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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"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_asn1_tlv_block_parse PORTABLE C */
/* 6.1.6 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses an ASN.1 type-length-value (TLV) block for use */
/* by the X509 parser. */
/* */
/* INPUT */
/* */
/* buffer Pointer to data to be parsed */
/* tlv_type Return block type */
/* tlv_tag_class Return class of the tag */
/* tlv_length Return parsed length */
/* tlv_data Return pointer to block data */
/* header_length Return length of block itself */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_certificate_parse Extract public key data */
/* _nx_secure_x509_certificate_revocation_list_parse */
/* Parse revocation list */
/* _nx_secure_x509_certificate_verify Verify a certificate */
/* _nx_secure_x509_crl_extensions_parse Parse extensions in crl */
/* _nx_secure_x509_crl_issuer_parse Parse issuer in crl */
/* _nx_secure_x509_crl_parse_entry Parse an entry in crl */
/* _nx_secure_x509_crl_revoked_certs_list_parse */
/* Parse revoked certificate list*/
/* in crl */
/* _nx_secure_x509_crl_signature_algorithm_parse */
/* Parse signature algorithm in */
/* crl */
/* _nx_secure_x509_crl_signature_data_parse */
/* Parse signature data in crl */
/* _nx_secure_x509_crl_tbscert_list_parse */
/* Parse TBSCertList in crl */
/* _nx_secure_x509_crl_update_times_parse */
/* Parse Update times in crl */
/* _nx_secure_x509_crl_verify Verify revocation list */
/* _nx_secure_x509_crl_version_parse Parse version in crl */
/* _nx_secure_x509_extended_key_usage_extension_parse */
/* Parse Extended KeyUsage */
/* extension */
/* _nx_secure_x509_distinguished_name_parse */
/* Parse Distinguished Name */
/* _nx_secure_x509_extension_find Find extension in certificate */
/* _nx_secure_x509_extract_name_oid_data Extract Distinguished Name */
/* _nx_secure_x509_extract_oid_data Extract OID data */
/* _nx_secure_x509_key_usage_extension_parse */
/* Parse KeyUsage extension */
/* _nx_secure_x509_parse_cert_data Parse certificate */
/* _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_signature_data Parse signature data 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 */
/* _nx_secure_x509_pkcs1_rsa_private_key_parse */
/* Parse RSA key (PKCS#1 format) */
/* _nx_secure_x509_pkcs7_decode Decode the PKCS#7 signature */
/* _nx_secure_x509_policy_qualifiers_parse */
/* Parse policy qualifiers */
/* _nx_secure_x509_subject_alt_names_find */
/* Find subject alt names */
/* */
/* 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_asn1_tlv_block_parse(const UCHAR *buffer, ULONG *buffer_length, USHORT *tlv_type,
USHORT *tlv_tag_class, ULONG *tlv_length,
const UCHAR **tlv_data, ULONG *header_length)
{
UINT current_index;
USHORT current_tag;
ULONG length;
ULONG length_bytes;
current_index = 0;
current_tag = buffer[current_index];
if (*buffer_length < 1)
{
return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG);
}
/* Handle multi-byte encoded tags. */
if ((current_tag & NX_SECURE_ASN_TAG_MULTIBYTE_MASK) == NX_SECURE_ASN_TAG_MULTIBYTE_MASK)
{
return(NX_SECURE_X509_MULTIBYTE_TAG_UNSUPPORTED);
}
else
{
*header_length = 1;
*buffer_length = *buffer_length - 1;
}
/* Get the class of the tag so we can return it. */
*tlv_tag_class = (USHORT)((current_tag & NX_SECURE_ASN_TAG_CLASS_MASK) >> 6);
/* Make sure we have a valid tag class. */
if (*tlv_tag_class == NX_SECURE_ASN_TAG_CLASS_APPLICATION ||
*tlv_tag_class == NX_SECURE_ASN_TAG_CLASS_PRIVATE)
{
/* The tag class is invalid, return error. */
return(NX_SECURE_X509_INVALID_TAG_CLASS);
}
/* The caller actually handles what happens based on the tag type. */
if (current_tag & NX_SECURE_ASN_TAG_CONSTRUCTED_MASK)
{
current_tag = current_tag & (USHORT)(~NX_SECURE_ASN_TAG_CONSTRUCTED_MASK);
}
/* Clear out the class and constructed bits before returning the tag value. */
*tlv_type = current_tag & NX_SECURE_ASN_TAG_MASK;
current_index++;
if (*buffer_length < 1)
{
return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG);
}
if (current_tag == NX_SECURE_ASN_TAG_NULL)
{
/* If tag is NULL, there is no length byte, just a value of zero, */
*tlv_length = 1;
/* Set the data pointer and return. */
*tlv_data = &buffer[current_index];
return(NX_SECURE_X509_SUCCESS);
}
/* Handle the length. */
length = buffer[current_index];
current_index++;
*header_length = *header_length + 1;
*buffer_length = *buffer_length - 1;
/* Check for multi-byte length by looking at the top bit of the length byte. */
if (length & 0x80)
{
/* Multi-byte length:
> 127, high bit is set, and lower 7 bits becomes the number of following bytes of *length*
so 841 bytes of Value is encoded as 0x82, 0x03, 0x49 (0x82 = 2 bytes of length, 0x0349 = 841).
*/
/* Mask off top bit to get the number of bytes in length. */
length_bytes = length & 0x7F;
length = 0;
/* Check for length too big to handle. */
if (length_bytes > 4 || length_bytes > *buffer_length)
{
return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG);
}
/* Update header length. */
*header_length = *header_length + length_bytes;
*buffer_length = *buffer_length - length_bytes;
while (length_bytes > 0)
{
/* Shift length one byte up and add in next byte. */
length <<= 8;
length += buffer[current_index];
/* Advance our index by one byte. */
current_index++;
length_bytes--;
}
}
else
{
/* Single-byte length:
<= 127 (7 bits), length is the number of bytes of Value */
*tlv_length = length;
}
if (length > *buffer_length)
{
return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG);
}
*buffer_length = *buffer_length - length;
/* Set the length to return to caller. */
*tlv_length = length;
/* Now, we can set the tld value */
*tlv_data = &buffer[current_index];
return(NX_SECURE_X509_SUCCESS);
}
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