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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Secure Component */
/** */
/** X.509 Digital Certificates */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SECURE_SOURCE_CODE
#include "nx_secure_x509.h"
static UINT _nx_secure_x509_parse_cert_data(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_version(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_serial_num(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_signature_algorithm(const UCHAR *buffer, ULONG length,
UINT *bytes_processed,
NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_issuer(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_validity(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_subject(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_public_key(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_unique_ids(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_extensions(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_parse_signature_data(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
static UINT _nx_secure_x509_extract_oid_data(const UCHAR *buffer, UINT oid, UINT oid_param, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert);
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_certificate_parse PORTABLE C */
/* 6.1.6 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses a DER-encoded X509 digital certificate and */
/* up pointers in the NX_SECURE_X509_CERT structure to the various */
/* fields needed by applications such as TLS. Note that to save memory */
/* the data is left in-place and not copied out into separate buffers. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Length of data in buffer */
/* bytes_processed Return bytes processed */
/* cert Return X509 structure */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* _nx_secure_x509_parse_signature_algorithm */
/* Parse signature algorithm in */
/* certificate */
/* _nx_secure_x509_parse_signature_data Parse signature data in */
/* certificate */
/* */
/* CALLED BY */
/* */
/* _nx_secure_tls_process_remote_certificate */
/* Process server certificate */
/* _nx_secure_x509_certificate_initialize */
/* Initialize certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* 04-02-2021 Timothy Stapko Modified comment(s), */
/* removed dependency on TLS, */
/* resulting in version 6.1.6 */
/* */
/**************************************************************************/
UINT _nx_secure_x509_certificate_parse(const UCHAR *buffer, UINT length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
UINT bytes;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
/* X509 Certificate structure:
* ASN.1 sequence: Certificate
* Sequence: Certificate data
* Version (e.g. X509v3)
* Serial Number
* Sequence: Signature algorithm
* Signature Algorithms (e.g. RSA_SHA-256)
* NULL
* Sequence: Issuer
* Set: Issuer information (multiple sets here - one per OID)
* Sequence: Information (multiple sequences here?)
* ASN.1 OID (e.g. Country/Region)
* ASN.1 String (e.g. "US")
* ...
* Sequence: Validity Period
* UTC Time: Not before (ASN.1 time value)
* UTC Time: Not After
* Sequence: Subject info (Common Name, etc. for this certificate)
* Set: Subject information (multiple sets here - one per OID)
* Sequence: Information (multiple sequences here?)
* ASN.1 OID (e.g. Country/Region)
* ASN.1 String (e.g. "US")
* ...
* Sequence: Public Key
* Sequence: Public key data
* ASN.1 OID (e.g. RSA)
* NULL
* ASN.1 Bit string - contains embedded key data in ASN.1 format:
* {
* 1 byte: padding (always 0?)
* ASN.1 Key information - sequence of 2 integers for RSA:
* Public Modulus followed by Public Exponent
* }
* ASN.1 Bit String: Extensions
* {
* ASN.1-encoded data for extensions
* }
* Sequence: Signature algorithm data
* ASN.1 OID (E.g RSA_SHA256)
* NULL
* ASN.1 Bit string: Signature data
*
* Parsing of this structure is as follows:
* - Each sequence is parsed by it's own function
* - The structure of each recursive sequence/set is encapsulated in the function that parses it
* - Some functions may be used in multiple places (e.g. subject info parsing)
* - At the lowest level, all parsing will be done by the ASN.1 TLV block parser.
