MINOR: ssl: add "ca-verify-file" directive

It's only available for bind line. "ca-verify-file" allows to separate
CA certificates from "ca-file". CA names sent in server hello message is
only compute from "ca-file". Typically, "ca-file" must be defined with
intermediate certificates and "ca-verify-file" with certificates to
ending the chain, like root CA.

Fix issue #404.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index b60a8d4..c09bf00 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -718,8 +718,9 @@
 
 ca-base <dir>
   Assigns a default directory to fetch SSL CA certificates and CRLs from when a
-  relative path is used with "ca-file" or "crl-file" directives. Absolute
-  locations specified in "ca-file" and "crl-file" prevail and ignore "ca-base".
+  relative path is used with "ca-file", "ca-verify-file" or "crl-file"
+  directives. Absolute locations specified in "ca-file", "ca-verify-file" and
+  "crl-file" prevail and ignore "ca-base".
 
 chroot <jail dir>
   Changes current directory to <jail dir> and performs a chroot() there before
@@ -11302,6 +11303,13 @@
   the dynamic generation of certificates is enabled. See
   'generate-certificates' for details.
 
+ca-verify-file <cafile>
+  This setting designates a PEM file from which to load CA certificates used to
+  verify client's certificate. It designates CA certificates which must not be
+  included in CA names sent in server hello message. Typically, "ca-file" must
+  be defined with intermediate certificates, and "ca-verify-file" with
+  certificates to ending the chain, like root CA.
+
 ciphers <ciphers>
   This setting is only available when support for OpenSSL was built in. It sets
   the string describing the list of cipher algorithms ("cipher suite") that are
@@ -11450,10 +11458,10 @@
 
         <crtfile> [\[<sslbindconf> ...\]] [[!]<snifilter> ...]
 
-  sslbindconf support "npn", "alpn", "verify", "ca-file", "no-ca-names",
-  crl-file", "ecdhe", "curves", "ciphers" configuration. With BoringSSL
-  and Openssl >= 1.1.1 "ssl-min-ver" and "ssl-max-ver" are also supported.
-  It override the configuration set in bind line for the certificate.
+  sslbindconf support "npn", "alpn", "verify", "ca-file", "ca-verify-file",
+  "no-ca-names", "crl-file", "ecdhe", "curves", "ciphers" configuration. With
+  BoringSSL and Openssl >= 1.1.1 "ssl-min-ver" and "ssl-max-ver" are also
+  supported. It override the configuration set in bind line for the certificate.
 
   Wildcards are supported in the SNI filter. Negative filter are also supported,
   only useful in combination with a wildcard filter to exclude a particular SNI.
@@ -11653,6 +11661,7 @@
 no-ca-names
   This setting is only available when support for OpenSSL was built in. It
   prevents from send CA names in server hello message when ca-file is used.
+  Use "ca-verify-file" instead of "ca-file" with "no-ca-names".
 
 no-sslv3
   This setting is only available when support for OpenSSL was built in. It
diff --git a/include/types/listener.h b/include/types/listener.h
index bcc57ae..eca03a4 100644
--- a/include/types/listener.h
+++ b/include/types/listener.h
@@ -127,7 +127,8 @@
 	unsigned int verify:3;     /* verify method (set of SSL_VERIFY_* flags) */
 	unsigned int no_ca_names:1;/* do not send ca names to clients (ca_file related) */
 	unsigned int early_data:1; /* early data allowed */
-	char *ca_file;             /* CAfile to use on verify */
+	char *ca_file;             /* CAfile to use on verify and ca-names */
+	char *ca_verify_file;      /* CAverify file to use on verify only */
 	char *crl_file;            /* CRLfile to use on verify */
 	char *ciphers;             /* cipher suite to use if non-null */
 #if (HA_OPENSSL_VERSION_NUMBER >= 0x10101000L && !defined OPENSSL_IS_BORINGSSL && !defined LIBRESSL_VERSION_NUMBER)
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 577f785..efb6b0e 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -4513,6 +4513,8 @@
 #endif
 		free(conf->ca_file);
 		conf->ca_file = NULL;
+		free(conf->ca_verify_file);
+		conf->ca_verify_file = NULL;
 		free(conf->crl_file);
 		conf->crl_file = NULL;
 		free(conf->ciphers);
@@ -5132,15 +5134,21 @@
 	SSL_CTX_set_verify(ctx, verify, ssl_sock_bind_verifycbk);
 	if (verify & SSL_VERIFY_PEER) {
 		char *ca_file = (ssl_conf && ssl_conf->ca_file) ? ssl_conf->ca_file : bind_conf->ssl_conf.ca_file;
+		char *ca_verify_file = (ssl_conf && ssl_conf->ca_verify_file) ? ssl_conf->ca_verify_file : bind_conf->ssl_conf.ca_verify_file;
 		char *crl_file = (ssl_conf && ssl_conf->crl_file) ? ssl_conf->crl_file : bind_conf->ssl_conf.crl_file;
-		if (ca_file) {
+		if (ca_file || ca_verify_file) {
 			/* set CAfile to verify */
-			if (!ssl_set_verify_locations_file(ctx, ca_file)) {
+			if (ca_file && !ssl_set_verify_locations_file(ctx, ca_file)) {
 				memprintf(err, "%sProxy '%s': unable to set CA file '%s' for bind '%s' at [%s:%d].\n",
 				          err && *err ? *err : "", curproxy->id, ca_file, bind_conf->arg, bind_conf->file, bind_conf->line);
 				cfgerr |= ERR_ALERT | ERR_FATAL;
 			}
-			if (!((ssl_conf && ssl_conf->no_ca_names) || bind_conf->ssl_conf.no_ca_names)) {
+			if (ca_verify_file && !ssl_set_verify_locations_file(ctx, ca_verify_file)) {
+				memprintf(err, "%sProxy '%s': unable to set CA-no-names file '%s' for bind '%s' at [%s:%d].\n",
+				          err && *err ? *err : "", curproxy->id, ca_verify_file, bind_conf->arg, bind_conf->file, bind_conf->line);
+				cfgerr |= ERR_ALERT | ERR_FATAL;
+			}
+			if (ca_file && !((ssl_conf && ssl_conf->no_ca_names) || bind_conf->ssl_conf.no_ca_names)) {
 				/* set CA names for client cert request, function returns void */
 				SSL_CTX_set_client_CA_list(ctx, SSL_dup_CA_list(ssl_get_client_ca_file(ca_file)));
 			}
@@ -8630,8 +8638,8 @@
 	return 1;
 }
 
