diff options
Diffstat (limited to 'lib/cert-session.c')
| -rw-r--r-- | lib/cert-session.c | 648 |
1 files changed, 648 insertions, 0 deletions
diff --git a/lib/cert-session.c b/lib/cert-session.c index 1ba55fa448..011ef1e167 100644 --- a/lib/cert-session.c +++ b/lib/cert-session.c @@ -35,6 +35,8 @@ #include <state.h> #include <datum.h> #include <algorithms.h> +#include <gnutls/ocsp.h> +#include "hello_ext.h" /* CERTIFICATE STUFF */ @@ -215,3 +217,649 @@ gnutls_certificate_set_verify_limits(gnutls_certificate_credentials_t res, res->verify_bits = max_bits; } +/* fifteen days */ +#define MAX_OCSP_VALIDITY_SECS (15*60*60*24) +#ifdef ENABLE_OCSP +/* If the certificate is revoked status will be GNUTLS_CERT_REVOKED. + * + * Returns: + * Zero on success, a negative error code otherwise. + */ +static int +check_ocsp_response(gnutls_session_t session, gnutls_x509_crt_t cert, + gnutls_x509_trust_list_t tl, + unsigned verify_flags, + gnutls_x509_crt_t *cand_issuers, unsigned cand_issuers_size, + gnutls_datum_t * data, unsigned int *ostatus) +{ + gnutls_ocsp_resp_t resp; + int ret; + unsigned int status, cert_status; + time_t rtime, vtime, ntime, now; + int check_failed = 0; + + now = gnutls_time(0); + + ret = gnutls_ocsp_resp_init(&resp); + if (ret < 0) + return gnutls_assert_val(ret); + + ret = gnutls_ocsp_resp_import(resp, data); + if (ret < 0) { + _gnutls_audit_log(session, + "There was an error parsing the OCSP response: %s.\n", + gnutls_strerror(ret)); + ret = gnutls_assert_val(0); + check_failed = 1; + *ostatus |= GNUTLS_CERT_INVALID_OCSP_STATUS; + goto cleanup; + } + + ret = gnutls_ocsp_resp_check_crt(resp, 0, cert); + if (ret < 0) { + ret = gnutls_assert_val(0); + _gnutls_audit_log(session, + "Got OCSP response with an unrelated certificate.\n"); + check_failed = 1; + *ostatus |= GNUTLS_CERT_INVALID_OCSP_STATUS; + goto cleanup; + } + + /* Attempt to verify against our trusted list */ + ret = gnutls_ocsp_resp_verify(resp, tl, &status, verify_flags); + if ((ret < 0 || status != 0) && cand_issuers_size > 0) { + /* Attempt to verify against the certificate list provided by the server */ + + ret = gnutls_ocsp_resp_verify_direct(resp, cand_issuers[0], &status, verify_flags); + /* if verification fails attempt to find whether any of the other + * bundled CAs is an issuer of the OCSP response */ + if ((ret < 0 || status != 0) && cand_issuers_size > 1) { + int ret2; + unsigned status2, i; + + for (i=1;i<cand_issuers_size;i++) { + ret2 = gnutls_ocsp_resp_verify_direct(resp, cand_issuers[i], &status2, verify_flags); + if (ret2 >= 0 && status2 == 0) { + status = status2; + ret = ret2; + break; + } + } + } + } + + if (ret < 0) { + ret = gnutls_assert_val(0); + gnutls_assert(); + check_failed = 1; + *ostatus |= GNUTLS_CERT_INVALID_OCSP_STATUS; + goto cleanup; + } + + /* do not consider revocation data if response was not verified */ + if (status != 0) { + ret = gnutls_assert_val(0); + check_failed = 1; + *ostatus |= GNUTLS_CERT_INVALID_OCSP_STATUS; + goto cleanup; + } + + ret = gnutls_ocsp_resp_get_single(resp, 0, NULL, NULL, NULL, NULL, + &cert_status, &vtime, &ntime, + &rtime, NULL); + if (ret < 0) { + _gnutls_audit_log(session, + "There was an error parsing the OCSP response: %s.\n", + gnutls_strerror(ret)); + ret = gnutls_assert_val(0); + check_failed = 1; + *ostatus |= GNUTLS_CERT_INVALID_OCSP_STATUS; + goto cleanup; + } + + if (cert_status == GNUTLS_OCSP_CERT_REVOKED) { + _gnutls_audit_log(session, + "The certificate was revoked via OCSP\n"); + check_failed = 1; + *ostatus |= GNUTLS_CERT_REVOKED; + ret = gnutls_assert_val(0); + goto cleanup; + } + + /* Report but do not fail on the following errors. That is + * because including the OCSP response in the handshake shouldn't + * cause more problems that not including it. + */ + if (ntime == -1) { + if (now - vtime > MAX_OCSP_VALIDITY_SECS) { + _gnutls_audit_log(session, + "The OCSP response is old\n"); + check_failed = 1; + *ostatus |= GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED; + goto