ocsp signer certificate and ocsp response signature can be verified

This commit is contained in:
Andreas Steffen
2007-03-08 23:29:04 +00:00
parent f5fbad4a62
commit 1bcb84605f
8 changed files with 495 additions and 64 deletions
@@ -136,12 +136,21 @@ struct credential_store_t {
ca_info_t* (*get_issuer) (credential_store_t *this, const x509_t* cert);
/**
* @brief Verify an X.509 certificate up to trust anchor including revocation checks
* @brief Verify an X.509 certificate up to trust anchor without any status checks
*
* @param this calling object
* @param cert certificate to be verified
* @return TRUE if trusted
*/
bool (*is_trusted) (credential_store_t *this, x509_t *cert);
/**
* @brief Verify an X.509 certificate up to trust anchor including status checks
*
* @param this calling object
* @param cert certificate to be verified
* @param found found a certificate copy in the credential store
* @return TRUE if trusted
* @return TRUE if valid, trusted, and current status is good
*/
bool (*verify) (credential_store_t *this, x509_t *cert, bool *found);
@@ -480,6 +480,60 @@ static void add_uris(ca_info_t *issuer, x509_t *cert)
iterator->destroy(iterator);
}
/**
* Implementation of credential_store_t.is_trusted
*/
static bool is_trusted(private_local_credential_store_t *this, x509_t *cert)
{
int pathlen;
DBG2(DBG_CFG, "establishing trust in certificate:");
for (pathlen = 0; pathlen < MAX_CA_PATH_LEN; pathlen++)
{
ca_info_t *issuer;
x509_t *issuer_cert;
rsa_public_key_t *issuer_public_key;
bool valid_signature;
DBG2(DBG_CFG, "subject: '%D'", cert->get_subject(cert));
DBG2(DBG_CFG, "issuer: '%D'", cert->get_issuer(cert));
issuer = get_issuer(this, cert);
if (issuer == NULL)
{
DBG1(DBG_CFG, "issuer info not found");
return FALSE;
}
DBG2(DBG_CFG, "issuer info found");
issuer_cert = issuer->get_certificate(issuer);
issuer_public_key = issuer_cert->get_public_key(issuer_cert);
valid_signature = cert->verify(cert, issuer_public_key);
if (!valid_signature)
{
DBG1(DBG_CFG, "certificate signature is invalid");
return FALSE;
}
DBG2(DBG_CFG, "certificate signature is valid");
/* check if cert is a self-signed root ca */
if (pathlen > 0 && cert->is_self_signed(cert))
{
DBG2(DBG_CFG, "reached self-signed root ca");
return TRUE;
}
else
{
/* go up one step in the trust chain */
cert = issuer_cert;
}
}
DBG1(DBG_CFG, "maximum ca path length of %d levels exceeded", MAX_CA_PATH_LEN);
return FALSE;
}
/**
* Implementation of credential_store_t.verify.
*/
@@ -491,6 +545,8 @@ static bool verify(private_local_credential_store_t *this, x509_t *cert, bool *f
x509_t *end_cert = cert;
x509_t *cert_copy = find_certificate(this->certs, end_cert);
DBG2(DBG_CFG, "verifying end entity certificate:");
*found = (cert_copy != NULL);
if (*found)
{
@@ -565,7 +621,7 @@ static bool verify(private_local_credential_store_t *this, x509_t *cert, bool *f
}
/* first check certificate revocation using ocsp */
status = issuer->verify_by_ocsp(issuer, cert, certinfo);
status = issuer->verify_by_ocsp(issuer, cert, certinfo, &this->public);
/* if ocsp service is not available then fall back to crl */
if ((status == CERT_UNDEFINED) || (status == CERT_UNKNOWN && this->strict))
@@ -1234,6 +1290,7 @@ local_credential_store_t * local_credential_store_create(bool strict)
this->public.credential_store.get_auth_certificate = (x509_t* (*) (credential_store_t*,u_int,identification_t*))get_auth_certificate;
this->public.credential_store.get_ca_certificate_by_keyid = (x509_t* (*) (credential_store_t*,chunk_t))get_ca_certificate_by_keyid;
this->public.credential_store.get_issuer = (ca_info_t* (*) (credential_store_t*,const x509_t*))get_issuer;
this->public.credential_store.is_trusted = (bool (*) (credential_store_t*,x509_t*))is_trusted;
this->public.credential_store.verify = (bool (*) (credential_store_t*,x509_t*,bool*))verify;
this->public.credential_store.add_end_certificate = (x509_t* (*) (credential_store_t*,x509_t*))add_end_certificate;
this->public.credential_store.add_auth_certificate = (x509_t* (*) (credential_store_t*,x509_t*,u_int))add_auth_certificate;
+1
View File
@@ -1,6 +1,7 @@
lib_LTLIBRARIES = libstrongswan.la
libstrongswan_la_SOURCES = \
credential_store.h \
library.c library.h \
chunk.c chunk.h \
debug.c debug.h \
+285
View File
@@ -0,0 +1,285 @@
/**
* @file credential_store.h
*
* @brief Interface credential_store_t.
