226 lines
7.7 KiB
C
226 lines
7.7 KiB
C
/*
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* (c) Copyright 2021 by Coinkite Inc. This file is covered by license found in COPYING-CC.
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*/
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#include "basics.h"
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#include "console.h"
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#include "aes.h"
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#include "stm32l4xx_hal.h"
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#include "constant_time.h"
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#include <string.h>
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// aes_init()
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//
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void
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aes_init(AES_CTX *ctx)
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{
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memset(ctx, 0, sizeof(AES_CTX));
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}
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// aes_add()
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//
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// - capture more data to be encrypted/decrypted
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//
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void
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aes_add(AES_CTX *ctx, const uint8_t data_in[], uint32_t len)
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{
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memcpy(ctx->pending+ctx->num_pending, data_in, len);
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ctx->num_pending += len;
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ASSERT(ctx->num_pending < sizeof(ctx->pending));
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}
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// word_pump_bytes()
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//
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// Return bytes as words. Handles misaligned inputs. Also byte-reverses.
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//
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static inline uint32_t
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word_pump_bytes(const uint8_t **src)
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{
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uint32_t rv;
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if(((uint32_t)src) & 0x3) {
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memcpy(&rv, *src, 4);
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} else {
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rv = *(uint32_t *)(*src);
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}
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(*src) += 4;
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return __REV(rv);
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}
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// aes_done()
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//
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// Do the decryption.
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//
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void
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aes_done(AES_CTX *ctx, uint8_t data_out[], uint32_t len, const uint8_t key[32], const uint8_t nonce[AES_BLOCK_SIZE])
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{
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ASSERT(len <= ctx->num_pending);
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// enable clock to block
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__HAL_RCC_AES_CLK_ENABLE();
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// most changes have to be made w/ module disabled
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AES->CR &= ~AES_CR_EN;
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// set the key size and operation mode
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MODIFY_REG(AES->CR, AES_CR_KEYSIZE, CRYP_KEYSIZE_256B);
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MODIFY_REG(AES->CR, AES_CR_DATATYPE|AES_CR_MODE|AES_CR_CHMOD,
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CRYP_DATATYPE_8B | CRYP_ALGOMODE_ENCRYPT | CRYP_CHAINMODE_AES_CTR);
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// load key and IV values
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const uint8_t *K = key;
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AES->KEYR7 = word_pump_bytes(&K);
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AES->KEYR6 = word_pump_bytes(&K);
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AES->KEYR5 = word_pump_bytes(&K);
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AES->KEYR4 = word_pump_bytes(&K);
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AES->KEYR3 = word_pump_bytes(&K);
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AES->KEYR2 = word_pump_bytes(&K);
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AES->KEYR1 = word_pump_bytes(&K);
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AES->KEYR0 = word_pump_bytes(&K);
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if(nonce) {
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const uint8_t *N = nonce;
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AES->IVR3 = word_pump_bytes(&N);
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AES->IVR2 = word_pump_bytes(&N);
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AES->IVR1 = word_pump_bytes(&N);
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AES->IVR0 = word_pump_bytes(&N);
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} else {
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AES->IVR3 = 0;
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AES->IVR2 = 0;
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AES->IVR1 = 0;
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AES->IVR0 = 0; // maybe should be byte-swapped one, but whatever
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}
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// Enable the Peripheral
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AES->CR |= AES_CR_EN;
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ASSERT((((uint32_t)&ctx->pending) & 3) == 0); // safe because of special attr
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uint32_t *p = (uint32_t *)ctx->pending;
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for(int i=0; i < ctx->num_pending; i += 16) {
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// Write the block to the AES engine
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AES->DINR = *p; p++;
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AES->DINR = *p; p++;
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AES->DINR = *p; p++;
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AES->DINR = *p; p++;
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// Wait for CCF flag to be raised
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while(HAL_IS_BIT_CLR(AES->SR, AES_SR_CCF)) {
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// no timeout -- just 75 cycles?
