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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 Crypto Component */
/** */
/** GCM Mode */
/** */
/**************************************************************************/
/**************************************************************************/
#include "nx_crypto_gcm.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_xor PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs XOR operation on the output buffer. */
/* */
/* INPUT */
/* */
/* plaintext Pointer to input plantext */
/* key Value to be xor'ed */
/* ciphertext Output buffer of 16 bytes */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_gcm_multi Compute multilication in GF */
/* _nx_crypto_gcm_ghash_update Compute GHASH */
/* _nx_crypto_gcm_gctr Perform GCTR operation */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), disabled */
/* unaligned access by default,*/
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_gcm_xor(UCHAR *plaintext, UCHAR *key, UCHAR *ciphertext)
{
#ifdef NX_CRYPTO_ENABLE_UNALIGNED_ACCESS
UINT *p = (UINT *)plaintext;
UINT *c = (UINT *)ciphertext;
UINT *k = (UINT *)key;
c[0] = p[0] ^ k[0];
c[1] = p[1] ^ k[1];
c[2] = p[2] ^ k[2];
c[3] = p[3] ^ k[3];
#else
ciphertext[0] = plaintext[0] ^ key[0];
ciphertext[1] = plaintext[1] ^ key[1];
ciphertext[2] = plaintext[2] ^ key[2];
ciphertext[3] = plaintext[3] ^ key[3];
ciphertext[4] = plaintext[4] ^ key[4];
ciphertext[5] = plaintext[5] ^ key[5];
ciphertext[6] = plaintext[6] ^ key[6];
ciphertext[7] = plaintext[7] ^ key[7];
ciphertext[8] = plaintext[8] ^ key[8];
ciphertext[9] = plaintext[9] ^ key[9];
ciphertext[10] = plaintext[10] ^ key[10];
ciphertext[11] = plaintext[11] ^ key[11];
ciphertext[12] = plaintext[12] ^ key[12];
ciphertext[13] = plaintext[13] ^ key[13];
ciphertext[14] = plaintext[14] ^ key[14];
ciphertext[15] = plaintext[15] ^ key[15];
#endif
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_inc32 PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function adds one for the last byte. */
/* */
/* INPUT */
/* */
/* counter_block Pointer to counter block */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_gcm_gctr Perform GCTR operation */
/* _nx_crypto_gcm_encrypt Perform GCM encrypt/decrypt */
/* */
/* 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 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_gcm_inc32(UCHAR *counter_block)
{
USHORT result;
/* Add one for last byte. */
result = (USHORT)(counter_block[15] + 1);
counter_block[15] = (UCHAR)(result & 0xFF);
/* Handle carry. */
result = (USHORT)((result >> 8) + counter_block[14]);
counter_block[14] = (UCHAR)(result & 0xFF);
result = (USHORT)((result >> 8) + counter_block[13]);
counter_block[13] = (UCHAR)(result & 0xFF);
result = (USHORT)((result >> 8) + counter_block[12]);
counter_block[12] = (UCHAR)(result & 0xFF);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_multi PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs multiplication in GF(2^128). */
/* */
/* INPUT */
/* */
/* x Pointer to X block */
/* y Pointer to Y block */
/* output Pointer to result block */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_xor Perform XOR operation */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_gcm_ghash_update Compute GHASH */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_gcm_multi(UCHAR *x, UCHAR *y, UCHAR *output)
{
UINT i;
INT j;
UCHAR v[NX_CRYPTO_GCM_BLOCK_SIZE];
UCHAR lsb;
UCHAR mask;
NX_CRYPTO_MEMSET(output, 0, NX_CRYPTO_GCM_BLOCK_SIZE);
NX_CRYPTO_MEMCPY(v, y, NX_CRYPTO_GCM_BLOCK_SIZE); /* Use case of memcpy is verified. */
