X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/50a3f20592c79da4acd409b59803dd5ff31b9781..b6054898ace169a0e5143117397a4f666a5e7283:/src/src/tls-gnu.c

diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index 2e1b9e4d3..bfe40b205 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -3,6 +3,7 @@
 *************************************************/
 
 /* 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 */
@@ -53,6 +54,9 @@ require current GnuTLS, then we'll drop support for the ancient libraries).
 # warning "GnuTLS library version too old; tls:cert event unsupported"
 # define DISABLE_EVENT
 #endif
+#if GNUTLS_VERSION_NUMBER >= 0x030000
+# define SUPPORT_SELFSIGN	/* Uncertain what version is first usable but 2.12.23 is not */
+#endif
 #if GNUTLS_VERSION_NUMBER >= 0x030306
 # define SUPPORT_CA_DIR
 #else
@@ -107,9 +111,11 @@ require current GnuTLS, then we'll drop support for the ancient libraries).
 # endif
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
-# if GNUTLS_VERSION_NUMBER < 0x030603
-#  error GNUTLS version too early for session-resumption
+#ifndef DISABLE_TLS_RESUME
+# if GNUTLS_VERSION_NUMBER >= 0x030603
+#  define EXIM_HAVE_TLS_RESUME
+# else
+#  warning "GnuTLS library version too old; resumption unsupported"
 # endif
 #endif
 
@@ -127,7 +133,7 @@ require current GnuTLS, then we'll drop support for the ancient libraries).
 void
 options_tls(void)
 {
-# ifdef EXPERIMENTAL_TLS_RESUME
+# ifndef DISABLE_TLS_RESUME
 builtin_macro_create_var(US"_RESUME_DECODE", RESUME_DECODE_STRING );
 # endif
 # ifdef EXIM_HAVE_TLS1_3
@@ -262,7 +268,7 @@ static BOOL gnutls_buggy_ocsp = FALSE;
 static BOOL exim_testharness_disable_ocsp_validity_check = FALSE;
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 static gnutls_datum_t server_sessticket_key;
 #endif
 
@@ -322,7 +328,7 @@ static void exim_gnutls_logger_cb(int level, const char *message);
 
 static int exim_sni_handling_cb(gnutls_session_t session);
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 static int
 tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when,
   unsigned incoming, const gnutls_datum_t * msg);
@@ -333,7 +339,7 @@ tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when,
 void
 tls_daemon_init(void)
 {
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 /* We are dependent on the GnuTLS implementation of the Session Ticket
 encryption; both the strength and the key rotation period.  We hope that
 the strength at least matches that of the ciphersuite (but GnuTLS does not
@@ -418,11 +424,14 @@ record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text)
 const uschar * msg;
 uschar * errstr;
 
-if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED)
-  msg = string_sprintf("A TLS fatal alert has been received: %s",
-    US gnutls_alert_get_name(gnutls_alert_get(state->session)));
-else
-  msg = US gnutls_strerror(rc);
+msg = rc == GNUTLS_E_FATAL_ALERT_RECEIVED
+  ? string_sprintf("A TLS fatal alert has been received: %s",
+      US gnutls_alert_get_name(gnutls_alert_get(state->session)))
+#ifdef GNUTLS_E_PREMATURE_TERMINATION
+  : rc == GNUTLS_E_PREMATURE_TERMINATION && errno
+  ? string_sprintf("%s: syscall: %s", US gnutls_strerror(rc), strerror(errno))
+#endif
+  : US gnutls_strerror(rc);
 
 (void) tls_error(when, msg, state->host, &errstr);
 
@@ -541,7 +550,10 @@ else
 
 /* peercert is set in peer_status() */
 tlsp->peerdn = state->peerdn;
-tlsp->sni =    state->received_sni;
+
+/* do not corrupt sni sent by client; record sni rxd by server */
+if (!state->host)
+  tlsp->sni = state->received_sni;
 
 /* record our certificate */
   {
@@ -717,7 +729,7 @@ else if (errno == ENOENT)
     debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename);
   }
 else
-  return tls_error(string_open_failed(errno, "\"%s\" for reading", filename),
+  return tls_error(string_open_failed("\"%s\" for reading", filename),
       NULL, NULL, errstr);
 
