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/* Copyright 2017 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Test RMA auth challenge/response
*/
#include <endian.h>
#include <stdio.h>
#include "common.h"
#include "chip/g/board_id.h"
#include "curve25519.h"
#include "base32.h"
#include "sha256.h"
#include "rma_auth.h"
#include "test_util.h"
#include "timer.h"
#include "util.h"
/* Placeholder implementations for testing */
static uint8_t placeholder_board_id[4] = {'Z', 'Z', 'C', 'R'};
static uint8_t placeholder_device_id[8] = {'T', 'H', 'X', 1, 1, 3, 8, 0xfe};
static int server_protocol_version = RMA_CHALLENGE_VERSION;
static uint8_t server_private_key[32] = RMA_TEST_SERVER_PRIVATE_KEY;
static int server_key_id = RMA_TEST_SERVER_KEY_ID;
void rand_bytes(void *buffer, size_t len)
{
FILE *f = fopen("/dev/urandom", "rb");
assert(f);
assert(fread(buffer, len, 1, f) == 1);
fclose(f);
}
int read_board_id(struct board_id *id)
{
memcpy(&id->type, placeholder_board_id, sizeof(id->type));
id->type_inv = ~id->type;
id->flags = 0xFF00;
return EC_SUCCESS;
}
int system_get_chip_unique_id(uint8_t **id)
{
*id = placeholder_device_id;
return sizeof(placeholder_device_id);
}
/**
* Simulate the server side of a RMA challenge-response.
*
* @param out_auth_code Buffer for generated authorization code
* (must be >= CR50_AUTH_CODE_CHARS + 1 chars)
* @param challenge Challenge from device
* @return 0 if success, non-zero if error.
*/
int rma_server_side(char *out_auth_code, const char *challenge)
{
int version, key_id;
uint32_t device_id[2];
uint8_t secret[32];
uint8_t hmac[32];
struct rma_challenge c;
uint8_t *cptr = (uint8_t *)&c;
/* Convert the challenge back into binary */
if (base32_decode(cptr, 8 * sizeof(c), challenge, 9) != 8 * sizeof(c)) {
printf("Error decoding challenge\n");
return -1;
}
version = RMA_CHALLENGE_GET_VERSION(c.version_key_id);
if (version != server_protocol_version) {
printf("Unsupported challenge version %d\n", version);
return -1;
}
key_id = RMA_CHALLENGE_GET_KEY_ID(c.version_key_id);
printf("\nChallenge: %s\n", challenge);
printf(" Version: %d\n", version);
printf(" Server KeyID: %d\n", key_id);
printf(" BoardID: %c%c%c%c\n",
isprint(c.board_id[0]) ? c.board_id[0] : '?',
isprint(c.board_id[1]) ? c.board_id[1] : '?',
isprint(c.board_id[2]) ? c.board_id[2] : '?',
isprint(c.board_id[3]) ? c.board_id[3] : '?');
memcpy(device_id, c.device_id, sizeof(device_id));
printf(" DeviceID: 0x%08x 0x%08x\n", device_id[0], device_id[1]);
if (key_id != server_key_id) {
printf("Unsupported KeyID %d\n", key_id);
return -1;
}
/*
* Make sure the current user is authorized to reset this board.
*
* Since this is just a test, here we'll just make sure the BoardID
* and DeviceID match what we expected.
*/
if (memcmp(c.board_id, placeholder_board_id, sizeof(c.board_id))) {
printf("BoardID mismatch\n");
return -1;
}
if (memcmp(c.device_id, placeholder_device_id, sizeof(c.device_id))) {
printf("DeviceID mismatch\n");
return -1;
}
/* Calculate the shared secret */
X25519(secret, server_private_key, c.device_pub_key);
/*
* Auth code is a truncated HMAC of the ephemeral public key, BoardID,
* and DeviceID.
*/
hmac_SHA256(hmac, secret, sizeof(secret), cptr + 1, sizeof(c) - 1);
if (base32_encode(out_auth_code, RMA_AUTHCODE_BUF_SIZE,
hmac, RMA_AUTHCODE_CHARS * 5, 0)) {
printf("Error encoding auth code\n");
return -1;
}
printf("Authcode: %s\n", out_auth_code);
return 0;
};
#define FORCE_TIME(t) { ts.val = (t); force_time(ts); }
/*
* rma_try_authcode expects a buffer that is at least RMA_AUTHCODE_CHARS long,
* so copy the input string to a buffer before calling the function.
*/
static int rma_try_authcode_pad(const char *code)
{
char authcode[RMA_AUTHCODE_BUF_SIZE];
memset(authcode, 0, sizeof(authcode));
strncpy(authcode, code, sizeof(authcode));
return rma_try_authcode(authcode);
}
static int test_rma_auth(void)
{
const char *challenge;
char authcode[RMA_AUTHCODE_BUF_SIZE];
timestamp_t ts;
/* Test rate limiting */
FORCE_TIME(9 * SECOND);
TEST_ASSERT(rma_create_challenge() == EC_ERROR_TIMEOUT);
TEST_ASSERT(rma_try_authcode_pad("Bad") == EC_ERROR_ACCESS_DENIED);
TEST_ASSERT(strlen(rma_get_challenge()) == 0);
FORCE_TIME(10 * SECOND);
TEST_ASSERT(rma_create_challenge() == 0);
TEST_ASSERT(strlen(rma_get_challenge()) == RMA_CHALLENGE_CHARS);
/* Test using up tries */
TEST_ASSERT(rma_try_authcode_pad("Bad") == EC_ERROR_INVAL);
TEST_ASSERT(strlen(rma_get_challenge()) == RMA_CHALLENGE_CHARS);
TEST_ASSERT(rma_try_authcode_pad("BadCodeZ") == EC_ERROR_INVAL);
TEST_ASSERT(strlen(rma_get_challenge()) == RMA_CHALLENGE_CHARS);
TEST_ASSERT(rma_try_authcode_pad("BadLongCode") == EC_ERROR_INVAL);
/* Out of tries now */
TEST_ASSERT(strlen(rma_get_challenge()) == 0);
TEST_ASSERT(rma_try_authcode_pad("Bad") == EC_ERROR_ACCESS_DENIED);
FORCE_TIME(19 * SECOND);
TEST_ASSERT(rma_create_challenge() == EC_ERROR_TIMEOUT);
TEST_ASSERT(strlen(rma_get_challenge()) == 0);
FORCE_TIME(21 * SECOND);
TEST_ASSERT(rma_create_challenge() == 0);
challenge = rma_get_challenge();
TEST_ASSERT(strlen(challenge) == RMA_CHALLENGE_CHARS);
TEST_ASSERT(rma_server_side(authcode, challenge) == 0);
TEST_ASSERT(rma_try_authcode(authcode) == EC_SUCCESS);
/*
* Make sure the server-side checks for fields work. That is, test
* our ability to test those fields...
*/
server_protocol_version++;
TEST_ASSERT(rma_server_side(authcode, challenge) == -1);
server_protocol_version--;
server_key_id++;
TEST_ASSERT(rma_server_side(authcode, challenge) == -1);
server_key_id--;
placeholder_board_id[0]++;
TEST_ASSERT(rma_server_side(authcode, challenge) == -1);
placeholder_board_id[0]--;
placeholder_device_id[0]++;
TEST_ASSERT(rma_server_side(authcode, challenge) == -1);
placeholder_device_id[0]--;
return EC_SUCCESS;
}
void run_test(void)
{
test_reset();
RUN_TEST(test_rma_auth);
test_print_result();
}
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