*
*/
/*
* Copyright (C) 2005-2006 Martin Willi
* Copyright (C) 2005 Jan Hutter
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#ifndef CREDENTIAL_STORE_H_
#define CREDENTIAL_STORE_H_
typedef struct credential_store_t credential_store_t;
#include <library.h>
#include <crypto/x509.h>
#include <crypto/ca.h>
#include <crypto/rsa/rsa_private_key.h>
#include <crypto/rsa/rsa_public_key.h>
#include <utils/identification.h>
/**
* @brief The interface for a credential_store backend.
*
* @b Constructors:
* - stroke_create()
*
* @ingroup config
*/
struct credential_store_t {
/**
* @brief Returns the secret shared by two specific IDs.
*
* The returned chunk must be destroyed by the caller after usage.
*
* @param this calling object
* @param my_id my ID identifiying the secret.
* @param other_id peer ID identifying the secret.
* @param[out] secret the pre-shared secret will be written there.
* @return
* - NOT_FOUND if no preshared secrets for specific ID could be found
* - SUCCESS
*
*/
status_t (*get_shared_key) (credential_store_t *this, identification_t *my_id, identification_t *other_id, chunk_t *shared_key);
/**
* @brief Returns the RSA public key of a specific ID.
*
* @param this calling object
* @param id identification_t object identifiying the key.
* @return public key, or NULL if not found
*/
rsa_public_key_t* (*get_rsa_public_key) (credential_store_t *this, identification_t *id);
/**
* @brief Returns the RSA public key of a specific ID if is trusted
*
* @param this calling object
* @param id identification_t object identifiying the key.
* @return public key, or NULL if not found or not trusted
*/
rsa_public_key_t* (*get_trusted_public_key) (credential_store_t *this, identification_t *id);
/**
* @brief Returns the RSA private key belonging to an RSA public key
*
* The returned rsa_private_key_t must be destroyed by the caller after usage.
*
* @param this calling object
* @param pubkey public key
* @return private key, or NULL if not found
*/
rsa_private_key_t* (*get_rsa_private_key) (credential_store_t *this, rsa_public_key_t *pubkey);
/**
* @brief Is there a matching RSA private key belonging to an RSA public key?
*
* @param this calling object
* @param pubkey public key
* @return TRUE if matching private key was found
*/
bool (*has_rsa_private_key) (credential_store_t *this, rsa_public_key_t *pubkey);
/**
* @brief Returns the certificate of a specific ID.
*
* @param this calling object
* @param id identification_t object identifiying the cert.
* @return certificate, or NULL if not found
*/
x509_t* (*get_certificate) (credential_store_t *this, identification_t *id);
/**
* @brief Returns the auth certificate of a specific subject distinguished name.
*
* @param this calling object
* @param auth_flags set of allowed authority types
* @param id identification_t object identifiying the cacert.
* @return certificate, or NULL if not found
*/
x509_t* (*get_auth_certificate) (credential_store_t *this, u_int auth_flags, identification_t *id);
/**
* @brief Returns the ca certificate of a specific keyID.