cleanup; + } + } else { + /* there is a newer OCSP answer, don't trust this one */ + if (ntime < now) { + _gnutls_audit_log(session, + "There is a newer OCSP response but was not provided by the server\n"); + check_failed = 1; + *ostatus |= GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED; + goto cleanup; + } + } + + ret = 0; + cleanup: + if (check_failed == 0) + session->internals.ocsp_check_ok = 1; + + gnutls_ocsp_resp_deinit(resp); + + return ret; +} + +#endif + +#define CLEAR_CERTS for(x=0;x<peer_certificate_list_size;x++) { \ + if (peer_certificate_list[x]) \ + gnutls_x509_crt_deinit(peer_certificate_list[x]); \ + } \ + gnutls_free( peer_certificate_list) + +#ifdef ENABLE_OCSP +static int +_gnutls_ocsp_verify_mandatory_stapling(gnutls_session_t session, + gnutls_x509_crt_t cert, + unsigned int * ocsp_status) +{ + gnutls_x509_tlsfeatures_t tlsfeatures; + int i, ret; + unsigned feature; + + /* RFC 7633: If cert has TLS feature GNUTLS_EXTENSION_STATUS_REQUEST, stapling is mandatory. + * + * At this point, we know that we did not get the certificate status. + * + * To proceed, first check whether we have requested the certificate status + */ + if (!_gnutls_hello_ext_is_present(session, GNUTLS_EXTENSION_STATUS_REQUEST)) { + return 0; + } + + ret = gnutls_x509_tlsfeatures_init(&tlsfeatures); + if (ret < 0) { + gnutls_assert(); + return ret; + } + + /* We have requested the status, now check whether the certificate mandates a response */ + if (gnutls_x509_crt_get_tlsfeatures(cert, tlsfeatures, 0, NULL) == 0) { + for (i = 0;; ++i) { + ret = gnutls_x509_tlsfeatures_get(tlsfeatures, i, &feature); + if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) { + break; + } + + if (ret < 0) { + gnutls_assert(); + goto cleanup; + } + + if (feature == 5 /* TLS ID for status request */) { + /* We sent a status request, the certificate mandates a reply, but we did not get any. */ + *ocsp_status |= GNUTLS_CERT_MISSING_OCSP_STATUS; + break; + } + } + } + + ret = 0; + cleanup: + gnutls_x509_tlsfeatures_deinit(tlsfeatures); + return ret; +} +#endif + +/*- + * _gnutls_x509_cert_verify_peers - return the peer's certificate status + * @session: is a gnutls session + * + * This function will try to verify the peer's certificate and return its status (TRUSTED, REVOKED etc.). + * The return value (status) should be one of the gnutls_certificate_status_t enumerated elements. + * However you must also check the peer's name in order to check if the verified certificate belongs to the + * actual peer. Returns a negative error code in case of an error, or GNUTLS_E_NO_CERTIFICATE_FOUND if no certificate was sent. + -*/ +static int +_gnutls_x509_cert_verify_peers(gnutls_session_t session, + gnutls_typed_vdata_st * data, + unsigned int elements, + unsigned int *status) +{ + cert_auth_info_t info; + gnutls_certificate_credentials_t cred; + gnutls_x509_crt_t *peer_certificate_list; + gnutls_datum_t resp; + int peer_certificate_list_size, i, x, ret; + gnutls_x509_crt_t *cand_issuers; + unsigned cand_issuers_size; + unsigned int ocsp_status = 0; + unsigned int verify_flags; + + /* No OCSP check so far */ + session->internals.ocsp_check_ok = 0; + + CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST); + + info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE); + if (info == NULL) { + gnutls_assert(); + return GNUTLS_E_INVALID_REQUEST; + } + + cred = (gnutls_certificate_credentials_t) + _gnutls_get_cred(session, GNUTLS_CRD_CERTIFICATE); + if (cred == NULL) { + gnutls_assert(); + return GNUTLS_E_INSUFFICIENT_CREDENTIALS; + } + + if (info->raw_certificate_list == NULL || info->ncerts == 0) + return GNUTLS_E_NO_CERTIFICATE_FOUND; + + if (info->ncerts > cred->verify_depth && cred->verify_depth > 0) { + gnutls_assert(); + return GNUTLS_E_CONSTRAINT_ERROR; + } + + verify_flags = + cred->verify_flags | session->internals.additional_verify_flags; + /* generate a list of gnutls_certs based on the auth