added starttls support to piler daemon

2024-12-24 04:20:12 +01:00 · 2012-10-28 20:36:46 +01:00 · 2012-10-28 20:36:46 +01:00 · dbbebbe5bf
commit dbbebbe5bf
parent d7f860c15b
13 changed files with 236 additions and 13 deletions
--- a/22
+++ b/22
@ -675,6 +675,7 @@ enable_option_checking
 enable_static_build
 enable_clamd
 enable_memcached
+enable_starttls
 with_piler_user
 '
      ac_precious_vars='build_alias
@ -1298,6 +1299,7 @@ Optional Features:
  --enable-static-build   build statically linked executables (default: dynamically linked)
  --enable-clamd          build clamd antivirus support
  --enable-memcached      build memcached support
+  --enable-starttls       build starttls support

 Optional Packages:
  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@ -3414,6 +3416,7 @@ have_mysql="no"
 have_tre="no"
 have_zip="no"
 have_zlib="no"
+have_starttls="no"

 pdftotext="no"
 catdoc="no"
@ -3485,6 +3488,16 @@ fi



+# Check whether --enable-starttls was given.
+if test "${enable_starttls+set}" = set; then :
+  enableval=$enable_starttls; have_starttls=$enableval
+else
+  have_starttls="no"
+fi
+
+
+
+

 for ac_header in math.h
 do :
@ -4339,6 +4352,15 @@ _ACEOF
   antispam_libs="$antispam_libs -lzip"
 fi

+if test "$have_starttls" = "yes"; then
+   echo "starttls support: yes"
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STARTTLS 1
+_ACEOF
+
+fi
+
 echo

 if test "$have_clamd" = "yes"; then
--- a/configure.in
+++ b/configure.in
@ -40,6 +40,7 @@ have_mysql="no"
 have_tre="no"
 have_zip="no"
 have_zlib="no"
+have_starttls="no"

 pdftotext="no"
 catdoc="no"
@ -99,6 +100,11 @@ AC_ARG_ENABLE(memcached,
        [  --enable-memcached      build memcached support], want_memcached=$enableval, want_memcached="no")


+AC_ARG_ENABLE(starttls,
+	[  --enable-starttls       build starttls support], have_starttls=$enableval, have_starttls="no")
+
+
+
 dnl math library

 AC_CHECK_HEADERS(math.h, have_math=yes, have_math=no)
@ -278,6 +284,11 @@ if test "$have_zip" = "yes"; then
   antispam_libs="$antispam_libs -lzip"
 fi

+if test "$have_starttls" = "yes"; then
+   echo "starttls support: yes"
+   AC_DEFINE_UNQUOTED(HAVE_STARTTLS, 1, [starttls support])
+fi
+
 echo

 if test "$have_clamd" = "yes"; then
--- a/etc/example.conf
+++ b/etc/example.conf
@ -47,6 +47,21 @@ backlog=20

 workdir=/var/piler/tmp

+;
+; starttls stuff
+;
+
+; whether to enable (1) or disable (0) starttls support
+tls_enable=0
+
+; PEM file containing both the certificate and the private key.
+; Make sure to create this file (and secure it with chmod 600 /usr/local/etc/piler.pem)
+; before turning on starttls support!
+pemfile=
+
+; cipher list to use, see 'man SSL_CTX_set_cipher_list' for more details
+cipher_list=HIGH:MEDIUM
+

 ; piler's own header to indicate previously archived messages
 piler_header_field=X-piler: piler already archived this email
--- a/piler-config.h.in
+++ b/piler-config.h.in
@ -17,3 +17,4 @@
 #undef HAVE_UNRTF
 #undef HAVE_ZIP

+#undef HAVE_STARTTLS
--- a/src/cfg.c
+++ b/src/cfg.c
@ -61,6 +61,7 @@ struct _parse_rule config_parse_rules[] =

