GnuTLS pretty much passes test suite.exim-4_80_RC1

Fixed assumption that tls_certificate non-NULL in server when TLS
advertised.
Weakened an !S_ISREG() to an S_ISDIR() to keep the test-suite happy.

Using:
  do { rc = gnutls_handshake(state->session);
  } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED));
is contra-indicated when you expect SIGALRM to be able to break you out
of the loop.  A little _too_ robust there.  Switching last part to:
  (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)
is rather more productive.

Only test not passing is 2025, which makes major assumptions about
cipher suites and needs to be revisited to see what it's trying to
achieve.  We fail the test because we successfully deliver the message
without expected errors, because other ciphersuites are available, since
we're no longer limited to a *very* short list embedded in the Exim
code.  That sort of failure I can live with.

1 files changed, 14 insertions, 10 deletions

diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index a9a82e88f..05a3e084c 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -578,7 +578,7 @@ if (!state->host)
   {
   if (!state->received_sni)
     {
-    if (Ustrstr(state->tls_certificate, US"tls_sni"))
+    if (state->tls_certificate && Ustrstr(state->tls_certificate, US"tls_sni"))
       {
       DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n");
       state->trigger_sni_changes = TRUE;
@@ -695,16 +695,18 @@ if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0)
   return DEFER;
   }
 
-if (!S_ISREG(statbuf.st_mode))
+/* The test suite passes in /dev/null; we could check for that path explicitly,
+but who knows if someone has some weird FIFO which always dumps some certs, or
+other weirdness.  The thing we really want to check is that it's not a
+directory, since while OpenSSL supports that, GnuTLS does not.
+So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */
+if (S_ISDIR(statbuf.st_mode))
   {
   DEBUG(D_tls)
-    debug_printf("verify certificates path is not a file: \"%s\"\n%s\n",
-        state->exp_tls_verify_certificates,
-        S_ISDIR(statbuf.st_mode)
-          ? " it's a directory, that's OpenSSL, this is GnuTLS"
-          : " (not a directory either)");
+    debug_printf("verify certificates path is a dir: \"%s\"\n",
+        state->exp_tls_verify_certificates);
   log_write(0, LOG_MAIN|LOG_PANIC,
-      "tls_verify_certificates \"%s\" is not a file",
+      "tls_verify_certificates \"%s\" is a directory",
       state->exp_tls_verify_certificates);
   return DEFER;
   }
@@ -1365,7 +1367,8 @@ if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
 do
   {
   rc = gnutls_handshake(state->session);
-  } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED));
+  } while ((rc == GNUTLS_E_AGAIN) ||
+      (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen));
 alarm(0);
 
 if (rc != GNUTLS_E_SUCCESS)
@@ -1500,7 +1503,8 @@ alarm(timeout);
 do
   {
   rc = gnutls_handshake(state->session);
-  } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED));
+  } while ((rc == GNUTLS_E_AGAIN) ||
+      (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen));
 alarm(0);
 
 if (rc != GNUTLS_E_SUCCESS)