*/
/* Parse a TLV block and get information to continue parsing. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, (ULONG *)&length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_INVALID_CERTIFICATE_SEQUENCE);
}
*bytes_processed = header_length;
length = tlv_length;
/* Next block should be the certificate data. */
status = _nx_secure_x509_parse_cert_data(tlv_data, tlv_length, &bytes, cert);
if (status != 0)
{
return(status);
}
*bytes_processed += bytes;
/* Following the certificate data is the signature algorithm data. */
tlv_data = &tlv_data[bytes];
length -= bytes;
status = _nx_secure_x509_parse_signature_algorithm(tlv_data, length, &bytes, cert);
if (status != 0)
{
return(status);
}
*bytes_processed += bytes;
/* Finally, the signature itself is at the end of the certificate. */
tlv_data = &tlv_data[bytes];
length -= bytes;
status = _nx_secure_x509_parse_signature_data(tlv_data, length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Return the number of bytes we processed. */
*bytes_processed += bytes;
if (cert -> nx_secure_x509_public_algorithm != NX_SECURE_TLS_X509_TYPE_RSA
#ifdef NX_SECURE_ENABLE_ECC_CIPHERSUITE
&& cert -> nx_secure_x509_public_algorithm != NX_SECURE_TLS_X509_TYPE_EC
#endif /* NX_SECURE_ENABLE_ECC_CIPHERSUITE */
)
{
return(NX_SECURE_X509_UNSUPPORTED_PUBLIC_CIPHER);
}
/* Successfully parsed an X509 certificate. */
return(NX_SECURE_X509_SUCCESS);
}
/* --- Helper functions. --- */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_extract_oid_data PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function extracts data from the certificate buffer associated */
/* with an OID, but not part of a Distinguished Name Field or */
/* extensions. This generally includes public keys and algorithm */
/* identifiers. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* oid Data type in OID */
/* oid_param Public key parameter OID */
/* length Length of data in buffer */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_public_key Parse public key in */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_extract_oid_data(const UCHAR *buffer, UINT oid, UINT oid_param, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
const UCHAR *sequence_data;
ULONG header_length;
UINT status;
#ifdef NX_SECURE_ENABLE_ECC_CIPHERSUITE
NX_SECURE_EC_PUBLIC_KEY *ec_pubkey;
#else
NX_CRYPTO_PARAMETER_NOT_USED(oid_param);
#endif /* NX_SECURE_ENABLE_ECC_CIPHERSUITE */
#ifdef NX_CRYPTO_STANDALONE_ENABLE
if (cert == NX_CRYPTO_NULL)
{
return(NX_CRYPTO_PTR_ERROR);
}
#else
NX_ASSERT(cert != NX_CRYPTO_NULL);
#endif /* NX_CRYPTO_STANDALONE_ENABLE */
/* IMPORTANT NOTE: This function MUST handle a NULL value for the "cert" parameter - we need to parse the
* certificate data no matter what, and in some cases we might want to parse past the data rather than saving
* it off in the cert structure. By passing the structure as NULL, this function should just pass over the parsed data.
*/
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status != 0)
{
*bytes_processed = 0;
return(status);
}
*bytes_processed = (header_length + tlv_length);
/* The RSA OID represents an ASN.1 structure rather than a simple field so handle it differently. */
if (oid == NX_SECURE_TLS_X509_TYPE_RSA)
{
/* RSA public key. ASN.1 formatted string with a leading 0 byte. */
if (tlv_length < 1)
{
return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG);
}
/* Parse the RSA bitstring - it is preceeded by a byte indicating the number of padding bytes
* added. Should always be 0. */
if (tlv_data[0] != 0)
{
return(NX_SECURE_X509_FOUND_NON_ZERO_PADDING);
}
length = tlv_length - 1;
/* First is a sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(&tlv_data[1], &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status || tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_MISSING_PUBLIC_KEY);
}
sequence_data = tlv_data;
length = tlv_length;
/* Inside is the public modulus. */
status = _nx_secure_x509_asn1_tlv_block_parse(sequence_data, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status || tlv_type != NX_SECURE_ASN_TAG_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_INVALID_PUBLIC_KEY);
}
/* The modulus has a 0 byte at the front we need to skip.
