Re: TCP/IP with 7.4 beta2 broken? - Mailing list pgsql-hackers

Tom Lane wrote:

>Andreas Pflug <pgadmin@pse-consulting.de> writes:
>
>
>>How about silently creating a IPV6 style host internally for every IPV4
>>pg_hba.conf entry? It won't make any sense to handle a real IPV4 address
>>different from an IPV4 address converted to IPV6 address space.
>>
>>
>
>Hmm.  I could go for that, if it weren't that there seem to be several
>different conventions for embedding IPv4 in IPv6.  Should we auto-create
>pg_hba.conf entries for all of the possibly equivalent addresses?
>
AFAICS RFC2253 states that an IPV4 node connecting should get the
Address ::ffff:<IPV4addr>, so this should be sufficient.

>What if that creates conflicts?
>
If there's a conflict, it isn't created by this automatic entry, but
revealed because it was already there.
    host 192.168.0.0/24
    host ::ffff:102.168.0.0/125
This is already a conflict, not getting better or worse if we add
    host ::ffff:102.168.0.0/120
as IPV6 duplicate for the first line.

I created a patch to hba.c which uses IPV4 entries as IPV6 entries if
running on a IPV6 system (which is detected from a port coming in as
AF_INET6)

Regards,
Andreas

? hba.conf.diff
Index: hba.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/libpq/hba.c,v
retrieving revision 1.111
diff -c -r1.111 hba.c
*** hba.c    4 Aug 2003 02:39:59 -0000    1.111
--- hba.c    2 Sep 2003 11:07:10 -0000
***************
*** 673,708 ****
          if (cidr_slash)
              *cidr_slash = '/';

!         if (file_ip_addr->ai_family != port->raddr.addr.ss_family)
          {
!             /* Wrong address family. */
              freeaddrinfo_all(hints.ai_family, file_ip_addr);
-             return;
-         }

!         /* Get the netmask */
!         if (cidr_slash)
          {
!             if (SockAddr_cidr_mask(&mask, cidr_slash + 1,
!                                    file_ip_addr->ai_family) < 0)
!                 goto hba_syntax;
          }
          else
          {
!             /* Read the mask field. */
!             line = lnext(line);
!             if (!line)
!                 goto hba_syntax;
!             token = lfirst(line);
!
!             ret = getaddrinfo_all(token, NULL, &hints, &file_ip_mask);
!             if (ret || !file_ip_mask)
!                 goto hba_syntax;
!
!             mask = (struct sockaddr_storage *) file_ip_mask->ai_addr;
!
!             if (file_ip_addr->ai_family != mask->ss_family)
!                 goto hba_syntax;
          }

          /* Read the rest of the line. */
--- 673,761 ----
          if (cidr_slash)
              *cidr_slash = '/';

!         if (file_ip_addr->ai_family == AF_INET && port->raddr.addr.ss_family == AF_INET6)
          {
!             /* port got a IPV6 address, but the current line is IPV4.
!              * We'll make a IPV6 entry from this line, to check if by chance the connecting port
!              * is a converted IPV4 address. */
!
!             char *v6addr=palloc(strlen(token)+8);
!             char *v6mask;
!
              freeaddrinfo_all(hints.ai_family, file_ip_addr);

!             if (cidr_slash)
!                 *cidr_slash = 0;
!             sprintf(v6addr, "::ffff:%s", token);
!             if (cidr_slash)
!                 *cidr_slash = '/';
!
!             ret = getaddrinfo_all(v6addr, NULL, &hints, &file_ip_addr);
!             if (ret || !file_ip_addr)
!             {
!                 ereport(LOG,
!                         (errcode(ERRCODE_CONFIG_FILE_ERROR),
!                          errmsg("could not interpret converted IP address \"%s\" in config file: %s",
!                                 token, gai_strerror(ret))));
!             }
!             if (cidr_slash)
!             {
!                 v6mask = palloc(20);
!                 sprintf(v6mask, "%d", atoi(cidr_slash+1)+96);
!                 if (SockAddr_cidr_mask(&mask, v6mask, file_ip_addr->ai_family) < 0)
!                     goto hba_syntax;
!             }
!             else
!             {
!                 line = lnext(line);
!                 if (!line)
!                     goto hba_syntax;
!                 token = lfirst(line);
!                 v6mask = palloc(strlen(token)+32);
!                 sprintf(v6mask, "ffff:ffff:ffff:ffff:ffff:ffff:%s", token);
!
!                 ret = getaddrinfo_all(v6mask, NULL, &hints, &file_ip_mask);
!                 if (ret || !file_ip_mask)
!                     goto hba_syntax;
!
!                 mask = (struct sockaddr_storage *) file_ip_mask->ai_addr;
!
!                 if (file_ip_addr->ai_family != mask->ss_family)
!                     goto hba_syntax;
!             }
!         }
!         else if (file_ip_addr->ai_family != port->raddr.addr.ss_family)
          {
!             /* Wrong address family. */
!             freeaddrinfo_all(hints.ai_family, file_ip_addr);
!             return;
          }
          else
          {
!             /* Get the netmask */
!             if (cidr_slash)
!             {
!                 if (SockAddr_cidr_mask(&mask, cidr_slash + 1,
!                                        file_ip_addr->ai_family) < 0)
!                     goto hba_syntax;
!             }
!             else
!             {
!                 /* Read the mask field. */
!                 line = lnext(line);
!                 if (!line)
!                     goto hba_syntax;
!                 token = lfirst(line);
!
!                 ret = getaddrinfo_all(token, NULL, &hints, &file_ip_mask);
!                 if (ret || !file_ip_mask)
!                     goto hba_syntax;
!
!                 mask = (struct sockaddr_storage *) file_ip_mask->ai_addr;
!
!                 if (file_ip_addr->ai_family != mask->ss_family)
!                     goto hba_syntax;
!             }
          }

          /* Read the rest of the line. */