#43853 [Opn->Bgs]: Some IP addresses are note resolved by gethostbyaddr()

ID: 43853 Updated by: derick@php.net Reported By: radonov at ecad dot tu-sofia dot bg -Status: Open +Status: Bogus Bug Type: Network related Operating System: Solaris PHP Version: 4.4.8, 5CVS Assigned To: ab5602 New Comment: K, marked as bogus then. Previous Comments: ------------------------------------------------------------------------ [2008-01-29 00:17:32] ab5602@php.net Proof is in the pudding: from gethostbyaddr() in OpenSolaris libresolv... ---------- if ((hp = _getrhbyaddr(addr, len, type)) == (struct hostent *)NULL) return ((struct hostent *)NULL); /* hang on to what we got as an answer */ (void) strcpy(hbuf, hp->h_name); /* check to make sure by doing a forward query */ if ((hp2 = res_gethostbyname(hbuf)) != (struct hostent *)NULL) ---------- ------------------------------------------------------------------------ [2008-01-28 23:52:53] ab5602@php.net Traced it down to another "security" bug in Solaris. The problem is that the IP: 78.130.136.12 does not reverse and forward to the same address. The below C code will not return a reverse lookup either. This appears to be a low-level Solaris specific security measure (bug IMHO) in gethostbyaddr() to stop the resolution of fake DNS info. Snooping, the network traffic on the lookup you can see it doing a reverse, then a forward to check the accuracy of the reverse: DNS C 12.136.130.78.in-addr.arpa. Internet PTR ? DNS R 12.136.130.78.in-addr.arpa. Internet PTR atlantis.botevgrad.com. DNS C atlantis.botevgrad.com. Internet Addr ? DNS R atlantis.botevgrad.com. Internet Addr 212.116.131.138 I'll mark this one as bogus in a few days, unless anyone else can come up with a good way to get around this? ----- gethostbyaddr() test code (need -lresolv and -lnsl) #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> typedef struct in_addr in_addr; typedef struct hostent hostent; int main (void) { auto in_addr addr; register hostent const *hp; inet_aton ("78.130.136.12", &addr); hp = gethostbyaddr ((char const *)&addr, sizeof addr, AF_INET); herror("resolver error"); if (hp) printf ("%s\n", hp->h_name); else printf ("No Reverse DNS for %s\n", inet_ntoa (addr)); return 0; } ------------------------------------------------------------------------ [2008-01-28 23:38:58] tony2001@php.net Cannot reproduce: php -r 'var_dump(gethostbyaddr("78.130.136.12"));' string(22) "atlantis.botevgrad.com" ------------------------------------------------------------------------ [2008-01-28 14:16:09] ab5602@php.net Confirmed bug in 5CVS. ------------------------------------------------------------------------ [2008-01-28 13:43:13] ab5602@php.net Confirmed under Solaris 9 and Solaris 10 too. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/43853 -- Edit this bug report at http://bugs.php.net/?id=43853&edit=1