* This is due to the modulus being encoded as an ASN.1 bit string, which may
* require padding bits to get to a multiple of 8 for byte alignment. The byte
* represents the number of padding bits, but in X509 it should always be 0. */
cert -> nx_secure_x509_public_key.rsa_public_key.nx_secure_rsa_public_modulus = &tlv_data[1];
cert -> nx_secure_x509_public_key.rsa_public_key.nx_secure_rsa_public_modulus_length = (USHORT)(tlv_length - 1);
/* Finally the public exponent. */
status = _nx_secure_x509_asn1_tlv_block_parse(&sequence_data[header_length + tlv_length], &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status || tlv_type != NX_SECURE_ASN_TAG_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_INVALID_PUBLIC_KEY);
}
/* Extract a pointer to the public exponent. */
cert -> nx_secure_x509_public_key.rsa_public_key.nx_secure_rsa_public_exponent = tlv_data;
cert -> nx_secure_x509_public_key.rsa_public_key.nx_secure_rsa_public_exponent_length = (USHORT)tlv_length;
}
#ifdef NX_SECURE_ENABLE_ECC_CIPHERSUITE
else if (oid == NX_SECURE_TLS_X509_TYPE_EC)
{
/* EC public key. */
/* Parse the EC bitstring - it is preceeded by a byte indicating the number of padding bytes
* added. Should always be 0. */
if (tlv_data[0] != 0)
{
return(NX_SECURE_X509_FOUND_NON_ZERO_PADDING);
}
ec_pubkey = &cert -> nx_secure_x509_public_key.ec_public_key;
ec_pubkey -> nx_secure_ec_public_key = &tlv_data[1];
ec_pubkey -> nx_secure_ec_public_key_length = (USHORT)(tlv_length - 1);
ec_pubkey -> nx_secure_ec_named_curve = oid_param;
}
#endif /* NX_SECURE_ENABLE_ECC_CIPHERSUITE */
/* Any additional special-case handling should go here. */
switch (oid)
{
case NX_SECURE_TLS_X509_TYPE_RSA_MD5:
case NX_SECURE_TLS_X509_TYPE_RSA_SHA_1:
case NX_SECURE_TLS_X509_TYPE_RSA_SHA_256:
case NX_SECURE_TLS_X509_TYPE_RSA_SHA_384:
case NX_SECURE_TLS_X509_TYPE_RSA_SHA_512:
case NX_SECURE_TLS_X509_TYPE_DSS_SHA_1:
case NX_SECURE_TLS_X509_TYPE_DH:
case NX_SECURE_TLS_X509_TYPE_RSA:
/*Public keys require additional parsing, handled above. */
default:
break;
}
/* We have successfully extracted our data based on the OID. */
return(NX_SECURE_X509_SUCCESS);
}
/* Parse the sequence that contains all the certificate data (e.g. Common Name and public key). */
/* Version (e.g. X509v3)
* Serial Number
* Sequence: Signature algorithm (NULL-terminated)
* Sequence: Issuer
* Sequence: Validity Period
* Sequence: Subject info (Common Name, etc. for this certificate)
* Sequence: Public Key
* ASN.1 Bit String: Extensions
*/
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_cert_data PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the ASN.1 sequence in an X.509 certificate that */
/* contains the identity information for the certificate. This is the */
/* high-level container for all the certificate information. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_parse_extensions Parse extension in certificate*/
/* _nx_secure_x509_parse_issuer Parse issuer in certificate */
/* _nx_secure_x509_parse_public_key Parse public key in */
/* certificate */
/* _nx_secure_x509_parse_serial_num Parse serial number in */
/* certificate */
/* _nx_secure_x509_parse_signature_algorithm */
/* Parse signature algorithm in */
/* certificate */
/* _nx_secure_x509_parse_subject Parse subject in certificate */
/* _nx_secure_x509_parse_unique_ids Parse unique IDs in */
/* certificate */
/* _nx_secure_x509_parse_validity Parse validity in certificate */
/* _nx_secure_x509_parse_version Parse version in certificate */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_certificate_parse Extract public key data */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_cert_data(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
UINT bytes;
UINT cur_length;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
/* Parse a TLV block and get information to continue parsing. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
/* Buffer should contain the certificate data sequence. */
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_INVALID_CERTIFICATE_DATA);
}
/* We need to save off a pointer to the certificate data and its length for
signature generation and verification later on. The certificate data
for verification includes the encapsulating ASN.1 sequence header. */
cert -> nx_secure_x509_certificate_data = buffer;
cert -> nx_secure_x509_certificate_data_length = tlv_length + header_length;
*bytes_processed = header_length;
/* First up is the version data. */