info + * raw certs. + */ + peer_certificate_list_size = info->ncerts; + peer_certificate_list = + gnutls_calloc(peer_certificate_list_size, + sizeof(gnutls_x509_crt_t)); + if (peer_certificate_list == NULL) { + gnutls_assert(); + return GNUTLS_E_MEMORY_ERROR; + } + + for (i = 0; i < peer_certificate_list_size; i++) { + ret = gnutls_x509_crt_init(&peer_certificate_list[i]); + if (ret < 0) { + gnutls_assert(); + CLEAR_CERTS; + return ret; + } + + ret = + gnutls_x509_crt_import(peer_certificate_list[i], + &info->raw_certificate_list[i], + GNUTLS_X509_FMT_DER); + if (ret < 0) { + gnutls_assert(); + CLEAR_CERTS; + return ret; + } + } + + /* Use the OCSP extension if any */ +#ifdef ENABLE_OCSP + if (verify_flags & GNUTLS_VERIFY_DISABLE_CRL_CHECKS) + goto skip_ocsp; + + for (i=0;i<peer_certificate_list_size;i++) { + ret = gnutls_ocsp_status_request_get2(session, i, &resp); + if (ret < 0) { + ret = _gnutls_ocsp_verify_mandatory_stapling(session, peer_certificate_list[i], &ocsp_status); + if (ret < 0) { + gnutls_assert(); + CLEAR_CERTS; + return ret; + } + + continue; + } + + cand_issuers = NULL; + cand_issuers_size = 0; + if (peer_certificate_list_size > i+1) { + cand_issuers = &peer_certificate_list[i+1]; + cand_issuers_size = peer_certificate_list_size-i-1; + } + + ret = + check_ocsp_response(session, + peer_certificate_list[i], + cred->tlist, + verify_flags, cand_issuers, + cand_issuers_size, + &resp, &ocsp_status); + + if (ret < 0) { + CLEAR_CERTS; + return gnutls_assert_val(ret); + } + } +#endif + + skip_ocsp: + /* Verify certificate + */ + ret = + gnutls_x509_trust_list_verify_crt2(cred->tlist, + peer_certificate_list, + peer_certificate_list_size, + data, elements, + verify_flags, status, NULL); + + if (ret < 0) { + gnutls_assert(); + CLEAR_CERTS; + return ret; + } + + CLEAR_CERTS; + + *status |= ocsp_status; + + return 0; +} + +/** + * gnutls_certificate_verify_peers2: + * @session: is a gnutls session + * @status: is the output of the verification + * + * This function will verify the peer's certificate and store + * the status in the @status variable as a bitwise OR of gnutls_certificate_status_t + * values or zero if the certificate is trusted. Note that value in @status + * is set only when the return value of this function is success (i.e, failure + * to trust a certificate does not imply a negative return value). + * The default verification flags used by this function can be overridden + * using gnutls_certificate_set_verify_flags(). + * + * This function will take into account the OCSP Certificate Status TLS extension, + * as well as the following X.509 certificate extensions: Name Constraints, + * Key Usage, and Basic Constraints (pathlen). + * + * To avoid denial of service attacks some + * default upper limits regarding the certificate key size and chain + * size are set. To override them use gnutls_certificate_set_verify_limits(). + * + * Note that you must also check the peer's name in order to check if + * the verified certificate belongs to the actual peer, see gnutls_x509_crt_check_hostname(), + * or use gnutls_certificate_verify_peers3(). + * + * Returns: %GNUTLS_E_SUCCESS (0) when the validation is performed, or a negative error code otherwise. + * A successful error code means that the @status parameter must be checked to obtain the validation status. + **/ +int +gnutls_certificate_verify_peers2(gnutls_session_t session, + unsigned int *status) +{ + return gnutls_certificate_verify_peers(session, NULL, 0, status); +} + +/** + * gnutls_certificate_verify_peers3: + * @session: is a gnutls session + * @hostname: is the expected name of the peer; may be %NULL + * @status: is the output of the verification + * + * This function will verify the peer's certificate and store the + * the status in the @status variable as a bitwise OR of gnutls_certificate_status_t + * values or zero if the certificate is trusted. Note that value in @status + * is set only when the return value of this function is