Add support for specifying SSL protocol version

The check_http -S/--ssl option now takes an optional argument which
specifies the desired SSL/TLS protocol version (#3285367 - Jason Lunn).

NEWS

@@ -6,6 +6,7 @@ This file documents the major additions and syntax changes between releases.
 	check_disk_smb now allows spaces in share names (#990948, #1370031, Debian #601699)
 	check_http now uses standard threshold functions (enables floating point and ranges)
 	check_http now checks for and prints the certificate cn (hostname) in SSL certificate checks (Stéphane Urbanovski)
+	check_http now supports an optional -S/--ssl value to choose the SSL protocol version (#3066166 - Jason Lunn)
 	Add perfdata to check_ssh (#3244097 - Marco Beck)
 	New option to check_smtp to ignore failures when sending QUIT (#3358348 - Duncan Ferguson)
 	New check_by_ssh -F option which allows for specifying an alternative ssh_config(5) file (#2895334 - Sven Nierlein)

THANKS.in

@@ -269,3 +269,4 @@ Ryan Kelly
 Stéphane Urbanovski
 Marco Beck
 Sebastian Harl
+Jason Lunn

plugins/check_http.c

@@ -34,7 +34,7 @@
 /* splint -I. -I../../plugins -I../../lib/ -I/usr/kerberos/include/ ../../plugins/check_http.c */
 
 const char *progname = "check_http";
-const char *copyright = "1999-2008";
+const char *copyright = "1999-2011";
 const char *email = "nagiosplug-devel@lists.sourceforge.net";
 
 #include "common.h"
@@ -59,6 +59,7 @@ enum {
 #ifdef HAVE_SSL
 int check_cert = FALSE;
 int days_till_exp;
+int ssl_version;
 char *randbuff;
 X509 *server_cert;
 #  define my_recv(buf, len) ((use_ssl) ? np_net_ssl_read(buf, len) : read(sd, buf, len))
@@ -188,7 +189,7 @@ process_arguments (int argc, char **argv)
     STD_LONG_OPTS,
     {"link", no_argument, 0, 'L'},
     {"nohtml", no_argument, 0, 'n'},
-    {"ssl", no_argument, 0, 'S'},
+    {"ssl", optional_argument, 0, 'S'},
     {"sni", no_argument, 0, SNI_OPTION},
     {"post", required_argument, 0, 'P'},
     {"method", required_argument, 0, 'j'},
@@ -234,7 +235,7 @@ process_arguments (int argc, char **argv)
   }
 
   while (1) {
-    c = getopt_long (argc, argv, "Vvh46t:c:w:A:k:H:P:j:T:I:a:b:e:p:s:R:r:u:f:C:nlLSm:M:N", longopts, &option);
+    c = getopt_long (argc, argv, "Vvh46t:c:w:A:k:H:P:j:T:I:a:b:e:p:s:R:r:u:f:C:nlLS::m:M:N", longopts, &option);
     if (c == -1 || c == EOF)
       break;
 
@@ -294,6 +295,13 @@ process_arguments (int argc, char **argv)
       usage4 (_("Invalid option - SSL is not available"));
 #endif
       use_ssl = TRUE;
+      if (optarg == NULL)
+        ssl_version = 0;
+      else {
+        ssl_version = atoi(optarg);
+        if (ssl_version < 1 || ssl_version > 3)
+            usage4 (_("Invalid option - Valid values for SSL Version are 1 (TLSv1), 2 (SSLv2) or 3 (SSLv3)"));
+      }
       if (specify_port == FALSE)
         server_port = HTTPS_PORT;
       break;
@@ -798,7 +806,7 @@ check_http (void)
     die (STATE_CRITICAL, _("HTTP CRITICAL - Unable to open TCP socket\n"));
 #ifdef HAVE_SSL
   if (use_ssl == TRUE) {
-    np_net_ssl_init_with_hostname(sd, (use_sni ? host_name : NULL));
+    np_net_ssl_init_with_hostname_and_version(sd, (use_sni ? host_name : NULL), ssl_version);
     if (check_cert == TRUE) {
       result = np_net_ssl_check_cert(days_till_exp);
       np_net_ssl_cleanup();
@@ -1323,8 +1331,9 @@ print_help (void)
   printf (UT_IPv46);
 
 #ifdef HAVE_SSL
-  printf (" %s\n", "-S, --ssl");
-  printf ("    %s\n", _("Connect via SSL. Port defaults to 443"));
+  printf (" %s\n", "-S, --ssl=VERSION");
+  printf ("    %s\n", _("Connect via SSL. Port defaults to 443. VERSION is optional, and prevents"));
+  printf ("    %s\n", _("auto-negotiation (1 = TLSv1, 2 = SSLv2, 3 = SSLv3)."));
   printf (" %s\n", "--sni");
   printf ("    %s\n", _("Enable SSL/TLS hostname extension support (SNI)"));
   printf (" %s\n", "-C, --certificate=INTEGER");
@@ -1433,6 +1442,6 @@ print_usage (void)
   printf ("       [-b proxy_auth] [-f <ok|warning|critcal|follow|sticky|stickyport>]\n");
   printf ("       [-e <expect>] [-s string] [-l] [-r <regex> | -R <case-insensitive regex>]\n");
   printf ("       [-P string] [-m <min_pg_size>:<max_pg_size>] [-4|-6] [-N] [-M <age>]\n");
-  printf ("       [-A string] [-k string] [-S] [--sni] [-C <age>] [-T <content-type>]\n");
+  printf ("       [-A string] [-k string] [-S <version>] [--sni] [-C <age>] [-T <content-type>]\n");
   printf ("       [-j method]\n");
 }

plugins/sslutils.c

@@ -41,6 +41,29 @@ int np_net_ssl_init (int sd) {
 }
 
 int np_net_ssl_init_with_hostname (int sd, char *host_name) {
+		return np_net_ssl_init_with_hostname_and_version(sd, host_name, 0);
+}
+
+int np_net_ssl_init_with_hostname_and_version (int sd, char *host_name, int version) {
+		const SSL_METHOD *method = NULL;
+
+		switch (version) {
+		case 0: /* Deafult to auto negotiation */
+			method = SSLv23_client_method();
+			break;
+		case 1: /* TLSv1 protocol */
+			method = TLSv1_client_method();
+			break;
+		case 2: /* SSLv2 protocol */
+			method = SSLv2_client_method();
+			break;
+		case 3: /* SSLv3 protocol */
+			method = SSLv3_client_method();
+			break;
+		default: /* Unsupported */
+			printf ("%s\n", _("CRITICAL - Unsupported SSL Protocol Version."));
+			return STATE_CRITICAL;
+		}
 		if (!initialized) {
 			/* Initialize SSL context */
 			SSLeay_add_ssl_algorithms ();
@@ -48,7 +71,7 @@ int np_net_ssl_init_with_hostname (int sd, char *host_name) {
 			OpenSSL_add_all_algorithms ();
 			initialized = 1;
 		}
-		if ((c = SSL_CTX_new (SSLv23_client_method ())) == NULL) {
+		if ((c = SSL_CTX_new (method)) == NULL) {
 				printf ("%s\n", _("CRITICAL - Cannot create SSL context."));
 				return STATE_CRITICAL;
 		}