[crypto] Parse OCSP responder URI from X.509 certificate

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/crypto/x509.c

@@ -487,7 +487,7 @@ static int x509_parse_validity ( struct x509_certificate *cert,
  * @ret rc		Return status code
  */
 static int x509_parse_common_name ( struct x509_certificate *cert,
-				    struct x509_name *name,
+				    struct x509_string *name,
 				    const struct asn1_cursor *raw ) {
 	struct asn1_cursor cursor;
 	struct asn1_cursor oid_cursor;
@@ -533,7 +533,7 @@ static int x509_parse_common_name ( struct x509_certificate *cert,
 static int x509_parse_subject ( struct x509_certificate *cert,
 				const struct asn1_cursor *raw ) {
 	struct x509_subject *subject = &cert->subject;
-	struct x509_name *name = &subject->name;
+	struct x509_string *name = &subject->name;
 	int rc;
 
 	/* Record raw subject */
@@ -750,7 +750,7 @@ static int x509_parse_extended_key_usage ( struct x509_certificate *cert,
 	memcpy ( &cursor, raw, sizeof ( cursor ) );
 	asn1_enter ( &cursor, ASN1_SEQUENCE );
 
-	/* Parse each extension in turn */
+	/* Parse each extended key usage in turn */
 	while ( cursor.len ) {
 		if ( ( rc = x509_parse_key_purpose ( cert, &cursor ) ) != 0 )
 			return rc;
@@ -760,14 +760,145 @@ static int x509_parse_extended_key_usage ( struct x509_certificate *cert,
 	return 0;
 }
 
+/**
+ * Parse X.509 certificate OCSP access method
+ *
+ * @v cert		X.509 certificate
+ * @v raw		ASN.1 cursor
+ * @ret rc		Return status code
+ */
+static int x509_parse_ocsp ( struct x509_certificate *cert,
+			     const struct asn1_cursor *raw ) {
+	struct x509_ocsp_responder *ocsp = &cert->extensions.auth_info.ocsp;
+	struct asn1_cursor cursor;
+	int rc;
+
+	/* Enter accessLocation */
+	memcpy ( &cursor, raw, sizeof ( cursor ) );
+	if ( ( rc = asn1_enter ( &cursor, ASN1_IMPLICIT_TAG ( 6 ) ) ) != 0 ) {
+		DBGC ( cert, "X509 %p OCSP does not contain "
+		       "uniformResourceIdentifier:\n", cert );
+		DBGC_HDA ( cert, 0, raw->data, raw->len );
+		return rc;
+	}
+
+	/* Record URI */
+	ocsp->uri.data = cursor.data;
+	ocsp->uri.len = cursor.len;
+	DBGC ( cert, "X509 %p OCSP URI is:\n", cert );
+	DBGC_HDA ( cert, 0, ocsp->uri.data, ocsp->uri.len );
+
+	return 0;
+}
+
+/** "id-ad-ocsp" object identifier */
+static uint8_t oid_ad_ocsp[] = { ASN1_OID_OCSP };
+
+/** Supported access methods */
+static struct x509_access_method x509_access_methods[] = {
+	{
+		.name = "OCSP",
+		.oid = ASN1_OID_CURSOR ( oid_ad_ocsp ),
+		.parse = x509_parse_ocsp,
+	},
+};
+
+/**
+ * Identify X.509 access method by OID
+ *
+ * @v oid		OID
+ * @ret method		Access method, or NULL
+ */
+static struct x509_access_method *
+x509_find_access_method ( const struct asn1_cursor *oid ) {
+	struct x509_access_method *method;
+	unsigned int i;
+
+	for ( i = 0 ; i < ( sizeof ( x509_access_methods ) /
+			    sizeof ( x509_access_methods[0] ) ) ; i++ ) {
+		method = &x509_access_methods[i];
+		if ( asn1_compare ( &method->oid, oid ) == 0 )
+			return method;
+	}
+
+	return NULL;
+}
+
+/**
+ * Parse X.509 certificate access description
+ *
+ * @v cert		X.509 certificate
+ * @v raw		ASN.1 cursor
+ * @ret rc		Return status code
+ */
+static int x509_parse_access_description ( struct x509_certificate *cert,
+					   const struct asn1_cursor *raw ) {
+	struct asn1_cursor cursor;
+	struct asn1_cursor subcursor;
+	struct x509_access_method *method;
+	int rc;
+
+	/* Enter keyPurposeId */
+	memcpy ( &cursor, raw, sizeof ( cursor ) );
+	asn1_enter ( &cursor, ASN1_SEQUENCE );
+
+	/* Try to identify access method */
+	memcpy ( &subcursor, &cursor, sizeof ( subcursor ) );
+	asn1_enter ( &subcursor, ASN1_OID );
+	method = x509_find_access_method ( &subcursor );
+	asn1_skip_any ( &cursor );
+	DBGC ( cert, "X509 %p found access method %s\n",
+	       cert, ( method ? method->name : "<unknown>" ) );
+
+	/* Parse access location, if applicable */
+	if ( method && ( ( rc = method->parse ( cert, &cursor ) ) != 0 ) )
+		return rc;
+
+	return 0;
+}
+
+/**
+ * Parse X.509 certificate authority information access
+ *
+ * @v cert		X.509 certificate
+ * @v raw		ASN.1 cursor
+ * @ret rc		Return status code
+ */
+static int x509_parse_authority_info_access ( struct x509_certificate *cert,
+					      const struct asn1_cursor *raw ) {
+	struct asn1_cursor cursor;
+	int rc;
+
+	/* Enter authorityInfoAccess */
+	memcpy ( &cursor, raw, sizeof ( cursor ) );
+	asn1_enter ( &cursor, ASN1_SEQUENCE );
+
+	/* Parse each access description in turn */
+	while ( cursor.len ) {
+		if ( ( rc = x509_parse_access_description ( cert,
+							    &cursor ) ) != 0 )
+			return rc;
+		asn1_skip_any ( &cursor );
+	}
+
+	return 0;
+}
+
 /** "id-ce-basicConstraints" object identifier */
-static uint8_t oid_ce_basic_constraints[] = { ASN1_OID_BASICCONSTRAINTS };
+static uint8_t oid_ce_basic_constraints[] =
+	{ ASN1_OID_BASICCONSTRAINTS };
 