success (i.e, failure + * to trust a certificate does not imply a negative return value). + * The default verification flags used by this function can be overridden + * using gnutls_certificate_set_verify_flags(). See the documentation + * of gnutls_certificate_verify_peers2() for details in the verification process. + * + * If the @hostname provided is non-NULL then this function will compare + * the hostname in the certificate against it. The comparison will follow + * the RFC6125 recommendations. If names do not match the + * %GNUTLS_CERT_UNEXPECTED_OWNER status flag will be set. + * + * In order to verify the purpose of the end-certificate (by checking the extended + * key usage), use gnutls_certificate_verify_peers(). + * + * Returns: %GNUTLS_E_SUCCESS (0) when the validation is performed, or a negative error code otherwise. + * A successful error code means that the @status parameter must be checked to obtain the validation status. + * + * Since: 3.1.4 + **/ +int +gnutls_certificate_verify_peers3(gnutls_session_t session, + const char *hostname, + unsigned int *status) +{ +gnutls_typed_vdata_st data; + + data.type = GNUTLS_DT_DNS_HOSTNAME; + data.size = 0; + data.data = (void*)hostname; + + return gnutls_certificate_verify_peers(session, &data, 1, status); +} + +/** + * gnutls_certificate_verify_peers: + * @session: is a gnutls session + * @data: an array of typed data + * @elements: the number of data elements + * @status: is the output of the verification + * + * This function will verify the peer's certificate and store the + * the status in the @status variable as a bitwise OR of gnutls_certificate_status_t + * values or zero if the certificate is trusted. Note that value in @status + * is set only when the return value of this function is success (i.e, failure + * to trust a certificate does not imply a negative return value). + * The default verification flags used by this function can be overridden + * using gnutls_certificate_set_verify_flags(). See the documentation + * of gnutls_certificate_verify_peers2() for details in the verification process. + * + * The acceptable @data types are %GNUTLS_DT_DNS_HOSTNAME, %GNUTLS_DT_RFC822NAME and %GNUTLS_DT_KEY_PURPOSE_OID. + * The former two accept as data a null-terminated hostname or email address, and the latter a null-terminated + * object identifier (e.g., %GNUTLS_KP_TLS_WWW_SERVER). + * + * If a DNS hostname is provided then this function will compare + * the hostname in the certificate against the given. If names do not match the + * %GNUTLS_CERT_UNEXPECTED_OWNER status flag will be set. + * If a key purpose OID is provided and the end-certificate contains the extended key + * usage PKIX extension, it will be required to be have the provided key purpose + * or be marked for any purpose, otherwise verification status will have the + * %GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE flag set. + * + * Returns: %GNUTLS_E_SUCCESS (0) when the validation is performed, or a negative error code otherwise. + * A successful error code means that the @status parameter must be checked to obtain the validation status. + * + * Since: 3.3.0 + **/ +int +gnutls_certificate_verify_peers(gnutls_session_t session, + gnutls_typed_vdata_st * data, + unsigned int elements, + unsigned int *status) +{ + cert_auth_info_t info; + + CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST); + + info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE); + if (info == NULL) { + return GNUTLS_E_NO_CERTIFICATE_FOUND; + } + + if (info->raw_certificate_list == NULL || info->ncerts == 0) + return GNUTLS_E_NO_CERTIFICATE_FOUND; + + + switch (gnutls_certificate_type_get(session)) { + case GNUTLS_CRT_X509: + return _gnutls_x509_cert_verify_peers(session, data, elements, + status); + default: + return GNUTLS_E_INVALID_REQUEST; + } +} + +/*- + * gnutls_x509_extract_certificate_expiration_time: + * @cert: should contain an X.509 DER encoded certificate + * + * This function