OpenSSL: tls_eccurves list support. Bug 2955

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 9243bd3f9babfbbd37bb8e6805f584d491bdb16d..7c8dee36f148242ca8c34e3fd55d791b9675a71f 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -18454,20 +18454,25 @@ prior to the 4.80 release, as Debian used to patch Exim to raise the minimum
 acceptable bound from 1024 to 2048.
 
 
-.option tls_eccurve main string&!! &`auto`&
+.option tls_eccurve main string list&!! &`auto`&
 .cindex TLS "EC cryptography"
-This option selects a EC curve for use by Exim when used with OpenSSL.
+This option selects EC curves for use by Exim when used with OpenSSL.
 It has no effect when Exim is used with GnuTLS.
 
-After expansion it must contain a valid EC curve parameter, such as
-&`prime256v1`&, &`secp384r1`&, or &`P-512`&. Consult your OpenSSL manual
-for valid selections.
+After expansion it must contain
+.new
+one or (only for OpenSSL versiona 1.1.1 onwards) more
+.wen
+EC curve names, such as &`prime256v1`&, &`secp384r1`&, or &`P-521`&.
+Consult your OpenSSL manual for valid curve names.
 
 For OpenSSL versions before (and not including) 1.0.2, the string
 &`auto`& selects &`prime256v1`&. For more recent OpenSSL versions
 &`auto`& tells the library to choose.
 
-If the option expands to an empty string, no EC curves will be enabled.
+.new
+If the option expands to an empty string, the effect is undefined.
+.wen
 
 
 .option tls_ocsp_file main string&!! unset

diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index b00399511557da1a415a13d3175762032c82b39f..c1e139e351c869000c09cb827354e8d31747c484 100644 (file)
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -19,6 +19,8 @@ Version 4.97
 
  5. The smtp transport option "max_rcpt" is now expanded before use.
 
+ 6. The tls_eccurve option for OpenSSL now takes a list of group names
+
 Version 4.96
 ------------
 

diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index 513ba0d3a5c5b54f01c5fded80cc5b5bdbf2d12a..96be7c4a20ba9dba77255dd866c7696042e23afd 100644 (file)
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -122,6 +122,7 @@ change this guard and punt the issue for a while longer. */
 #  define EXIM_HAVE_OPENSSL_CIPHER_STD_NAME
 #  define EXIM_HAVE_EXP_CHNL_BNGNG
 #  define EXIM_HAVE_OPENSSL_OCSP_RESP_GET0_SIGNER
+#  define EXIM_HAVE_OPENSSL_SET1_GROUPS
 # else
 #  define OPENSSL_BAD_SRVR_OURCERT
 # endif
@@ -700,6 +701,41 @@ return TRUE;
 *               Initialize for ECDH              *
 *************************************************/
 
+/* "auto" needs to be handled carefully.
+OpenSSL <  1.0.2: we do not select anything, but fallback to prime256v1
+OpenSSL <  1.1.0: we have to call SSL_CTX_set_ecdh_auto
+                  (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
+OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
+                  https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
+
+*/
+
+static uschar *
+init_ecdh_auto(SSL_CTX * ctx)
+{
+#if OPENSSL_VERSION_NUMBER < 0x10002000L
+DEBUG(D_tls) debug_printf(
+  " ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
+return US"prime256v1";
+
+#else
+# if defined SSL_CTRL_SET_ECDH_AUTO
+
+DEBUG(D_tls) debug_printf(
+  " ECDH OpenSSL 1.0.2+: temp key parameter settings: autoselection\n");
+SSL_CTX_set_ecdh_auto(sctx, 1);
+return NULL;
+
+# else
+
+DEBUG(D_tls) debug_printf(
+  " ECDH OpenSSL 1.1.0+: temp key parameter settings: library default selection\n");
+return NULL;
+
+# endif
+#endif
+}
+
 /* Load parameters for ECDH encryption.  Server only.
 
