TLS: Process OCSP SingleResponse(s)
This completes OCSP stapling support on the TLS client side. Each SingleResponse value is iterated until a response matching the server certificate is found. The validity time of the SingleResponse is verified and certStatus good/revoked is reported if all validation step succeed. Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen
parent
8e3271dcd1
commit
f163ed8bae
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@ -64,6 +64,291 @@ static int ocsp_responder_id_match(struct x509_certificate *signer,
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}
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static unsigned int ocsp_hash_data(struct asn1_oid *alg, const u8 *data,
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size_t data_len, u8 *hash)
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{
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const u8 *addr[1] = { data };
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size_t len[1] = { data_len };
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char buf[100];
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if (x509_sha1_oid(alg)) {
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if (sha1_vector(1, addr, len, hash) < 0)
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return 0;
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wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA1)", hash, 20);
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return 20;
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}
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if (x509_sha256_oid(alg)) {
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if (sha256_vector(1, addr, len, hash) < 0)
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return 0;
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wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA256)", hash, 32);
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return 32;
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}
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if (x509_sha384_oid(alg)) {
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if (sha384_vector(1, addr, len, hash) < 0)
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return 0;
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wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA384)", hash, 48);
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return 48;
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}
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if (x509_sha512_oid(alg)) {
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if (sha512_vector(1, addr, len, hash) < 0)
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return 0;
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wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA512)", hash, 64);
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return 64;
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}
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asn1_oid_to_str(alg, buf, sizeof(buf));
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wpa_printf(MSG_DEBUG, "OCSP: Could not calculate hash with alg %s",
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buf);
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return 0;
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}
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static int tls_process_ocsp_single_response(struct tlsv1_client *conn,
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struct x509_certificate *cert,
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struct x509_certificate *issuer,
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const u8 *resp, size_t len,
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enum tls_ocsp_result *res)
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{
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struct asn1_hdr hdr;
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const u8 *pos, *end;
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struct x509_algorithm_identifier alg;
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const u8 *name_hash, *key_hash;
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size_t name_hash_len, key_hash_len;
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const u8 *serial_number;
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size_t serial_number_len;
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u8 hash[64];
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unsigned int hash_len;
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unsigned int cert_status;
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os_time_t update;
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struct os_time now;
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wpa_hexdump(MSG_MSGDUMP, "OCSP: SingleResponse", resp, len);
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/*
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* SingleResponse ::= SEQUENCE {
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* certID CertID,
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* certStatus CertStatus,
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* thisUpdate GeneralizedTime,
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* nextUpdate [0] EXPLICIT GeneralizedTime OPTIONAL,
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* singleExtensions [1] EXPLICIT Extensions OPTIONAL }
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*/
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/* CertID ::= SEQUENCE */
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if (asn1_get_next(resp, len, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_SEQUENCE) {
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wpa_printf(MSG_DEBUG,
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"OCSP: Expected SEQUENCE (CertID) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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return -1;
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}
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pos = hdr.payload;
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end = hdr.payload + hdr.length;
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/*
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* CertID ::= SEQUENCE {
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* hashAlgorithm AlgorithmIdentifier,
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* issuerNameHash OCTET STRING,
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* issuerKeyHash OCTET STRING,
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* serialNumber CertificateSerialNumber }
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*/
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/* hashAlgorithm AlgorithmIdentifier */
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if (x509_parse_algorithm_identifier(pos, end - pos, &alg, &pos))
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return -1;
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/* issuerNameHash OCTET STRING */
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_OCTETSTRING) {
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wpa_printf(MSG_DEBUG,
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"OCSP: Expected OCTET STRING (issuerNameHash) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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return -1;
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}
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name_hash = hdr.payload;
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name_hash_len = hdr.length;
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wpa_hexdump(MSG_DEBUG, "OCSP: issuerNameHash",
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name_hash, name_hash_len);
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pos = hdr.payload + hdr.length;
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wpa_hexdump(MSG_DEBUG, "OCSP: Issuer subject DN",
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issuer->subject_dn, issuer->subject_dn_len);
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hash_len = ocsp_hash_data(&alg.oid, issuer->subject_dn,
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issuer->subject_dn_len, hash);
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if (hash_len == 0 || name_hash_len != hash_len ||
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os_memcmp(name_hash, hash, hash_len) != 0) {
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wpa_printf(MSG_DEBUG, "OCSP: issuerNameHash mismatch");
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wpa_hexdump(MSG_DEBUG, "OCSP: Calculated issuerNameHash",
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hash, hash_len);
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return -1;
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}
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/* issuerKeyHash OCTET STRING */
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_OCTETSTRING) {
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wpa_printf(MSG_DEBUG,
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"OCSP: Expected OCTET STRING (issuerKeyHash) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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return -1;
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}
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key_hash = hdr.payload;
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key_hash_len = hdr.length;
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wpa_hexdump(MSG_DEBUG, "OCSP: issuerKeyHash", key_hash, key_hash_len);
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pos = hdr.payload + hdr.length;
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hash_len = ocsp_hash_data(&alg.oid, issuer->public_key,
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issuer->public_key_len, hash);
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if (hash_len == 0 || key_hash_len != hash_len ||
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os_memcmp(key_hash, hash, hash_len) != 0) {
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wpa_printf(MSG_DEBUG, "OCSP: issuerKeyHash mismatch");
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wpa_hexdump(MSG_DEBUG, "OCSP: Calculated issuerKeyHash",
