[krbdev.mit.edu #3140] kerberos client unable to parse ipv6 addresses from krb5.conf

[Public Submitter via RT]

While testing the kerberos release with a ipv6 configuration, we found
that kerberos client is not able to parse v6 addresses from the krb5.conf 
configuration file.

Proposed fix:

<krb path>/lib/krb5/os/locate_kdc.c has been modified and the fix was
tested to correctly parse the ipv6 addresses.

The unified diffs is enclosed below
**************************************************************************

***************
*** 382,393 ****
                cp = strchr(host, '\t');
                if (cp)
                    *cp = 0;
!               cp = strchr(host, ':');
!               if (cp)
!                   *cp = 0;
            }
        }
      } else {
        krb5_xfree(host);
      }
   
--- 382,423 ----
                cp = strchr(host, '\t');
                if (cp)
                    *cp = 0;
!                 if ( host[0] == '[' )  {
!                   if (cp = strchr(host,']'))  { /* [ipv6]:port */
!                        char * tmp_host ;
!                        int     host_len ;
!                        struct in6_addr in6 ;
!
!                        host_len  = cp - host - 1 ; /* here (cp > host) */
!                        tmp_host = (char*) malloc(host_len+1) ;
!                        if (tmp_host) {
!                          strncpy(tmp_host, host+1 , host_len );
!                          tmp_host[host_len] = '\0' ;
!                         } else {
!                           profile_free_list(hostlist);
!                           krb5_xfree(masterlist);
!                           return ENOMEM ;
                          }
+                        /* Only if the addr b/w '[' and ']' is IPV6 addr */
+                        if ( inet_pton(AF_INET6, tmp_host, &in6 ) > 0 )
+                         {
+                          host++;/* Move to v6 addr location from '['*/
+                          port = strchr(cp, ':');
+                           *cp = 0 ;       /* The ipv6 address ends
before ']' */
                          }
+
+                       krb5_xfree(tmp_host);
+                   }          /* hostname:port or only hostname */
                   } else  {
+           struct in6_addr in6 ;
+            if ( inet_pton(AF_INET6, host, &in6) <= 0 ) {
+                                      /* Its not ipv6 address */
+               port = strchr(host, ':');
+              }
+            }
+         }
+       }
+       } else {
          krb5_xfree(host);
        }
   
***************
*** 416,422 ****
--- 446,484 ----
        cp = strchr(host, '\t');
        if (cp)
            *cp = 0;
+                 if ( host[0] == '[' )  {
+                   if (cp = strchr(host,']'))  { /* [ipv6]:port */
+                        char * tmp_host ;
+                        int     host_len ;
+                        struct in6_addr in6 ;
+
+                        host_len  = cp - host - 1 ; /* here (cp > host) */
+                        tmp_host = (char*) malloc(host_len+1) ;
+                        if (tmp_host) {
+                          strncpy(tmp_host, host+1 , host_len );
+                          tmp_host[host_len] = '\0' ;
+                         } else {
+                           profile_free_list(hostlist);
+                           krb5_xfree(masterlist);
+                           return ENOMEM ;
+                         }
+                        /* Only if the addr b/w '[' and ']' is IPV6 addr */
+                        if ( inet_pton(AF_INET6, tmp_host, &in6 ) > 0 )
+                         {
+                          host++;/* Move to v6 addr location from '['*/
+                          port = strchr(cp, ':');
+                           *cp = 0 ;       /* The ipv6 address ends
before ']' */
+                         }
+
+                       krb5_xfree(tmp_host);
+                   }          /* hostname:port or only hostname */
+                } else {
+            struct in6_addr in6 ;
+            if ( inet_pton(AF_INET6, host, &in6) <= 0 ) {
+                                      /* Its not ipv6 address */
                port = strchr(host, ':');
+            }
+         }
        if (port) {
            *port = 0;
            port++;
***************
*** 453,467 ****
            p1 = udpport;
            p2 = sec_udpport;
        }
-
        if (socktype != 0)
!           code = add_host_to_list (addrlist, hostlist[i], p1, p2,
                                     socktype, family);
        else {
!           code = add_host_to_list (addrlist, hostlist[i], p1, p2,
                                     SOCK_DGRAM, family);
            if (code == 0)
!               code = add_host_to_list (addrlist, hostlist[i], p1, p2,
                                         SOCK_STREAM, family);
        }
        if (code) {
--- 515,528 ----
            p1 = udpport;
            p2 = sec_udpport;
        }
        if (socktype != 0)
!           code = add_host_to_list (addrlist, host, p1, p2,
                                     socktype, family);
        else {
!           code = add_host_to_list (addrlist, host, p1, p2,
                                     SOCK_DGRAM, family);
            if (code == 0)
!               code = add_host_to_list (addrlist, host, p1, p2,
                                         SOCK_STREAM, family);
        }
        if (code) {
***************
*** 481,486 ****
--- 542,548 ----
      if (masterlist)
          profile_free_list(masterlist);
   
+
      return 0;
  }
   
***************
        if (code) {
--- 515,528 ----
            p1 = udpport;
            p2 = sec_udpport;
        }
        if (socktype != 0)
!           code = add_host_to_list (addrlist, host, p1, p2,
                                     socktype, family);
        else {
!           code = add_host_to_list (addrlist, host, p1, p2,
                                     SOCK_DGRAM, family);
            if (code == 0)
!               code = add_host_to_list (addrlist, host, p1, p2,
                                         SOCK_STREAM, family);
        }
        if (code) {
***************
*** 481,486 ****
--- 542,548 ----
      if (masterlist)
          profile_free_list(masterlist);
   
+
      return 0;
  }
   
***************
*** 587,593 ****
   
      code = krb5_locate_srv_conf_1(context, realm, profname, &al,
get_masters,
                                  socktype, dflport1, dflport2, family);
-
  #ifdef KRB5_DNS_LOOKUP
      if (code && dnsname != 0) {
        int use_dns = _krb5_use_dns_kdc(context);
--- 649,654 ----