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}
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// clear CCF flag
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SET_BIT(AES->CR, CRYP_CCF_CLEAR);
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// work in place, overwrite what we just wrote
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uint32_t *out = p - 4;
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*out = AES->DOUTR; out++;
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*out = AES->DOUTR; out++;
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*out = AES->DOUTR; out++;
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*out = AES->DOUTR;
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}
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memcpy(data_out, ctx->pending, len);
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memset(ctx, 0, sizeof(AES_CTX));
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// reset state of chip block, and leave clock off as well
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__HAL_RCC_AES_CLK_ENABLE();
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__HAL_RCC_AES_FORCE_RESET();
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__HAL_RCC_AES_RELEASE_RESET();
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__HAL_RCC_AES_CLK_DISABLE();
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}
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#ifndef RELEASE
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// aes_selftest()
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//
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void
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aes_selftest(void)
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{
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puts2("AES selftest: ");
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/*
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>>> import pyaes
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>>> pyaes.AESModeOfOperationCTR(bytes(32), pyaes.Counter(0)).encrypt(b'Zack')
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b'\x86\xf4\xa3\x13'
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*/
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AES_CTX ctx;
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static const uint8_t key[32] = { };
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static const uint8_t nonce[16] = { };
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static const uint8_t msg[4] = "Zack";
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static const uint8_t expect[4] = { 0x86, 0xf4, 0xa3, 0x13 };
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uint8_t tmp[4];
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aes_init(&ctx);
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aes_add(&ctx, msg, 4);
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aes_done(&ctx, tmp, 4, key, nonce);
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ASSERT(check_equal(tmp, expect, 4));
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aes_init(&ctx);
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aes_add(&ctx, expect, 4);
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aes_done(&ctx, tmp, 4, key, nonce);
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ASSERT(check_equal(tmp, msg, 4));
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#if 0
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// passes, but big
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/*
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>>> pyaes.Counter(0x102030405060708090a0b0c0d0e0f0).value
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[0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240]
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>>> pyaes.AESModeOfOperationCTR(bytes(32), pyaes.Counter(0x102030405060708090a0b0c0d0e0f0)).encrypt(bytes(512)).hex()
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*/
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static const uint8_t long_nonce[16] = { 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240 };
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static const uint8_t long_exp[512] = {
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0x88, 0x6f, 0x2f, 0x0c, 0xa7, 0x1f, 0x00, 0xed, 0xfd, 0xf8, 0x2d, 0x62, 0xf7, 0xf2, 0xc9,
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0xd3, 0x0e, 0xb3, 0xc4, 0xf6, 0xff, 0x3e, 0x3d, 0xc9, 0x6d, 0x26, 0x09, 0x70, 0x97, 0x6a,
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0xef, 0x60, 0x59, 0x20, 0xb2, 0xb1, 0x61, 0x92, 0xe1, 0x19, 0xa5, 0xcb, 0x24, 0xf3, 0x1e,
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0x9a, 0x82, 0x71, 0x4f, 0x73, 0x21, 0x1e, 0x51, 0x4f, 0xed, 0x05, 0x77, 0xd8, 0x8b, 0x11,
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0x5b, 0x38, 0x64, 0xb8, 0xf8, 0x6c, 0xf3, 0xb0, 0xa8, 0x3f, 0xe2, 0x17, 0xd5, 0x6f, 0xc2,
