/
delegator_tz.c
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/
delegator_tz.c
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#include <stdio.h>
#include <string.h>
#include <user_ta_header_defines.h>
#include <tee_internal_api.h>
#include <tee_internal_api_extensions.h>
#ifdef ATTR_REF
#undef ATTR_REF
#endif
#define ATTR_REF(CNT, ATTR, BUF) \
TEE_InitRefAttribute(&attrs[(CNT)++], (ATTR), (BUF).b, (BUF).sz)
#define LOG_RET(ret) \
if((ret)!=TEE_SUCCESS) { \
EMSG("ERR: %d %X", __LINE__, ret); \
return ret; \
}
// Calculates size of an array
#define ARRAY_SIZE(a) ((sizeof((a))) / sizeof((a)[0]))
/*
* Called when the instance of the TA is created. This is the first call in
* the TA.
*/
TEE_Result TA_CreateEntryPoint(void)
{
DMSG("has been called");
return TEE_SUCCESS;
}
/*
* Called when the instance of the TA is destroyed if the TA has not
* crashed or panicked. This is the last call in the TA.
*/
void TA_DestroyEntryPoint(void) {
DMSG("has been called");
}
/*
* Called when a new session is opened to the TA. *sess_ctx can be updated
* with a value to be able to identify this session in subsequent calls to the
* TA. In this function you will normally do the global initialization for the
* TA.
*/
TEE_Result TA_OpenSessionEntryPoint(uint32_t param_types,
TEE_Param __maybe_unused params[4],
void __maybe_unused **sess_ctx) {
const uint32_t exp_param_types =
TEE_PARAM_TYPES(TEE_PARAM_TYPE_NONE,
TEE_PARAM_TYPE_NONE,
TEE_PARAM_TYPE_NONE,
TEE_PARAM_TYPE_NONE);
DMSG("has been called");
if (param_types != exp_param_types) {
return TEE_ERROR_BAD_PARAMETERS;
}
/* Unused parameters */
(void)¶ms;
(void)&sess_ctx;
/*
* The DMSG() macro is non-standard, TEE Internal API doesn't
* specify any means to logging from a TA.
*/
/* If return value != TEE_SUCCESS the session will not be created. */
return TEE_SUCCESS;
}
/*
* Called when a session is closed, sess_ctx hold the value that was
* assigned by TA_OpenSessionEntryPoint().
*/
void TA_CloseSessionEntryPoint(void __maybe_unused *sess_ctx)
{
(void)&sess_ctx; /* Unused parameter */
EMSG("Session closed\n");
}
// Creates new ECC key
static TEE_ObjectHandle create_ecc_key(struct keypair_t *kp) {
TEE_Result res;
TEE_ObjectHandle obj = TEE_HANDLE_NULL;
TEE_Attribute attrs[4];
struct ECC_t *ecc;
size_t cnt = 0;
ecc = &kp->u.ecc;
res = TEE_AllocateTransientObject(
TEE_TYPE_ECDSA_KEYPAIR,
ecc->x.sz * 8,
&obj);
if (res != TEE_SUCCESS) {
EMSG("E: TEE_AllocateTransientObject failed");
goto err;
}
ATTR_REF(cnt, TEE_ATTR_ECC_PRIVATE_VALUE, ecc->scalar);
ATTR_REF(cnt, TEE_ATTR_ECC_PUBLIC_VALUE_X, ecc->x);
ATTR_REF(cnt, TEE_ATTR_ECC_PUBLIC_VALUE_Y, ecc->y);
TEE_InitValueAttribute(&attrs[cnt++], TEE_ATTR_ECC_CURVE,ecc->curve_id, 0);
// TODO: ecc->scalar shouldn't be extractable, but we store it with
// the public key, and I need to be able to extract it.
