Use getnameinfo instead of gethostbyaddr.

diff --git a/ChangeLog b/ChangeLog
index e50c038d78d721b2e5991a692f2dc88812a791f8..b5a733ac711b0fe62faa9339c7178f4b09879ddd 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+Use getnameinfo instead of gethostbyaddr.
 Remove gateways from the ROUTES and add to GATEWAYS
 define #INFO_COMPAT if you wish your .info file to add support for some
 old 1.x and 2.x structure.

diff --git a/configure.c b/configure.c
index 55415af08c4cf65942b17d18cc215ae006d9bf0a..bfd5ee8a4ba9d3bb4897b2ca8c37b473f6c554ab 100644 (file)
--- a/configure.c
+++ b/configure.c
@@ -505,11 +505,8 @@ int configure (const options_t *options, interface_t *iface,
        route_t *route = NULL;
        route_t *new_route = NULL;
        route_t *old_route = NULL;
-       struct hostent *he = NULL;
        char newhostname[HOSTNAME_MAX_LEN] = {0};
        char curhostname[HOSTNAME_MAX_LEN] = {0};
-       char *dname = NULL;
-       int dnamel = 0;
 
        if (! options || ! iface || ! dhcp)
                return -1;
@@ -666,16 +663,41 @@ int configure (const options_t *options, interface_t *iface,
 
        /* Now we have made a resolv.conf we can obtain a hostname if we need one */
        if (options->dohostname && ! dhcp->hostname) {
-               he = gethostbyaddr (inet_ntoa (dhcp->address),
-                                                       sizeof (struct in_addr), AF_INET);
-               if (he) {
-                       dname = he->h_name;
-                       while (*dname > 32)
-                               dname++;
-                       dnamel = dname - he->h_name;
-                       memcpy (newhostname, he->h_name, dnamel);
-                       newhostname[dnamel] = 0;
+               union {
+                       struct sockaddr sa;
+                       struct sockaddr_in sin;
+               } su;
+               socklen_t salen;
+               char addr[NI_MAXHOST];
+               struct addrinfo hints, *res;
+
+               salen = sizeof (struct sockaddr);
+               memset (&su.sa, 0, salen);
+               su.sin.sin_family = AF_INET;
+               su.sin.sin_len = sizeof (struct sockaddr_in);
+               memcpy (&su.sin.sin_addr, &dhcp->address, sizeof (struct in_addr));
+
+               if (getnameinfo (&su.sa, salen, addr, sizeof (addr),
+                                                NULL, 0, NI_NAMEREQD) == 0) {
+                       memset (&hints, 0, sizeof (hints));
+                       hints.ai_socktype = SOCK_DGRAM;
+                       hints.ai_flags = AI_NUMERICHOST;
+                       /* Check for a malicious PTR record */
+                       if (getaddrinfo (addr, "0", &hints, &res) == 0) {
+                               freeaddrinfo (res);
+                               addr[0] = '\0';
+                               logger (LOG_DEBUG, "malicious PTR record detected");
+                       }
                }
+               
+               /* Split the hostname from the domain */
+               if (addr[0]) {
+                       char *p = addr;
+                       char *token = strsep (&p, ".");
+                       if (token)
+                               strlcpy (newhostname, token, sizeof (newhostname));
+               } else
+                       logger (LOG_ERR, "failed to lookup the hostname");
        }
 
        gethostname (curhostname, sizeof (curhostname));

diff --git a/dhcpcd.8 b/dhcpcd.8
index f200f4012530d4e5d5fa3170262a864f6876e8aa..eec47653b72b0ae9ce7ada7047d898042cc49b24 100644 (file)
--- a/dhcpcd.8
+++ b/dhcpcd.8
@@ -1,6 +1,6 @@
 .\" $Id$
 .\"
-.TH DHCPCD 8 "27 February 2007" "dhcpcd 3.0"
+.TH DHCPCD 8 "18 April 2007" "dhcpcd 3.0"
 
 .SH NAME
 dhcpcd \- DHCP client daemon
@@ -183,7 +183,8 @@ By default
 .B dhcpcd
 will NOT set hostname of the host to the hostname option
 received from DHCP server unless the current hostname is blank, (none) or
-localhost.
+localhost. If no hostname is returned by the DHCP server then we attempt
+to lookup the hostname via DNS.
 .TP
 .BI \-F \ none | ptr | both
 Forces