   { "archive_emails_not_having_message_id", "integer", (void*) int_parser, offsetof(struct __config, archive_emails_not_having_message_id), "0", sizeof(int)},
   { "backlog", "integer", (void*) int_parser, offsetof(struct __config, backlog), "20", sizeof(int)},
+   { "cipher_list", "string", (void*) string_parser, offsetof(struct __config, cipher_list), "HIGH:MEDIUM", MAXVAL-1},
   { "clamd_addr", "string", (void*) string_parser, offsetof(struct __config, clamd_addr), "", MAXVAL-1},
   { "clamd_port", "integer", (void*) int_parser, offsetof(struct __config, clamd_port), "0", sizeof(int)},
   { "clamd_socket", "string", (void*) string_parser, offsetof(struct __config, clamd_socket), CLAMD_SOCKET, MAXVAL-1},
@ -85,11 +86,13 @@ struct _parse_rule config_parse_rules[] =
   { "mysqldb", "string", (void*) string_parser, offsetof(struct __config, mysqldb), "piler", MAXVAL-1},
   { "mysql_connect_timeout", "integer", (void*) int_parser, offsetof(struct __config, mysql_connect_timeout), "2", sizeof(int)},
   { "number_of_worker_processes", "integer", (void*) int_parser, offsetof(struct __config, number_of_worker_processes), "10", sizeof(int)},
+   { "pemfile", "string", (void*) string_parser, offsetof(struct __config, pemfile), "", MAXVAL-1},
   { "pidfile", "string", (void*) string_parser, offsetof(struct __config, pidfile), PIDFILE, MAXVAL-1},
   { "piler_header_field", "string", (void*) string_parser, offsetof(struct __config, piler_header_field), "", MAXVAL-1},
   { "queuedir", "string", (void*) string_parser, offsetof(struct __config, queuedir), QUEUE_DIR, MAXVAL-1},
   { "session_timeout", "integer", (void*) int_parser, offsetof(struct __config, session_timeout), "420", sizeof(int)},
   { "spam_header_line", "string", (void*) string_parser, offsetof(struct __config, spam_header_line), "", MAXVAL-1},
+   { "tls_enable", "integer", (void*) int_parser, offsetof(struct __config, tls_enable), "0", sizeof(int)},
   { "update_counters_to_memcached", "integer", (void*) int_parser, offsetof(struct __config, update_counters_to_memcached), "0", sizeof(int)},
   { "username", "string", (void*) string_parser, offsetof(struct __config, username), "piler", MAXVAL-1},
   { "use_antivirus", "integer", (void*) int_parser, offsetof(struct __config, use_antivirus), "1", sizeof(int)},
--- a/src/cfg.h
+++ b/src/cfg.h
@ -20,6 +20,10 @@ struct __config {
   int clamd_port;
   char clamd_socket[MAXVAL];

+   int tls_enable;
+   char pemfile[MAXVAL];
+   char cipher_list[MAXVAL];
+
   int use_antivirus;

   char memcached_servers[MAXVAL];
--- a/src/config.h
+++ b/src/config.h
@ -13,7 +13,7 @@

 #define VERSION "0.1.21"

-#define BUILD 719
+#define BUILD 722

 #define HOSTID "mailarchiver"

--- a/src/defs.h
+++ b/src/defs.h
@ -178,6 +178,7 @@ struct session_data {
   char attachments[SMALLBUFSIZE];
   char internal_sender, internal_recipient, external_recipient;
   int direction;
+   int tls;
   int spam_message;
   int fd, hdr_len, tot_len, num_of_rcpt_to, rav;
   int need_scan;
@ -239,6 +240,8 @@ struct memcached_server {
 struct __data {
   int folder;
   char recursive_folder_names;
+   char starttls[TINYBUFSIZE];
+
 #ifdef HAVE_TRE
   struct rule *archiving_rules;
   struct rule *retention_rules;
--- a/src/imap.c
+++ b/src/imap.c
@ -218,7 +218,6 @@ int connect_to_imap_server(int sd, int *seq, char *imapserver, char *username, c
   unsigned long host=0;
   struct sockaddr_in remote_addr;
   X509* server_cert;
-   SSL_METHOD *meth;
   char *str;


