mirror of
https://github.com/Telecominfraproject/OpenCellular.git
synced 2026-01-07 16:11:43 +00:00
282765fdd4
RMA auth uses X25519 to generate a relatively small challenge and response. Currently, nothing calls the rma_auth code. We'll need console and TPM vendor commands to do so. BUG=b:37952913 BRANCH=none TEST=make buildall Change-Id: Iec7f2d0e3dc8243f79b009ead16bb3ba9f1bef9d Signed-off-by: Randall Spangler <rspangler@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/544184
124 lines
3.2 KiB
C
124 lines
3.2 KiB
C
/* 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.
|
|
*/
|
|
|
|
/* RMA authorization challenge-response */
|
|
|
|
#include "common.h"
|
|
#include "base32.h"
|
|
#include "chip/g/board_id.h"
|
|
#include "curve25519.h"
|
|
#include "rma_auth.h"
|
|
#include "sha256.h"
|
|
#include "system.h"
|
|
#include "timer.h"
|
|
#include "util.h"
|
|
|
|
/* Minimum time since system boot or last challenge before making a new one */
|
|
#define CHALLENGE_INTERVAL (10 * SECOND)
|
|
|
|
/* Number of tries to properly enter auth code */
|
|
#define MAX_AUTHCODE_TRIES 3
|
|
|
|
/* Server public key and key ID */
|
|
static const uint8_t server_pub_key[32] = CONFIG_RMA_AUTH_SERVER_PUBLIC_KEY;
|
|
static const uint8_t server_key_id = CONFIG_RMA_AUTH_SERVER_KEY_ID;
|
|
|
|
static char challenge[RMA_CHALLENGE_BUF_SIZE];
|
|
static char authcode[RMA_AUTHCODE_BUF_SIZE];
|
|
static int tries_left;
|
|
static uint64_t last_challenge_time;
|
|
|
|
/**
|
|
* Create a new RMA challenge/response
|
|
*
|
|
* @return EC_SUCCESS, EC_ERROR_TIMEOUT if too soon since the last challenge,
|
|
* or other non-zero error code.
|
|
*/
|
|
int rma_create_challenge(void)
|
|
{
|
|
uint8_t temp[32]; /* Private key or HMAC */
|
|
uint8_t secret[32];
|
|
struct rma_challenge c;
|
|
struct board_id bid;
|
|
uint8_t *device_id;
|
|
uint8_t *cptr = (uint8_t *)&c;
|
|
uint64_t t;
|
|
|
|
/* Clear the current challenge and authcode, if any */
|
|
memset(challenge, 0, sizeof(challenge));
|
|
memset(authcode, 0, sizeof(authcode));
|
|
|
|
/* Rate limit challenges */
|
|
t = get_time().val;
|
|
if (t - last_challenge_time < CHALLENGE_INTERVAL)
|
|
return EC_ERROR_TIMEOUT;
|
|
last_challenge_time = t;
|
|
|
|
memset(&c, 0, sizeof(c));
|
|
c.version_key_id = RMA_CHALLENGE_VKID_BYTE(
|
|
RMA_CHALLENGE_VERSION, server_key_id);
|
|
|
|
if (read_board_id(&bid))
|
|
return EC_ERROR_UNKNOWN;
|
|
memcpy(c.board_id, &bid.type, sizeof(c.board_id));
|
|
|
|
if (system_get_chip_unique_id(&device_id) != sizeof(c.device_id))
|
|
return EC_ERROR_UNKNOWN;
|
|
memcpy(c.device_id, device_id, sizeof(c.device_id));
|
|
|
|
/* Calculate a new ephemeral key pair */
|
|
X25519_keypair(c.device_pub_key, temp);
|
|
|
|
/* Encode the challenge */
|
|
if (base32_encode(challenge, sizeof(challenge), cptr, 8 * sizeof(c), 9))
|
|
return EC_ERROR_UNKNOWN;
|
|
|
|
/* Calculate the shared secret */
|
|
X25519(secret, temp, server_pub_key);
|
|
|
|
/*
|
|
* Auth code is a truncated HMAC of the ephemeral public key, BoardID,
|
|
* and DeviceID. Those are all in the right order in the challenge
|
|
* struct, after the version/key id byte.
|
|
*/
|
|
hmac_SHA256(temp, secret, sizeof(secret), cptr + 1, sizeof(c) - 1);
|
|
if (base32_encode(authcode, sizeof(authcode), temp,
|
|
RMA_AUTHCODE_CHARS * 5, 0))
|
|
return EC_ERROR_UNKNOWN;
|
|
|
|
tries_left = MAX_AUTHCODE_TRIES;
|
|
return EC_SUCCESS;
|
|
}
|
|
|
|
const char *rma_get_challenge(void)
|
|
{
|
|
return challenge;
|
|
}
|
|
|
|
int rma_try_authcode(const char *code)
|
|
{
|
|
int rv = EC_ERROR_INVAL;
|
|
|
|
/* Fail if out of tries */
|
|
if (!tries_left)
|
|
return EC_ERROR_ACCESS_DENIED;
|
|
|
|
if (safe_memcmp(authcode, code, RMA_AUTHCODE_CHARS)) {
|
|
/* Mismatch */
|
|
tries_left--;
|
|
} else {
|
|
rv = EC_SUCCESS;
|
|
tries_left = 0;
|
|
}
|
|
|
|
/* Clear challenge and response if out of tries */
|
|
if (!tries_left) {
|
|
memset(challenge, 0, sizeof(challenge));
|
|
memset(authcode, 0, sizeof(authcode));
|
|
}
|
|
|
|
return rv;
|
|
}
|