Move errno-protection into string_open_failed()

[exim.git] / src / src / tls-gnu.c

diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index 826a3fdc555ee51bd0736fa8289a5575e13e6bef..6308f10df4d00bb29ef55b0f88c8365a200dbe3d 100644 (file)
--- 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 +424,16 @@ 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
+  ? errno == ECONNRESET                /* Outlook does this to us right after sending us QUIT */
+  ? string_sprintf("syscall: %s", strerror(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);
 
@@ -717,7 +728,7 @@ 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 +835,19 @@ 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 +1007,10 @@ 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 +1042,7 @@ 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 +2335,7 @@ 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 +2449,7 @@ 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 +2557,7 @@ 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 +2608,9 @@ 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 +2690,7 @@ 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 +2823,7 @@ if (gnutls_session_is_resumed(state->session))
 
 tls_save_session(tlsp, state->session, host);
 }
-#endif /* EXPERIMENTAL_TLS_RESUME */
+#endif /* !DISABLE_TLS_RESUME */
 
 
 /*************************************************
@@ -2960,7 +2977,7 @@ if (request_ocsp)
   }
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 tls_client_resume_prehandshake(state, tlsp, host, ob);
 #endif
 
@@ -3060,7 +3077,7 @@ if (request_ocsp)
   }
 #endif
 
-#ifdef EXPERIMENTAL_TLS_RESUME
+#ifdef EXIM_HAVE_TLS_RESUME
 tls_client_resume_posthandshake(state, tlsp, host);
 #endif
 
@@ -3142,7 +3159,7 @@ tls_refill(unsigned lim)
 exim_gnutls_state_st * state = &state_server;
 ssize_t inbytes;
 
-DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n",
+DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(session=%p, buffer=%p, buffersize=%u)\n",
   state->session, state->xfer_buffer, ssl_xfer_buffer_size);
 
 sigalrm_seen = FALSE;
@@ -3305,7 +3322,7 @@ if (state->xfer_buffer_lwm < state->xfer_buffer_hwm)
         state->xfer_buffer_hwm - state->xfer_buffer_lwm);
 
 DEBUG(D_tls)
-  debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n",
+  debug_printf("Calling gnutls_record_recv(session=%p, buffer=%p, len=" SIZE_T_FMT ")\n",
       state->session, buff, len);
 
 do
@@ -3353,9 +3370,14 @@ 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__,
@@ -3363,7 +3385,7 @@ DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__,
 
 while (left > 0)
   {
-  DEBUG(D_tls) debug_printf("gnutls_record_send(%p, %p, " SIZE_T_FMT ")\n",
+  DEBUG(D_tls) debug_printf("gnutls_record_send(session=%p, buffer=%p, left=" SIZE_T_FMT ")\n",
       state->session, buff, left);
 
   do
@@ -3371,6 +3393,7 @@ 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__);
@@ -3396,10 +3419,25 @@ 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