From 06f14421ea8644d12a7b0be6b583114869f9c451 Mon Sep 17 00:00:00 2001 From: Jouni Malinen Date: Mon, 14 Dec 2015 12:31:35 +0200 Subject: [PATCH] TLS: Parse OCSPResponse to extract BasicOCSPResponse This adds the next step for OCSP stapling. The received OCSPResponse is parsed to get the BasicOCSPResponse. This commit does not yet process the BasicOCSPResponse. Signed-off-by: Jouni Malinen --- src/tls/tlsv1_client_ocsp.c | 149 +++++++++++++++++++++++++++++++++++- 1 file changed, 146 insertions(+), 3 deletions(-) diff --git a/src/tls/tlsv1_client_ocsp.c b/src/tls/tlsv1_client_ocsp.c index 8d64527eb..bcc7a8605 100644 --- a/src/tls/tlsv1_client_ocsp.c +++ b/src/tls/tlsv1_client_ocsp.c @@ -10,17 +10,160 @@ #include "common.h" #include "crypto/tls.h" +#include "asn1.h" #include "tlsv1_common.h" #include "tlsv1_record.h" #include "tlsv1_client.h" #include "tlsv1_client_i.h" -enum tls_ocsp_result tls_process_ocsp_response(struct tlsv1_client *conn, - const u8 *resp, size_t len) +/* RFC 6960, 4.2.1: OCSPResponseStatus ::= ENUMERATED */ +enum ocsp_response_status { + OCSP_RESP_STATUS_SUCCESSFUL = 0, + OCSP_RESP_STATUS_MALFORMED_REQ = 1, + OCSP_RESP_STATUS_INT_ERROR = 2, + OCSP_RESP_STATUS_TRY_LATER = 3, + /* 4 not used */ + OCSP_RESP_STATUS_SIG_REQUIRED = 5, + OCSP_RESP_STATUS_UNAUTHORIZED = 6, +}; + + +static int is_oid_basic_ocsp_resp(struct asn1_oid *oid) { - wpa_hexdump(MSG_MSGDUMP, "TLSv1: OCSPResponse", resp, len); + return oid->len == 10 && + oid->oid[0] == 1 /* iso */ && + oid->oid[1] == 3 /* identified-organization */ && + oid->oid[2] == 6 /* dod */ && + oid->oid[3] == 1 /* internet */ && + oid->oid[4] == 5 /* security */ && + oid->oid[5] == 5 /* mechanisms */ && + oid->oid[6] == 7 /* id-pkix */ && + oid->oid[7] == 48 /* id-ad */ && + oid->oid[8] == 1 /* id-pkix-ocsp */ && + oid->oid[9] == 1 /* id-pkix-ocsp-basic */; +} + + +static enum tls_ocsp_result +tls_process_basic_ocsp_response(struct tlsv1_client *conn, const u8 *resp, + size_t len) +{ + wpa_hexdump(MSG_MSGDUMP, "OCSP: BasicOCSPResponse", resp, len); + + /* + * RFC 6960, 4.2.1: + * BasicOCSPResponse ::= SEQUENCE { + * tbsResponseData ResponseData, + * signatureAlgorithm AlgorithmIdentifier, + * signature BIT STRING, + * certs [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL } + */ /* TODO */ return TLS_OCSP_NO_RESPONSE; } + + +enum tls_ocsp_result tls_process_ocsp_response(struct tlsv1_client *conn, + const u8 *resp, size_t len) +{ + struct asn1_hdr hdr; + const u8 *pos, *end; + u8 resp_status; + struct asn1_oid oid; + char obuf[80]; + + wpa_hexdump(MSG_MSGDUMP, "TLSv1: OCSPResponse", resp, len); + + /* + * RFC 6960, 4.2.1: + * OCSPResponse ::= SEQUENCE { + * responseStatus OCSPResponseStatus, + * responseBytes [0] EXPLICIT ResponseBytes OPTIONAL } + */ + + 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 (OCSPResponse) - found class %d tag 0x%x", + hdr.class, hdr.tag); + return TLS_OCSP_INVALID; + } + pos = hdr.payload; + end = hdr.payload + hdr.length; + + /* OCSPResponseStatus ::= ENUMERATED */ + if (asn1_get_next(pos, end - pos, &hdr) < 0 || + hdr.class != ASN1_CLASS_UNIVERSAL || + hdr.tag != ASN1_TAG_ENUMERATED || + hdr.length != 1) { + wpa_printf(MSG_DEBUG, + "OCSP: Expected ENUMERATED (responseStatus) - found class %d tag 0x%x length %u", + hdr.class, hdr.tag, hdr.length); + return TLS_OCSP_INVALID; + } + resp_status = hdr.payload[0]; + wpa_printf(MSG_DEBUG, "OCSP: responseStatus %u", resp_status); + pos = hdr.payload + hdr.length; + if (resp_status != OCSP_RESP_STATUS_SUCCESSFUL) { + wpa_printf(MSG_DEBUG, "OCSP: No stapling result"); + return TLS_OCSP_NO_RESPONSE; + } + + /* responseBytes [0] EXPLICIT ResponseBytes OPTIONAL */ + if (pos == end) + return TLS_OCSP_NO_RESPONSE; + + if (asn1_get_next(pos, end - pos, &hdr) < 0 || + hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC || + hdr.tag != 0) { + wpa_printf(MSG_DEBUG, + "OCSP: Expected [0] EXPLICIT (responseBytes) - found class %d tag 0x%x", + hdr.class, hdr.tag); + return TLS_OCSP_INVALID; + } + + /* + * ResponseBytes ::= SEQUENCE { + * responseType OBJECT IDENTIFIER, + * response OCTET STRING } + */ + + if (asn1_get_next(hdr.payload, hdr.length, &hdr) < 0 || + hdr.class != ASN1_CLASS_UNIVERSAL || + hdr.tag != ASN1_TAG_SEQUENCE) { + wpa_printf(MSG_DEBUG, + "OCSP: Expected SEQUENCE (ResponseBytes) - found class %d tag 0x%x", + hdr.class, hdr.tag); + return TLS_OCSP_INVALID; + } + pos = hdr.payload; + end = hdr.payload + hdr.length; + + /* responseType OBJECT IDENTIFIER */ + if (asn1_get_oid(pos, end - pos, &oid, &pos)) { + wpa_printf(MSG_DEBUG, + "OCSP: Failed to parse OID (responseType)"); + return TLS_OCSP_INVALID; + } + asn1_oid_to_str(&oid, obuf, sizeof(obuf)); + wpa_printf(MSG_DEBUG, "OCSP: responseType %s", obuf); + if (!is_oid_basic_ocsp_resp(&oid)) { + wpa_printf(MSG_DEBUG, "OCSP: Ignore unsupported response type"); + return TLS_OCSP_NO_RESPONSE; + } + + /* response 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 (response) - found class %d tag 0x%x", + hdr.class, hdr.tag); + return TLS_OCSP_INVALID; + } + + return tls_process_basic_ocsp_response(conn, hdr.payload, hdr.length); +}