sm-notify: sm-notify doesn't handle localhost properly

It looks like the existing algorithm for verifying the passed-in bind
address is as broken as statd_matchhostname() used to be: for IP
addresses, AI_CANONNAME is useless.  We need to have getnameinfo(3) or
equivalent in there.

Clean up: extract the logic that verifies the command line bind
address into its own function, and make it handle canonical name
lookup correctly.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
index f05eadf5d5b43e2be52525ac5c515a4253c80fcd..2421f8bb4f043ed73ea0e58f2b37f6030f49eecb 100644 (file)
--- a/utils/statd/sm-notify.c
+++ b/utils/statd/sm-notify.c
@@ -93,6 +93,101 @@ smn_lookup(const char *name)
        return ai;
 }
 
+#ifdef HAVE_GETNAMEINFO
+static char *
+smn_get_hostname(const struct sockaddr *sap, const socklen_t salen,
+               const char *name)
+{
+       char buf[NI_MAXHOST];
+       int error;
+
+       error = getnameinfo(sap, salen, buf, sizeof(buf), NULL, 0, NI_NAMEREQD);
+       if (error != 0) {
+               xlog(L_ERROR, "my_name '%s' is unusable: %s",
+                       name, gai_strerror(error));
+               return NULL;
+       }
+       return strdup(buf);
+}
+#else  /* !HAVE_GETNAMEINFO */
+static char *
+smn_get_hostname(const struct sockaddr *sap,
+               __attribute__ ((unused)) const socklen_t salen,
+               const char *name)
+{
+       const struct sockaddr_in *sin = (const struct sockaddr_in *)(char *)sap;
+       const struct in_addr *addr = &sin->sin_addr;
+       struct hostent *hp;
+
+       if (sap->sa_family != AF_INET) {
+               xlog(L_ERROR, "my_name '%s' is unusable: Bad address family",
+                       name);
+               return NULL;
+       }
+
+       hp = gethostbyaddr(addr, (socklen_t)sizeof(addr), AF_INET);
+       if (hp == NULL) {
+               xlog(L_ERROR, "my_name '%s' is unusable: %s",
+                       name, hstrerror(h_errno));
+               return NULL;
+       }
+       return strdup(hp->h_name);
+}
+#endif /* !HAVE_GETNAMEINFO */
+
+/*
+ * Presentation addresses are converted to their canonical hostnames.
+ * If the IP address does not map to a hostname, it is an error:
+ * we never send a presentation address as the argument of SM_NOTIFY.
+ *
+ * If "name" is not a presentation address, it is left alone.  This
+ * allows the administrator some flexibility if DNS isn't configured
+ * exactly how sm-notify prefers it.
+ *
+ * Returns NUL-terminated C string containing the result, or NULL
+ * if the canonical name doesn't exist or cannot be determined.
+ * The caller must free the result with free(3).
+ */
+__attribute_malloc__
+static char *
+smn_verify_my_name(const char *name)
+{
+       struct addrinfo *ai = NULL;
+       struct addrinfo hint = {
+#ifdef IPV6_SUPPORTED
+               .ai_family      = AF_UNSPEC,
+#else  /* !IPV6_SUPPORTED */
+               .ai_family      = AF_INET,
+#endif /* !IPV6_SUPPORTED */
+               .ai_flags       = AI_NUMERICHOST,
+       };
+       char *retval;
+       int error;
+
+       error = getaddrinfo(name, NULL, &hint, &ai);
+       switch (error) {
+       case 0:
+               /* @name was a presentation address */
+               retval = smn_get_hostname(ai->ai_addr, ai->ai_addrlen, name);
+               freeaddrinfo(ai);
+               if (retval == NULL)
+                       return NULL;
+               break;
+       case EAI_NONAME:
+               /* @name was not a presentation address */
+               retval = strdup(name);
+               break;
+       default:
+               xlog(L_ERROR, "my_name '%s' is unusable: %s",
+                       name, gai_strerror(error));
+               return NULL;
+       }
+
+       xlog(D_GENERAL, "Canonical name for my_name '%s': %s",
+                       name, retval);
+       return retval;
+}
+
 __attribute_malloc__
 static struct nsm_host *
 smn_alloc_host(const char *hostname, const char *mon_name,
@@ -416,32 +511,14 @@ usage:            fprintf(stderr,
        }
 
        if (opt_srcaddr != NULL) {
-               struct addrinfo *ai = NULL;
-               struct addrinfo hint = {
-                       .ai_family      = AF_UNSPEC,
-                       .ai_flags       = AI_NUMERICHOST,
-               };
-
-               if (getaddrinfo(opt_srcaddr, NULL, &hint, &ai))
-                       /* not a presentation address - use it */
-                       strncpy(nsm_hostname, opt_srcaddr, sizeof(nsm_hostname));
-               else {
-                       /* was a presentation address - look it up in
-                        * /etc/hosts, so it can be used for my_name */
-                       int error;
+               char *name;
 
-                       freeaddrinfo(ai);
-                       hint.ai_flags = AI_CANONNAME;
-                       error = getaddrinfo(opt_srcaddr, NULL, &hint, &ai);
-                       if (error != 0) {
-                               xlog(L_ERROR, "Bind address %s is unusable: %s",
-                                               opt_srcaddr, gai_strerror(error));
-                               exit(1);
-                       }
-                       strncpy(nsm_hostname, ai->ai_canonname,
-                                                       sizeof(nsm_hostname));
-                       freeaddrinfo(ai);
-               }
+               name = smn_verify_my_name(opt_srcaddr);
+               if (name == NULL)
+                       exit(1);
+
+               strncpy(nsm_hostname, name, sizeof(nsm_hostname));
+               free(name);
        }
 
        (void)nsm_retire_monitored_hosts();