mask = 0x80;
for (i = 0; i < NX_CRYPTO_GCM_BLOCK_SIZE_BITS; i++)
{
/* output = output xor v when the ith bit of x is set. */
if (*x & mask)
{
_nx_crypto_gcm_xor(output, v, output);
}
/* Store the LSB before shift right. */
j = NX_CRYPTO_GCM_BLOCK_SIZE - 1;
lsb = v[j];
/* v = v >> 1 */
for (; j > 0; j--)
{
v[j] = (UCHAR)((v[j] >> 1) | (v[j - 1] << 7));
}
v[0] = v[0] >> 1;
/* v = v xor R when LSB of v is set. */
if (lsb & 1)
{
v[0] = v[0] ^ 0xe1;
}
mask = mask >> 1;
if (!mask)
{
mask = 0x80;
x++;
}
}
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_ghash_update PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function updates GHASH with new input from the caller. The */
/* input is padded so that the length is a multiple of the block size. */
/* */
/* INPUT */
/* */
/* hkey Pointer to hash key */
/* input Pointer to bytes of input */
/* input_length Length of bytes of input */
/* output Pointer to updated hash */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_xor Perform XOR operation */
/* _nx_crypto_gcm_multi Perform multiplication in GF */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_gcm_encrypt Perform GCM encrypt/decrypt */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_gcm_ghash_update(UCHAR *hkey, UCHAR *input, UINT input_length, UCHAR *output)
{
UCHAR tmp_block[NX_CRYPTO_GCM_BLOCK_SIZE];
UINT i, n;
n = input_length >> NX_CRYPTO_GCM_BLOCK_SIZE_SHIFT;
for (i = 0; i < n; i++)
{
/* output = (output xor input) multi hkey */
_nx_crypto_gcm_xor(output, input, tmp_block);
_nx_crypto_gcm_multi(tmp_block, hkey, output);
input += NX_CRYPTO_GCM_BLOCK_SIZE;
}
input_length -= n << NX_CRYPTO_GCM_BLOCK_SIZE_SHIFT;
if (input_length > 0)
{
/* Pad the block with zeros when the input length is not
multiple of the block size. */
NX_CRYPTO_MEMCPY(tmp_block, input, input_length); /* Use case of memcpy is verified. */
NX_CRYPTO_MEMSET(&tmp_block[input_length], 0, sizeof(tmp_block) - input_length);
_nx_crypto_gcm_xor(output, tmp_block, tmp_block);
_nx_crypto_gcm_multi(tmp_block, hkey, output);
}
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_gctr PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs GCTR mode encryption and decryption. The */
/* counter block is updated after calling this function. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* crypto_function Pointer to crypto function */
/* input Pointer to bytes of input */
/* output Pointer to output buffer */
/* length Length of bytes of input */
/* counter_block Pointer to counter block */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_xor Perform XOR operation */
/* _nx_crypto_gcm_inc32 Increase the counter by one */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_gcm_encrypt Perform GCM encrypt/decrypt */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_gcm_gctr(VOID *crypto_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UCHAR *output, UINT length, UCHAR *counter_block)
{
UCHAR aes_output[NX_CRYPTO_GCM_BLOCK_SIZE];
UINT i, n;
n = length >> NX_CRYPTO_GCM_BLOCK_SIZE_SHIFT;
for (i = 0; i < n; i++)
{
/* Encrypt the counter. */
crypto_function(crypto_metadata, counter_block, aes_output, NX_CRYPTO_GCM_BLOCK_SIZE);
/* XOR the input with encrypted counter. */
_nx_crypto_gcm_xor(input, aes_output, output);
/* Increase the counter block. */
_nx_crypto_gcm_inc32(counter_block);
input += NX_CRYPTO_GCM_BLOCK_SIZE;
output += NX_CRYPTO_GCM_BLOCK_SIZE;
}
length -= n << NX_CRYPTO_GCM_BLOCK_SIZE_SHIFT;
if (length > 0)
{
crypto_function(crypto_metadata, counter_block, aes_output, NX_CRYPTO_GCM_BLOCK_SIZE);
/* Perform XOR operation on local buffer when