status = _nx_secure_x509_parse_version(tlv_data, tlv_length, &bytes, cert);
if (status != 0)
{
return(status);
}
cur_length = tlv_length;
/* Next is the serial number. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
status = _nx_secure_x509_parse_serial_num(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Signature algorithm (embedded in the certificate information). */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
status = _nx_secure_x509_parse_signature_algorithm(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Issuer data. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
status = _nx_secure_x509_parse_issuer(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Validity period. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
status = _nx_secure_x509_parse_validity(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Subject information. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
status = _nx_secure_x509_parse_subject(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Public key. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
status = _nx_secure_x509_parse_public_key(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
/* Optional Issuer and Subject Unique IDs. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
/* The following fields are all optional, so stop parsing with success if
they were not included. */
if (cur_length == 0)
{
return(NX_SECURE_X509_SUCCESS);
}
status = _nx_secure_x509_parse_unique_ids(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
*bytes_processed += bytes;
/* Parse extensions. */
tlv_data = &tlv_data[bytes];
cur_length -= bytes;
*bytes_processed += bytes;
/* The following fields are all optional, so stop parsing with success if
they were not included. */
if (cur_length == 0)
{
return(NX_SECURE_X509_SUCCESS);
}
status = _nx_secure_x509_parse_extensions(tlv_data, cur_length, &bytes, cert);
if (status != 0)
{
return(status);
}
*bytes_processed += bytes;
/* Parsed X509 certificate data successfully. */
return(NX_SECURE_X509_SUCCESS);
}
/* X509 certificate version parsing. NOTE: X509v1 certificates do NOT have a version field! */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_version PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the optional version field in an X.509 */
/* certificate. If the field is omitted, the certificate must be a */
/* version 1 X.509 certificate. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_version(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
NX_CRYPTO_PARAMETER_NOT_USED(cert);
/* Parse a TLV block and get information to continue parsing. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
/* Check to see if version exists. If the version is present it will have a type
* of NX_SECURE_ASN_TAG_BER. Otherwise it is an X509v1 certificate or invalid
* (determined higher up the call stack). */
if (tlv_type == NX_SECURE_ASN_TAG_BER && tlv_type_class == NX_SECURE_ASN_TAG_CLASS_CONTEXT)
{
/* Version is the payload byte. */
cert -> nx_secure_x509_version = (USHORT)tlv_data[0];
/* Return the number of bytes we processed. */
*bytes_processed = header_length + tlv_length;
}
else
{
/* No Version field found, assume X509v1. */
cert -> nx_secure_x509_version = NX_SECURE_X509_VERSION_1;
/* No bytes processed since the field was omitted. */
*bytes_processed = 0;
}
/* Always return success - this field is optional. */
return(NX_SECURE_X509_SUCCESS);
}
/* X509 certificate serial number parsing. */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_serial_num PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the serial number field of an X.509 */
/* certificate. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_serial_num(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
NX_CRYPTO_PARAMETER_NOT_USED(cert);
/* Parse a TLV block and get information to continue parsing. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
/* Check to see if version exists. If the version is present it will have a type
* of NX_SECURE_ASN_TAG_BER. Otherwise it is an X509v1 certificate or invalid
* (determined higher up the call stack). */
if (tlv_type != NX_SECURE_ASN_TAG_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Save off the serial number in case someone wants it. */
cert -> nx_secure_x509_serial_number = tlv_data;
cert -> nx_secure_x509_serial_number_length = (USHORT)tlv_length;
/* Return the number of bytes we processed. */
*bytes_processed = header_length + tlv_length;
