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authorJouni Malinen <j@w1.fi>2015-12-16 23:45:51 (GMT)
committerJouni Malinen <j@w1.fi>2015-12-17 09:28:38 (GMT)
commitf163ed8bae4668bb088bd7a339fd9c948ac02b99 (patch)
tree6fbaa6e2606f9f089c0ae7d9657b85106a4ee7e9 /src/tls
parent8e3271dcd1086a0ed40e1f019abb0699f6d24af6 (diff)
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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>
Diffstat (limited to 'src/tls')
-rw-r--r--src/tls/tlsv1_client_ocsp.c288
1 files changed, 287 insertions, 1 deletions
diff --git a/src/tls/tlsv1_client_ocsp.c b/src/tls/tlsv1_client_ocsp.c
index 28657cc..2d5cdb9 100644
--- a/src/tls/tlsv1_client_ocsp.c
+++ b/src/tls/tlsv1_client_ocsp.c
@@ -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);