remaining input length is smaller than block size. */
_nx_crypto_gcm_xor(input, aes_output, aes_output);
NX_CRYPTO_MEMCPY(output, aes_output, length); /* Use case of memcpy is verified. */
}
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_encrypt_init PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function initialize the GCM mode for encryption. */
/* */
/* Note, the first byte of iv represents the length of IV excluding its*/
/* first byte. For example, 0x0401020304 indicates the length of IV is */
/* 4 bytes and the content of IV is 0x01020304. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* gcm_metadata Pointer to GCM metadata */
/* crypto_function Pointer to crypto function */
/* additional_data Pointer to additional data */
/* additional_len Length of additional data */
/* iv Pointer to Initial Vector */
/* block_size Block size of crypto algorithm*/
/* */
/* OUTPUT */
/* */
/* status */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_ghash_update Update GHASH */
/* _nx_crypto_gcm_inc32 Increase the counter by one */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_gcm_operation Handle AES encrypt or decrypt */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_gcm_encrypt_init(VOID *crypto_metadata, NX_CRYPTO_GCM *gcm_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
VOID *additional_data, UINT additional_len,
UCHAR *iv, UINT block_size)
{
UCHAR *hkey = gcm_metadata -> nx_crypto_gcm_hkey;
UCHAR *j0 = gcm_metadata -> nx_crypto_gcm_j0;
UCHAR *s = gcm_metadata -> nx_crypto_gcm_s;
UCHAR *counter = gcm_metadata -> nx_crypto_gcm_counter;
UCHAR tmp_block[NX_CRYPTO_GCM_BLOCK_SIZE];
UCHAR iv_len;
/* Check the block size. */
if (block_size != NX_CRYPTO_GCM_BLOCK_SIZE)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Generate hash key by encrypt the zero block. */
NX_CRYPTO_MEMSET(hkey, 0, NX_CRYPTO_GCM_BLOCK_SIZE);
crypto_function(crypto_metadata, hkey, hkey, NX_CRYPTO_GCM_BLOCK_SIZE);
/* Generate the pre-counter block j0. */
iv_len = iv[0];
iv = iv + 1;
if (iv_len == NX_CRYPTO_GCM_BLOCK_SIZE - 4)
{
/* When the length of IV is 12 then 1 is appended to IV to form j0. */
/* j0 in increased before GCTR. */
NX_CRYPTO_MEMCPY(j0, iv, iv_len); /* Use case of memcpy is verified. */
j0[12] = 0;
j0[13] = 0;
j0[14] = 0;
j0[15] = 1;
}
else
{
/* When the length of IV is not 12 then apply GHASH to the IV. */
NX_CRYPTO_MEMSET(j0, 0, NX_CRYPTO_GCM_BLOCK_SIZE);
_nx_crypto_gcm_ghash_update(hkey, iv, iv_len, j0);
/* Apply GHASH to the length of IV to form j0.*/
NX_CRYPTO_MEMSET(tmp_block, 0, NX_CRYPTO_GCM_BLOCK_SIZE);
tmp_block[NX_CRYPTO_GCM_BLOCK_SIZE - 2] = (UCHAR)(((iv_len << 3) & 0xFF00) >> 8);
tmp_block[NX_CRYPTO_GCM_BLOCK_SIZE - 1] = (UCHAR)((iv_len << 3) & 0x00FF);
_nx_crypto_gcm_ghash_update(hkey, tmp_block, NX_CRYPTO_GCM_BLOCK_SIZE, j0);
}
/* Apply GHASH to the additional authenticated data. */
NX_CRYPTO_MEMSET(s, 0, NX_CRYPTO_GCM_BLOCK_SIZE);
_nx_crypto_gcm_ghash_update(hkey, additional_data, additional_len, s);
/* Initial counter block for GCTR is j0 + 1. */
NX_CRYPTO_MEMCPY(counter, j0, NX_CRYPTO_GCM_BLOCK_SIZE); /* Use case of memcpy is verified. */
_nx_crypto_gcm_inc32(counter);
gcm_metadata -> nx_crypto_gcm_additional_data_len = additional_len;
gcm_metadata -> nx_crypto_gcm_input_total_length = 0;
#ifdef NX_SECURE_KEY_CLEAR
NX_CRYPTO_MEMSET(tmp_block, 0, sizeof(tmp_block));
#endif
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_encrypt_update PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function updates data for GCM encryption. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* gcm_metadata Pointer to GCM metadata */