*
* @param this calling object
* @param keyid identification_t object identifiying the cacert.
* @return certificate, or NULL if not found
*/
x509_t* (*get_ca_certificate_by_keyid) (credential_store_t *this, chunk_t keyid);
/**
* @brief Returns the issuing ca of a given certificate.
*
* @param this calling object
* @param cert certificate for which issuer ca info is required
* @return ca info, or NULL if not found
*/
ca_info_t* (*get_issuer) (credential_store_t *this, const x509_t* cert);
/**
* @brief Verify an X.509 certificate up to trust anchor without any status checks
*
* @param this calling object
* @param cert certificate to be verified
* @return TRUE if trusted
*/
bool (*is_trusted) (credential_store_t *this, x509_t *cert);
/**
* @brief Verify an X.509 certificate up to trust anchor including status checks
*
* @param this calling object
* @param cert certificate to be verified
* @param found found a certificate copy in the credential store
* @return TRUE if valid, trusted, and current status is good
*/
bool (*verify) (credential_store_t *this, x509_t *cert, bool *found);
/**
* @brief If an end certificate does not already exists in the credential store then add it.
*
* @param this calling object
* @param cert certificate to be added
* @return pointer to the added or already existing certificate
*/
x509_t* (*add_end_certificate) (credential_store_t *this, x509_t *cert);
/**
* @brief If an authority certificate does not already exists in the credential store then add it.
*
* @param this calling object
* @param cert authority certificate to be added
* @param auth_flag authority flags to add to the certificate
* @return pointer to the added or already existing certificate
*/
x509_t* (*add_auth_certificate) (credential_store_t *this, x509_t *cert, u_int auth_flag);
/**
* @brief If a ca info record does not already exists in the credential store then add it.
*
* @param this calling object
* @param ca_info ca info record to be added
*/
void (*add_ca_info) (credential_store_t *this, ca_info_t *ca_info);
/**
* @brief Release a ca info record with a given name.
*
* @param this calling object
* @param name name of the ca info record to be released
* @return
* - SUCCESS, or
* - NOT_FOUND
*/
status_t (*release_ca_info) (credential_store_t *this, const char *name);
/**
* @brief Create an iterator over all end certificates.
*
* @param this calling object
* @return iterator
*/
iterator_t* (*create_cert_iterator) (credential_store_t *this);
/**
* @brief Create an iterator over all authority certificates.
*
* @param this calling object
* @return iterator
*/
iterator_t* (*create_auth_cert_iterator) (credential_store_t *this);
/**
* @brief Create an iterator over all CA info records
*
* @param this calling object
* @return iterator
*/
iterator_t* (*create_cainfo_iterator) (credential_store_t *this);
/**
* @brief Check if there are any CRLs.
*
* @param this calling object
* @param out output stream
* @param utc either utc or local time
*/
void (*list_crls) (credential_store_t *this, FILE *out, bool utc);
/**
* @brief Loads ca certificates from a default directory.
*
* Certificates in both DER and PEM format are accepted
*
* @param this calling object
*/
void (*load_ca_certificates) (credential_store_t *this);
/**
* @brief Loads ocsp certificates from a default directory.
*
* Certificates in both DER and PEM format are accepted
*
* @param this calling object
*/
void (*load_ocsp_certificates) (credential_store_t *this);
/**
* @brief Loads CRLs from a default directory.
*
* Certificates in both DER and PEM format are accepted
*
* @param this calling object
* @param path directory to load crls from
*/
void (*load_crls) (credential_store_t *this);
/**
* @brief Loads secrets in ipsec.secrets
*
* Currently, all RSA private key files must be in unencrypted form
* either in DER or PEM format.
*
* @param this calling object
*/
void (*load_secrets) (credential_store_t *this);
/**
* @brief Destroys a credential_store_t object.
*
* @param this calling object
*/
void (*destroy) (credential_store_t *this);
};
/**
* @brief Creates a credential_store_t instance.
