425 lines
11 KiB
C
425 lines
11 KiB
C
/*
|
|
* Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
|
|
*
|
|
* SPDX-License-Identifier: BSD-3-Clause
|
|
*/
|
|
|
|
#include <assert.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
|
|
#include <platform_def.h>
|
|
|
|
#include <common/debug.h>
|
|
#include <common/tbbr/cot_def.h>
|
|
#include <drivers/auth/auth_common.h>
|
|
#include <drivers/auth/auth_mod.h>
|
|
#include <drivers/auth/crypto_mod.h>
|
|
#include <drivers/auth/img_parser_mod.h>
|
|
#include <plat/common/platform.h>
|
|
|
|
/* ASN.1 tags */
|
|
#define ASN1_INTEGER 0x02
|
|
|
|
#define return_if_error(rc) \
|
|
do { \
|
|
if (rc != 0) { \
|
|
return rc; \
|
|
} \
|
|
} while (0)
|
|
|
|
#pragma weak plat_set_nv_ctr2
|
|
|
|
/* Pointer to CoT */
|
|
extern const auth_img_desc_t *const *const cot_desc_ptr;
|
|
extern unsigned int auth_img_flags[MAX_NUMBER_IDS];
|
|
|
|
static int cmp_auth_param_type_desc(const auth_param_type_desc_t *a,
|
|
const auth_param_type_desc_t *b)
|
|
{
|
|
if ((a->type == b->type) && (a->cookie == b->cookie)) {
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* This function obtains the requested authentication parameter data from the
|
|
* information extracted from the parent image after its authentication.
|
|
*/
|
|
static int auth_get_param(const auth_param_type_desc_t *param_type_desc,
|
|
const auth_img_desc_t *img_desc,
|
|
void **param, unsigned int *len)
|
|
{
|
|
int i;
|
|
|
|
if (img_desc->authenticated_data == NULL)
|
|
return 1;
|
|
|
|
for (i = 0 ; i < COT_MAX_VERIFIED_PARAMS ; i++) {
|
|
if (0 == cmp_auth_param_type_desc(param_type_desc,
|
|
img_desc->authenticated_data[i].type_desc)) {
|
|
*param = img_desc->authenticated_data[i].data.ptr;
|
|
*len = img_desc->authenticated_data[i].data.len;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Authenticate an image by matching the data hash
|
|
*
|
|
* This function implements 'AUTH_METHOD_HASH'. To authenticate an image using
|
|
* this method, the image must contain:
|
|
*
|
|
* - The data to calculate the hash from
|
|
*
|
|
* The parent image must contain:
|
|
*
|
|
* - The hash to be matched with (including hash algorithm)
|
|
*
|
|
* For a successful authentication, both hashes must match. The function calls
|
|
* the crypto-module to check this matching.
|
|
*
|
|
* Parameters:
|
|
* param: parameters to perform the hash authentication
|
|
* img_desc: pointer to image descriptor so we can know the image type
|
|
* and parent image
|
|
* img: pointer to image in memory
|
|
* img_len: length of image (in bytes)
|
|
*
|
|
* Return:
|
|
* 0 = success, Otherwise = error
|
|
*/
|
|
static int auth_hash(const auth_method_param_hash_t *param,
|
|
const auth_img_desc_t *img_desc,
|
|
void *img, unsigned int img_len)
|
|
{
|
|
void *data_ptr, *hash_der_ptr;
|
|
unsigned int data_len, hash_der_len;
|
|
int rc = 0;
|
|
|
|
/* Get the hash from the parent image. This hash will be DER encoded
|
|
* and contain the hash algorithm */
|
|
rc = auth_get_param(param->hash, img_desc->parent,
|
|
&hash_der_ptr, &hash_der_len);
|
|
return_if_error(rc);
|
|
|
|
/* Get the data to be hashed from the current image */
|
|
rc = img_parser_get_auth_param(img_desc->img_type, param->data,
|
|
img, img_len, &data_ptr, &data_len);
|
|
return_if_error(rc);
|
|
|
|
/* Ask the crypto module to verify this hash */
|
|
rc = crypto_mod_verify_hash(data_ptr, data_len,
|
|
hash_der_ptr, hash_der_len);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Authenticate by digital signature
|
|
*
|
|
* This function implements 'AUTH_METHOD_SIG'. To authenticate an image using
|
|
* this method, the image must contain:
|
|
*
|
|
* - Data to be signed
|
|
* - Signature
|
|
* - Signature algorithm
|
|
*
|
|
* We rely on the image parser module to extract this data from the image.