@ -237,11 +236,10 @@ int connect_to_imap_server(int sd, int *seq, char *imapserver, char *username, c

   if(use_ssl == 1){

-      SSLeay_add_ssl_algorithms();
-      meth = SSLv3_client_method();
+      SSL_library_init();
      SSL_load_error_strings();

-      data->ctx = SSL_CTX_new(meth);
+      data->ctx = SSL_CTX_new(SSLv3_client_method());
      CHK_NULL(data->ctx, "internal SSL error");

      data->ssl = SSL_new(data->ctx);
@ -314,6 +312,7 @@ void close_connection(int sd, struct __data *data, int use_ssl){
      SSL_shutdown(data->ssl);
      SSL_free(data->ssl);
      SSL_CTX_free(data->ctx);
+      ERR_free_strings();
   }
 }

--- a/src/misc.c
+++ b/src/misc.c
@ -322,12 +322,67 @@ int write1(int sd, char *buf, int use_ssl, SSL *ssl){
 }


+int ssl_want_retry(SSL *ssl, int ret, int timeout){
+   int i;
+   fd_set fds;
+   struct timeval tv;
+   int sock;
+
+   // something went wrong.  I'll retry, die quietly, or complain
+   i = SSL_get_error(ssl, ret);
+   if(i == SSL_ERROR_NONE)
+      return 1;
+ 
+   tv.tv_sec = timeout/1000;
+   tv.tv_usec = 0;
+   FD_ZERO(&fds);
+ 
+   switch(i){
+      case SSL_ERROR_WANT_READ: // pause until the socket is readable
+          sock = SSL_get_rfd(ssl);
+          FD_SET(sock, &fds);
+          i = select(sock+1, &fds, 0, 0, &tv);
+          break;
+ 
+      case SSL_ERROR_WANT_WRITE: // pause until the socket is writeable
+         sock = SSL_get_wfd(ssl);
+         FD_SET(sock, &fds);
+         i = select(sock+1, 0, &fds, 0, &tv);
+         break;
+ 
+      case SSL_ERROR_ZERO_RETURN: // the sock closed, just return quietly
+         i = 0;
+         break;
+ 
+      default: // ERROR - unexpected error code
+         i = -1;
+         break;
+   };
+
+   return i;
+}
+
+
+int ssl_read_timeout(SSL *ssl, void *buf, int len, int timeout){
+   int i;
+
+   while(1){
+      i = SSL_read(ssl, (char*)buf, len);
+      if(i > 0) break;
+      i = ssl_want_retry(ssl, i, timeout);
+      if(i <= 0) break;
+   }
+
+   return i;
+}
+
+
 int recvtimeoutssl(int s, char *buf, int len, int timeout, int use_ssl, SSL *ssl){

    memset(buf, 0, len);

    if(use_ssl == 1){
-       return SSL_read(ssl, buf, len-1);
+       return ssl_read_timeout(ssl, buf, len-1, timeout);
    }
    else {
       return recvtimeout(s, buf, len-1, timeout);
--- a/src/piler.c
+++ b/src/piler.c
@ -21,6 +21,8 @@
 #include <unistd.h>
 #include <locale.h>
 #include <errno.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
 #include <piler.h>


@ -247,6 +249,13 @@ void clean_exit(){

   unlink(cfg.pidfile);

+#ifdef HAVE_STARTTLS
+   if(data.ctx){
+      SSL_CTX_free(data.ctx);
+      ERR_free_strings();
+   }
+#endif
+
   exit(1);
 }

