmp1 = (struct seclist *) malloc(sizeof (struct seclist));
+ slist = tmp1;
+ while (fgets(strung,MAXLINE,fp)) {
+ line++;
+ if (strung[strlen(strung) - 1] != '\n'){
+ syslog(LOG_ERR|LOG_DAEMON,
+ "ypserv: %s line %d: too long\n",ACCFILE,line);
+ exit(1);
+ }
+ if (strung[0] == '#')
+ continue;
+ if (sscanf(strung,"%16s%16s",nmask,net) < 2) {
+ syslog(LOG_ERR|LOG_DAEMON,
+ "ypserv: %s line %d: missing fields\n",ACCFILE,line);
+ exit(1);
+ }
+ maskin = inet_addr(nmask);
+ if (maskin == -1 && strcmp(nmask, "255.255.255.255") != 0) {
+ syslog(LOG_ERR|LOG_DAEMON,
+ "ypserv: %s line %d: error in netmask\n",ACCFILE,line);
+ exit(1);
+ }
+ netin = inet_addr(net);
+ if (netin == -1 && strcmp(net, "255.255.255.255") != 0) {
+ syslog(LOG_ERR|LOG_DAEMON,
+ "ypserv: %s line %d: error in address\n",ACCFILE,line);
+ exit(1);
+ }
+
+ if ((maskin & netin) != netin) {
+ syslog(LOG_ERR|LOG_DAEMON,
+ "ypserv: %s line %d: netmask does not match network\n",
+ ACCFILE,line);
+ exit(1);
+ }
+ tmp1->mask = maskin;
+ tmp1->net = netin;
+ tmp1->next = (struct seclist *) malloc(sizeof (struct seclist));
+ tmp2 = tmp1;
+ tmp1 = tmp1->next;
+ }
+ tmp2->next = NULL;
+
+ }
+ else {
+ syslog(LOG_INFO|LOG_DAEMON,"ypserv: no %s file\n",ACCFILE);
+ nofile = 1 ;
+ }
+ }
+
+ check_secure_net(caller)
+ struct sockaddr_in *caller;
+ {
+
+ struct seclist *tmp;
+ tmp = slist ;
+ if (nofile)
+ return(1);
+ while (tmp != NULL) {
+ if ((caller->sin_addr.s_addr & tmp->mask) == tmp->net){
+ return(1);
+ }
+ tmp = tmp->next;
+ }
+ syslog(LOG_ERR|LOG_DAEMON,"ypserv: access denied for %s\n",
+ inet_ntoa(caller->sin_addr));
+ return(0);
+ }
======================================================================
------------------------------------------------------------------------
End of Core Security Digest Volume 1 Issue 4
**********************
END OF DOCUMENT
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