return(NX_SECURE_X509_SUCCESS);
}
/* X509 certificate signature algorithm parsing. Used at both the top level and in the certificate sequence. */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_signature_algorithm PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the signature algorithm field in an X.509 */
/* certificate. The signature algorithm is found both in certificate */
/* data sequence and with the public key information. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_oid_parse Parse OID in certificate */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* _nx_secure_x509_certificate_parse Extract public key data */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_signature_algorithm(const UCHAR *buffer, ULONG length,
UINT *bytes_processed,
NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
UINT oid;
ULONG header_length;
UINT status;
UCHAR oid_found = NX_CRYPTO_FALSE;
/* The signature algorithm is an OID and has optionally associated parameters. */
*bytes_processed = 0;
/* First, parse the sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Limit the length to the sequence length. */
length = tlv_length;
/* While the tag is not NULL and we don't run out of buffer, keep parsing OIDs. */
*bytes_processed += header_length;
while (length > 0)
{
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status != 0)
{
return status;
}
/* Update bytes processed. */
*bytes_processed += (header_length + tlv_length);
/* Now check out what we got. */
if (tlv_type == NX_SECURE_ASN_TAG_OID)
{
_nx_secure_x509_oid_parse(tlv_data, tlv_length, &oid);
cert -> nx_secure_x509_signature_algorithm = oid;
oid_found = NX_CRYPTO_TRUE;
}
else if (tlv_type == NX_SECURE_ASN_TAG_NULL)
{
break;
}
else
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Advance the data pointer. */
tlv_data = &tlv_data[tlv_length];
}
if (oid_found == NX_CRYPTO_TRUE)
{
return(NX_SECURE_X509_SUCCESS);
}
/* We were expecting a signature algorithm OID but didn't find one. */
return(NX_SECURE_X509_MISSING_SIGNATURE_ALGORITHM);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_issuer PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the issuer distinguished name in an X.509 */
/* certificate. The issuer distinguished name is used to link the */
/* certificate to the CA certificate that signed it. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_distinguished_name_parse */
/* Parse Distinguished Name */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_issuer(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
UINT bytes;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
/* First, parse the sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Now, pass the issuer certificate to populate it with the id info. Note that
* even if the issuer cert is NULL, we still need to parse the information -
* the parse_id function handles NULL appropriately. */
status = _nx_secure_x509_distinguished_name_parse(tlv_data, tlv_length, &bytes, &cert -> nx_secure_x509_issuer);
/* Return the number of bytes we processed. */
*bytes_processed = bytes + header_length;
return status;
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_validity PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the validity period fields in an X.509 */
/* certificate. The fields "Not Before" and "Not After" define an */
/* explicit time period during which the certificate is valid. The the */
/* current date and time fall outside that period, the certificate is */
/* considered invalid and should not be trusted. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_validity(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
const UCHAR *current_buffer;
NX_CRYPTO_PARAMETER_NOT_USED(cert);
/* First, parse the sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Return the number of bytes we processed. */
*bytes_processed = header_length + tlv_length;
length = tlv_length;
/* Advance to our next item. */
current_buffer = &buffer[0] + header_length;
/* Parse the "not before" field. */
status = _nx_secure_x509_asn1_tlv_block_parse(current_buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if ((tlv_type != NX_SECURE_ASN_TAG_UTC_TIME && tlv_type != NX_SECURE_ASN_TAG_GENERALIZED_TIME) || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
cert -> nx_secure_x509_validity_format = tlv_type;
cert -> nx_secure_x509_not_before = tlv_data;
cert -> nx_secure_x509_not_before_length = (USHORT)tlv_length;