*
* @param strict enforce a strict crl policy
* @return credential store instance.
*
* @ingroup config
*/
credential_store_t *credential_store_create(bool strict);
#endif /*CREDENTIAL_STORE_H_*/
+6 -4
View File
@@ -382,8 +382,10 @@ err:
/**
* Implements ca_info_t.verify_by_ocsp.
*/
static cert_status_t verify_by_ocsp(private_ca_info_t* this, const x509_t *cert,
certinfo_t *certinfo)
static cert_status_t verify_by_ocsp(private_ca_info_t* this,
const x509_t *cert,
certinfo_t *certinfo,
credential_store_t *credentials)
{
bool found = FALSE;
@@ -419,7 +421,7 @@ static cert_status_t verify_by_ocsp(private_ca_info_t* this, const x509_t *cert,
DBG2("ocsp status is not in cache");
ocsp = ocsp_create(this->cacert, this->ocspuris);
ocsp->fetch(ocsp, certinfo);
ocsp->fetch(ocsp, certinfo, credentials);
ocsp->destroy(ocsp);
}
@@ -555,7 +557,7 @@ ca_info_t *ca_info_create(const char *name, x509_t *cacert)
this->public.add_ocspuri = (void (*) (ca_info_t*,chunk_t))add_ocspuri;
this->public.get_certificate = (x509_t* (*) (ca_info_t*))get_certificate;
this->public.verify_by_crl = (cert_status_t (*) (ca_info_t*,const x509_t*,certinfo_t*))verify_by_crl;
this->public.verify_by_ocsp = (cert_status_t (*) (ca_info_t*,const x509_t*,certinfo_t*))verify_by_ocsp;
this->public.verify_by_ocsp = (cert_status_t (*) (ca_info_t*,const x509_t*,certinfo_t*,credential_store_t*))verify_by_ocsp;
this->public.destroy = (void (*) (ca_info_t*))destroy;
return &this->public;
+4 -1
View File
@@ -28,6 +28,8 @@ typedef struct ca_info_t ca_info_t;
#include <library.h>
#include <chunk.h>
#include <credential_store.h>
#include "x509.h"
#include "crl.h"
@@ -151,9 +153,10 @@ struct ca_info_t {
* @param this ca info object
* @param cert certificate to be verified
* @param certinfo detailed certificate status information
* @param credentials credential store needed for trust path verification
* @return certificate status
*/
cert_status_t (*verify_by_ocsp) (ca_info_t* this, const x509_t* cert, certinfo_t* certinfo);
cert_status_t (*verify_by_ocsp) (ca_info_t* this, const x509_t* cert, certinfo_t* certinfo, credential_store_t* credentials);
/**
* @brief Destroys a ca info record
+125 -54
View File
@@ -38,6 +38,7 @@
#include <debug.h>
#include "hashers/hasher.h"
#include "rsa/rsa_public_key.h"
#include "certinfo.h"
#include "x509.h"
#include "ocsp.h"
@@ -107,18 +108,48 @@ struct response_t {
chunk_t nonce;
int algorithm;
chunk_t signature;
x509_t *responder_cert;
/**
* @brief Destroys the response_t object
*
* @param this response_t to destroy
*/
void (*destroy) (response_t *this);
};
const response_t empty_response = {
{ NULL, 0 } , /* tbs */
NULL , /* responder_id_name */
{ NULL, 0 } , /* responder_id_key */
UNDEFINED_TIME, /* produced_at */
{ NULL, 0 } , /* single_response */
{ NULL, 0 } , /* nonce */
OID_UNKNOWN , /* signature_algorithm */
{ NULL, 0 } /* signature */
};
/**
* Implements response_t.destroy.