|
|
* The parent image must contain:
|
|
*
|
|
* - Public key (or a hash of it)
|
|
*
|
|
* If the parent image contains only a hash of the key, we will try to obtain
|
|
* the public key from the image itself (i.e. self-signed certificates). In that
|
|
* case, the signature verification is considered just an integrity check and
|
|
* the authentication is established by calculating the hash of the key and
|
|
* comparing it with the hash obtained from the parent.
|
|
*
|
|
* If the image has no parent (NULL), it means it has to be authenticated using
|
|
* the ROTPK stored in the platform. Again, this ROTPK could be the key itself
|
|
* or a hash of it.
|
|
*
|
|
* Return: 0 = success, Otherwise = error
|
|
*/
|
|
static int auth_signature(const auth_method_param_sig_t *param,
|
|
const auth_img_desc_t *img_desc,
|
|
void *img, unsigned int img_len)
|
|
{
|
|
void *data_ptr, *pk_ptr, *pk_hash_ptr, *sig_ptr, *sig_alg_ptr;
|
|
unsigned int data_len, pk_len, pk_hash_len, sig_len, sig_alg_len;
|
|
unsigned int flags = 0;
|
|
int rc = 0;
|
|
|
|
/* Get the data to be signed from current image */
|
|
rc = img_parser_get_auth_param(img_desc->img_type, param->data,
|
|
img, img_len, &data_ptr, &data_len);
|
|
return_if_error(rc);
|
|
|
|
/* Get the signature from current image */
|
|
rc = img_parser_get_auth_param(img_desc->img_type, param->sig,
|
|
img, img_len, &sig_ptr, &sig_len);
|
|
return_if_error(rc);
|
|
|
|
/* Get the signature algorithm from current image */
|
|
rc = img_parser_get_auth_param(img_desc->img_type, param->alg,
|
|
img, img_len, &sig_alg_ptr, &sig_alg_len);
|
|
return_if_error(rc);
|
|
|
|
/* Get the public key from the parent. If there is no parent (NULL),
|
|
* the certificate has been signed with the ROTPK, so we have to get
|
|
* the PK from the platform */
|
|
if (img_desc->parent) {
|
|
rc = auth_get_param(param->pk, img_desc->parent,
|
|
&pk_ptr, &pk_len);
|
|
} else {
|
|
rc = plat_get_rotpk_info(param->pk->cookie, &pk_ptr, &pk_len,
|
|
&flags);
|
|
}
|
|
return_if_error(rc);
|
|
|
|
if (flags & (ROTPK_IS_HASH | ROTPK_NOT_DEPLOYED)) {
|
|
/* If the PK is a hash of the key or if the ROTPK is not
|
|
deployed on the platform, retrieve the key from the image */
|
|
pk_hash_ptr = pk_ptr;
|
|
pk_hash_len = pk_len;
|
|
rc = img_parser_get_auth_param(img_desc->img_type,
|
|
param->pk, img, img_len,
|
|
&pk_ptr, &pk_len);
|
|
return_if_error(rc);
|
|
|
|
/* Ask the crypto module to verify the signature */
|
|
rc = crypto_mod_verify_signature(data_ptr, data_len,
|
|
sig_ptr, sig_len,
|
|
sig_alg_ptr, sig_alg_len,
|
|
pk_ptr, pk_len);
|
|
return_if_error(rc);
|
|
|
|
if (flags & ROTPK_NOT_DEPLOYED) {
|
|
NOTICE("ROTPK is not deployed on platform. "
|
|
"Skipping ROTPK verification.\n");
|
|
} else {
|
|
/* Ask the crypto-module to verify the key hash */
|
|
rc = crypto_mod_verify_hash(pk_ptr, pk_len,
|
|
pk_hash_ptr, pk_hash_len);
|
|
}
|
|
} else {
|
|
/* Ask the crypto module to verify the signature */
|
|
rc = crypto_mod_verify_signature(data_ptr, data_len,
|
|
sig_ptr, sig_len,
|
|
sig_alg_ptr, sig_alg_len,
|
|
pk_ptr, pk_len);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Authenticate by Non-Volatile counter
|
|
*
|
|
* To protect the system against rollback, the platform includes a non-volatile
|
|
* counter whose value can only be increased. All certificates include a counter
|
|
* value that should not be lower than the value stored in the platform. If the
|
|
* value is larger, the counter in the platform must be updated to the new
|
|
* value.