/* crypto_function Pointer to crypto function */
/* input Pointer to bytes of input */
/* output Pointer to output buffer */
/* length Length of bytes of input */
/* block_size Block size of crypto algorithm*/
/* */
/* OUTPUT */
/* */
/* status */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_gctr Update data for GCM mode */
/* _nx_crypto_gcm_ghash_update Update GHASH */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_gcm_operation Handle AES encrypt or decrypt */
/* */
/* 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 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_gcm_encrypt_update(VOID *crypto_metadata, NX_CRYPTO_GCM *gcm_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UCHAR *output, UINT length,
UINT block_size)
{
UCHAR *hkey = gcm_metadata -> nx_crypto_gcm_hkey;
UCHAR *s = gcm_metadata -> nx_crypto_gcm_s;
UCHAR *counter = gcm_metadata -> nx_crypto_gcm_counter;
/* Check the block size. */
if (block_size != NX_CRYPTO_GCM_BLOCK_SIZE)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Invoke GCTR function to encrypt or decrypt the input message. */
_nx_crypto_gcm_gctr(crypto_metadata, crypto_function, input, output, length, counter);
/* Apply GHASH to the cipher text. */
_nx_crypto_gcm_ghash_update(hkey, output, length, s);
gcm_metadata -> nx_crypto_gcm_input_total_length += length;
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_encrypt_calculate PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function calculates TAG for GCM mode. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* gcm_metadata Pointer to GCM metadata */
/* crypto_function Pointer to crypto function */
/* output Pointer to output buffer */
/* icv_len Length of TAG */
/* block_size Block size of crypto algorithm*/
/* */
/* OUTPUT */
/* */
/* status */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_gctr Update data for GCM mode */
/* _nx_crypto_gcm_ghash_update Update GHASH */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_gcm_operation Handle AES encrypt or decrypt */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_gcm_encrypt_calculate(VOID *crypto_metadata, NX_CRYPTO_GCM *gcm_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *output, UINT icv_len, UINT block_size)
{
UCHAR *hkey = gcm_metadata -> nx_crypto_gcm_hkey;
UCHAR *j0 = gcm_metadata -> nx_crypto_gcm_j0;
UCHAR *s = gcm_metadata -> nx_crypto_gcm_s;
UCHAR tmp_block[NX_CRYPTO_GCM_BLOCK_SIZE];
UINT additional_len = gcm_metadata -> nx_crypto_gcm_additional_data_len;
UINT length;
/* Check the block size. */
if (block_size != NX_CRYPTO_GCM_BLOCK_SIZE)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Apply GHASH to the length of additional authenticated data and the length of cipher text. */
length = gcm_metadata -> nx_crypto_gcm_input_total_length;
tmp_block[0] = 0;
tmp_block[1] = 0;
tmp_block[2] = 0;
tmp_block[3] = 0;
tmp_block[4] = (UCHAR)(((additional_len << 3) & 0xFF000000) >> 24);
tmp_block[5] = (UCHAR)(((additional_len << 3) & 0x00FF0000) >> 16);
tmp_block[6] = (UCHAR)(((additional_len << 3) & 0x0000FF00) >> 8);
tmp_block[7] = (UCHAR)((additional_len << 3) & 0x000000FF);
tmp_block[8] = 0;
tmp_block[9] = 0;
tmp_block[10] = 0;
tmp_block[11] = 0;
tmp_block[12] = (UCHAR)(((length << 3) & 0xFF000000) >> 24);
tmp_block[13] = (UCHAR)(((length << 3) & 0x00FF0000) >> 16);
tmp_block[14] = (UCHAR)(((length << 3) & 0x0000FF00) >> 8);
tmp_block[15] = (UCHAR)((length << 3) & 0x000000FF);
_nx_crypto_gcm_ghash_update(hkey, tmp_block, NX_CRYPTO_GCM_BLOCK_SIZE, s);
/* Encrypt the GHASH result using GCTR with j0 as initial counter block.