 For now, we stick to NIST P-256 because: it's simple and easy to configure;
@@ -730,72 +766,76 @@ init_ecdh(SSL_CTX * sctx, uschar ** errstr)
 return TRUE;
 #else
 
-uschar * exp_curve;
-int nid, rc;
-
 # ifndef EXIM_HAVE_ECDH
 DEBUG(D_tls)
   debug_printf(" No OpenSSL API to define ECDH parameters, skipping\n");
 return TRUE;
 # else
 
+uschar * exp_curve;
+int ngroups, rc, sep;
+const uschar * curves_list,  * curve;
+#  ifdef EXIM_HAVE_OPENSSL_SET1_GROUPS
+int nids[16];
+#  else
+int nids[1];
+#  endif
+
 if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr))
   return FALSE;
 
 /* Is the option deliberately empty? */
 
 if (!exp_curve || !*exp_curve)
-  {
-#if OPENSSL_VERSION_NUMBER >= 0x10002000L
-  DEBUG(D_tls) debug_printf( " ECDH OpenSSL 1.0.2+: clearing curves list\n");
-  (void) SSL_CTX_set1_curves(sctx, &nid, 0);
-#endif
   return TRUE;
-  }
 
-/* "auto" needs to be handled carefully.
- * OpenSSL <  1.0.2: we do not select anything, but fallback to prime256v1
- * OpenSSL <  1.1.0: we have to call SSL_CTX_set_ecdh_auto
- *                   (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
- * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
- *                   https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
- */
-if (Ustrcmp(exp_curve, "auto") == 0)
-  {
-#if OPENSSL_VERSION_NUMBER < 0x10002000L
-  DEBUG(D_tls) debug_printf(
-    " ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
-  exp_curve = US"prime256v1";
-#else
-# if defined SSL_CTRL_SET_ECDH_AUTO
-  DEBUG(D_tls) debug_printf(
-    " ECDH OpenSSL 1.0.2+: temp key parameter settings: autoselection\n");
-  SSL_CTX_set_ecdh_auto(sctx, 1);
-  return TRUE;
-# else
-  DEBUG(D_tls) debug_printf(
-    " ECDH OpenSSL 1.1.0+: temp key parameter settings: library default selection\n");
-  return TRUE;
-# endif
-#endif
-  }
+/* Limit the list to hardwired array size. Drop out if any element is "suto". */
 
-if (  (nid = OBJ_sn2nid       (CCS exp_curve)) == NID_undef
-#   ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
-   && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef
-#   endif
-   )
-  {
-  uschar * s = string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve);
-  DEBUG(D_tls) debug_printf("TLS error '%s'\n", s);
-  if (errstr) *errstr = s;
-  return FALSE;
-  }
+curves_list = exp_curve;
+sep = 0;
+for (ngroups = 0;
+       ngroups < nelem(nids)
+    && (curve = string_nextinlist(&curves_list, &sep, NULL, 0));
+    )
+  if (Ustrcmp(curve, "auto") == 0)
+    {
+    DEBUG(D_tls) if (ngroups > 0)
+      debug_printf(" tls_eccurve 'auto' item takes precedence\n");
+    if ((exp_curve = init_ecdh_auto(sctx))) break; /* have a curve name to set */
+    return TRUE;                                  /* all done */
+    }
+  else
+    ngroups++;
 
