1 files changed, 118 insertions, 38 deletions

diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c
index 1996c6d3..fc0ae2c4 100644
--- a/plugins/check_smtp.c
+++ b/plugins/check_smtp.c
@@ -3,7 +3,7 @@
 * Monitoring check_smtp plugin
 * 
 * License: GPL
-* Copyright (c) 2000-2007 Monitoring Plugins Development Team
+* Copyright (c) 2000-2023 Monitoring Plugins Development Team
 * 
 * Description:
 * 
@@ -42,27 +42,26 @@ const char *email = "devel@monitoring-plugins.org";
 #ifdef HAVE_SSL
 int check_cert = FALSE;
 int days_till_exp_warn, days_till_exp_crit;
-#  define my_recv(buf, len) ((use_ssl && ssl_established) ? np_net_ssl_read(buf, len) : read(sd, buf, len))
-#  define my_send(buf, len) ((use_ssl && ssl_established) ? np_net_ssl_write(buf, len) : send(sd, buf, len, 0))
+#  define my_recv(buf, len) (((use_starttls || use_ssl) && ssl_established) ? np_net_ssl_read(buf, len) : read(sd, buf, len))
+#  define my_send(buf, len) (((use_starttls || use_ssl) && ssl_established) ? np_net_ssl_write(buf, len) : send(sd, buf, len, 0))
 #else /* ifndef HAVE_SSL */
 #  define my_recv(buf, len) read(sd, buf, len)
 #  define my_send(buf, len) send(sd, buf, len, 0)
 #endif
 
 enum {
-        SMTP_PORT       = 25
+        SMTP_PORT       = 25,
+        SMTPS_PORT      = 465
 };
+#define PROXY_PREFIX "PROXY TCP4 0.0.0.0 0.0.0.0 25 25\r\n"
 #define SMTP_EXPECT "220"
 #define SMTP_HELO "HELO "
 #define SMTP_EHLO "EHLO "
+#define SMTP_LHLO "LHLO "
 #define SMTP_QUIT "QUIT\r\n"
 #define SMTP_STARTTLS "STARTTLS\r\n"
 #define SMTP_AUTH_LOGIN "AUTH LOGIN\r\n"
 
-#ifndef HOST_MAX_BYTES
-#define HOST_MAX_BYTES 255
-#endif
-
 #define EHLO_SUPPORTS_STARTTLS 1
 
 int process_arguments (int, char **);
@@ -85,6 +84,7 @@ int eflags = 0;
 int errcode, excode;
 
 int server_port = SMTP_PORT;
+int server_port_option = 0;
 char *server_address = NULL;
 char *server_expect = NULL;
 char *mail_command = NULL;
@@ -105,7 +105,11 @@ double critical_time = 0;
 int check_critical_time = FALSE;
 int verbose = 0;
 int use_ssl = FALSE;
+int use_starttls = FALSE;
+int use_sni = FALSE;
+short use_proxy_prefix = FALSE;
 short use_ehlo = FALSE;
+short use_lhlo = FALSE;
 short ssl_established = 0;
 char *localhostname = NULL;
 int sd;
@@ -128,6 +132,7 @@ main (int argc, char **argv)
         char *cmd_str = NULL;
         char *helocmd = NULL;
         char *error_msg = "";
+        char *server_response = NULL;
         struct timeval tv;
 
         /* Catch pipe errors in read/write - sometimes occurs when writing QUIT */
@@ -155,7 +160,9 @@ main (int argc, char **argv)
                         return STATE_CRITICAL;
                 }
         }
-        if(use_ehlo)
+        if(use_lhlo)
+                xasprintf (&helocmd, "%s%s%s", SMTP_LHLO, localhostname, "\r\n");
+        else if(use_ehlo)
                 xasprintf (&helocmd, "%s%s%s", SMTP_EHLO, localhostname, "\r\n");
         else
                 xasprintf (&helocmd, "%s%s%s", SMTP_HELO, localhostname, "\r\n");
@@ -182,6 +189,26 @@ main (int argc, char **argv)
         result = my_tcp_connect (server_address, server_port, &sd);
 
         if (result == STATE_OK) { /* we connected */
+                /* If requested, send PROXY header */
+                if (use_proxy_prefix) {
+                        if (verbose)
+                                printf ("Sending header %s\n", PROXY_PREFIX);
+                        my_send(PROXY_PREFIX, strlen(PROXY_PREFIX));
+                }
+
+#ifdef HAVE_SSL
+                if (use_ssl) {
+                        result = np_net_ssl_init_with_hostname(sd, (use_sni ? server_address : NULL));
+                        if (result != STATE_OK) {
+                                printf (_("CRITICAL - Cannot create SSL context.\n"));
+                                close(sd);
+                                np_net_ssl_cleanup();
+                                return STATE_CRITICAL;
+                        } else {
+                                ssl_established = 1;
+                        }
+                }
+#endif
 