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hash, hash_len);
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return -1;
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}
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/* serialNumber CertificateSerialNumber ::= INTEGER */
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_INTEGER ||
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hdr.length < 1 || hdr.length > X509_MAX_SERIAL_NUM_LEN) {
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wpa_printf(MSG_DEBUG, "OCSP: No INTEGER tag found for serialNumber; class=%d tag=0x%x length=%u",
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hdr.class, hdr.tag, hdr.length);
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return -1;
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}
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serial_number = hdr.payload;
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serial_number_len = hdr.length;
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while (serial_number_len > 0 && serial_number[0] == 0) {
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serial_number++;
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serial_number_len--;
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}
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wpa_hexdump(MSG_MSGDUMP, "OCSP: serialNumber", serial_number,
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serial_number_len);
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if (serial_number_len != cert->serial_number_len ||
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os_memcmp(serial_number, cert->serial_number,
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serial_number_len) != 0) {
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wpa_printf(MSG_DEBUG, "OCSP: serialNumber mismatch");
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return -1;
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}
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pos = end;
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end = resp + len;
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/* certStatus CertStatus ::= CHOICE */
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC) {
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wpa_printf(MSG_DEBUG,
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"OCSP: Expected CHOICE (CertStatus) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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return -1;
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}
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cert_status = hdr.tag;
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wpa_printf(MSG_DEBUG, "OCSP: certStatus=%u", cert_status);
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wpa_hexdump(MSG_DEBUG, "OCSP: CertStatus additional data",
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hdr.payload, hdr.length);
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pos = hdr.payload + hdr.length;
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os_get_time(&now);
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/* thisUpdate GeneralizedTime */
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_GENERALIZEDTIME ||
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x509_parse_time(hdr.payload, hdr.length, hdr.tag, &update) < 0) {
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wpa_printf(MSG_DEBUG, "OCSP: Failed to parse thisUpdate");
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return -1;
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}
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wpa_printf(MSG_DEBUG, "OCSP: thisUpdate %lu", (unsigned long) update);
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pos = hdr.payload + hdr.length;
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if ((unsigned long) now.sec < (unsigned long) update) {
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wpa_printf(MSG_DEBUG,
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"OCSP: thisUpdate time in the future (response not yet valid)");
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return -1;
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}
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/* nextUpdate [0] EXPLICIT GeneralizedTime OPTIONAL */
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if (pos < end) {
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if (asn1_get_next(pos, end - pos, &hdr) < 0)
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return -1;
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if (hdr.class == ASN1_CLASS_CONTEXT_SPECIFIC && hdr.tag == 0) {
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const u8 *next = hdr.payload + hdr.length;
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if (asn1_get_next(hdr.payload, hdr.length, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_GENERALIZEDTIME ||
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x509_parse_time(hdr.payload, hdr.length, hdr.tag,
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&update) < 0) {
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wpa_printf(MSG_DEBUG,
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"OCSP: Failed to parse nextUpdate");
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return -1;
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}
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wpa_printf(MSG_DEBUG, "OCSP: nextUpdate %lu",
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(unsigned long) update);
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pos = next;
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if ((unsigned long) now.sec > (unsigned long) update) {
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wpa_printf(MSG_DEBUG, "OCSP: nextUpdate time in the past (response has expired)");
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return -1;
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}
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}
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}
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/* singleExtensions [1] EXPLICIT Extensions OPTIONAL */
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if (pos < end) {
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wpa_hexdump(MSG_MSGDUMP, "OCSP: singleExtensions",
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pos, end - pos);
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/* Ignore for now */
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}
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if (cert_status == 0 /* good */)
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*res = TLS_OCSP_GOOD;
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else if (cert_status == 1 /* revoked */)
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*res = TLS_OCSP_REVOKED;
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else
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return -1;
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return 0;
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}
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static enum tls_ocsp_result
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tls_process_ocsp_responses(struct tlsv1_client *conn,
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struct x509_certificate *issuer, const u8 *resp,
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size_t len)
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{
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struct asn1_hdr hdr;
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const u8 *pos, *end;
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enum tls_ocsp_result res;
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pos = resp;
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end = resp + len;
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while (pos < end) {
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/* SingleResponse ::= SEQUENCE */
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_SEQUENCE) {
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wpa_printf(MSG_DEBUG,
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"OCSP: Expected SEQUENCE (SingleResponse) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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return TLS_OCSP_INVALID;
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}
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if (tls_process_ocsp_single_response(conn, conn->server_cert,
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issuer,
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hdr.payload, hdr.length,
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&res) == 0)
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return res;
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pos = hdr.payload + hdr.length;
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}
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wpa_printf(MSG_DEBUG,
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"OCSP: Did not find a response matching the server certificate");
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return TLS_OCSP_NO_RESPONSE;
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}
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static enum tls_ocsp_result
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tls_process_basic_ocsp_response(struct tlsv1_client *conn, const u8 *resp,
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size_t len)
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@ -369,7 +654,8 @@ tls_process_basic_ocsp_response(struct tlsv1_client *conn, const u8 *resp,
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return TLS_OCSP_INVALID;
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}
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/* TODO: Check responses */
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return tls_process_ocsp_responses(conn, issuer, responses,
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responses_len);
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no_resp:
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x509_free_name(&name);
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