@ -257,6 +266,27 @@ void fatal(char *s){
 }


+#ifdef HAVE_STARTTLS
+int init_ssl(){
+
+   SSL_library_init();
+   SSL_load_error_strings();
+
+   data.ctx = SSL_CTX_new(SSLv23_server_method());
+
+   if(data.ctx == NULL){ syslog(LOG_PRIORITY, "SSL_CTX_new() failed"); return ERR; }
+
+   if(SSL_CTX_set_cipher_list(data.ctx, cfg.cipher_list) == 0){ syslog(LOG_PRIORITY, "failed to set cipher list: '%s'", cfg.cipher_list); return ERR; }
+
+   if(SSL_CTX_use_PrivateKey_file(data.ctx, cfg.pemfile, SSL_FILETYPE_PEM) != 1){ syslog(LOG_PRIORITY, "cannot load private key from %s", cfg.pemfile); return ERR; }
+
+   if(SSL_CTX_use_certificate_file(data.ctx, cfg.pemfile, SSL_FILETYPE_PEM) != 1){ syslog(LOG_PRIORITY, "cannot load certificate from %s", cfg.pemfile); return ERR; }
+
+   return OK;
+}
+#endif
+
+
 void initialise_configuration(){
   struct session_data sdata;

@ -293,6 +323,14 @@ void initialise_configuration(){
   data.archiving_rules = NULL;
   data.retention_rules = NULL;

+   memset(data.starttls, 0, TINYBUFSIZE);
+
+#ifdef HAVE_STARTTLS
+   if(cfg.tls_enable > 0 && data.ctx == NULL && init_ssl() == OK){
+      snprintf(data.starttls, TINYBUFSIZE-1, "250-STARTTLS\r\n");
+   }
+#endif
+
   mysql_init(&(sdata.mysql));
   mysql_options(&(sdata.mysql), MYSQL_OPT_CONNECT_TIMEOUT, (const char*)&cfg.mysql_connect_timeout);
   if(mysql_real_connect(&(sdata.mysql), cfg.mysqlhost, cfg.mysqluser, cfg.mysqlpwd, cfg.mysqldb, cfg.mysqlport, cfg.mysqlsocket, 0) == 0){
@ -347,6 +385,8 @@ int main(int argc, char **argv){
   data.recursive_folder_names = 0;
   data.archiving_rules = NULL;
   data.retention_rules = NULL;
+   data.ctx = NULL;
+   data.ssl = NULL;


   initialise_configuration();
--- a/src/session.c
+++ b/src/session.c
@ -14,6 +14,8 @@
 #include <signal.h>
 #include <syslog.h>
 #include <time.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
 #include <piler.h>


@ -31,10 +33,15 @@ int handle_smtp_session(int new_sd, struct __data *data, struct __config *cfg){
   struct timezone tz;
   struct timeval tv1, tv2;

+#ifdef HAVE_STARTTLS
+   int starttls = 0;
+   char ssl_error[SMALLBUFSIZE];
+#endif

   state = SMTP_STATE_INIT;

   init_session_data(&sdata);
+   sdata.tls = 0;

   bzero(&counters, sizeof(counters));

@ -70,7 +77,7 @@ int handle_smtp_session(int new_sd, struct __data *data, struct __config *cfg){
   send(new_sd, buf, strlen(buf), 0);
   if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, buf);

-   while((n = recvtimeout(new_sd, puf, MAXBUFSIZE, TIMEOUT)) > 0){
+   while((n = recvtimeoutssl(new_sd, puf, MAXBUFSIZE, TIMEOUT, sdata.tls, data->ssl)) > 0){
         pos = 0;

         /* accept mail data */
@ -120,7 +127,8 @@ int handle_smtp_session(int new_sd, struct __data *data, struct __config *cfg){
                  for(i=0; i<sdata.num_of_rcpt_to; i++){
               #endif

