nfs: fix host_reliable_addrinfo

[nfs-utils.git] / support / export / hostname.c

diff --git a/support/export/hostname.c b/support/export/hostname.c
index efcb75cdb97260a12b2feea32949c83c1a873624..3e949a18fe52255b51a4d77713f28b1679f16b75 100644 (file)
--- a/support/export/hostname.c
+++ b/support/export/hostname.c
@@ -258,17 +258,19 @@ host_canonname(const struct sockaddr *sap)
  * @sap: pointer to socket address to look up
  *
  * Reverse and forward lookups are performed to ensure the address has
- * proper forward and reverse mappings.
+ * matching forward and reverse mappings.
  *
- * Returns address info structure with ai_canonname filled in, or NULL
- * if no information is available for @sap.  Caller must free the returned
- * structure with freeaddrinfo(3).
+ * Returns addrinfo structure with just the provided address with
+ * ai_canonname filled in. If there is a problem with resolution or
+ * the resolved records don't match up properly then it returns NULL
+ *
+ * Caller must free the returned structure with freeaddrinfo(3).
  */
 __attribute_malloc__
 struct addrinfo *
 host_reliable_addrinfo(const struct sockaddr *sap)
 {
-       struct addrinfo *ai;
+       struct addrinfo *ai, *a;
        char *hostname;
 
        hostname = host_canonname(sap);
@@ -276,9 +278,31 @@ host_reliable_addrinfo(const struct sockaddr *sap)
                return NULL;
 
        ai = host_addrinfo(hostname);
+       if (!ai)
+               goto out_free_hostname;
 
-       free(hostname);
+       /* make sure there's a matching address in the list */
+       for (a = ai; a; a = a->ai_next)
+               if (nfs_compare_sockaddr(a->ai_addr, sap))
+                       break;
+
+       freeaddrinfo(ai);
+       if (!a)
+               goto out_free_hostname;
+
+       /* get addrinfo with just the original address */
+       ai = host_numeric_addrinfo(sap);
+       if (!ai)
+               goto out_free_hostname;
+
+       /* and populate its ai_canonname field */
+       free(ai->ai_canonname);
+       ai->ai_canonname = hostname;
        return ai;
+
+out_free_hostname:
+       free(hostname);
+       return NULL;
 }
 
 /**