// It would be better to store public and private key separately.
res = TEE_RestrictObjectUsage1(obj, TEE_USAGE_EXTRACTABLE|TEE_USAGE_SIGN);
if (res != TEE_SUCCESS ) {
EMSG("E: TEE_RestrictObjectUsage1 failed");
goto err;
}
res = TEE_PopulateTransientObject(obj, attrs, cnt);
if (res != TEE_SUCCESS) {
EMSG("E: TEE_PopulateTransientObject failed");
goto err;
}
return obj;
err:
TEE_FreeTransientObject(obj);
return TEE_HANDLE_NULL;
}
// Puts the key to the storage
static TEE_Result install_key(uint32_t param_types, TEE_Param params[4]) {
TEE_Result ret;
TEE_ObjectHandle transient_obj = TEE_HANDLE_NULL;
TEE_ObjectHandle persistant_obj = TEE_HANDLE_NULL;
uint32_t exp_param_types;
struct keypair_t *kp;
uint8_t key_id[SHA256_SIZE];
exp_param_types = TEE_PARAM_TYPES(TEE_PARAM_TYPE_MEMREF_INPUT,
TEE_PARAM_TYPE_MEMREF_INPUT,
TEE_PARAM_TYPE_NONE,
TEE_PARAM_TYPE_NONE);
if (param_types != exp_param_types ||
params[1].memref.size != ARRAY_SIZE(key_id)) {
return TEE_ERROR_BAD_PARAMETERS;
}
kp = (struct keypair_t*)params[0].memref.buffer;
if (sizeof(*kp) != params[0].memref.size) {
EMSG("E: wrong size of keypair_t struct");
return TEE_ERROR_BAD_PARAMETERS;
}
// Only ECC supported
if (kp->type != KEYTYPE_ECC) {
EMSG("E: only ECC keys supported");
return TEE_ERROR_BAD_PARAMETERS;
}
transient_obj = create_ecc_key(kp);
if (transient_obj == TEE_HANDLE_NULL) {
EMSG("E: Can't create transient object");
return TEE_ERROR_BAD_PARAMETERS;
}
// Input TEE_CreatePersistentObject can't be NWd shared buffer
memcpy(key_id, params[1].memref.buffer, params[1].memref.size);
ret = TEE_CreatePersistentObject(
TEE_STORAGE_PRIVATE,
key_id, ARRAY_SIZE(key_id),
TEE_DATA_FLAG_ACCESS_WRITE,
transient_obj,
NULL/*data*/, 0 /*data_len*/, &persistant_obj);
if (ret) {
EMSG("E: Create");
return ret;
}
IMSG("New key [%02X%02X%02X%02X%02X] registered",
key_id[0], key_id[1], key_id[2], key_id[3], key_id[4]);
TEE_FreeTransientObject(transient_obj);
TEE_CloseObject(persistant_obj);
return TEE_SUCCESS;
}
// Performs key deletion from the secure storage
static TEE_Result del_key(uint32_t param_types, TEE_Param params[4]) {
TEE_Result ret;
char key_id[SHA256_SIZE] = {0};
TEE_ObjectHandle obj = TEE_HANDLE_NULL;
const uint32_t exp_param_types =
TEE_PARAM_TYPES(TEE_PARAM_TYPE_MEMREF_INPUT,
TEE_PARAM_TYPE_NONE,
TEE_PARAM_TYPE_NONE,
TEE_PARAM_TYPE_NONE);
if (param_types != exp_param_types)
return TEE_ERROR_BAD_PARAMETERS;
if (params[0].memref.size > sizeof(key_id)) {
EMSG("E: filename too long (>255)");
return TEE_ERROR_BAD_PARAMETERS;
}
memcpy(key_id, params[0].memref.buffer,
params[0].memref.size);
ret = TEE_OpenPersistentObject(
TEE_STORAGE_PRIVATE,
key_id, params[0].memref.size,
TEE_DATA_FLAG_ACCESS_WRITE_META, &obj);
if (ret) {
EMSG("E: Can't open");
return ret;
}
IMSG("Key [%02X%02X%02X%02X%02X] unregistered",
key_id[0], key_id[1], key_id[2], key_id[3], key_id[4]);
TEE_CloseAndDeletePersistentObject(obj);
return TEE_SUCCESS;
}
// returns public key of installed key-pair to the normal world
static TEE_Result get_public_key(uint32_t param_types, TEE_Param params[4]) {
uint32_t exp_param_types;
char key_id[SHA256_SIZE] = {0};
TEE_Result ret;
TEE_ObjectHandle obj = TEE_HANDLE_NULL;
