]> git.ipfire.org Git - thirdparty/hostap.git/commitdiff
TLS: Process OCSP SingleResponse(s)
authorJouni Malinen <j@w1.fi>
Wed, 16 Dec 2015 23:45:51 +0000 (01:45 +0200)
committerJouni Malinen <j@w1.fi>
Thu, 17 Dec 2015 09:28:38 +0000 (11:28 +0200)
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>
src/tls/tlsv1_client_ocsp.c

index 28657cc49459a4d85c93e3fe6c196242bfc41250..2d5cdb94aa9bdfd12c30ca9788cbe888d5804be2 100644 (file)
@@ -64,6 +64,291 @@ static int ocsp_responder_id_match(struct x509_certificate *signer,
 }
 
 
+static unsigned int ocsp_hash_data(struct asn1_oid *alg, const u8 *data,
+                                  size_t data_len, u8 *hash)
+{
+       const u8 *addr[1] = { data };
+       size_t len[1] = { data_len };
+       char buf[100];
+
+       if (x509_sha1_oid(alg)) {
+               if (sha1_vector(1, addr, len, hash) < 0)
+                       return 0;
+               wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA1)", hash, 20);
+               return 20;
+       }
+
+       if (x509_sha256_oid(alg)) {
+               if (sha256_vector(1, addr, len, hash) < 0)
+                       return 0;
+               wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA256)", hash, 32);
+               return 32;
+       }
+
+       if (x509_sha384_oid(alg)) {
+               if (sha384_vector(1, addr, len, hash) < 0)
+                       return 0;
+               wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA384)", hash, 48);
+               return 48;
+       }
+
+       if (x509_sha512_oid(alg)) {
+               if (sha512_vector(1, addr, len, hash) < 0)
+                       return 0;
+               wpa_hexdump(MSG_MSGDUMP, "OCSP: Hash (SHA512)", hash, 64);
+               return 64;
+       }
+
+
+       asn1_oid_to_str(alg, buf, sizeof(buf));
+       wpa_printf(MSG_DEBUG, "OCSP: Could not calculate hash with alg %s",
+                  buf);
+       return 0;
+}
+
+
+static int tls_process_ocsp_single_response(struct tlsv1_client *conn,
+                                           struct x509_certificate *cert,
+                                           struct x509_certificate *issuer,
+                                           const u8 *resp, size_t len,
+                                           enum tls_ocsp_result *res)
+{
+       struct asn1_hdr hdr;
+       const u8 *pos, *end;
+       struct x509_algorithm_identifier alg;
+       const u8 *name_hash, *key_hash;
+       size_t name_hash_len, key_hash_len;
+       const u8 *serial_number;
+       size_t serial_number_len;
+       u8 hash[64];
+       unsigned int hash_len;
+       unsigned int cert_status;
+       os_time_t update;
+       struct os_time now;
+
+       wpa_hexdump(MSG_MSGDUMP, "OCSP: SingleResponse", resp, len);
+
+       /*
+        * SingleResponse ::= SEQUENCE {
+        *    certID                       CertID,
+        *    certStatus                   CertStatus,
+        *    thisUpdate                   GeneralizedTime,
+        *    nextUpdate         [0]       EXPLICIT GeneralizedTime OPTIONAL,
+        *    singleExtensions   [1]       EXPLICIT Extensions OPTIONAL }
+        */
+
+       /* CertID ::= SEQUENCE */
+       if (asn1_get_next(resp, len, &hdr) < 0 ||
+           hdr.class != ASN1_CLASS_UNIVERSAL ||
+           hdr.tag != ASN1_TAG_SEQUENCE) {
+               wpa_printf(MSG_DEBUG,
+                          "OCSP: Expected SEQUENCE (CertID) - found class %d tag 0x%x",
+                          hdr.class, hdr.tag);
+               return -1;
+       }
+       pos = hdr.payload;
+       end = hdr.payload + hdr.length;
+
+       /*
+        * CertID ::= SEQUENCE {
+        *    hashAlgorithm           AlgorithmIdentifier,
+        *    issuerNameHash          OCTET STRING,
+        *    issuerKeyHash           OCTET STRING,
+        *    serialNumber            CertificateSerialNumber }
+        */
+
+       /* hashAlgorithm  AlgorithmIdentifier */
+       if (x509_parse_algorithm_identifier(pos, end - pos, &alg, &pos))
+               return -1;
+
+       /* issuerNameHash  OCTET STRING */
+       if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+           hdr.class != ASN1_CLASS_UNIVERSAL ||