/* Advance to our next item. */
current_buffer = current_buffer + (tlv_length + header_length);
/* Parse the "not after" field. */
status = _nx_secure_x509_asn1_tlv_block_parse(current_buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if ((tlv_type != NX_SECURE_ASN_TAG_UTC_TIME && tlv_type != NX_SECURE_ASN_TAG_GENERALIZED_TIME) || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
cert -> nx_secure_x509_not_after = tlv_data;
cert -> nx_secure_x509_not_after_length = (USHORT)tlv_length;
return(NX_SECURE_X509_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_subject PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the subject field of an X.509 certificate. This */
/* field consists of an X.509 Distinguished Name that provides the */
/* identity information for the certificate. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_distinguished_name_parse */
/* Parse Distinguished Name */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_subject(const UCHAR *buffer, ULONG length, UINT *bytes_processed,
NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
UINT bytes;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
/* First, parse the sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Now, pass the issuer certificate to populate it with the id info. Note that
* even if the issuer cert is NULL, we still need to parse the information -
* the parse_id function handles NULL appropriately. */
status = _nx_secure_x509_distinguished_name_parse(tlv_data, tlv_length, &bytes, &cert -> nx_secure_x509_distinguished_name);
/* Return the number of bytes we processed. */
*bytes_processed = bytes + header_length;
return status;
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_public_key PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the public key field of an X.509 certificate. */
/* The field consists of an OID indicating the algorithm (e.g. RSA) and */
/* an ASN.1 bit string containing a DER-encoded public key, the format */
/* of which varies with the algorithm. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_extract_oid_data Extract OID data */
/* _nx_secure_x509_oid_parse Parse OID in certificate */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_public_key(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
UINT bytes = 0;
const UCHAR *tlv_data;
const UCHAR *bitstring_ptr;
ULONG bitstring_len;
ULONG header_length;
UINT oid;
UINT oid_parameter;
UINT status;
/* Extract public key information, encoded as ASN.1 in an ASN.1 bitstring, and populate the certificate. */
/* Sequence: Public Key
* Sequence: Public key data
* ASN.1 OID (e.g. RSA)
* NULL or parameters
* ASN.1 Bit string - contains embedded key data in ASN.1 format:
* {
* 1 byte: padding (always 0?)
* ASN.1 Key information - sequence of 2 integers for RSA:
* Public Modulus followed by Public Exponent
* }
*/
/* The public key is a sequence of OIDs that is terminated by a NULL ASN.1 tag. */
*bytes_processed = 0;
/* First, parse the outermost sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Save off a pointer into our sequence - we will need it to jump to the public key data,
* which follows the public key id in the outermost sequence. */
bitstring_ptr = tlv_data;
*bytes_processed += header_length;
length = tlv_length;
/* Next, parse the OID sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_SEQUENCE || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Update byte count. */
*bytes_processed += header_length;
/* Advance sequence pointer to the next item in the outermost sequence (following the id sequence) */
bitstring_ptr = &bitstring_ptr[(header_length + tlv_length)];
/* The length we use to parse the bitstring should be equal to the length of the entire buffer
* minus the length of the OID sequence. */
bitstring_len = length;
length = tlv_length;
/* Next in the buffer should be an OID to id the public key algorithm. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status != 0)
{
return status;
}
/* Update bytes processed. */
*bytes_processed += (header_length + tlv_length);
/* Now check out what we got. Should be an OID... */
if (tlv_type == NX_SECURE_ASN_TAG_OID)
{
/* The OID is in the data we extracted. */
_nx_secure_x509_oid_parse(tlv_data, tlv_length, &oid);
cert -> nx_secure_x509_public_algorithm = oid;
/* The OID is followed by a NULL or a parameter OID. */
tlv_data = &tlv_data[tlv_length];
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
if (status != 0)
{
return status;
}