 /* If ret < 0, either the cache file does not exist, or the data it contains
@@ -824,13 +836,19 @@ gnutls_x509_privkey_t pkey = NULL;
 const uschar * where;
 int rc;
 
+#ifndef SUPPORT_SELFSIGN
+where = US"library too old";
+rc = GNUTLS_E_NO_CERTIFICATE_FOUND;
+if (TRUE) goto err;
+#endif
+
 where = US"initialising pkey";
 if ((rc = gnutls_x509_privkey_init(&pkey))) goto err;
 
 where = US"initialising cert";
 if ((rc = gnutls_x509_crt_init(&cert))) goto err;
 
-where = US"generating pkey";
+where = US"generating pkey";	/* Hangs on 2.12.23 */
 if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA,
 #ifdef SUPPORT_PARAM_TO_PK_BITS
 # ifndef GNUTLS_SEC_PARAM_MEDIUM
@@ -990,10 +1008,10 @@ return gnutls_ext_raw_parse(NULL, tls_server_servercerts_ext, msg, 0);
  "Handshake Protocol: Certificate" record.
 So we need to spot the Certificate handshake message, parse it and spot any status_request extension(s)
 
-This is different to tls1.2 - where it is a separate record (wireshake term) / handshake message (gnutls term).
+This is different to tls1.2 - where it is a separate record (wireshark term) / handshake message (gnutls term).
 */
 
-#if defined(EXPERIMENTAL_TLS_RESUME) || defined(SUPPORT_GNUTLS_EXT_RAW_PARSE)
+#if defined(EXIM_HAVE_TLS_RESUME) || defined(SUPPORT_GNUTLS_EXT_RAW_PARSE)
 /* Callback for certificate-status, on server. We sent stapled OCSP. */
 static int
 tls_server_certstatus_cb(gnutls_session_t session, unsigned int htype,
@@ -1025,7 +1043,7 @@ switch (htype)
 # endif
   case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS:
     return tls_server_certstatus_cb(sess, htype, when, incoming, msg);
-# ifdef EXPERIMENTAL_TLS_RESUME
+# ifdef EXIM_HAVE_TLS_RESUME
   case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET:
     return tls_server_ticket_cb(sess, htype, when, incoming, msg);
 # endif
@@ -2318,7 +2336,7 @@ else
 }
 
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 static int
 tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when,
   unsigned incoming, const gnutls_datum_t * msg)
@@ -2432,7 +2450,7 @@ DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n");
 #endif
   }
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 tls_server_resume_prehandshake(state);
 #endif
 
@@ -2540,7 +2558,7 @@ if (gnutls_session_get_flags(state->session) & GNUTLS_SFLAGS_EXT_MASTER_SECRET)
   tls_in.ext_master_secret = TRUE;
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 tls_server_resume_posthandshake(state);
 #endif
 
@@ -2591,9 +2609,9 @@ if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK)
   {
   state->exp_tls_verify_cert_hostnames =
 #ifdef SUPPORT_I18N
-    string_domain_utf8_to_alabel(host->name, NULL);
+    string_domain_utf8_to_alabel(host->certname, NULL);
 #else
-    host->name;
+    host->certname;
 #endif
   DEBUG(D_tls)
     debug_printf("TLS: server cert verification includes hostname: \"%s\".\n",
@@ -2673,7 +2691,7 @@ return TRUE;
 
 
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 /* On the client, get any stashed session for the given IP from hints db
 and apply it to the ssl-connection for attempted resumption.  Although
 there is a gnutls_session_ticket_enable_client() interface it is
@@ -2806,7 +2824,7 @@ if (gnutls_session_is_resumed(state->session))
 
 tls_save_session(tlsp, state->session, host);
 }
-#endif	/* EXPERIMENTAL_TLS_RESUME */
+#endif	/* !DISABLE_TLS_RESUME */
 
