Define and use get_reliable_hostbyname

diff --git a/ChangeLog b/ChangeLog
index ba0545dac7f34fc0e16ae33b974e08dc619d93fb..c181e21e53210e3e574263b0a4186925074ef428 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2003-05-21  NeilBrown <neilb@cse.unsw.edu.au>
+
+       * support/export/hostname.c(get_reliable_hostbyaddr): new function
+       to get host name from address with full checking of authenticity.
+       * support/include/misc.h: declare above function
+       * utils/mountd/auth.c(auth_authenticate_internal): remove all
+       logic for authenticating address.
+       * utils/mountd/auth.c(auth_authenticate): call new
+       get_reliable_hostbyaddr to to hostname lookup before calling _internal.
+       
+       
 2003-03-30  NeilBrown <neilb@cse.unsw.edu.au>
 
        * tools/rpcgen/rpc_main.c(find_cpp): removed

diff --git a/support/export/hostname.c b/support/export/hostname.c
index 299fe9937b4d03606dcbc14a749cae3bd7e057a7..f88e0a485290cb878ab670f4b6917648c3903485 100644 (file)
--- a/support/export/hostname.c
+++ b/support/export/hostname.c
@@ -16,6 +16,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <stdlib.h>
+#include <xlog.h>
 #ifdef TEST
 #define xmalloc malloc
 #else
@@ -216,6 +217,57 @@ matchhostname (const char *h1, const char *h2)
   return status;
 }
 
+
+/* Map IP to hostname, and then map back to addr to make sure it is a
+ * reliable hostname 
+ */
+struct hostent *
+get_reliable_hostbyaddr(const char *addr, int len, int type)
+{
+       struct hostent *hp;
+
+       char **sp;
+       struct hostent *forward = NULL;
+       char *tmpname;
+
+       hp = gethostbyaddr(addr, len , type);
+       if (!hp)
+               return hp;
+
+       /* must make sure the hostent is authorative. */
+
+       hp = hostent_dup (hp);
+       tmpname = xstrdup((hp)->h_name);
+       if (tmpname) {
+               forward = gethostbyname(tmpname);
+               free(tmpname);
+       }
+       if (forward) {
+               /* now make sure the "addr" is in the list */
+               for (sp = forward->h_addr_list ; *sp ; sp++) {
+                       if (memcmp(*sp, addr, forward->h_length)==0)
+                               break;
+               }
+               
+               if (!*sp) {
+                       /* it was a FAKE */
+                       xlog(L_WARNING, "Fake hostname %s for %s - forward lookup doesn't match reverse",
+                            forward->h_name, inet_ntoa(*(struct in_addr*)addr));
+                       return NULL;
+               }
+               free (hp);
+               hp = hostent_dup (forward);
+       }
+       else {
+               /* never heard of it. misconfigured DNS? */
+               xlog(L_WARNING, "Fake hostname %s for %s - forward lookup doesn't exist",
+                    forward->h_name, inet_ntoa(*(struct in_addr*)addr));
+               return NULL;
+       }
+       return hp;
+}
+
+
 #ifdef TEST
 void
 print_host (struct hostent *hp)

diff --git a/support/include/misc.h b/support/include/misc.h
index a3cdcfdf4740bef88d61964c140685f6966bdd31..7d099d06ae8b1b1a5b8bc4d334c3afcbfd7be218 100644 (file)
--- a/support/include/misc.h
+++ b/support/include/misc.h
@@ -20,5 +20,6 @@ int   matchhostname(const char *h1, const char *h2);
 struct hostent;
 struct hostent *hostent_dup(struct hostent *hp);
 struct hostent *get_hostent (const char *addr, int len, int type);
+struct hostent *get_reliable_hostbyaddr(const char *addr, int len, int type);
 