-# if OPENSSL_VERSION_NUMBER < 0x30000000L
+/* Translate to NIDs */
+
+curves_list = exp_curve;
+for (ngroups = 0; curve = string_nextinlist(&curves_list, &sep, NULL, 0);
+     ngroups++)
+  if (  (nids[ngroups] = OBJ_sn2nid       (CCS curve)) == NID_undef
+#  ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
+     && (nids[ngroups] = EC_curve_nist2nid(CCS curve)) == NID_undef
+#  endif
+     )
+    {
+    uschar * s = string_sprintf("Unknown curve name in tls_eccurve '%s'", curve);
+    DEBUG(D_tls) debug_printf("TLS error: %s\n", s);
+    if (errstr) *errstr = s;
+    return FALSE;
+    }
+
+#  ifdef EXIM_HAVE_OPENSSL_SET1_GROUPS
+/* Set the groups */
+
+if ((rc = SSL_CTX_set1_groups(sctx, nids, ngroups)) == 0)
+  tls_error(string_sprintf("Error enabling '%s' group(s)", exp_curve), NULL, NULL, errstr);
+else
+  DEBUG(D_tls) debug_printf(" ECDH: enabled '%s' group(s)\n", exp_curve);
+
+#  else                /* Cannot handle a list; only 1 element nids array */
  {
   EC_KEY * ecdh;
-  if (!(ecdh = EC_KEY_new_by_curve_name(nid)))
+  if (!(ecdh = EC_KEY_new_by_curve_name(nids[0])))
     {
     tls_error(US"Unable to create ec curve", NULL, NULL, errstr);
     return FALSE;
@@ -810,15 +850,7 @@ if (  (nid = OBJ_sn2nid       (CCS exp_curve)) == NID_undef
     DEBUG(D_tls) debug_printf(" ECDH: enabled '%s' curve\n", exp_curve);
   EC_KEY_free(ecdh);
  }
-
-#else  /* v 3.0.0 + */
-
-if ((rc = SSL_CTX_set1_groups(sctx, &nid, 1)) == 0)
-  tls_error(string_sprintf("Error enabling '%s' group", exp_curve), NULL, NULL, errstr);
-else
-  DEBUG(D_tls) debug_printf(" ECDH: enabled '%s' group\n", exp_curve);
-
-#endif
+#  endif       /*!EXIM_HAVE_OPENSSL_SET1_GROUPS*/
 
 return !!rc;
 

diff --git a/src/src/tls.c b/src/src/tls.c
index 4a23aaae934d74922d3c49e4a63c27ca86e78c32..f7be5293ded2175f7214515cc4521671db312976 100644 (file)
--- a/src/src/tls.c
+++ b/src/src/tls.c
@@ -106,7 +106,8 @@ Returns:    TRUE if OK; result may still be NULL after forced failure
 */
 
 static BOOL
-expand_check(const uschar *s, const uschar *name, uschar **result, uschar ** errstr)
+expand_check(const uschar * s, const uschar * name,
+  uschar ** result, uschar ** errstr)
 {
 if (!s)
   *result = NULL;

diff --git a/test/confs/2149 b/test/confs/2149
index 3369288bb2e7b7c2c40ae5e41042e5bea68945de..1782391decc4c77be63e9fbae64c00e46cee7b90 100644 (file)
--- a/test/confs/2149
+++ b/test/confs/2149
@@ -30,22 +30,13 @@ client:
   errors_to =  ""
 
 server:
-  driver =     accept
-  retry_use_local_part
-  transport =  local_delivery
-
+  driver =     redirect
+  data =       :blackhole:
 
 # ----- Transports -----
 
 begin transports
 
-local_delivery:
-  driver =     appendfile
-  file =       DIR/test-mail/$local_part
-  create_file =        DIR/test-mail
-  headers_add =        TLS: cipher=$tls_cipher peerdn=$tls_peerdn
-  user =       CALLER
-
 send_to_server:
   driver =     smtp
   allow_localhost