The result is the authentication tag. */
_nx_crypto_gcm_gctr(crypto_metadata, crypto_function, s, s, NX_CRYPTO_GCM_BLOCK_SIZE, j0);
/* Append authentication tag to the end of the cipher text. */
NX_CRYPTO_MEMCPY(output, s, icv_len); /* Use case of memcpy is verified. */
#ifdef NX_SECURE_KEY_CLEAR
NX_CRYPTO_MEMSET(tmp_block, 0, sizeof(tmp_block));
#endif
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_decrypt_update PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function updates data for GCM decryption. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* gcm_metadata Pointer to GCM metadata */
/* crypto_function Pointer to crypto function */
/* input Pointer to bytes of input */
/* output Pointer to output buffer */
/* length Length of bytes of input */
/* block_size Block size of crypto algorithm*/
/* */
/* OUTPUT */
/* */
/* status */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_gctr Update data for GCM mode */
/* _nx_crypto_gcm_ghash_update Update GHASH */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_gcm_operation Handle AES encrypt or decrypt */
/* */
/* 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 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_gcm_decrypt_update(VOID *crypto_metadata, NX_CRYPTO_GCM *gcm_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UCHAR *output, UINT length,
UINT block_size)
{
UCHAR *hkey = gcm_metadata -> nx_crypto_gcm_hkey;
UCHAR *s = gcm_metadata -> nx_crypto_gcm_s;
UCHAR *counter = gcm_metadata -> nx_crypto_gcm_counter;
/* Check the block size. */
if (block_size != NX_CRYPTO_GCM_BLOCK_SIZE)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Apply GHASH to the cipher text. */
_nx_crypto_gcm_ghash_update(hkey, input, length, s);
/* Invoke GCTR function to encrypt or decrypt the input message. */
_nx_crypto_gcm_gctr(crypto_metadata, crypto_function, input, output, length, counter);
gcm_metadata -> nx_crypto_gcm_input_total_length += length;
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_gcm_decrypt_calculate PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function verifies the TAG for GCM mode. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* gcm_metadata Pointer to GCM metadata */
/* crypto_function Pointer to crypto function */
/* input Pointer to TAG buffer */
/* icv_len Length of TAG */
/* block_size Block size of crypto algorithm*/
/* */
/* OUTPUT */
/* */
/* status */
/* */
/* CALLS */
/* */
/* _nx_crypto_gcm_gctr Update data for GCM mode */
/* _nx_crypto_gcm_ghash_update Update GHASH */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_gcm_operation Handle AES encrypt or decrypt */
/* */
/* 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 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_gcm_decrypt_calculate(VOID *crypto_metadata, NX_CRYPTO_GCM *gcm_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UINT icv_len, UINT block_size)
{
UCHAR *hkey = gcm_metadata -> nx_crypto_gcm_hkey;
UCHAR *j0 = gcm_metadata -> nx_crypto_gcm_j0;
UCHAR *s = gcm_metadata -> nx_crypto_gcm_s;
UCHAR tmp_block[NX_CRYPTO_GCM_BLOCK_SIZE];
UINT additional_len = gcm_metadata -> nx_crypto_gcm_additional_data_len;
UINT length;
UINT i;
/* Check the block size. */
if (block_size != NX_CRYPTO_GCM_BLOCK_SIZE)
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Apply GHASH to the length of additional authenticated data and the length of cipher text. */
length = gcm_metadata -> nx_crypto_gcm_input_total_length;
tmp_block[0] = 0;
tmp_block[1] = 0;
tmp_block[2] = 0;
tmp_block[3] = 0;
tmp_block[4] = (UCHAR)(((additional_len << 3) & 0xFF000000) >> 24);
tmp_block[5] = (UCHAR)(((additional_len << 3) & 0x00FF0000) >> 16);
tmp_block[6] = (UCHAR)(((additional_len << 3) & 0x0000FF00) >> 8);
tmp_block[7] = (UCHAR)((additional_len << 3) & 0x000000FF);
tmp_block[8] = 0;
tmp_block[9] = 0;
tmp_block[10] = 0;
tmp_block[11] = 0;
tmp_block[12] = (UCHAR)(((length << 3) & 0xFF000000) >> 24);
tmp_block[13] = (UCHAR)(((length << 3) & 0x00FF0000) >> 16);
tmp_block[14] = (UCHAR)(((length << 3) & 0x0000FF00) >> 8);
tmp_block[15] = (UCHAR)((length << 3) & 0x000000FF);
_nx_crypto_gcm_ghash_update(hkey, tmp_block, NX_CRYPTO_GCM_BLOCK_SIZE, s);
#ifdef NX_SECURE_KEY_CLEAR
NX_CRYPTO_MEMSET(tmp_block, 0, sizeof(tmp_block));
#endif
/* Encrypt the GHASH result using GCTR with j0 as initial counter block.
The result is the authentication tag. */
_nx_crypto_gcm_gctr(crypto_metadata, crypto_function, s, s, NX_CRYPTO_GCM_BLOCK_SIZE, j0);
for (i = 0; i < icv_len; i++)
{
if (input[i] != s[i])
{
/* Authentication failed. */
return(NX_CRYPTO_AUTHENTICATION_FAILED);
}
}
return(NX_CRYPTO_SUCCESS);
}
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