|
|
*
|
|
* Return: 0 = success, Otherwise = error
|
|
*/
|
|
static int auth_nvctr(const auth_method_param_nv_ctr_t *param,
|
|
const auth_img_desc_t *img_desc,
|
|
void *img, unsigned int img_len)
|
|
{
|
|
char *p;
|
|
void *data_ptr = NULL;
|
|
unsigned int data_len, len, i;
|
|
unsigned int cert_nv_ctr, plat_nv_ctr;
|
|
int rc = 0;
|
|
|
|
/* Get the counter value from current image. The AM expects the IPM
|
|
* to return the counter value as a DER encoded integer */
|
|
rc = img_parser_get_auth_param(img_desc->img_type, param->cert_nv_ctr,
|
|
img, img_len, &data_ptr, &data_len);
|
|
return_if_error(rc);
|
|
|
|
/* Parse the DER encoded integer */
|
|
assert(data_ptr);
|
|
p = (char *)data_ptr;
|
|
if (*p != ASN1_INTEGER) {
|
|
/* Invalid ASN.1 integer */
|
|
return 1;
|
|
}
|
|
p++;
|
|
|
|
/* NV-counters are unsigned integers up to 32-bit */
|
|
len = (unsigned int)(*p & 0x7f);
|
|
if ((*p & 0x80) || (len > 4)) {
|
|
return 1;
|
|
}
|
|
p++;
|
|
|
|
/* Check the number is not negative */
|
|
if (*p & 0x80) {
|
|
return 1;
|
|
}
|
|
|
|
/* Convert to unsigned int. This code is for a little-endian CPU */
|
|
cert_nv_ctr = 0;
|
|
for (i = 0; i < len; i++) {
|
|
cert_nv_ctr = (cert_nv_ctr << 8) | *p++;
|
|
}
|
|
|
|
/* Get the counter from the platform */
|
|
rc = plat_get_nv_ctr(param->plat_nv_ctr->cookie, &plat_nv_ctr);
|
|
return_if_error(rc);
|
|
|
|
if (cert_nv_ctr < plat_nv_ctr) {
|
|
/* Invalid NV-counter */
|
|
return 1;
|
|
} else if (cert_nv_ctr > plat_nv_ctr) {
|
|
rc = plat_set_nv_ctr2(param->plat_nv_ctr->cookie,
|
|
img_desc, cert_nv_ctr);
|
|
return_if_error(rc);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int plat_set_nv_ctr2(void *cookie, const auth_img_desc_t *img_desc __unused,
|
|
unsigned int nv_ctr)
|
|
{
|
|
return plat_set_nv_ctr(cookie, nv_ctr);
|
|
}
|
|
|
|
/*
|
|
* Return the parent id in the output parameter '*parent_id'
|
|
*
|
|
* Return value:
|
|
* 0 = Image has parent, 1 = Image has no parent or parent is authenticated
|
|
*/
|
|
int auth_mod_get_parent_id(unsigned int img_id, unsigned int *parent_id)
|
|
{
|
|
const auth_img_desc_t *img_desc = NULL;
|
|
|
|
assert(parent_id != NULL);
|
|
|
|
/* Get the image descriptor */
|
|
img_desc = cot_desc_ptr[img_id];
|
|
|
|
/* Check if the image has no parent (ROT) */
|
|
if (img_desc->parent == NULL) {
|
|
*parent_id = 0;
|
|
return 1;
|
|
}
|
|
|
|
/* Check if the parent has already been authenticated */
|
|
if (auth_img_flags[img_desc->parent->img_id] & IMG_FLAG_AUTHENTICATED) {
|
|
*parent_id = 0;
|
|
return 1;
|
|
}
|
|
|
|
*parent_id = img_desc->parent->img_id;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Initialize the different modules in the authentication framework