exp_param_types = TEE_PARAM_TYPES(
TEE_PARAM_TYPE_MEMREF_INPUT,
TEE_PARAM_TYPE_MEMREF_INOUT,
TEE_PARAM_TYPE_MEMREF_INOUT,
TEE_PARAM_TYPE_NONE);
if (param_types != exp_param_types) {
EMSG("Unexpected params");
return TEE_ERROR_BAD_PARAMETERS;
}
if (params[0].memref.size < SHA256_SIZE) {
EMSG("key-id must be SHA256 hash");
return TEE_ERROR_BAD_PARAMETERS;
}
memcpy(key_id, params[0].memref.buffer, params[0].memref.size);
ret = TEE_OpenPersistentObject(
TEE_STORAGE_PRIVATE,
key_id, ARRAY_SIZE(key_id),
TEE_DATA_FLAG_ACCESS_READ, &obj);
if (ret) {
EMSG("E: Open 0x%X", ret);
return ret;
}
ret = TEE_SUCCESS;
ret |= TEE_GetObjectBufferAttribute(obj, TEE_ATTR_ECC_PUBLIC_VALUE_X,
params[1].memref.buffer, ¶ms[1].memref.size);
ret |= TEE_GetObjectBufferAttribute(obj, TEE_ATTR_ECC_PUBLIC_VALUE_Y,
params[2].memref.buffer, ¶ms[2].memref.size);
if (ret) {
EMSG("E: Can't extract public attributes for ECC key");
goto end;
}
IMSG("Public key for ID [%02X%02X%02X%02X%02X] returned",
key_id[0], key_id[1], key_id[2], key_id[3], key_id[4]);
end:
TEE_CloseObject(obj);
return TEE_SUCCESS;
}
// Performs ECDSA signing with a key from secure storage
static TEE_Result sign_ecdsa(uint32_t param_types, TEE_Param params[4]) {
TEE_Result ret;
TEE_OperationHandle op = TEE_HANDLE_NULL;
TEE_ObjectHandle obj = TEE_HANDLE_NULL;
uint8_t key_id[SHA256_SIZE];
const uint32_t exp_param_types =
TEE_PARAM_TYPES(
TEE_PARAM_TYPE_MEMREF_INPUT,
TEE_PARAM_TYPE_MEMREF_INPUT,
TEE_PARAM_TYPE_MEMREF_INOUT,
TEE_PARAM_TYPE_NONE);
if ((param_types != exp_param_types) ||
(params[0].memref.size > ARRAY_SIZE(key_id))) {
return TEE_ERROR_BAD_PARAMETERS;
}
// Must be local
memcpy(key_id, params[0].memref.buffer, params[0].memref.size);
IMSG("Sign for a key ID [%02X%02X%02X%02X%02X] requested",
key_id[0], key_id[1], key_id[2], key_id[3], key_id[4]);
ret = TEE_OpenPersistentObject(
TEE_STORAGE_PRIVATE,
key_id, ARRAY_SIZE(key_id),
TEE_DATA_FLAG_ACCESS_READ, &obj);
if (ret) {
EMSG("E: Can't open");
return ret;
}
// perform ECDSA sigining
ret = TEE_AllocateOperation(&op, TEE_ALG_ECDSA_P256, TEE_MODE_SIGN, 256);
LOG_RET(ret);
ret = TEE_SetOperationKey(op, obj);
LOG_RET(ret);
ret = TEE_AsymmetricSignDigest(op, NULL, 0,
params[1].memref.buffer, params[1].memref.size,
params[2].memref.buffer, ¶ms[2].memref.size);
LOG_RET(ret);
TEE_CloseObject(obj);
TEE_FreeOperation(op);
IMSG("Message signed with key ID [%02X%02X%02X%02X%02X]",
key_id[0], key_id[1], key_id[2], key_id[3], key_id[4]);
return TEE_SUCCESS;
}
/*
* Called when a TA is invoked. sess_ctx hold that value that was
* assigned by TA_OpenSessionEntryPoint(). The rest of the paramters
* comes from normal world.
*/
TEE_Result TA_InvokeCommandEntryPoint(void __maybe_unused *sess_ctx,
uint32_t cmd_id,
uint32_t param_types, TEE_Param params[4]) {
(void)&sess_ctx; /* Unused parameter */
switch (cmd_id) {
case TA_INSTALL_KEYS:
return install_key(param_types, params);
case TA_DEL_KEYS:
return del_key(param_types, params);
case TA_GET_PUB_KEY:
return get_public_key(param_types, params);
case TA_SIGN_ECC:
return sign_ecdsa(param_types, params);
default:
EMSG("Request not supported");
return TEE_ERROR_BAD_PARAMETERS;
}
}