                 /* watch for the SMTP connection string and */
                 /* return a WARNING status if we couldn't read any data */
@@ -189,44 +216,32 @@ main (int argc, char **argv)
                         printf (_("recv() failed\n"));
                         return STATE_WARNING;
                 }
-                else {
-                        if (verbose)
-                                printf ("%s", buffer);
-                        /* strip the buffer of carriage returns */
-                        strip (buffer);
-                        /* make sure we find the response we are looking for */
-                        if (!strstr (buffer, server_expect)) {
-                                if (server_port == SMTP_PORT)
-                                        printf (_("Invalid SMTP response received from host: %s\n"), buffer);
-                                else
-                                        printf (_("Invalid SMTP response received from host on port %d: %s\n"),
-                                                                        server_port, buffer);
-                                return STATE_WARNING;
-                        }
-                }
+
+                /* save connect return (220 hostname ..) for later use */
+                xasprintf(&server_response, "%s", buffer);
 
                 /* send the HELO/EHLO command */
-                send(sd, helocmd, strlen(helocmd), 0);
+                my_send(helocmd, strlen(helocmd));
 
                 /* allow for response to helo command to reach us */
                 if (recvlines(buffer, MAX_INPUT_BUFFER) <= 0) {
                         printf (_("recv() failed\n"));
                         return STATE_WARNING;
-                } else if(use_ehlo){
+                } else if(use_ehlo || use_lhlo){
                         if(strstr(buffer, "250 STARTTLS") != NULL ||
                            strstr(buffer, "250-STARTTLS") != NULL){
                                 supports_tls=TRUE;
                         }
                 }
 
-                if(use_ssl && ! supports_tls){
+                if(use_starttls && ! supports_tls){
                         printf(_("WARNING - TLS not supported by server\n"));
                         smtp_quit();
                         return STATE_WARNING;
                 }
 
 #ifdef HAVE_SSL
-                if(use_ssl) {
+                if(use_starttls) {
                   /* send the STARTTLS command */
                   send(sd, SMTP_STARTTLS, strlen(SMTP_STARTTLS), 0);
 
@@ -236,11 +251,11 @@ main (int argc, char **argv)
                     smtp_quit();
                     return STATE_UNKNOWN;
                   }
-                  result = np_net_ssl_init(sd);
+                  result = np_net_ssl_init_with_hostname(sd, (use_sni ? server_address : NULL));
                   if(result != STATE_OK) {
                     printf (_("CRITICAL - Cannot create SSL context.\n"));
-                    np_net_ssl_cleanup();
                     close(sd);
+                    np_net_ssl_cleanup();
                     return STATE_CRITICAL;
                   } else {
                         ssl_established = 1;
@@ -284,12 +299,31 @@ main (int argc, char **argv)
                 }
 #endif
 
+                if (verbose)
+                        printf ("%s", buffer);
+
+                /* save buffer for later use */
+                xasprintf(&server_response, "%s%s", server_response, buffer);
+                /* strip the buffer of carriage returns */
+                strip (server_response);
+
+                /* make sure we find the droids we are looking for */
+                if (!strstr (server_response, server_expect)) {
+                        if (server_port == SMTP_PORT)
+                                printf (_("Invalid SMTP response received from host: %s\n"), server_response);
+                        else
+                                printf (_("Invalid SMTP response received from host on port %d: %s\n"),
+                                                                                server_port, server_response);
+                        return STATE_WARNING;
+                }
+
                 if (send_mail_from) {
                   my_send(cmd_str, strlen(cmd_str));
                   if (recvlines(buffer, MAX_INPUT_BUFFER) >= 1 && verbose)
                     printf("%s", buffer);
                 }
 
+                n = 0;
                 while (n < ncommands) {
                         xasprintf (&cmd_str, "%s%s", commands[n], "\r\n");
                         my_send(cmd_str, strlen(cmd_str));
@@ -446,6 +480,10 @@ process_arguments (int argc, char **argv)
         int c;
         char* temp;
 
+        enum {
+          SNI_OPTION
+        };
+
         int option = 0;
         static struct option longopts[] = {
                 {"hostname", required_argument, 0, 'H'},
@@ -466,9 +504,14 @@ process_arguments (int argc, char **argv)
                 {"use-ipv4", no_argument, 0, '4'},
                 {"use-ipv6", no_argument, 0, '6'},
                 {"help", no_argument, 0, 'h'},
+                {"lmtp", no_argument, 0, 'L'},
+                {"ssl", no_argument, 0, 's'},
+                {"tls", no_argument, 0, 's'},
                 {"starttls",no_argument,0,'S'},
+                {"sni", no_argument, 0, SNI_OPTION},
                 {"certificate",required_argument,0,'D'},
                 {"ignore-quit-failure",no_argument,0,'q'},
+                {"proxy",no_argument,0,'r'},
                 {0, 0, 0, 0}
         };
 