 /** "id-ce-keyUsage" object identifier */
-static uint8_t oid_ce_key_usage[] = { ASN1_OID_KEYUSAGE };
+static uint8_t oid_ce_key_usage[] =
+	{ ASN1_OID_KEYUSAGE };
 
 /** "id-ce-extKeyUsage" object identifier */
-static uint8_t oid_ce_ext_key_usage[] = { ASN1_OID_EXTKEYUSAGE };
+static uint8_t oid_ce_ext_key_usage[] =
+	{ ASN1_OID_EXTKEYUSAGE };
+
+/** "id-pe-authorityInfoAccess" object identifier */
+static uint8_t oid_pe_authority_info_access[] =
+	{ ASN1_OID_AUTHORITYINFOACCESS };
 
 /** Supported certificate extensions */
 static struct x509_extension x509_extensions[] = {
@@ -786,6 +917,11 @@ static struct x509_extension x509_extensions[] = {
 		.oid = ASN1_OID_CURSOR ( oid_ce_ext_key_usage ),
 		.parse = x509_parse_extended_key_usage,
 	},
+	{
+		.name = "authorityInfoAccess",
+		.oid = ASN1_OID_CURSOR ( oid_pe_authority_info_access ),
+		.parse = x509_parse_authority_info_access,
+	},
 };
 
 /**

src/include/ipxe/asn1.h

@@ -53,6 +53,9 @@ struct asn1_cursor {
 /** ASN.1 set */
 #define ASN1_SET 0x31
 
+/** ASN.1 implicit tag */
+#define ASN1_IMPLICIT_TAG( number) ( 0x80 | (number) )
+
 /** ASN.1 explicit tag */
 #define ASN1_EXPLICIT_TAG( number) ( 0xa0 | (number) )
 
@@ -158,6 +161,20 @@ struct asn1_cursor {
 	ASN1_OID_TRIPLE ( 113549 ), ASN1_OID_SINGLE ( 1 ),	\
 	ASN1_OID_SINGLE ( 7 ), ASN1_OID_SINGLE ( 2 )
 