-                     send(new_sd, SMTP_RESP_421_ERR_WRITE_FAILED, strlen(SMTP_RESP_421_ERR_WRITE_FAILED), 0);
+                     //send(new_sd, SMTP_RESP_421_ERR_WRITE_FAILED, strlen(SMTP_RESP_421_ERR_WRITE_FAILED), 0);
+                     write1(new_sd, SMTP_RESP_421_ERR_WRITE_FAILED, sdata.tls, data->ssl);

               #ifdef HAVE_LMTP
                  }
@ -213,7 +221,8 @@ int handle_smtp_session(int new_sd, struct __data *data, struct __config *cfg){

                  if(inj == ERR) snprintf(sdata.acceptbuf, SMALLBUFSIZE-1, "451 %s <%s>\r\n", sdata.ttmpfile, rctptoemail);

-                  send(new_sd, sdata.acceptbuf, strlen(sdata.acceptbuf), 0);
+                  //send(new_sd, sdata.acceptbuf, strlen(sdata.acceptbuf), 0);
+                  write1(new_sd, sdata.acceptbuf, sdata.tls, data->ssl);

                  if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, sdata.acceptbuf);

@ -288,7 +297,9 @@ AFTER_PERIOD:
         if(strncasecmp(buf, SMTP_CMD_EHLO, strlen(SMTP_CMD_EHLO)) == 0 || strncasecmp(buf, LMTP_CMD_LHLO, strlen(LMTP_CMD_LHLO)) == 0){
            if(state == SMTP_STATE_INIT) state = SMTP_STATE_HELO;

-            snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_250_EXTENSIONS, cfg->hostid);
+            if(sdata.tls == 0) snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_250_EXTENSIONS, cfg->hostid, data->starttls);
+            else snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_250_EXTENSIONS, cfg->hostid, "");
+
            strncat(resp, buf, MAXBUFSIZE-1);

            continue;
@ -306,6 +317,29 @@ AFTER_PERIOD:
         }


+      #ifdef HAVE_STARTTLS
+         if(cfg->tls_enable > 0 && strncasecmp(buf, SMTP_CMD_STARTTLS, strlen(SMTP_CMD_STARTTLS)) == 0 && strlen(data->starttls) > 4 && sdata.tls == 0){
+            if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: starttls request from client", sdata.ttmpfile);
+
+            if(data->ctx){
+               data->ssl = SSL_new(data->ctx);
+               if(data->ssl){
+                  if(SSL_set_fd(data->ssl, new_sd) == 1){
+                     strncat(resp, SMTP_RESP_220_READY_TO_START_TLS, MAXBUFSIZE-1);
+                     starttls = 1;
+                     state = SMTP_STATE_INIT;
+
+                     continue;
+                  } syslog(LOG_PRIORITY, "%s: SSL_set_fd() failed", sdata.ttmpfile);
+               } syslog(LOG_PRIORITY, "%s: SSL_new() failed", sdata.ttmpfile);
+            } syslog(LOG_PRIORITY, "%s: SSL ctx is null!", sdata.ttmpfile);
+
+
+            strncat(resp, SMTP_RESP_454_ERR_TLS_TEMP_ERROR, MAXBUFSIZE-1);
+            continue;
+         }
+      #endif
+

         if(strncasecmp(buf, SMTP_CMD_MAIL_FROM, strlen(SMTP_CMD_MAIL_FROM)) == 0){

@ -433,9 +467,32 @@ AFTER_PERIOD:
      /* now we can send our buffered response */