 
 /*************************************************
@@ -2853,7 +2871,7 @@ DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", cctx->so
 /* If dane is flagged, have either request or require dane for this host, and
 a TLSA record found.  Therefore, dane verify required.  Which implies cert must
 be requested and supplied, dane verify must pass, and cert verify irrelevant
-(incl.  hostnames), and (caller handled) require_tls */
+(incl.  hostnames), and (caller handled) require_tls and sni=$domain */
 
 if (conn_args->dane && ob->dane_require_tls_ciphers)
   {
@@ -2880,6 +2898,7 @@ if (!cipher_list)
       cipher_list, &state, tlsp, errstr) != OK)
     return FALSE;
 
+
 #ifdef MEASURE_TIMING
   report_time_since(&t0, US"client tls_init (delta)");
 #endif
@@ -2960,7 +2979,7 @@ if (request_ocsp)
   }
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 tls_client_resume_prehandshake(state, tlsp, host, ob);
 #endif
 
@@ -3060,7 +3079,7 @@ if (request_ocsp)
   }
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 tls_client_resume_posthandshake(state, tlsp, host);
 #endif
 
@@ -3353,9 +3372,14 @@ tls_write(void * ct_ctx, const uschar * buff, size_t len, BOOL more)
 ssize_t outbytes;
 size_t left = len;
 exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server;
-#ifdef SUPPORT_CORK
 
-if (more && !state->corked) gnutls_record_cork(state->session);
+#ifdef SUPPORT_CORK
+if (more && !state->corked)
+  {
+  DEBUG(D_tls) debug_printf("gnutls_record_cork(session=%p)\n", state->session);
+  gnutls_record_cork(state->session);
+  state->corked = TRUE;
+  }
 #endif
 
 DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__,
@@ -3371,10 +3395,27 @@ while (left > 0)
   while (outbytes == GNUTLS_E_AGAIN);
 
   DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes);
+
   if (outbytes < 0)
     {
-    DEBUG(D_tls) debug_printf("%s: gnutls_record_send err\n", __FUNCTION__);
-    record_io_error(state, outbytes, US"send", NULL);
+#ifdef GNUTLS_E_PREMATURE_TERMINATION
+    if (  outbytes == GNUTLS_E_PREMATURE_TERMINATION && errno == ECONNRESET
+       && !ct_ctx && f.smtp_in_quit
+       )
+      {					/* Outlook, dammit */
+      if (LOGGING(protocol_detail))
+	log_write(0, LOG_MAIN, "[%s] after QUIT, client reset TCP before"
+	  " SMTP response and TLS close\n", sender_host_address);
+      else
+	DEBUG(D_tls) debug_printf("[%s] SSL_write: after QUIT,"
+	  " client reset TCP before TLS close\n", sender_host_address);
+      }
+    else
+#endif
+      {
+      DEBUG(D_tls) debug_printf("%s: gnutls_record_send err\n", __FUNCTION__);
+      record_io_error(state, outbytes, US"send", NULL);
+      }
     return -1;
     }
   if (outbytes == 0)
@@ -3396,10 +3437,25 @@ if (len > INT_MAX)
   }
 
 #ifdef SUPPORT_CORK
-if (more != state->corked)
+if (!more && state->corked)
   {
-  if (!more) (void) gnutls_record_uncork(state->session, 0);
-  state->corked = more;
+  DEBUG(D_tls) debug_printf("gnutls_record_uncork(session=%p)\n", state->session);
+  do
+    /* We can't use GNUTLS_RECORD_WAIT here, as it retries on
+    GNUTLS_E_AGAIN || GNUTLS_E_INTR, which would break our timeout set by alarm().
+    The GNUTLS_E_AGAIN should not happen ever, as our sockets are blocking anyway.
+    But who knows. (That all relies on the fact that GNUTLS_E_INTR and GNUTLS_E_AGAIN
+    match the EINTR and EAGAIN errno values.) */
+    outbytes = gnutls_record_uncork(state->session, 0);
+  while (outbytes == GNUTLS_E_AGAIN);
+
+  if (outbytes < 0)
+    {
+    record_io_error(state, len, US"uncork", NULL);
+    return -1;
+    }
+
+  state->corked = FALSE;
   }
 #endif