Multiple verifier reference identities.

Implemented as STACK_OF(OPENSSL_STRING).

crypto/x509/x509_lcl.h

@@ -60,7 +60,7 @@
 
 struct X509_VERIFY_PARAM_ID_st
 	{
-	unsigned char *host;	/* If not NULL hostname to match */
+	STACK_OF(OPENSSL_STRING) *hosts;	/* Set of acceptable names */
 	unsigned int hostflags;	/* Flags to control matching features */
 	unsigned char *email;	/* If not NULL email address to match */
 	size_t emaillen;

crypto/x509/x509_vfy.c

@@ -743,12 +743,27 @@ static int check_id_error(X509_STORE_CTX *ctx, int errcode)
 	return ctx->verify_cb(0, ctx);
 	}
 
+static int check_hosts(X509 *x, X509_VERIFY_PARAM_ID *id)
+	{
+	int i;
+	int n = sk_OPENSSL_STRING_num(id->hosts);
+	unsigned char *name;
+
+	for (i = 0; i < n; ++i)
+		{
+		name = (unsigned char *)sk_OPENSSL_STRING_value(id->hosts, i);
+		if (X509_check_host(x, name, 0, id->hostflags)) > 0)
+			return 1;
+		}
+	return n == 0;
+	}
+
 static int check_id(X509_STORE_CTX *ctx)
 	{
 	X509_VERIFY_PARAM *vpm = ctx->param;
 	X509_VERIFY_PARAM_ID *id = vpm->id;
 	X509 *x = ctx->cert;
-	if (id->host && X509_check_host(x, id->host, 0, id->hostflags) <= 0)
+	if (id->hosts && !check_hosts(x, id) <= 0)
 		{
 		if (!check_id_error(ctx, X509_V_ERR_HOSTNAME_MISMATCH))
 			return 0;

crypto/x509/x509_vfy.h

@@ -560,6 +560,8 @@ int X509_VERIFY_PARAM_set1_policies(X509_VERIFY_PARAM *param,
 
 int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
 				const unsigned char *name, size_t namelen);
+int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param,
+				const unsigned char *name, size_t namelen);
 void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param,
 					unsigned int flags);
 int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param,

crypto/x509/x509_vpm.c

@@ -69,6 +69,63 @@
 
 /* X509_VERIFY_PARAM functions */
 
+#define SET_HOST 0
+#define ADD_HOST 1
+
+static char *str_copy(const char *s) { return OPENSSL_strdup(s); }
+static void str_free(char *s) { OPENSSL_free(s); }
+
+#define string_stack_free(sk) sk_OPENSSL_STRING_pop_free(sk, str_free)
+
+static int int_x509_param_set_hosts(X509_VERIFY_PARAM_ID *id, int mode,
+				    const unsigned char *name, size_t namelen)
+	{
+	char *copy;
+
+	/*
+	 * Refuse names with embedded NUL bytes, except perhaps as final byte.
+	 * XXX: Do we need to push an error onto the error stack?
+	 */
+	if (namelen == 0)
+		namelen = name ? strlen((char *)name) : 0;
+	else if (name && memchr(name, '\0', namelen > 1 ? namelen-1 : namelen))
+		 return 0;
+	if (name && name[namelen-1] == '\0')
+		--namelen;
+
+	if (mode == SET_HOST && id->hosts)
+		{
+		string_stack_free(id->hosts);
+		id->hosts = NULL;
+		}
+	if (name == NULL || namelen == 0)
+		return 1;
+
+	copy = BUF_strndup((char *)name, namelen);
+	if (copy == NULL)
+		return 0;
+
+	if (id->hosts == NULL &&
+	    (id->hosts = sk_OPENSSL_STRING_new_null()) == NULL)
+		{
+		OPENSSL_free(copy);
+		return 0;
+		}
+
+	if (!sk_OPENSSL_STRING_push(id->hosts, copy))
+		{
+		OPENSSL_free(copy);
+		if (sk_OPENSSL_STRING_num(id->hosts) == 0)
+			{
+			sk_OPENSSL_STRING_free(id->hosts);
+			id->hosts = NULL;
+			}
+		return 0;
+		}
+
+	return 1;
+	}
+
 static void x509_verify_param_zero(X509_VERIFY_PARAM *param)
 	{
 	X509_VERIFY_PARAM_ID *paramid;
@@ -87,10 +144,10 @@ static void x509_verify_param_zero(X509_VERIFY_PARAM *param)
 		param->policies = NULL;
 		}
 	paramid = param->id;
-	if (paramid->host)
+	if (paramid->hosts)
 		{
-		OPENSSL_free(paramid->host);
-		paramid->host = NULL;
+		string_stack_free(paramid->hosts);
+		paramid->hosts = NULL;
 		}
 	if (paramid->email)
 		{
@@ -234,11 +291,23 @@ int X509_VERIFY_PARAM_inherit(X509_VERIFY_PARAM *dest,
 			return 0;
 		}
 
