Make "system" location for certificate CA bundle the default

5 files changed, 15 insertions, 9 deletions

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 89fb5841e..843379b6d 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -16494,7 +16494,7 @@ preference order of the available ciphers. Details are given in sections
 See &%tls_verify_hosts%& below.
 
 
-.option tls_verify_certificates main string&!! unset
+.option tls_verify_certificates main string&!! system
 .cindex "TLS" "client certificate verification"
 .cindex "certificate" "verification of client"
 The value of this option is expanded, and must then be either the
@@ -16505,7 +16505,8 @@ match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&.
 
 The "system" value for the option will use a
 system default location compiled into the SSL library.
-This is not available for GnuTLS versions preceding 3.0.20 and an explicit location
+This is not available for GnuTLS versions preceding 3.0.20,
+and will be taken as empty; an explicit location
 must be specified.
 
 The use of a directory for the option value is not avilable for GnuTLS versions
@@ -23471,7 +23472,7 @@ limited to being the initial component of a 3-or-more component FQDN.
 There is no equivalent checking on client certificates.
 
 
-.option tls_verify_certificates smtp string&!! unset
+.option tls_verify_certificates smtp string&!! system
 .cindex "TLS" "server certificate verification"
 .cindex "certificate" "verification of server"
 .vindex "&$host$&"
@@ -23483,7 +23484,8 @@ a file or directory containing permitted certificates for servers,
 for use when setting up an encrypted connection.
 
 The "system" value for the option will use a location compiled into the SSL library.
-This is not available for GnuTLS versions preceding 3.0.20 and an explicit location
+This is not available for GnuTLS versions preceding 3.0.20; a value of "system"
+is taken as empty and an explicit location
 must be specified.
 
 The use of a directory for the option value is not avilable for GnuTLS versions
@@ -26492,7 +26494,7 @@ if it requests it. If the server is Exim, it will request a certificate only if
 &%tls_verify_hosts%& or &%tls_try_verify_hosts%& matches the client.
 
 If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it
-specified a collection of expected server certificates.
+specifies a collection of expected server certificates.
 These may be the system default set (depeding on library version),
 a file or,
 depnding on liibrary version, a directory,
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 0e9b7ddca..f0acc09d0 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -18,7 +18,7 @@ JH/04 Certificate name checking on server certificates, when exim is a client,
       EXPERIMENTAL_CERTNAMES is withdrawn.
 
 JH/05 The value of the tls_verify_certificates smtp transport and main options
-      can now be the word "system" to access the system default CA bundle.
+      default to the word "system" to access the system default CA bundle.
       For GnuTLS, only version 3.0.20 or later.
 
 
diff --git a/src/src/globals.c b/src/src/globals.c
index a7beec602..1b09008a1 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -166,7 +166,7 @@ uschar *tls_privatekey         = NULL;
 BOOL    tls_remember_esmtp     = FALSE;
 uschar *tls_require_ciphers    = NULL;
 uschar *tls_try_verify_hosts   = NULL;
-uschar *tls_verify_certificates= NULL;
+uschar *tls_verify_certificates= US"system";
 uschar *tls_verify_hosts       = NULL;
 #endif
 
diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index 4943f48b7..42d04224a 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -853,7 +853,11 @@ error message is provided. However, if we just refrain from setting anything up
 in that case, certificate verification fails, which seems to be the correct
 behaviour. */
 
-if (state->tls_verify_certificates && *state->tls_verify_certificates)
+if (  state->tls_verify_certificates && *state->tls_verify_certificates
+#ifndef SUPPORT_SYSDEFAULT_CABUNDLE
+   && Ustrcmp(state->exp_tls_verify_certificates, "system") != 0
+#endif
+   )
   {
   if (!expand_check_tlsvar(tls_verify_certificates))
     return DEFER;
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index fe0e733f8..7bc0fa086 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -255,7 +255,7 @@ smtp_transport_options_block smtp_transport_option_defaults = {
   NULL,                /* gnutls_require_mac */
   NULL,                /* gnutls_require_proto */
   NULL,                /* tls_sni */
-  NULL,                /* tls_verify_certificates */
+  US"system",          /* tls_verify_certificates */
   EXIM_CLIENT_DH_DEFAULT_MIN_BITS,
                        /* tls_dh_min_bits */
   TRUE,                /* tls_tempfail_tryclear */