+           hdr.tag != ASN1_TAG_OCTETSTRING) {
+               wpa_printf(MSG_DEBUG,
+                          "OCSP: Expected OCTET STRING (issuerNameHash) - found class %d tag 0x%x",
+                          hdr.class, hdr.tag);
+               return -1;
+       }
+       name_hash = hdr.payload;
+       name_hash_len = hdr.length;
+       wpa_hexdump(MSG_DEBUG, "OCSP: issuerNameHash",
+                   name_hash, name_hash_len);
+       pos = hdr.payload + hdr.length;
+
+       wpa_hexdump(MSG_DEBUG, "OCSP: Issuer subject DN",
+                   issuer->subject_dn, issuer->subject_dn_len);
+       hash_len = ocsp_hash_data(&alg.oid, issuer->subject_dn,
+                                 issuer->subject_dn_len, hash);
+       if (hash_len == 0 || name_hash_len != hash_len ||
+           os_memcmp(name_hash, hash, hash_len) != 0) {
+               wpa_printf(MSG_DEBUG, "OCSP: issuerNameHash mismatch");
+               wpa_hexdump(MSG_DEBUG, "OCSP: Calculated issuerNameHash",
+                           hash, hash_len);
+               return -1;
+       }
+
+       /* issuerKeyHash  OCTET STRING */
+       if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+           hdr.class != ASN1_CLASS_UNIVERSAL ||
+           hdr.tag != ASN1_TAG_OCTETSTRING) {
+               wpa_printf(MSG_DEBUG,
+                          "OCSP: Expected OCTET STRING (issuerKeyHash) - found class %d tag 0x%x",
+                          hdr.class, hdr.tag);
+               return -1;
+       }
+       key_hash = hdr.payload;
+       key_hash_len = hdr.length;
+       wpa_hexdump(MSG_DEBUG, "OCSP: issuerKeyHash", key_hash, key_hash_len);
+       pos = hdr.payload + hdr.length;
+
+       hash_len = ocsp_hash_data(&alg.oid, issuer->public_key,
+                                 issuer->public_key_len, hash);
+       if (hash_len == 0 || key_hash_len != hash_len ||
+           os_memcmp(key_hash, hash, hash_len) != 0) {
+               wpa_printf(MSG_DEBUG, "OCSP: issuerKeyHash mismatch");
+               wpa_hexdump(MSG_DEBUG, "OCSP: Calculated issuerKeyHash",
+                           hash, hash_len);
+               return -1;
+       }
+
+       /* serialNumber CertificateSerialNumber ::= INTEGER */
+       if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+           hdr.class != ASN1_CLASS_UNIVERSAL ||
+           hdr.tag != ASN1_TAG_INTEGER ||
+           hdr.length < 1 || hdr.length > X509_MAX_SERIAL_NUM_LEN) {
+               wpa_printf(MSG_DEBUG, "OCSP: No INTEGER tag found for serialNumber; class=%d tag=0x%x length=%u",
+                          hdr.class, hdr.tag, hdr.length);
+               return -1;
+       }
+       serial_number = hdr.payload;
+       serial_number_len = hdr.length;
+       while (serial_number_len > 0 && serial_number[0] == 0) {
+               serial_number++;
+               serial_number_len--;
+       }
+       wpa_hexdump(MSG_MSGDUMP, "OCSP: serialNumber", serial_number,
+                   serial_number_len);
+
+       if (serial_number_len != cert->serial_number_len ||
+           os_memcmp(serial_number, cert->serial_number,
+                     serial_number_len) != 0) {
+               wpa_printf(MSG_DEBUG, "OCSP: serialNumber mismatch");
+               return -1;
+       }
+
+       pos = end;
+       end = resp + len;
+
+       /* certStatus CertStatus ::= CHOICE */
+       if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+           hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC) {
+               wpa_printf(MSG_DEBUG,
+                          "OCSP: Expected CHOICE (CertStatus) - found class %d tag 0x%x",
+                          hdr.class, hdr.tag);
+               return -1;
+       }
+       cert_status = hdr.tag;
+       wpa_printf(MSG_DEBUG, "OCSP: certStatus=%u", cert_status);
+       wpa_hexdump(MSG_DEBUG, "OCSP: CertStatus additional data",
+                   hdr.payload, hdr.length);
+       pos = hdr.payload + hdr.length;
+
+       os_get_time(&now);
+       /* thisUpdate  GeneralizedTime */
+       if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+           hdr.class != ASN1_CLASS_UNIVERSAL ||
+           hdr.tag != ASN1_TAG_GENERALIZEDTIME ||
+           x509_parse_time(hdr.payload, hdr.length, hdr.tag, &update) < 0) {