*/
static void response_destroy(response_t *this)
{
DESTROY_IF(this->responder_id_name);
DESTROY_IF(this->responder_cert);
}
/**
* Creates a response_t object
*/
static response_t* response_create(void)
{
response_t *this = malloc_thing(response_t);
this->tbs = chunk_empty;
this->responder_id_name = NULL;
this->responder_id_key = chunk_empty;
this->produced_at = UNDEFINED_TIME;
this->responses = chunk_empty;
this->nonce = chunk_empty;
this->algorithm = OID_UNKNOWN;
this->signature = chunk_empty;
this->responder_cert = NULL;
this->destroy = (void (*) (response_t*))response_destroy;
return this;
}
/* single response container */
typedef struct single_response single_response_t;
@@ -452,15 +483,6 @@ static chunk_t ocsp_build_request(private_ocsp_t *this)
return signature;
}
/**
* Check if the OCSP response has a valid signature
*/
static bool ocsp_valid_response(response_t *res)
{
/* TODO */
return FALSE;
}
/**
* parse a basic OCSP response
*/
@@ -529,24 +551,8 @@ static bool ocsp_parse_basic_response(chunk_t blob, int level0, response_t *res)
case BASIC_RESPONSE_CERTIFICATE:
{
chunk_t blob = chunk_clone(object);
x509_t *cert = x509_create_from_chunk(blob, level+1);
if (cert == NULL)
{
break;
}
if (cert->is_ocsp_signer(cert))
{
DBG2("received OCSP signer certificate");
cert->destroy(cert);
/* TODO trust_authcert_candidate(cert, NULL))
add_authcert(cert, AUTH_OCSP); */
}
else
{
DBG1("embedded ocsp certificate rejected");
cert->destroy(cert);
}
res->responder_cert = x509_create_from_chunk(blob, level+1);
}
break;
}
@@ -558,7 +564,7 @@ static bool ocsp_parse_basic_response(chunk_t blob, int level0, response_t *res)
/**
* parse an ocsp response and return the result as a response_t struct
*/
static response_status ocsp_parse_response(chunk_t blob, response_t * res)
static response_status ocsp_parse_response(chunk_t blob, response_t *res)
{
asn1_ctx_t ctx;
chunk_t object;
@@ -625,6 +631,32 @@ static response_status ocsp_parse_response(chunk_t blob, response_t * res)
return rStatus;
}
/**
* Check if the OCSP response has a valid signature
*/
static bool ocsp_valid_response(response_t *res, x509_t *ocsp_cert)
{
rsa_public_key_t *public_key;
time_t until = UNDEFINED_TIME;
err_t ugh;
DBG2("verifying ocsp response signature:");
DBG2("signer: '%D'", ocsp_cert->get_subject(ocsp_cert));
DBG2("issuer: '%D'", ocsp_cert->get_issuer(ocsp_cert));
ugh = ocsp_cert->is_valid(ocsp_cert, &until);
if (ugh != NULL)
{
DBG1("ocsp signer certificate %s", ugh);
return FALSE;
}
DBG2("ocsp signer certificate is valid");
public_key = ocsp_cert->get_public_key(ocsp_cert);
return public_key->verify_emsa_pkcs1_signature(public_key, res->tbs, res->signature) == SUCCESS;
}
/**
* parse a single OCSP response
*/
@@ -706,39 +738,76 @@ static void process_single_response(private_ocsp_t *this, single_response_t *sre
/**
* verify and process ocsp response and update the ocsp cache
*/
void ocsp_process_response(private_ocsp_t *this, chunk_t reply)
void ocsp_process_response(private_ocsp_t *this, chunk_t blob, credential_store_t *credentials)
{
response_t res = empty_response;
x509_t *ocsp_cert = NULL;
response_t *res = response_create();
/* parse the ocsp response without looking at the single responses yet */
response_status status = ocsp_parse_response(reply, &res);
response_status status = ocsp_parse_response(blob, res);
if (status != STATUS_SUCCESSFUL)
{
DBG1("error in ocsp response");
return;
goto err;
}
/* check if there was a nonce in the request */
if (this->nonce.ptr != NULL && res.nonce.ptr == NULL)
