X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/b367453a08bff7123dfe0b841de290e17372ad7c..ef2e5890df09193717f9d345ffaaa406e2d8aae7:/src/src/tls-gnu.c

diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index 796581b0e..4f1039903 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -3,10 +3,9 @@
 *************************************************/
 
 /* Copyright (c) University of Cambridge 1995 - 2018 */
-/* Copyright (c) The Exim Maintainers 2020 */
-/* See the file NOTICE for conditions of use and distribution. */
-
 /* Copyright (c) Phil Pennock 2012 */
+/* Copyright (c) The Exim Maintainers 2020 - 2021 */
+/* See the file NOTICE for conditions of use and distribution. */
 
 /* This file provides TLS/SSL support for Exim using the GnuTLS library,
 one of the available supported implementations.  This file is #included into
@@ -90,9 +89,6 @@ require current GnuTLS, then we'll drop support for the ancient libraries).
 #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP)
 # define SUPPORT_SRV_OCSP_STACK
 #endif
-#if GNUTLS_VERSION_NUMBER >= 0x030600
-# define GNUTLS_AUTO_DHPARAMS
-#endif
 #if GNUTLS_VERSION_NUMBER >= 0x030603
 # define EXIM_HAVE_TLS1_3
 # define SUPPORT_GNUTLS_EXT_RAW_PARSE
@@ -266,13 +262,11 @@ static exim_gnutls_state_st state_server = {
   .fd_out =		-1,
 };
 
-#ifndef GNUTLS_AUTO_DHPARAMS
 /* dh_params are initialised once within the lifetime of a process using TLS;
 if we used TLS in a long-lived daemon, we'd have to reconsider this.  But we
 don't want to repeat this. */
 
 static gnutls_dh_params_t dh_server_params = NULL;
-#endif
 
 static int ssl_session_timeout = 7200;	/* Two hours */
 
@@ -689,7 +683,6 @@ if (!state->host)
 
 
 
-#ifndef GNUTLS_AUTO_DHPARAMS
 /*************************************************
 *            Setup up DH parameters              *
 *************************************************/
@@ -712,7 +705,7 @@ init_server_dh(uschar ** errstr)
 {
 int fd, rc;
 unsigned int dh_bits;
-gnutls_datum_t m = {.data = NULL, .size = 0};
+gnutls_datum_t m;
 uschar filename_buf[PATH_MAX];
 uschar *filename = NULL;
 size_t sz;
@@ -725,6 +718,9 @@ DEBUG(D_tls) debug_printf("Initialising GnuTLS server params\n");
 if ((rc = gnutls_dh_params_init(&dh_server_params)))
   return tls_error_gnu(NULL, US"gnutls_dh_params_init", rc, errstr);
 
+m.data = NULL;
+m.size = 0;
+
 if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr))
   return DEFER;
 
@@ -874,12 +870,14 @@ if (rc < 0)
     return tls_error_sys(US"Unable to open temp file", errno, NULL, errstr);
   (void)exim_chown(temp_fn, exim_uid, exim_gid);   /* Probably not necessary */
 
-  /* GnuTLS overshoots!  If we ask for 2236, we might get 2237 or more.  But
-  there's no way to ask GnuTLS how many bits there really are.  We can ask
-  how many bits were used in a TLS session, but that's it!  The prime itself
-  is hidden behind too much abstraction.  So we ask for less, and proceed on
-  a wing and a prayer.  First attempt, subtracted 3 for 2233 and got 2240.  */
-
+  /* GnuTLS overshoots!
+   * If we ask for 2236, we might get 2237 or more.
+   * But there's no way to ask GnuTLS how many bits there really are.
+   * We can ask how many bits were used in a TLS session, but that's it!
+   * The prime itself is hidden behind too much abstraction.
+   * So we ask for less, and proceed on a wing and a prayer.
+   * First attempt, subtracted 3 for 2233 and got 2240.
+   */
   if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10)
     {
     dh_bits_gen = dh_bits - 10;
@@ -942,7 +940,6 @@ if (rc < 0)
 DEBUG(D_tls) debug_printf("initialized server D-H parameters\n");
 return OK;
 }
-#endif
 
 
 
@@ -1079,7 +1076,8 @@ static int
 tls_server_clienthello_ext(void * ctx, unsigned tls_id,
   const uschar * data, unsigned size)
 {
-/* https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml */
+/* The values for tls_id are documented here:
+https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml */
 switch (tls_id)
   {
   case 5:	/* Status Request */
@@ -1952,7 +1950,6 @@ tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr)
 int rc;
 const host_item *host = state->host;  /* macro should be reconsidered? */
 