-	if (test_x509_verify_param_copy_id(host, NULL))
+	/* Copy the host flags if and only if we're copying the host list */
+	if (test_x509_verify_param_copy_id(hosts, NULL))
 		{
-		if (!X509_VERIFY_PARAM_set1_host(dest, id->host, 0))
-			return 0;
-		dest->id->hostflags = id->hostflags;
+		if (dest->id->hosts)
+			{
+			string_stack_free(dest->id->hosts);
+			dest->id->hosts = NULL;
+			}
+		if (id->hosts)
+			{
+			dest->id->hosts =
+			    sk_OPENSSL_STRING_deep_copy(id->hosts,
+							str_copy, str_free);
+			if (dest->id->hosts == NULL)
+				return 0;
+			dest->id->hostflags = id->hostflags;
+			}
 		}
 
 	if (test_x509_verify_param_copy_id(email, NULL))
@@ -398,7 +467,13 @@ int X509_VERIFY_PARAM_set1_policies(X509_VERIFY_PARAM *param,
 int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
 				const unsigned char *name, size_t namelen)
 	{
-	return int_x509_param_set1(&param->id->host, NULL, name, namelen);
+	return int_x509_param_set_hosts(param->id, SET_HOST, name, namelen);
+	}
+
+int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param,
+				const unsigned char *name, size_t namelen)
+	{
+	return int_x509_param_set_hosts(param->id, ADD_HOST, name, namelen);
 	}
 
 void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param,

doc/crypto/X509_VERIFY_PARAM_set_flags.pod

@@ -2,7 +2,7 @@
 
 =head1 NAME
 
-X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags, X509_VERIFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose, X509_VERIFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth, X509_VERIFY_PARAM_get_depth, X509_VERIFY_PARAM_set_time, X509_VERIFY_PARAM_add0_policy, X509_VERIFY_PARAM_set1_policies, X509_VERIFY_PARAM_set1_host, X509_VERIFY_PARAM_set_hostflags, X509_VERIFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip, X509_VERIFY_PARAM_set1_ip_asc - X509 verification parameters
+X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags, X509_VERIFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose, X509_VERIFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth, X509_VERIFY_PARAM_get_depth, X509_VERIFY_PARAM_set_time, X509_VERIFY_PARAM_add0_policy, X509_VERIFY_PARAM_set1_policies, X509_VERIFY_PARAM_set1_host, X509_VERIFY_PARAM_add1_host, X509_VERIFY_PARAM_set_hostflags, X509_VERIFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip, X509_VERIFY_PARAM_set1_ip_asc - X509 verification parameters
 
 =head1 SYNOPSIS
 
@@ -28,6 +28,8 @@ X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags, X509_VERIFY_PARAM_ge
 
  int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
 				 const unsigned char *name, size_t namelen);
+ int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param,
+                                 const unsigned char *name, size_t namelen);
  void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param,
 				      unsigned int flags);
  int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param,
@@ -72,16 +74,26 @@ X509_VERIFY_PARAM_set_depth() sets the maximum verification depth to B<depth>.
 That is the maximum number of untrusted CA certificates that can appear in a
 chain.
 
-X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to B<name>.  If
-B<name> is NUL-terminated, B<namelen> may be zero, otherwise B<namelen> must
-be set to the length of B<name>.  When a hostname is specified, certificate
-verification automatically invokes L<X509_check_host(3)> with flags equal to
-the B<flags> argument given to B<X509_VERIFY_PARAM_set_hostflags()> (default
-zero).  Applications are strongly advised to use this interface in preference
-to explicitly calling L<X509_check_host(3)>, hostname checks are
-out of scope with the DANE-EE(3) certificate usage, and the internal
-check will be suppressed as appropriate when DANE support is added
-to OpenSSL.
+X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to
+B<name> clearing any previously specified host name or names.  If
+B<name> is NULL, or empty the list of hostnames is cleared, and
+name checks are not performed on the peer certificate.  If B<name>
+is NUL-terminated, B<namelen> may be zero, otherwise B<namelen>
+must be set to the length of B<name>.  When a hostname is specified,
+certificate verification automatically invokes L<X509_check_host(3)>
+with flags equal to the B<flags> argument given to
+B<X509_VERIFY_PARAM_set_hostflags()> (default zero).  Applications
+are strongly advised to use this interface in preference to explicitly
+calling L<X509_check_host(3)>, hostname checks are out of scope
+with the DANE-EE(3) certificate usage, and the internal check will
+be suppressed as appropriate when DANE support is added to OpenSSL.
+
+X509_VERIFY_PARAM_add1_host() adds B<name> as an additional reference
+identifer that can match the peer's certificate.  Any previous names
+set via X509_VERIFY_PARAM_set1_host() or X509_VERIFY_PARAM_add1_host()
+are retained, no change is made if B<name> is NULL or empty.  When
+multiple names are configured, the peer is considered verified when
+any name matches.
 
 X509_VERIFY_PARAM_set1_email() sets the expected RFC822 email address to
 B<email>.  If B<email> is NUL-terminated, B<emaillen> may be zero, otherwise

doc/crypto/X509_check_host.pod

@@ -109,6 +109,7 @@ X509_check_ip_asc() can also return -2 if the IP address string is malformed.
 
 L<SSL_get_verify_result(3)|SSL_get_verify_result(3)>,
 L<X509_VERIFY_PARAM_set1_host(3)|X509_VERIFY_PARAM_set1_host(3)>,
+L<X509_VERIFY_PARAM_add1_host(3)|X509_VERIFY_PARAM_add1_host(3)>,
 L<X509_VERIFY_PARAM_set1_email(3)|X509_VERIFY_PARAM_set1_email(3)>,
 L<X509_VERIFY_PARAM_set1_ip(3)|X509_VERIFY_PARAM_set1_ip(3)>,
 L<X509_VERIFY_PARAM_set1_ipasc(3)|X509_VERIFY_PARAM_set1_ipasc(3)>