diff --git a/test/log/2149 b/test/log/2149
index 3832ba076d978fd1740744b4a62fbd8b7d3ad15f..91b48eee4bee763bb11c7ee0599d71b5a142841e 100644 (file)
--- a/test/log/2149
+++ b/test/log/2149
@@ -5,41 +5,48 @@
 1999-03-02 09:44:33 10HmaZ-0005vi-00 => explicitauto@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbA-0005vi-00"
 1999-03-02 09:44:33 10HmaZ-0005vi-00 Completed
 1999-03-02 09:44:33 10HmbB-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmbB-0005vi-00 => explicitempty@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbC-0005vi-00"
+1999-03-02 09:44:33 10HmbB-0005vi-00 => prime256v1@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbC-0005vi-00"
 1999-03-02 09:44:33 10HmbB-0005vi-00 Completed
 1999-03-02 09:44:33 10HmbD-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmbD-0005vi-00 => prime256v1@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbE-0005vi-00"
+1999-03-02 09:44:33 10HmbD-0005vi-00 => secp384r1@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbE-0005vi-00"
 1999-03-02 09:44:33 10HmbD-0005vi-00 Completed
 1999-03-02 09:44:33 10HmbF-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmbF-0005vi-00 => secp384r1@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbG-0005vi-00"
+1999-03-02 09:44:33 10HmbF-0005vi-00 H=127.0.0.1 [127.0.0.1]: a TLS session is required, but an attempt to start TLS failed
+1999-03-02 09:44:33 10HmbF-0005vi-00 == user_fail@test.ex R=client T=send_to_server defer (-38) H=127.0.0.1 [127.0.0.1]: a TLS session is required, but an attempt to start TLS failed
+1999-03-02 09:44:33 10HmbF-0005vi-00 ** user_fail@test.ex: retry timeout exceeded
+1999-03-02 09:44:33 10HmbF-0005vi-00 user_fail@test.ex: error ignored
 1999-03-02 09:44:33 10HmbF-0005vi-00 Completed
-1999-03-02 09:44:33 10HmbH-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmbH-0005vi-00 H=127.0.0.1 [127.0.0.1]: a TLS session is required, but an attempt to start TLS failed
-1999-03-02 09:44:33 10HmbH-0005vi-00 == user_fail@test.ex R=client T=send_to_server defer (-38) H=127.0.0.1 [127.0.0.1]: a TLS session is required, but an attempt to start TLS failed
-1999-03-02 09:44:33 10HmbH-0005vi-00 ** user_fail@test.ex: retry timeout exceeded
-1999-03-02 09:44:33 10HmbH-0005vi-00 user_fail@test.ex: error ignored
-1999-03-02 09:44:33 10HmbH-0005vi-00 Completed
+1999-03-02 09:44:33 10HmbG-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmbG-0005vi-00 => user_list2@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbH-0005vi-00"
+1999-03-02 09:44:33 10HmbG-0005vi-00 Completed
+1999-03-02 09:44:33 10HmbI-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmbI-0005vi-00 => user_list_auto@test.ex R=client T=send_to_server H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbJ-0005vi-00"
+1999-03-02 09:44:33 10HmbI-0005vi-00 Completed
 