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0xc1, 0x2b, 0x9e, 0x9d, 0x0c, 0x89, 0xc1, 0x65, 0x8e, 0xce, 0xb3, 0x21, 0x6d, 0xbb, 0x23,
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0x5f, 0x5e, 0x3d, 0x52, 0x61, 0x7f, 0x61, 0x37, 0xd9, 0xea, 0x3a, 0x27, 0xce, 0x80, 0x05,
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0xf0, 0x85, 0x73, 0xed, 0xc5, 0x1f, 0x72, 0x3b, 0x91, 0x6d, 0x75, 0xd8, 0x70, 0xc1, 0x07,
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0x0f, 0xf3, 0x96, 0x2d, 0x68, 0x6e, 0x44, 0x6b, 0x6c, 0x5f, 0x81, 0x28, 0xe5, 0x0a, 0xb1,
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0xff, 0x29, 0x79, 0x55, 0xda, 0x95, 0x9b, 0x29, 0xd6, 0x55, 0x87, 0x59, 0xf9, 0xc0, 0xbf,
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0x90, 0xba, 0xb1, 0xc1, 0x0c, 0x91, 0xb5, 0x90, 0x3a, 0x9b, 0xf9, 0x0d, 0xa1, 0xcd, 0x47,
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0x9b, 0xad, 0xa4, 0x8f, 0xa4, 0x98, 0x42, 0x88, 0x65, 0x36, 0x8d, 0x29, 0xb1, 0xa3, 0x78,
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0x76, 0x6a, 0x17, 0xee, 0xa5, 0x32, 0xed, 0x3c, 0x79, 0x2d, 0xa7, 0x6c, 0x91, 0x36, 0x56,
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0x8b, 0x30, 0x45, 0xf2, 0x9e, 0xef, 0x12, 0xc3, 0x5e, 0x59, 0xdf, 0x6d, 0x8b, 0xf5, 0x80,
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0xf4, 0x45, 0x37, 0xcb, 0x6a, 0x8f, 0x68, 0x11, 0x0e, 0x11, 0x90, 0x3c, 0xd4, 0x95, 0xaa,
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0x43, 0xad, 0xa1, 0x1d, 0x44, 0x19, 0x23, 0xcc, 0xb9, 0xa8, 0x8e, 0x55, 0xbd, 0xb3, 0x7c,
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0xa0, 0x99, 0xbc, 0xeb, 0x77, 0x89, 0xf7, 0x35, 0x1e, 0x2b, 0x7c, 0x02, 0x31, 0x2b, 0x0e,
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0xc2, 0x40, 0x0a, 0x9f, 0xe0, 0xbf, 0x10, 0xac, 0xec, 0x22, 0x19, 0x4c, 0x73, 0x96, 0xad,
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0x46, 0x58, 0x71, 0x58, 0x64, 0x4d, 0x16, 0xb6, 0xc8, 0x9d, 0x3c, 0x10, 0x39, 0x15, 0x41,
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0x60, 0xb0, 0xd3, 0xa1, 0xd9, 0x5a, 0x74, 0xef, 0x94, 0x1e, 0xbd, 0xff, 0x21, 0x01, 0x66,
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0x3d, 0xbf, 0x02, 0x94, 0xf8, 0x8f, 0xb6, 0xab, 0xf6, 0x66, 0xc5, 0xdd, 0x31, 0x02, 0x90,
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0xcc, 0x71, 0x73, 0xd8, 0xb8, 0x52, 0x20, 0xa6, 0x5f, 0xcf, 0x9d, 0xcb, 0xae, 0x34, 0xee,
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0xa1, 0x4a, 0x42, 0x68, 0x1e, 0x02, 0x71, 0x08, 0x67, 0xaf, 0xe5, 0x05, 0xb4, 0x17, 0x0d,
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0x90, 0xba, 0x96, 0x0d, 0x22, 0x99, 0xb1, 0xd4, 0x30, 0xf5, 0x6b, 0x5f, 0xab, 0xf3, 0xbf,
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0x85, 0xee, 0xf0, 0xde, 0x52, 0x79, 0x36, 0xec, 0x0f, 0x87, 0x9f, 0xb9, 0x66, 0xe5, 0x71,
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0x1b, 0x57, 0x88, 0x83, 0x84, 0x7e, 0xbb, 0x16, 0x12, 0x10, 0xda, 0x8a, 0x69, 0x67, 0x10,
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0x97, 0x53, 0x22, 0x32, 0x3a, 0x22, 0x03, 0x1f, 0xa8, 0x3a, 0x65, 0xec, 0x64, 0x5b, 0x2e,
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0x33, 0xdc, 0x03, 0x64, 0x35, 0xfb, 0xca, 0x43, 0x4d, 0x41, 0xd2, 0xbd, 0x32, 0xa0, 0xe0,
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0xff, 0x74, 0x30, 0xa0, 0x39, 0x72, 0x57, 0xf0, 0xa7, 0xd3, 0xa7, 0xb0, 0x05, 0x19, 0x7d,
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0xbe, 0x6b, 0x49, 0x76, 0x2d, 0x23, 0x8a, 0x58, 0x2e, 0xfc, 0x75, 0x39, 0xe2, 0xf9, 0x4c,
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0xcc, 0x4b, 0x71, 0x94, 0x4c, 0xe1, 0x57, 0x95, 0xf8, 0x83, 0x2d, 0x00, 0x30, 0xca, 0xca,
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0xc0, 0x1c, 0xb5, 0x8f, 0xc9, 0x4f, 0xdf, 0x82, 0x41, 0x6f, 0x64, 0xbf, 0x9c, 0xa7, 0xa1,
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0x2f, 0xdb, 0x28, 0x6c, 0xda, 0x16, 0x2f, 0x25, 0x9d, 0x81, 0x44, 0xd7, 0xee, 0x8e, 0x7b,
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0x59, 0x8a, 0x24, 0x59, 0x03, 0x4e, 0x48, 0x7a, 0xfd, 0x3c, 0x76, 0x97, 0xa5, 0xac, 0xbb,
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0xea, 0x83 };
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aes_init(&ctx);
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ctx.num_pending = 512;
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uint8_t tmp2[512];
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aes_done(&ctx, tmp2, 512, key, long_nonce);
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ASSERT(check_equal(tmp2, long_exp, 512));
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#endif
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puts("PASS");
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}
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#endif
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// EOF
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