if (this->nonce.ptr != NULL && res->nonce.ptr == NULL)
{
DBG1("ocsp response contains no nonce, replay attack possible");
}
/* check if the nonces are identical */
if (res.nonce.ptr != NULL && !chunk_equals(res.nonce, this->nonce))
if (res->nonce.ptr != NULL && !chunk_equals(res->nonce, this->nonce))
{
DBG1("invalid nonce in ocsp response");
return;
goto err;
}
/* check if the response is signed by a trusted key */
if (!ocsp_valid_response(&res))
/* check if we received a trusted responder certificate */
if (res->responder_cert)
{
DBG1("invalid ocsp response");
return;
if (res->responder_cert->is_ocsp_signer(res->responder_cert))
{
DBG2("received certificate is ocsp signer");
if (credentials->is_trusted(credentials, res->responder_cert))
{
DBG2("received ocsp signer certificate is trusted");
ocsp_cert = credentials->add_auth_certificate(credentials,
res->responder_cert, AUTH_OCSP);
res->responder_cert = NULL;
}
else
{
DBG1("received ocsp signer certificate is not trusted - rejected");
}
}
else
{
DBG1("received certificate is no ocsp signer - rejected");
}
}
DBG2("valid ocsp response");
/* if we didn't receive a trusted responder cert, search the credential store */
if (ocsp_cert == NULL)
{
ocsp_cert = credentials->get_auth_certificate(credentials,
AUTH_OCSP|AUTH_CA, res->responder_id_name);
if (ocsp_cert == NULL)
{
DBG1("no ocsp signer certificate found");
goto err;
}
}
/* check the response signature */
if (!ocsp_valid_response(res, ocsp_cert))
{
DBG1("ocsp response signature is invalid");
goto err;
}
DBG2("ocsp response signature is valid");
/* now parse the single responses one at a time */
{
@@ -747,13 +816,13 @@ void ocsp_process_response(private_ocsp_t *this, chunk_t reply)
chunk_t object;
int objectID = 0;
asn1_init(&ctx, res.responses, 0, FALSE, FALSE);
asn1_init(&ctx, res->responses, 0, FALSE, FALSE);
while (objectID < RESPONSES_ROOF)
{
if (!extract_object(responsesObjects, &objectID, &object, &level, &ctx))
{
return;
goto err;
}
if (objectID == RESPONSES_SINGLE_RESPONSE)
{
@@ -767,12 +836,14 @@ void ocsp_process_response(private_ocsp_t *this, chunk_t reply)
objectID++;
}
}
err:
res->destroy(res);
}
/**
* Implements ocsp_t.fetch.
*/
static void fetch(private_ocsp_t *this, certinfo_t *certinfo)
static void fetch(private_ocsp_t *this, certinfo_t *certinfo, credential_store_t *credentials)
{
chunk_t request;
chunk_t response;
@@ -816,7 +887,7 @@ static void fetch(private_ocsp_t *this, certinfo_t *certinfo)
return;
}
DBG3("ocsp response: %B", &response);
ocsp_process_response(this, response);
ocsp_process_response(this, response, credentials);
free(response.ptr);
}
@@ -853,7 +924,7 @@ ocsp_t *ocsp_create(x509_t *cacert, linked_list_t *uris)
}
/* public functions */
this->public.fetch = (void (*) (ocsp_t*,certinfo_t*))fetch;
this->public.fetch = (void (*) (ocsp_t*,certinfo_t*,credential_store_t*))fetch;
this->public.destroy = (void (*) (ocsp_t*))destroy;
return &this->public;
+5 -2
View File
@@ -27,7 +27,9 @@
typedef struct ocsp_t ocsp_t;
#include "utils/linked_list.h"
#include <credential_store.h>
#include <utils/linked_list.h>
#include "certinfo.h"
/* constants */
@@ -57,8 +59,9 @@ struct ocsp_t {
*
* @param uris linked list of ocsp uris
* @param certinfo certificate status info to be updated
* @param credentials credential store needed for trust path verification
*/
void (*fetch) (ocsp_t *this, certinfo_t *certinfo);
void (*fetch) (ocsp_t *this, certinfo_t *certinfo, credential_store_t *credentials);
/**
* @brief Destroys the ocsp_t object.