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/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2025-present Eclipse ThreadX Contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Secure Component */
/** */
/** X.509 Digital Certificates */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SECURE_SOURCE_CODE
#include "nx_secure_x509.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_extended_key_usage_extension_parse PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses through an X.509 certificate for an Extended */
/* KeyUsage extension for a a specific key usage provided by the */
/* caller. If the extension is not found or if the specified usage is */
/* not present in the extension, an error is returned. */
/* */
/* INPUT */
/* */
/* certificate Pointer to X.509 certificate */
/* key_usage Key usage OID to find */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* _nx_secure_x509_extension_find Find extension in certificate */
/* _nx_secure_x509_oid_parse Parse OID in certificate */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/**************************************************************************/
UINT _nx_secure_x509_extended_key_usage_extension_parse(NX_SECURE_X509_CERT *certificate,
UINT key_usage)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
const UCHAR *current_buffer;
ULONG length;
ULONG header_length;
UINT status;
UINT usage_oid;
NX_SECURE_X509_EXTENSION key_usage_extension;
/* Find and parse the keyUsage extension. */
/* ExtendedKeyUsage ASN.1 format:
id-ce-extKeyUsage OBJECT IDENTIFIER ::= { id-ce 37 }
ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
KeyPurposeId ::= OBJECT IDENTIFIER
*/
/* Find the KeyUsage extension in the certificate. */
status = _nx_secure_x509_extension_find(certificate, &key_usage_extension, NX_SECURE_TLS_X509_TYPE_EXTENDED_KEY_USAGE);
/* See if extension present - it is OK if not present! */
if (status != NX_SECURE_X509_SUCCESS)
{
return(status);
}
/* The length of our extensions is the length of the sequence. */
current_buffer = key_usage_extension.nx_secure_x509_extension_data;
length = key_usage_extension.nx_secure_x509_extension_data_length;
/* Parse the 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))
{
/* We were expecting a bitfield but got something else. */
return(NX_SECURE_X509_INVALID_EXTENSION_SEQUENCE);
}
/* The names are in the body of the sequence structure, so use our tlv_data and length. */
current_buffer = tlv_data;
length = tlv_length;
/* Loop through OIDs to find the one we are looking for. */
while (length > 0)
{
/* First, parse the OID tag (if it exists). */
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 sequence does not contain OIDs, error. */
if (!(tlv_type_class == NX_SECURE_ASN_TAG_CLASS_UNIVERSAL && tlv_type == NX_SECURE_ASN_TAG_OID))
{
return(NX_SECURE_X509_INVALID_EXTENSION_SEQUENCE);
}
current_buffer += header_length;
/* The OID is in the data we extracted. */
_nx_secure_x509_oid_parse(tlv_data, tlv_length, &usage_oid);
/* If our OID matches the passed-in key usage OID type, success! */
if (usage_oid == key_usage)
{
return(NX_SECURE_X509_SUCCESS);
}
current_buffer += tlv_length;
}
/* Got through the entire list but didn't find the specified key usage. */
return(NX_SECURE_X509_EXT_KEY_USAGE_NOT_FOUND);
}
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