+               wpa_printf(MSG_DEBUG, "OCSP: Failed to parse thisUpdate");
+               return -1;
+       }
+       wpa_printf(MSG_DEBUG, "OCSP: thisUpdate %lu", (unsigned long) update);
+       pos = hdr.payload + hdr.length;
+       if ((unsigned long) now.sec < (unsigned long) update) {
+               wpa_printf(MSG_DEBUG,
+                          "OCSP: thisUpdate time in the future (response not yet valid)");
+               return -1;
+       }
+
+       /* nextUpdate  [0]  EXPLICIT GeneralizedTime OPTIONAL */
+       if (pos < end) {
+               if (asn1_get_next(pos, end - pos, &hdr) < 0)
+                       return -1;
+               if (hdr.class == ASN1_CLASS_CONTEXT_SPECIFIC && hdr.tag == 0) {
+                       const u8 *next = hdr.payload + hdr.length;
+
+                       if (asn1_get_next(hdr.payload, hdr.length, &hdr) < 0 ||
+                           hdr.class != ASN1_CLASS_UNIVERSAL ||
+                           hdr.tag != ASN1_TAG_GENERALIZEDTIME ||
+                           x509_parse_time(hdr.payload, hdr.length, hdr.tag,
+                                           &update) < 0) {
+                               wpa_printf(MSG_DEBUG,
+                                          "OCSP: Failed to parse nextUpdate");
+                               return -1;
+                       }
+                       wpa_printf(MSG_DEBUG, "OCSP: nextUpdate %lu",
+                                  (unsigned long) update);
+                       pos = next;
+                       if ((unsigned long) now.sec > (unsigned long) update) {
+                               wpa_printf(MSG_DEBUG, "OCSP: nextUpdate time in the past (response has expired)");
+                               return -1;
+                       }
+               }
+       }
+
+       /* singleExtensions  [1]  EXPLICIT Extensions OPTIONAL */
+       if (pos < end) {
+               wpa_hexdump(MSG_MSGDUMP, "OCSP: singleExtensions",
+                           pos, end - pos);
+               /* Ignore for now */
+       }
+
+       if (cert_status == 0 /* good */)
+               *res = TLS_OCSP_GOOD;
+       else if (cert_status == 1 /* revoked */)
+               *res = TLS_OCSP_REVOKED;
+       else
+               return -1;
+       return 0;
+}
+
+
+static enum tls_ocsp_result
+tls_process_ocsp_responses(struct tlsv1_client *conn,
+                          struct x509_certificate *issuer, const u8 *resp,
+                          size_t len)
+{
+       struct asn1_hdr hdr;
+       const u8 *pos, *end;
+       enum tls_ocsp_result res;
+
+       pos = resp;
+       end = resp + len;
+       while (pos < end) {
+               /* SingleResponse ::= SEQUENCE */
+               if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+                   hdr.class != ASN1_CLASS_UNIVERSAL ||
+                   hdr.tag != ASN1_TAG_SEQUENCE) {
+                       wpa_printf(MSG_DEBUG,
+                                  "OCSP: Expected SEQUENCE (SingleResponse) - found class %d tag 0x%x",
+                                  hdr.class, hdr.tag);
+                       return TLS_OCSP_INVALID;
+               }
+               if (tls_process_ocsp_single_response(conn, conn->server_cert,
+                                                    issuer,
+                                                    hdr.payload, hdr.length,
+                                                    &res) == 0)
+                       return res;
+               pos = hdr.payload + hdr.length;
+       }
+
+       wpa_printf(MSG_DEBUG,
+                  "OCSP: Did not find a response matching the server certificate");
+       return TLS_OCSP_NO_RESPONSE;
+}
+
+
 static enum tls_ocsp_result
 tls_process_basic_ocsp_response(struct tlsv1_client *conn, const u8 *resp,
                                size_t len)
@@ -369,7 +654,8 @@ tls_process_basic_ocsp_response(struct tlsv1_client *conn, const u8 *resp,
                    return TLS_OCSP_INVALID;
        }
 
-       /* TODO: Check responses */
+       return tls_process_ocsp_responses(conn, issuer, responses,
+                                         responses_len);
 
 no_resp:
        x509_free_name(&name);