oid_parameter = 0;
if (tlv_type == NX_SECURE_ASN_TAG_OID)
{
/* The OID is in the data we extracted. */
_nx_secure_x509_oid_parse(tlv_data, tlv_length, &oid_parameter);
}
else if (tlv_type != NX_SECURE_ASN_TAG_NULL || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Update our bytes count. */
*bytes_processed += (header_length + tlv_length);
/* Extract the data in the block following the OID sequence. Use the calculated remaining
* length for the length of the data going in. */
status = _nx_secure_x509_extract_oid_data(bitstring_ptr, oid, oid_parameter, bitstring_len, &bytes, cert);
if (status != 0)
{
return status;
}
/* Update the processed byte count with the extracted OID data. */
*bytes_processed += (bytes);
}
else
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* All good! */
return(NX_SECURE_X509_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_unique_ids PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the optional isserUniqueID and subjectUniqueID */
/* bit strings in an X.509 certificate. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_unique_ids(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
const UCHAR *current_buffer;
UINT processed_id;
NX_CRYPTO_PARAMETER_NOT_USED(cert);
/* Extract unique identifiers for issuer and subject, if present. */
/* issuerUniqueID ::= ASN.1 Bit String OPTIONAL
* subjectUniqueID ::= ASN.1 Bit String OPTIONAL
*/
/* First, parse the next item which may be an ID or the item following the IDs in the X.509 spec if they were omitted. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
*bytes_processed = 0;
current_buffer = buffer;
/* If we process either ID, then we need to do a version check (v2 or v3 only). If neither is
encountered skip the version check. */
processed_id = NX_CRYPTO_FALSE;
/* Check for the OPTIONAL issuer unique ID. */
if (tlv_type_class == NX_SECURE_ASN_TAG_CLASS_CONTEXT && tlv_type == NX_SECURE_X509_TAG_ISSUER_UNIQUE_ID)
{
/* We processed an ID, mark for version check. */
processed_id = NX_CRYPTO_TRUE;
/* The field is an IMPLICIT bit string, so the data just follows the context-specific tag. */
/* Save off a pointer to the issuer unique identifier data and its length. */
cert -> nx_secure_x509_issuer_identifier = &tlv_data[1];
cert -> nx_secure_x509_issuer_identifier_length = (USHORT)(tlv_length - 1);
/* Return the number of bytes we processed. */
*bytes_processed += (header_length + tlv_length);
/* Advance to our next item. */
current_buffer = ¤t_buffer[header_length + tlv_length];
/* Padding data? */
if (length > 0)
{
/* Parse the next item which might be another ID or perhaps the extensions. */
status = _nx_secure_x509_asn1_tlv_block_parse(current_buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
}
}
/* Check for the OPTIONAL subject unique id field. */
if (tlv_type_class == NX_SECURE_ASN_TAG_CLASS_CONTEXT && tlv_type == NX_SECURE_X509_TAG_SUBJECT_UNIQUE_ID)
{
/* We processed an ID, mark for version check. */
processed_id = NX_CRYPTO_TRUE;
/* The field is an IMPLICIT bit string, so the data just follows the context-specific tag. */
/* Save off a pointer to the issuer unique identifier data and its length. */
cert -> nx_secure_x509_subject_identifier = &tlv_data[1];
cert -> nx_secure_x509_subject_identifier_length = (USHORT)(tlv_length - 1);
/* Return the number of bytes we processed. */
*bytes_processed += (header_length + tlv_length);
}
/* If we processed either field, make sure this is version 2 or 3. */
if(processed_id)
{
if (cert -> nx_secure_x509_version != NX_SECURE_X509_VERSION_2 && cert -> nx_secure_x509_version != NX_SECURE_X509_VERSION_3)
{
return(NX_SECURE_X509_INVALID_VERSION);
}
}
/* If neither ID field was parsed, bytes_processed should be 0. */
return(NX_SECURE_X509_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_extensions PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the extensions sequence in an X.509 */
/* certificate. The extensions themselves are not parsed here, but a */
/* pointer to the beginning of the DER-encoded sequence is saved in */
/* the certificate structure so that the extension-specific helper */
/* functions can easily find and parse the extensions later. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_extensions(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
const UCHAR *current_buffer;
ULONG header_length;
UINT status;
/* Extract any extension information present in the certificate buffer and populate the certificate structure.
