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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"
static VOID _nx_secure_asn1_parse_unsigned_integer(const UCHAR *data, ULONG length,
const UCHAR **target, USHORT *target_length);
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_x509_pkcs1_rsa_private_key_parse PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses a DER-encoded PKCS#1-formatted private RSA key */
/* for use with X509 certificates. */
/* */
/* INPUT */
/* */
/* buffer Pointer data to be parsed */
/* length Length of data in buffer */
/* bytes_processed Return bytes processed */
/* rsa_key Return RSA key structure */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_asn1_parse_unsigned_integer */
/* Parse unsigned interger */
/* _nx_secure_x509_asn1_tlv_block_parse Parse ASN.1 block */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_certificate_initialize */
/* Initialize certificate */
/* */
/**************************************************************************/
UINT _nx_secure_x509_pkcs1_rsa_private_key_parse(const UCHAR *buffer, UINT length,
UINT *bytes_processed,
NX_SECURE_RSA_PRIVATE_KEY *rsa_key)
{
USHORT tlv_type;
USHORT tlv_type_class;
ULONG tlv_length;
const UCHAR *tlv_data;
ULONG header_length;
ULONG seq_length;
UINT status;
USHORT version;
/* Parse an ASN.1 DER-encoded PKCS#1 formatted RSA private key file. */
/* From RFC 3447, PKCS #1. */
/* RSAPrivateKey ::= SEQUENCE { */
/* version Version, */
/* modulus INTEGER, -- n */
/* publicExponent INTEGER, -- e */
/* privateExponent INTEGER, -- d */
/* prime1 INTEGER, -- p */
/* prime2 INTEGER, -- q */
/* exponent1 INTEGER, -- d mod (p-1) */
/* exponent2 INTEGER, -- d mod (q-1) */
/* coefficient INTEGER, -- (inverse of q) mod p */
/* otherPrimeInfos OtherPrimeInfos OPTIONAL */
/* } */
/* */
/* Version ::= INTEGER { two-prime(0), multi(1) } */
/* (CONSTRAINED BY */
/* {-- version must be multi if otherPrimeInfos present --}) */
/* */
/* */
/* OtherPrimeInfos ::= SEQUENCE SIZE(1..MAX) OF OtherPrimeInfo */
/* */
/* OtherPrimeInfo ::= SEQUENCE { */
/* prime INTEGER, -- ri */
/* exponent INTEGER, -- di */
/* coefficient INTEGER -- ti */
/* } */
/* 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;
seq_length = tlv_length;
/* First item in the RSA key sequence is a version field. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &seq_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_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Update byte count. */
*bytes_processed += (header_length + tlv_length);
/* Version has 2 values: two-prime(0) and multi(1). It is multi only if the "OtherPrimeInfo" field is present. */
version = tlv_data[0];
if (version != 0x00 && version != 0x01)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Advance our working pointer past the last field. */
tlv_data = &tlv_data[tlv_length];
/* Parse our next field, the modulus. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &seq_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_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Update byte count. */
*bytes_processed += (header_length + tlv_length);
/* The modulus is an integer, so no padding bytes are needed (as with a BITSTRING). */
if (rsa_key != NULL)
{
_nx_secure_asn1_parse_unsigned_integer(tlv_data, tlv_length, &rsa_key -> nx_secure_rsa_public_modulus,
&rsa_key -> nx_secure_rsa_public_modulus_length);
}
/* Advance our working pointer past the last field. */
tlv_data = &tlv_data[tlv_length];
/* Parse our next field, the public exponent. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &seq_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_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Update byte count. */
*bytes_processed += (header_length + tlv_length);
/* The exponent is an integer, so no padding bytes are needed (as with a BITSTRING). */
if (rsa_key != NULL)
{
_nx_secure_asn1_parse_unsigned_integer(tlv_data, tlv_length, &rsa_key -> nx_secure_rsa_public_exponent,
&rsa_key -> nx_secure_rsa_public_exponent_length);
}
/* Advance our working pointer past the last field. */
tlv_data = &tlv_data[tlv_length];
/* Parse our next field, the private exponent. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &seq_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_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Update byte count. */
*bytes_processed += (header_length + tlv_length);
/* The value is an integer, so no padding bytes are needed (as with a BITSTRING). */
if (rsa_key != NULL)
{
_nx_secure_asn1_parse_unsigned_integer(tlv_data, tlv_length, &rsa_key -> nx_secure_rsa_private_exponent,
&rsa_key -> nx_secure_rsa_private_exponent_length);
}
/* Advance our working pointer past the last field. */
tlv_data = &tlv_data[tlv_length];
/* Parse our next field, the private prime P. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &seq_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_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Update byte count. */
*bytes_processed += (header_length + tlv_length);
/* The modulus is an integer, so no padding bytes are needed (as with a BITSTRING). */
if (rsa_key != NULL)
{
_nx_secure_asn1_parse_unsigned_integer(tlv_data, tlv_length, &rsa_key -> nx_secure_rsa_private_prime_p,
&rsa_key -> nx_secure_rsa_private_prime_p_length);
}
/* Advance our working pointer past the last field. */
tlv_data = &tlv_data[tlv_length];
/* Parse our next field, the private prime Q. */
status = _nx_secure_x509_asn1_tlv_block_parse(tlv_data, &seq_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_INTEGER || tlv_type_class != NX_SECURE_ASN_TAG_CLASS_UNIVERSAL)
{
return(NX_SECURE_PKCS1_INVALID_PRIVATE_KEY);
}
/* Update byte count. */
*bytes_processed += (header_length + tlv_length);
/* The value is an integer, so no padding bytes are needed (as with a BITSTRING). */
if (rsa_key != NULL)
{
_nx_secure_asn1_parse_unsigned_integer(tlv_data, tlv_length, &rsa_key -> nx_secure_rsa_private_prime_q,
&rsa_key -> nx_secure_rsa_private_prime_q_length);
}
return(NX_SECURE_X509_SUCCESS);
}
/* This is a helper function to parse DER-encoded signed integers found in the RSA key file.
It converts the signed integer into an unsigned character block for use in RSA calculations.
DER-encoded integers are in 2's-complement format and thus can be negative. All
RSA keys are unsigned integers so we need to compensate for the extra padding.
If the first byte is 0x00, check the top bit of the next byte. If that bit
is set, then discard the 0x00 byte. */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_asn1_parse_unsigned_integer PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses an ASN.1 DER-encoded unsigned integer. */
/* */
/* INPUT */
/* */
/* data Pointer data to be parsed */
/* length Length of data in buffer */
/* target Return target processed */
/* target_length Return length of target */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_secure_x509_pkcs1_rsa_private_key_parse */
/* Parse RSA private key field */
/* */
/**************************************************************************/
static VOID _nx_secure_asn1_parse_unsigned_integer(const UCHAR *data, ULONG length,
const UCHAR **target, USHORT *target_length)
{
UINT offset;
/* If there is only one byte, don't do anything. */
if (length <= 1)
{
return;
}
/* Default is not to skip the first byte. */
offset = 0;
if (data[0] == 0x00 && ((data[1] & 0x80) != 0))
{
/* Discard the first byte when copying to the target. */
offset = 1;
}
/* Finally set the data pointer and length based on our offset. */
*target = &data[offset];
*target_length = (USHORT)(length - offset);
}
|