 ******** SERVER ********
 1999-03-02 09:44:33 exim x.yz daemon started: pid=p1234, no queue runs, listening for SMTP on port PORT_D
 1999-03-02 09:44:33 10HmaY-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmaX-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmaY-0005vi-00 => optnotpresent <optnotpresent@test.ex> R=server T=local_delivery
+1999-03-02 09:44:33 10HmaY-0005vi-00 => :blackhole: <optnotpresent@test.ex> R=server
 1999-03-02 09:44:33 10HmaY-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=p1235, no queue runs, listening for SMTP on port PORT_D
 1999-03-02 09:44:33 10HmbA-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmaZ-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmbA-0005vi-00 => explicitauto <explicitauto@test.ex> R=server T=local_delivery
+1999-03-02 09:44:33 10HmbA-0005vi-00 => :blackhole: <explicitauto@test.ex> R=server
 1999-03-02 09:44:33 10HmbA-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=p1236, no queue runs, listening for SMTP on port PORT_D
 1999-03-02 09:44:33 10HmbC-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmbB-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmbC-0005vi-00 => explicitempty <explicitempty@test.ex> R=server T=local_delivery
+1999-03-02 09:44:33 10HmbC-0005vi-00 => :blackhole: <prime256v1@test.ex> R=server
 1999-03-02 09:44:33 10HmbC-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=p1237, no queue runs, listening for SMTP on port PORT_D
 1999-03-02 09:44:33 10HmbE-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmbD-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmbE-0005vi-00 => prime256v1 <prime256v1@test.ex> R=server T=local_delivery
+1999-03-02 09:44:33 10HmbE-0005vi-00 => :blackhole: <secp384r1@test.ex> R=server
 1999-03-02 09:44:33 10HmbE-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=p1238, no queue runs, listening for SMTP on port PORT_D
-1999-03-02 09:44:33 10HmbG-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmbF-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmbG-0005vi-00 => secp384r1 <secp384r1@test.ex> R=server T=local_delivery
-1999-03-02 09:44:33 10HmbG-0005vi-00 Completed
+1999-03-02 09:44:33 TLS error on connection from localhost (myhost.test.ex) [127.0.0.1] Unknown curve name in tls_eccurve 'bogus'
 1999-03-02 09:44:33 exim x.yz daemon started: pid=p1239, no queue runs, listening for SMTP on port PORT_D
-1999-03-02 09:44:33 TLS error on connection from localhost (myhost.test.ex) [127.0.0.1] Unknown curve name tls_eccurve 'bogus'
+1999-03-02 09:44:33 10HmbH-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmbG-0005vi-00@myhost.test.ex
+1999-03-02 09:44:33 10HmbH-0005vi-00 => :blackhole: <user_list2@test.ex> R=server
+1999-03-02 09:44:33 10HmbH-0005vi-00 Completed
+1999-03-02 09:44:33 exim x.yz daemon started: pid=p1240, no queue runs, listening for SMTP on port PORT_D
+1999-03-02 09:44:33 10HmbJ-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=no S=sss id=E10HmbI-0005vi-00@myhost.test.ex
+1999-03-02 09:44:33 10HmbJ-0005vi-00 => :blackhole: <user_list_auto@test.ex> R=server
+1999-03-02 09:44:33 10HmbJ-0005vi-00 Completed

diff --git a/test/scripts/2100-OpenSSL/2149 b/test/scripts/2100-OpenSSL/2149
index f1af49907e1ec529f93cd0cc5f93ac41b025bfac..18b43bd5ef36c0c1e484a3542276ea1a70eebe54 100644 (file)
--- a/test/scripts/2100-OpenSSL/2149
+++ b/test/scripts/2100-OpenSSL/2149
@@ -17,16 +17,8 @@ exim -odf explicitauto@test.ex
 ****
 killdaemon
 #
-# Explicit tls_eccurve setting of ""
-# - unclear this works.  At least with OpenSSL 3.0.5 we still get an x25519 keyshare in the Server Hello
-exim -DSERVER=server -DDATA= -bd -oX PORT_D
-****
-exim -odf explicitempty@test.ex
-****
-killdaemon
-#
 # prime256v1
-# Oddly,  3.0.5 packets show an EC-groups negotiation of C:x255519 S:secp256r1 C:secp384r1 S:secp384r1.
+# Oddly,  3.0.5 packets show an EC-groups negotiation of C:x255519 S:secp256r1 C:secp256r1 S:secp256r1.
 # Hoever, note that RFC 8446 (TLS1.3) does NOT include prime256v1 as one of the allowable
 # supported groups (and it's not in the client "supported groups" extension, so what we see seems good.
 exim -DSERVER=server -DDATA=prime256v1 -bd -oX PORT_D
@@ -50,5 +42,20 @@ exim -odf user_fail@test.ex
 ****
 killdaemon
 #
+# Two-element list - will fail for pre- 1.1.1 OpenSSL
+# - the Hello Retry Req goes out with the earliest one from the list which matches the client's Supported Groups
+exim -DSERVER=server -DDATA=P-521:secp384r1 -bd -oX PORT_D
+****
+exim -odf user_list2@test.ex
+****
+killdaemon
+#
+#
+# List with an "auto" element embedded, which should override.
+exim -DSERVER=server '-DDATA= P-521 : P-384 : auto : P-256' -bd -oX PORT_D
+****
+exim -odf user_list_auto@test.ex
+****
+killdaemon
 #
 no_message_check