|
|
*/
|
|
void auth_mod_init(void)
|
|
{
|
|
/* Check we have a valid CoT registered */
|
|
assert(cot_desc_ptr != NULL);
|
|
|
|
/* Crypto module */
|
|
crypto_mod_init();
|
|
|
|
/* Image parser module */
|
|
img_parser_init();
|
|
}
|
|
|
|
/*
|
|
* Authenticate a certificate/image
|
|
*
|
|
* Return: 0 = success, Otherwise = error
|
|
*/
|
|
int auth_mod_verify_img(unsigned int img_id,
|
|
void *img_ptr,
|
|
unsigned int img_len)
|
|
{
|
|
const auth_img_desc_t *img_desc = NULL;
|
|
const auth_method_desc_t *auth_method = NULL;
|
|
void *param_ptr;
|
|
unsigned int param_len;
|
|
int rc, i;
|
|
|
|
/* Get the image descriptor from the chain of trust */
|
|
img_desc = cot_desc_ptr[img_id];
|
|
|
|
/* Ask the parser to check the image integrity */
|
|
rc = img_parser_check_integrity(img_desc->img_type, img_ptr, img_len);
|
|
return_if_error(rc);
|
|
|
|
/* Authenticate the image using the methods indicated in the image
|
|
* descriptor. */
|
|
if (img_desc->img_auth_methods == NULL)
|
|
return 1;
|
|
for (i = 0 ; i < AUTH_METHOD_NUM ; i++) {
|
|
auth_method = &img_desc->img_auth_methods[i];
|
|
switch (auth_method->type) {
|
|
case AUTH_METHOD_NONE:
|
|
rc = 0;
|
|
break;
|
|
case AUTH_METHOD_HASH:
|
|
rc = auth_hash(&auth_method->param.hash,
|
|
img_desc, img_ptr, img_len);
|
|
break;
|
|
case AUTH_METHOD_SIG:
|
|
rc = auth_signature(&auth_method->param.sig,
|
|
img_desc, img_ptr, img_len);
|
|
break;
|
|
case AUTH_METHOD_NV_CTR:
|
|
rc = auth_nvctr(&auth_method->param.nv_ctr,
|
|
img_desc, img_ptr, img_len);
|
|
break;
|
|
default:
|
|
/* Unknown authentication method */
|
|
rc = 1;
|
|
break;
|
|
}
|
|
return_if_error(rc);
|
|
}
|
|
|
|
/* Extract the parameters indicated in the image descriptor to
|
|
* authenticate the children images. */
|
|
if (img_desc->authenticated_data != NULL) {
|
|
for (i = 0 ; i < COT_MAX_VERIFIED_PARAMS ; i++) {
|
|
if (img_desc->authenticated_data[i].type_desc == NULL) {
|
|
continue;
|
|
}
|
|
|
|
/* Get the parameter from the image parser module */
|
|
rc = img_parser_get_auth_param(img_desc->img_type,
|
|
img_desc->authenticated_data[i].type_desc,
|
|
img_ptr, img_len, ¶m_ptr, ¶m_len);
|
|
return_if_error(rc);
|
|
|
|
/* Check parameter size */
|
|
if (param_len > img_desc->authenticated_data[i].data.len) {
|
|
return 1;
|
|
}
|
|
|
|
/* Copy the parameter for later use */
|
|
memcpy((void *)img_desc->authenticated_data[i].data.ptr,
|
|
(void *)param_ptr, param_len);
|
|
}
|
|
}
|
|
|
|
/* Mark image as authenticated */
|
|
auth_img_flags[img_desc->img_id] |= IMG_FLAG_AUTHENTICATED;
|
|
|
|
return 0;
|
|
}
|