 #endif /* MISC_H */

diff --git a/utils/mountd/auth.c b/utils/mountd/auth.c
index d88c46f31b52563827aac1aedfe5703e7fbc182f..eb9cdebad2314093efba87b0e20bfb63e9b6da26 100644 (file)
--- a/utils/mountd/auth.c
+++ b/utils/mountd/auth.c
@@ -25,15 +25,10 @@ enum auth_error
   no_entry,
   not_exported,
   illegal_port,
-  faked_hostent,
-  no_forward_dns,
   success
 };
 
 static void            auth_fixpath(char *path);
-static nfs_export*     auth_authenticate_internal
-  (char *what, struct sockaddr_in *caller, char *path,
-   struct hostent **hpp, enum auth_error *error);
 static char    *export_file = NULL;
 
 void
@@ -66,56 +61,12 @@ auth_reload()
 
 static nfs_export *
 auth_authenticate_internal(char *what, struct sockaddr_in *caller,
-                          char *path, struct hostent **hpp,
+                          char *path, struct hostent *hp,
                           enum auth_error *error)
 {
-       struct in_addr          addr = caller->sin_addr;
        nfs_export              *exp;
 
-       if (path[0] != '/') {
-               *error = bad_path;
-               return NULL;
-       }
-       auth_fixpath(path);
-
-       if (!(*hpp = gethostbyaddr((const char *)&addr, sizeof(addr), AF_INET)))
-               *hpp = get_hostent((const char *)&addr, sizeof(addr),
-                                  AF_INET);
-       else {
-               /* must make sure the hostent is authorative. */
-               char **sp;
-               struct hostent *forward = NULL;
-               char *tmpname;
-
-               *hpp = hostent_dup (*hpp);
-               tmpname = xstrdup((*hpp)->h_name);
-               if (tmpname) {
-                       forward = gethostbyname(tmpname);
-                       free(tmpname);
-               }
-               if (forward) {
-                       /* now make sure the "addr" is in the list */
-                       for (sp = forward->h_addr_list ; *sp ; sp++) {
-                               if (memcmp(*sp, &addr, forward->h_length)==0)
-                                       break;
-                       }
-               
-                       if (!*sp) {
-                               /* it was a FAKE */
-                               *error = faked_hostent;
-                               return NULL;
-                       }
-                       free (*hpp);
-                       *hpp = hostent_dup (forward);
-               }
-               else {
-                       /* never heard of it. misconfigured DNS? */
-                       *error = no_forward_dns;
-                       return NULL;
-               }
-       }
-
-       if (!(exp = export_find(*hpp, path))) {
+       if (!(exp = export_find(hp, path))) {
                *error = no_entry;
                return NULL;
        }
@@ -154,15 +105,20 @@ auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
 
        strncpy(epath, path, sizeof (epath) - 1);
        epath[sizeof (epath) - 1] = '\0';
+       auth_fixpath(epath); /* strip duplicate '/' etc */
+
+       hp = get_reliable_hostbyaddr((const char*)&caller->sin_addr, sizeof(struct in_addr),
+                                    AF_INET);
+       if (!hp)
+               hp = get_hostent((const char*)&caller->sin_addr, sizeof(struct in_addr),
+                                    AF_INET);
+       if (!hp)
+               return exp;
 
        /* Try the longest matching exported pathname. */
        while (1) {
-               if (hp) {
-                       free (hp);
-                       hp = NULL;
-               }
                exp = auth_authenticate_internal(what, caller, epath,
-                                                &hp, &error);
+                                                hp, &error);
                if (exp || (error != not_exported && error != no_entry))
                        break;
                /* We have to treat the root, "/", specially. */
@@ -171,6 +127,7 @@ auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
                if (p == epath) p++;
                *p = '\0';
        }
+       free(hp);
 
        switch (error) {
        case bad_path:
@@ -198,16 +155,6 @@ auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
                     what, hp->h_name, path, epath, ntohs(caller->sin_port));
                break;
 
-       case faked_hostent:
-               xlog(L_WARNING, "refused %s request from %s (%s) for %s (%s): DNS forward lookup does't match with reverse",
-                    what, inet_ntoa(addr), hp->h_name, path, epath);
-               break;
-
-       case no_forward_dns:
-               xlog(L_WARNING, "refused %s request from %s (%s) for %s (%s): no DNS forward lookup",
-                    what, inet_ntoa(addr), hp->h_name, path, epath);
-               break;
-
        case success:
                xlog(L_NOTICE, "authenticated %s request from %s:%d for %s (%s)",
                     what, hp->h_name, ntohs(caller->sin_port), path, epath);