+/** ASN.1 OID for id-pe-authorityInfoAccess (1.3.6.1.5.5.7.1.1) */
+#define ASN1_OID_AUTHORITYINFOACCESS				\
+	ASN1_OID_INITIAL ( 1, 3 ), ASN1_OID_SINGLE ( 6 ),	\
+	ASN1_OID_SINGLE ( 1 ), ASN1_OID_SINGLE ( 5 ),		\
+	ASN1_OID_SINGLE ( 5 ), ASN1_OID_SINGLE ( 7 ),		\
+	ASN1_OID_SINGLE ( 1 ), ASN1_OID_SINGLE ( 1 )
+
+/** ASN.1 OID for id-ad-ocsp (1.3.6.1.5.5.7.48.1) */
+#define ASN1_OID_OCSP						\
+	ASN1_OID_INITIAL ( 1, 3 ), ASN1_OID_SINGLE ( 6 ),	\
+	ASN1_OID_SINGLE ( 1 ), ASN1_OID_SINGLE ( 5 ),		\
+	ASN1_OID_SINGLE ( 5 ), ASN1_OID_SINGLE ( 7 ),		\
+	ASN1_OID_SINGLE ( 48 ), ASN1_OID_SINGLE ( 1 )
+
 /** Define an ASN.1 cursor containing an OID */
 #define ASN1_OID_CURSOR( oid_value ) {				\
 		.data = oid_value,				\

src/include/ipxe/x509.h

@@ -50,9 +50,9 @@ struct x509_validity {
 	struct x509_time not_after;
 };
 
-/** An X.509 name */
-struct x509_name {
-	/** Name (not NUL-terminated) */
+/** An X.509 string */
+struct x509_string {
+	/** String (not NUL-terminated) */
 	const void *data;
 	/** Length of name */
 	size_t len;
@@ -71,7 +71,7 @@ struct x509_subject {
 	/** Raw subject */
 	struct asn1_cursor raw;
 	/** Common name */
-	struct x509_name name;
+	struct x509_string name;
 	/** Public key information */
 	struct x509_public_key public_key;
 };
@@ -128,6 +128,18 @@ enum x509_extended_key_usage_bits {
 	X509_CODE_SIGNING = 0x0001,
 };
 
+/** X.509 certificate OCSP responder */
+struct x509_ocsp_responder {
+	/** URI */
+	struct x509_string uri;
+};
+
+/** X.509 certificate authority information access */
+struct x509_authority_info_access {
+	/** OCSP responder */
+	struct x509_ocsp_responder ocsp;
+};
+
 /** An X.509 certificate extensions set */
 struct x509_extensions {
 	/** Basic constraints */
@@ -136,6 +148,8 @@ struct x509_extensions {
 	struct x509_key_usage usage;
 	/** Extended key usage */
 	struct x509_extended_key_usage ext_usage;
+	/** Authority information access */
+	struct x509_authority_info_access auth_info;
 };
 
 /** An X.509 certificate */
@@ -188,6 +202,22 @@ struct x509_key_purpose {
 	unsigned int bits;
 };
 
+/** An X.509 access method */
+struct x509_access_method {
+	/** Name */
+	const char *name;
+	/** Object identifier */
+	struct asn1_cursor oid;
+	/** Parse access method
+	 *
+	 * @v cert		X.509 certificate
+	 * @v raw		ASN.1 cursor
+	 * @ret rc		Return status code
+	 */
+	int ( * parse ) ( struct x509_certificate *cert,
+			  const struct asn1_cursor *raw );
+};
+
 /** An X.509 root certificate store */
 struct x509_root {
 	/** Fingerprint digest algorithm */

src/net/tls.c

@@ -1347,7 +1347,7 @@ static int tls_new_certificate ( struct tls_session *tls,
 	struct pubkey_algorithm *pubkey = cipherspec->suite->pubkey;
 	struct tls_certificate_context context;
 	struct x509_certificate cert;
-	struct x509_name *name = &cert.subject.name;
+	struct x509_string *name = &cert.subject.name;
 	struct x509_public_key *key = &cert.subject.public_key;
 	time_t now;
 	int rc;