-#ifndef GNUTLS_AUTO_DHPARAMS
 /* Create D-H parameters, or read them from the cache file. This function does
 its own SMTP error messaging. This only happens for the server, TLS D-H ignores
 client-side params. */
@@ -1962,10 +1959,10 @@ if (!state->host)
   if (!dh_server_params)
     if ((rc = init_server_dh(errstr)) != OK) return rc;
 
-  /* Unnecessary & discouraged with 3.6.0 or later */
+  /* Unnecessary & discouraged with 3.6.0 or later, according to docs.  But without it,
+  no DHE- ciphers are advertised. */
   gnutls_certificate_set_dh_params(state->lib_state.x509_cred, dh_server_params);
   }
-#endif
 
 /* Link the credentials to the session. */
 
@@ -2112,7 +2109,7 @@ if (!state->lib_state.pri_string)
   if ((rc = creds_load_pristring(state, p, &errpos)))
     return tls_error_gnu(state, string_sprintf(
 			"gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"",
-			p, errpos - CS p, errpos),
+			p, (long)(errpos - CS p), errpos),
 		    rc, errstr);
   }
 else
@@ -3046,6 +3043,9 @@ ALARM_CLR(0);
 
 if (rc != GNUTLS_E_SUCCESS)
   {
+  DEBUG(D_tls) debug_printf(" error %d from gnutls_handshake: %s\n",
+    rc, gnutls_strerror(rc));
+
   /* It seems that, except in the case of a timeout, we have to close the
   connection right here; otherwise if the other end is running OpenSSL it hangs
   until the server times out. */
@@ -3053,11 +3053,13 @@ if (rc != GNUTLS_E_SUCCESS)
   if (sigalrm_seen)
     {
     tls_error(US"gnutls_handshake", US"timed out", NULL, errstr);
+    (void) event_raise(event_action, US"tls:fail:connect", *errstr);
     gnutls_db_remove_session(state->session);
     }
   else
     {
     tls_error_gnu(state, US"gnutls_handshake", rc, errstr);
+    (void) event_raise(event_action, US"tls:fail:connect", *errstr);
     (void) gnutls_alert_send_appropriate(state->session, rc);
     gnutls_deinit(state->session);
     gnutls_certificate_free_credentials(state->lib_state.x509_cred);
@@ -3137,10 +3139,10 @@ state->xfer_buffer = store_malloc(ssl_xfer_buffer_size);
 receive_getc = tls_getc;
 receive_getbuf = tls_getbuf;
 receive_get_cache = tls_get_cache;
+receive_hasc = tls_hasc;
 receive_ungetc = tls_ungetc;
 receive_feof = tls_feof;
 receive_ferror = tls_ferror;
-receive_smtp_buffered = tls_smtp_buffered;
 
 return OK;
 }
@@ -3739,10 +3741,10 @@ if (!ct_ctx)	/* server */
   receive_getc =	smtp_getc;
   receive_getbuf =	smtp_getbuf;
   receive_get_cache =	smtp_get_cache;
+  receive_hasc =	smtp_hasc;
   receive_ungetc =	smtp_ungetc;
   receive_feof =	smtp_feof;
   receive_ferror =	smtp_ferror;
-  receive_smtp_buffered = smtp_buffered;
   }
 
 gnutls_deinit(state->session);
@@ -3853,6 +3855,13 @@ if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm)
 return state->xfer_buffer[state->xfer_buffer_lwm++];
 }
 
+BOOL
+tls_hasc(void)
+{
+exim_gnutls_state_st * state = &state_server;
+return state->xfer_buffer_lwm < state->xfer_buffer_hwm;
+}
+
 uschar *
 tls_getbuf(unsigned * len)
 {
@@ -3893,7 +3902,7 @@ if (n > 0)
 
 
 BOOL
-tls_could_read(void)
+tls_could_getc(void)
 {
 return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm
  || gnutls_record_check_pending(state_server.session) > 0;
@@ -4200,7 +4209,7 @@ DEBUG(D_tls)
 rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos);
 validate_check_rc(string_sprintf(
       "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"",
-      expciphers, errpos - CS expciphers, errpos));
+      expciphers, (long)(errpos - CS expciphers), errpos));
 
 #undef return_deinit
 #undef validate_check_rc