* Extensions are encoded as ASN.1 in a sequence, so extract and parse that separately. */
/* ASN.1 Sequence: Extensions
* {
* ASN.1-encoded data for extensions
* }
*/
/* First, parse the context-specific tag (if it exists). */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
/* If the next item up is not a sequence, then it isn't an extensions block. */
if (!(tlv_type_class == NX_SECURE_ASN_TAG_CLASS_CONTEXT && tlv_type == NX_SECURE_X509_TAG_EXTENSIONS))
{
/* No extensions block is OK because it is non-existent in v1 and v2, and
OPTIONAL in v3. */
return(NX_SECURE_X509_SUCCESS);
}
/* We have an extensions sequence, this MUST be a version 3 certificate,
or we have an error. */
if (cert -> nx_secure_x509_version != NX_SECURE_X509_VERSION_3)
{
return(NX_SECURE_X509_INVALID_VERSION);
}
*bytes_processed = header_length + tlv_length;
current_buffer = tlv_data;
length = tlv_length;
/* Next, parse the extensions sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(current_buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
/* If the next item up is not a sequence, then it isn't an extensions block. */
if (!(tlv_type_class == NX_SECURE_ASN_TAG_CLASS_UNIVERSAL && tlv_type == NX_SECURE_ASN_TAG_SEQUENCE))
{
/* No extensions block is OK because it is non-existent in v1 and v2, and
OPTIONAL in v3. */
return(NX_SECURE_X509_SUCCESS);
}
/* Save off the start of the extensions sequence so we can parse it later when needed. */
cert -> nx_secure_x509_extensions_data = tlv_data;
cert -> nx_secure_x509_extensions_data_length = tlv_length;
/* We have saved off the extensions data successfully. */
return(NX_SECURE_X509_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_parse_signature_data PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the certificate signature field in an X.509 */
/* certificate. The signature data consists of a hash of the */
/* certificate data that is encrypted using the issuer's private key. */
/* Decrypting the hash with the issuer's public key and checking the */
/* result against a locally-computed hash cryptographically ties a */
/* certificate to its issuer. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Return bytes processed */
/* bytes_processed Number of bytes being */
/* consumed by the oid */
/* cert The certificate */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_certificate_parse Extract public key data */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_x509_parse_signature_data(const UCHAR *buffer, ULONG length,
UINT *bytes_processed, NX_SECURE_X509_CERT *cert)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
ULONG header_length;
UINT status;
/* Extract the signature data, which is a hash of the certificate data which is then encrypted using the issuer's
* private key. This function extracts the encrypted hash but decryption/authentication is done elsewhere. */
/* ASN.1 Bit string: Signature data */
/* First, parse the sequence. */
status = _nx_secure_x509_asn1_tlv_block_parse(buffer, &length, &tlv_type, &tlv_type_class, &tlv_length, &tlv_data, &header_length);
/* Make sure we parsed the block alright. */
if (status != 0)
{
return(status);
}
if (tlv_type != NX_SECURE_ASN_TAG_BIT_STRING || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_X509_UNEXPECTED_ASN1_TAG);
}
/* Save off a pointer to the signature data and its length. */
/* Signature has a 0 byte at the front we need to skip.
* This is due to the data being encoded as an ASN.1 bit string, which may
* require padding bits to get to a multiple of 8 for byte alignment. The byte
* represents the number of padding bits, but in X509 it should always be 0. */
cert -> nx_secure_x509_signature_data = &tlv_data[1];
cert -> nx_secure_x509_signature_data_length = tlv_length - 1;
/* Return the number of bytes we processed. */
*bytes_processed = header_length + tlv_length;
return(NX_SECURE_X509_SUCCESS);
}