-/* parse the "ca-file" bind keyword */
-static int ssl_bind_parse_ca_file(char **args, int cur_arg, struct proxy *px, struct ssl_bind_conf *conf, char **err)
+/* for ca-file and ca-verify-file */
+static int ssl_bind_parse_ca_file_common(char **args, int cur_arg, char **ca_file_p, char **err)
 {
 	if (!*args[cur_arg + 1]) {
 		memprintf(err, "'%s' : missing CAfile path", args[cur_arg]);
@@ -8639,21 +8647,37 @@
 	}
 
 	if ((*args[cur_arg + 1] != '/') && global_ssl.ca_base)
-		memprintf(&conf->ca_file, "%s/%s", global_ssl.ca_base, args[cur_arg + 1]);
+		memprintf(ca_file_p, "%s/%s", global_ssl.ca_base, args[cur_arg + 1]);
 	else
-		memprintf(&conf->ca_file, "%s", args[cur_arg + 1]);
+		memprintf(ca_file_p, "%s", args[cur_arg + 1]);
 
-	if (!ssl_store_load_locations_file(conf->ca_file)) {
-		memprintf(err, "'%s' : unable to load %s", args[cur_arg], conf->ca_file);
+	if (!ssl_store_load_locations_file(*ca_file_p)) {
+		memprintf(err, "'%s' : unable to load %s", args[cur_arg], *ca_file_p);
 		return ERR_ALERT | ERR_FATAL;
 	}
 	return 0;
 }
+
+/* parse the "ca-file" bind keyword */
+static int ssl_bind_parse_ca_file(char **args, int cur_arg, struct proxy *px, struct ssl_bind_conf *conf, char **err)
+{
+	return ssl_bind_parse_ca_file_common(args, cur_arg, &conf->ca_file, err);
+}
 static int bind_parse_ca_file(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
 {
 	return ssl_bind_parse_ca_file(args, cur_arg, px, &conf->ssl_conf, err);
 }
 
+/* parse the "ca-verify-file" bind keyword */
+static int ssl_bind_parse_ca_verify_file(char **args, int cur_arg, struct proxy *px, struct ssl_bind_conf *conf, char **err)
+{
+	return ssl_bind_parse_ca_file_common(args, cur_arg, &conf->ca_verify_file, err);
+}
+static int bind_parse_ca_verify_file(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
+{
+	return ssl_bind_parse_ca_verify_file(args, cur_arg, px, &conf->ssl_conf, err);
+}
+
 /* parse the "ca-sign-file" bind keyword */
 static int bind_parse_ca_sign_file(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
 {
@@ -11674,7 +11698,8 @@
 static struct ssl_bind_kw ssl_bind_kws[] = {
 	{ "allow-0rtt",            ssl_bind_parse_allow_0rtt,       0 }, /* allow 0-RTT */
 	{ "alpn",                  ssl_bind_parse_alpn,             1 }, /* set ALPN supported protocols */
-	{ "ca-file",               ssl_bind_parse_ca_file,          1 }, /* set CAfile to process verify on client cert */
+	{ "ca-file",               ssl_bind_parse_ca_file,          1 }, /* set CAfile to process ca-names and verify on client cert */
+	{ "ca-verify-file",        ssl_bind_parse_ca_verify_file,   1 }, /* set CAverify file to process verify on client cert */
 	{ "ciphers",               ssl_bind_parse_ciphers,          1 }, /* set SSL cipher suite */
 #if (HA_OPENSSL_VERSION_NUMBER >= 0x10101000L)
 	{ "ciphersuites",          ssl_bind_parse_ciphersuites,     1 }, /* set TLS 1.3 cipher suite */
@@ -11695,7 +11720,8 @@
 static struct bind_kw_list bind_kws = { "SSL", { }, {
 	{ "allow-0rtt",            bind_parse_allow_0rtt,         0 }, /* Allow 0RTT */
 	{ "alpn",                  bind_parse_alpn,               1 }, /* set ALPN supported protocols */
-	{ "ca-file",               bind_parse_ca_file,            1 }, /* set CAfile to process verify on client cert */
+	{ "ca-file",               bind_parse_ca_file,            1 }, /* set CAfile to process ca-names and verify on client cert */
+	{ "ca-verify-file",        bind_parse_ca_verify_file,     1 }, /* set CAverify file to process verify on client cert */
 	{ "ca-ignore-err",         bind_parse_ignore_err,         1 }, /* set error IDs to ignore on verify depth > 0 */
 	{ "ca-sign-file",          bind_parse_ca_sign_file,       1 }, /* set CAFile used to generate and sign server certs */
 	{ "ca-sign-pass",          bind_parse_ca_sign_pass,       1 }, /* set CAKey passphrase */