will return the certificate's expiration time in UNIX + * time (ie seconds since 00:00:00 UTC January 1, 1970). Returns a + * + * (time_t) -1 in case of an error. + * + -*/ +static time_t +_gnutls_x509_get_raw_crt_expiration_time(const gnutls_datum_t * cert) +{ + gnutls_x509_crt_t xcert; + time_t result; + + result = gnutls_x509_crt_init(&xcert); + if (result < 0) + return (time_t) - 1; + + result = gnutls_x509_crt_import(xcert, cert, GNUTLS_X509_FMT_DER); + if (result < 0) { + gnutls_x509_crt_deinit(xcert); + return (time_t) - 1; + } + + result = gnutls_x509_crt_get_expiration_time(xcert); + + gnutls_x509_crt_deinit(xcert); + + return result; +} + +/** + * gnutls_certificate_expiration_time_peers: + * @session: is a gnutls session + * + * This function will return the peer's certificate expiration time. + * + * Returns: (time_t)-1 on error. + * + * Deprecated: gnutls_certificate_verify_peers2() now verifies expiration times. + **/ +time_t gnutls_certificate_expiration_time_peers(gnutls_session_t session) +{ + cert_auth_info_t info; + + CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST); + + info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE); + if (info == NULL) { + return (time_t) - 1; + } + + if (info->raw_certificate_list == NULL || info->ncerts == 0) { + gnutls_assert(); + return (time_t) - 1; + } + + switch (gnutls_certificate_type_get(session)) { + case GNUTLS_CRT_X509: + return + _gnutls_x509_get_raw_crt_expiration_time(&info-> + raw_certificate_list + [0]); + default: + return (time_t) - 1; + } +} + +/*- + * _gnutls_x509_extract_certificate_activation_time - return the peer's certificate activation time + * @cert: should contain an X.509 DER encoded certificate + * + * This function will return the certificate's activation time in UNIX time + * (ie seconds since 00:00:00 UTC January 1, 1970). + * + * Returns a (time_t) -1 in case of an error. + * + -*/ +static time_t +_gnutls_x509_get_raw_crt_activation_time(const gnutls_datum_t * cert) +{ + gnutls_x509_crt_t xcert; + time_t result; + + result = gnutls_x509_crt_init(&xcert); + if (result < 0) + return (time_t) - 1; + + result = gnutls_x509_crt_import(xcert, cert, GNUTLS_X509_FMT_DER); + if (result < 0) { + gnutls_x509_crt_deinit(xcert); + return (time_t) - 1; + } + + result = gnutls_x509_crt_get_activation_time(xcert); + + gnutls_x509_crt_deinit(xcert); + + return result; +} + +/** + * gnutls_certificate_activation_time_peers: + * @session: is a gnutls session + * + * This function will return the peer's certificate activation time. + * + * Returns: (time_t)-1 on error. + * + * Deprecated: gnutls_certificate_verify_peers2() now verifies activation times. + **/ +time_t gnutls_certificate_activation_time_peers(gnutls_session_t session) +{ + cert_auth_info_t info; + + CHECK_AUTH(GNUTLS_CRD_CERTIFICATE, GNUTLS_E_INVALID_REQUEST); + + info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE); + if (info == NULL) { + return (time_t) - 1; + } + + if (info->raw_certificate_list == NULL || info->ncerts == 0) { + gnutls_assert(); + return (time_t) - 1; + } + + switch (gnutls_certificate_type_get(session)) { + case GNUTLS_CRT_X509: + return + _gnutls_x509_get_raw_crt_activation_time(&info-> + raw_certificate_list + [0]); + default: + return (time_t) - 1; + } +} + +/** + * gnutls_certificate_server_set_request: + * @session: is a #gnutls_session_t type. + * @req: is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE + * + * This function specifies if we (in case of a server) are going to + * send a certificate request message to the client. If @req is + * GNUTLS_CERT_REQUIRE then the server will return the %GNUTLS_E_NO_CERTIFICATE_FOUND + * error if the peer does not provide a certificate. If you do not call this + * function then the client will not be asked to send a certificate. + **/ +void +gnutls_certificate_server_set_request(gnutls_session_t session, + gnutls_certificate_request_t req) +{ + session->internals.send_cert_req = req; +} |