@@ -485,7 +528,7 @@ process_arguments (int argc, char **argv)
         }
 
         while (1) {
-                c = getopt_long (argc, argv, "+hVv46t:p:f:e:c:w:H:C:R:SD:F:A:U:P:q",
+                c = getopt_long (argc, argv, "+hVv46Lrt:p:f:e:c:w:H:C:R:sSD:F:A:U:P:q",
                                  longopts, &option);
 
                 if (c == -1 || c == EOF)
@@ -502,7 +545,7 @@ process_arguments (int argc, char **argv)
                         break;
                 case 'p':                                                                       /* port */
                         if (is_intpos (optarg))
-                                server_port = atoi (optarg);
+                                server_port_option = atoi (optarg);
                         else
                                 usage4 (_("Port must be a positive integer"));
                         break;
@@ -607,11 +650,29 @@ process_arguments (int argc, char **argv)
 #else
                         usage (_("SSL support not available - install OpenSSL and recompile"));
 #endif
+                case 's':
+                /* ssl */
+                        use_ssl = TRUE;
+                        server_port = SMTPS_PORT;
+                        break;
                 case 'S':
                 /* starttls */
-                        use_ssl = TRUE;
+                        use_starttls = TRUE;
                         use_ehlo = TRUE;
                         break;
+                case SNI_OPTION:
+#ifdef HAVE_SSL
+                        use_sni = TRUE;
+#else
+                        usage (_("SSL support not available - install OpenSSL and recompile"));
+#endif
+                        break;
+                case 'r':
+                        use_proxy_prefix = TRUE;
+                        break;
+                case 'L':
+                        use_lhlo = TRUE;
+                        break;
                 case '4':
                         address_family = AF_INET;
                         break;
@@ -655,6 +716,14 @@ process_arguments (int argc, char **argv)
         if (from_arg==NULL)
                 from_arg = strdup(" ");
 
+        if (use_starttls && use_ssl) {
+                usage4 (_("Set either -s/--ssl/--tls or -S/--starttls"));
+        }
+
+        if (server_port_option != 0) {
+                server_port = server_port_option;
+        }
+
         return validate_arguments ();
 }
 
@@ -764,10 +833,12 @@ recvlines(char *buf, size_t bufsize)
 int
 my_close (void)
 {
+        int result;
+        result = close(sd);
 #ifdef HAVE_SSL
-  np_net_ssl_cleanup();
+        np_net_ssl_cleanup();
 #endif
-  return close(sd);
+        return result;
 }
 
 
@@ -805,11 +876,18 @@ print_help (void)
   printf ("    %s\n", _("FROM-address to include in MAIL command, required by Exchange 2000")),
   printf (" %s\n", "-F, --fqdn=STRING");
   printf ("    %s\n", _("FQDN used for HELO"));
+  printf (" %s\n", "-r, --proxy");
+  printf ("    %s\n", _("Use PROXY protocol prefix for the connection."));
 #ifdef HAVE_SSL
   printf (" %s\n", "-D, --certificate=INTEGER[,INTEGER]");
   printf ("    %s\n", _("Minimum number of days a certificate has to be valid."));
+  printf (" %s\n", "-s, --ssl, --tls");
+  printf ("    %s\n", _("Use SSL/TLS for the connection."));
+  printf (_("    Sets default port to %d.\n"), SMTPS_PORT);
   printf (" %s\n", "-S, --starttls");
   printf ("    %s\n", _("Use STARTTLS for the connection."));
+  printf (" %s\n", "--sni");
+  printf ("    %s\n", _("Enable SSL/TLS hostname extension support (SNI)"));
 #endif
 
         printf (" %s\n", "-A, --authtype=STRING");
@@ -818,6 +896,8 @@ print_help (void)
   printf ("    %s\n", _("SMTP AUTH username"));
   printf (" %s\n", "-P, --authpass=STRING");
   printf ("    %s\n", _("SMTP AUTH password"));
+  printf (" %s\n", "-L, --lmtp");
+  printf ("    %s\n", _("Send LHLO instead of HELO/EHLO"));
   printf (" %s\n", "-q, --ignore-quit-failure");
   printf ("    %s\n", _("Ignore failure when sending QUIT command to server"));
    
@@ -828,9 +908,9 @@ print_help (void)
         printf (UT_VERBOSE);
 
         printf("\n");
-        printf ("%s\n", _("Successul connects return STATE_OK, refusals and timeouts return"));
+        printf ("%s\n", _("Successful connects return STATE_OK, refusals and timeouts return"));
   printf ("%s\n", _("STATE_CRITICAL, other errors return STATE_UNKNOWN.  Successful"));
-  printf ("%s\n", _("connects, but incorrect reponse messages from the host result in"));
+  printf ("%s\n", _("connects, but incorrect response messages from the host result in"));
   printf ("%s\n", _("STATE_WARNING return values."));
 
         printf (UT_SUPPORT);
@@ -844,6 +924,6 @@ print_usage (void)
   printf ("%s\n", _("Usage:"));
   printf ("%s -H host [-p port] [-4|-6] [-e expect] [-C command] [-R response] [-f from addr]\n", progname);
   printf ("[-A authtype -U authuser -P authpass] [-w warn] [-c crit] [-t timeout] [-q]\n");
-  printf ("[-F fqdn] [-S] [-D warn days cert expire[,crit days cert expire]] [-v] \n");
+  printf ("[-F fqdn] [-S] [-L] [-D warn days cert expire[,crit days cert expire]] [-r] [--sni] [-v] \n");
 }