mirror of
https://github.com/vanhoefm/fragattacks.git
synced 2025-01-29 16:24:03 -05:00
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
@ -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);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user