      if(strlen(resp) > 0){
-         send(new_sd, resp, strlen(resp), 0);
+         //send(new_sd, resp, strlen(resp), 0);
+         write1(new_sd, resp, sdata.tls, data->ssl);
+
         if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, resp);
         memset(resp, 0, MAXBUFSIZE);
+
+      #ifdef HAVE_STARTTLS
+         if(starttls == 1 && sdata.tls == 0){
+
+            if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: waiting for ssl handshake", sdata.ttmpfile);
+
+            rc = SSL_accept(data->ssl);
+
+            if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: SSL_accept() finished", sdata.ttmpfile);
+
+            if(rc == 1){
+               sdata.tls = 1;
+            }
+            else {
+               ERR_error_string_n(ERR_get_error(), ssl_error, SMALLBUFSIZE);
+               syslog(LOG_PRIORITY, "%s: SSL_accept() failed, rc=%d, errorcode: %d, error text: %s\n", sdata.ttmpfile, rc, SSL_get_error(data->ssl, rc), ssl_error);
+            }
+         }
+      #endif
+
+
      }

      if(state == SMTP_STATE_FINISHED){
@ -451,7 +508,9 @@ AFTER_PERIOD:

   if(state < SMTP_STATE_QUIT && inj == ERR){
      snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_421_ERR, cfg->hostid);
-      send(new_sd, buf, strlen(buf), 0);
+      //send(new_sd, buf, strlen(buf), 0);
+      write1(new_sd, buf, sdata.tls, data->ssl);
+
      if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, buf);

      if(sdata.fd != -1){
@ -475,6 +534,13 @@ QUITTING:
   mysql_close(&(sdata.mysql));
 #endif

+#ifdef HAVE_STARTTLS
+   if(sdata.tls == 1){
+      SSL_shutdown(data->ssl);
+      SSL_free(data->ssl);
+   }
+#endif
+
   if(cfg->verbosity >= _LOG_INFO) syslog(LOG_PRIORITY, "processed %llu messages", counters.c_rcvd);

   return (int)counters.c_rcvd;
--- a/src/smtpcodes.h
+++ b/src/smtpcodes.h
@ -26,13 +26,15 @@
 #define SMTP_CMD_NOOP "NOOP"
 #define SMTP_CMD_XFORWARD "XFORWARD"
 #define SMTP_CMD_XCLIENT "XCLIENT"
+#define SMTP_CMD_STARTTLS "STARTTLS"

 // SMTP responses

 #define SMTP_RESP_220_BANNER "220 %s ESMTP\r\n"
+#define SMTP_RESP_220_READY_TO_START_TLS "220 Ready to start TLS\r\n"
 #define SMTP_RESP_221_GOODBYE "221 %s Goodbye\r\n"
 #define SMTP_RESP_250_OK "250 Ok\r\n"
-#define SMTP_RESP_250_EXTENSIONS "250-%s\r\n250-PIPELINING\r\n250-SIZE\r\n250 8BITMIME\r\n"
+#define SMTP_RESP_250_EXTENSIONS "250-%s\r\n250-PIPELINING\r\n%s250-SIZE\r\n250 8BITMIME\r\n"

 #define SMTP_RESP_354_DATA_OK "354 Send mail data; end it with <CRLF>.<CRLF>\r\n"

@ -41,9 +43,11 @@
 #define SMTP_RESP_421_ERR_WRITE_FAILED "421 writing queue file failed\r\n"
 #define SMTP_RESP_450_ERR_CMD_NOT_IMPLEMENTED "450 command not implemented\r\n"
 #define SMTP_RESP_451_ERR "451 Error in processing, try again later\r\n"
+#define SMTP_RESP_454_ERR_TLS_TEMP_ERROR "454 TLS not available currently\r\n"

 #define SMTP_RESP_502_ERR "502 Command not implemented\r\n"
 #define SMTP_RESP_503_ERR "503 Bad command sequence\r\n"
+#define SMTP_RESP_530_ERR_MUST_ISSUE_STARTTLS_FIRST "530 MUST issue STARTTLS command first\r\n"
 #define SMTP_RESP_550_ERR "550 Access denied.\r\n"
 #define SMTP_RESP_550_ERR_PREF "550 Access denied."
 #define SMTP_RESP_550_INVALID_RECIPIENT "550 Unknown recipient\r\n"