Author: Dmitry M. Maslennikov <rlz at altlinux.org>
diff --git a/samba/source/client/cifs.upcall.c b/samba/source/client/cifs.upcall.c
index 238b861..4461636 100644
--- a/samba/source/client/cifs.upcall.c
+++ b/samba/source/client/cifs.upcall.c
@@ -209,6 +209,31 @@ cifs_resolver(const key_serial_t key, const char *key_descr)
 	return 0;
 }
 
+const char *
+cifs_get_cname(const char * name)
+{
+	static char buf[NI_MAXHOST];
+	struct addrinfo * info;
+	int ret = getaddrinfo(name, 0, 0, &info);
+	if(ret)
+	{
+		syslog(LOG_WARNING, "getaddrinfo: %s",
+			gai_strerror(ret));
+		return NULL;
+	}
+	ret = getnameinfo(info->ai_addr, info->ai_addrlen,
+		buf, sizeof(buf), 0, 0, 0);
+	if(ret)
+	{
+		syslog(LOG_WARNING, "getnameinfo: %s",
+			gai_strerror(ret));
+		freeaddrinfo(info);
+		return NULL;
+	}
+	freeaddrinfo(info);
+	return buf;
+}
+
 static void
 usage(void)
 {
@@ -316,8 +341,13 @@ int main(const int argc, char *const argv[])
 			char *princ;
 			size_t len;
 
+			const char * cname = cifs_get_cname(hostname);
+			if (!cname) {
+				rc = 1;
+				break;
+			}
 			/* for "cifs/" service name + terminating 0 */
-			len = strlen(hostname) + 5 + 1;
+			len = strlen(cname) + 5 + 1;
 			princ = SMB_XMALLOC_ARRAY(char, len);
 			if (!princ) {
 				rc = 1;
@@ -328,7 +358,7 @@ int main(const int argc, char *const argv[])
 			} else {
 				strlcpy(princ, "host/", len);
 			}
-			strlcpy(princ + 5, hostname, len - 5);
+			strlcpy(princ + 5, cname, len - 5);
 
 			if (sectype == MS_KRB5)
 				oid = OID_KERBEROS5_OLD;