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/*
*
* Copyright 2015-2016, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "src/core/lib/security/json_token.h"
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
#include "src/core/lib/security/b64.h"
#include "src/core/lib/support/string.h"
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
/* --- Constants. --- */
/* 1 hour max. */
gpr_timespec grpc_max_auth_token_lifetime() {
gpr_timespec out;
out.tv_sec = 3600;
out.tv_nsec = 0;
out.clock_type = GPR_TIMESPAN;
return out;
}
#define GRPC_JWT_RSA_SHA256_ALGORITHM "RS256"
#define GRPC_JWT_TYPE "JWT"
/* --- Override for testing. --- */
static grpc_jwt_encode_and_sign_override g_jwt_encode_and_sign_override = NULL;
/* --- grpc_auth_json_key. --- */
static const char *json_get_string_property(const grpc_json *json,
const char *prop_name) {
grpc_json *child;
for (child = json->child; child != NULL; child = child->next) {
if (strcmp(child->key, prop_name) == 0) break;
}
if (child == NULL || child->type != GRPC_JSON_STRING) {
gpr_log(GPR_ERROR, "Invalid or missing %s property.", prop_name);
return NULL;
}
return child->value;
}
static int set_json_key_string_property(const grpc_json *json,
const char *prop_name,
char **json_key_field) {
const char *prop_value = json_get_string_property(json, prop_name);
if (prop_value == NULL) return 0;
*json_key_field = gpr_strdup(prop_value);
return 1;
}
int grpc_auth_json_key_is_valid(const grpc_auth_json_key *json_key) {
return (json_key != NULL) &&
strcmp(json_key->type, GRPC_AUTH_JSON_TYPE_INVALID);
}
grpc_auth_json_key grpc_auth_json_key_create_from_json(const grpc_json *json) {
grpc_auth_json_key result;
BIO *bio = NULL;
const char *prop_value;
int success = 0;
memset(&result, 0, sizeof(grpc_auth_json_key));
result.type = GRPC_AUTH_JSON_TYPE_INVALID;
if (json == NULL) {
gpr_log(GPR_ERROR, "Invalid json.");
goto end;
}
prop_value = json_get_string_property(json, "type");
if (prop_value == NULL ||
strcmp(prop_value, GRPC_AUTH_JSON_TYPE_SERVICE_ACCOUNT)) {
goto end;
}
result.type = GRPC_AUTH_JSON_TYPE_SERVICE_ACCOUNT;
if (!set_json_key_string_property(json, "private_key_id",
&result.private_key_id) ||
!set_json_key_string_property(json, "client_id", &result.client_id) ||
!set_json_key_string_property(json, "client_email",
&result.client_email)) {
goto end;
}
prop_value = json_get_string_property(json, "private_key");
if (prop_value == NULL) {
goto end;
}
bio = BIO_new(BIO_s_mem());
success = BIO_puts(bio, prop_value);
if ((success < 0) || ((size_t)success != strlen(prop_value))) {
gpr_log(GPR_ERROR, "Could not write into openssl BIO.");
goto end;
}
result.private_key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, "");
if (result.private_key == NULL) {
gpr_log(GPR_ERROR, "Could not deserialize private key.");
goto end;
}
success = 1;
end:
if (bio != NULL) BIO_free(bio);
if (!success) grpc_auth_json_key_destruct(&result);
return result;
}
grpc_auth_json_key grpc_auth_json_key_create_from_string(
const char *json_string) {
char *scratchpad = gpr_strdup(json_string);
grpc_json *json = grpc_json_parse_string(scratchpad);
grpc_auth_json_key result = grpc_auth_json_key_create_from_json(json);
if (json != NULL) grpc_json_destroy(json);
gpr_free(scratchpad);
return result;
}
void grpc_auth_json_key_destruct(grpc_auth_json_key *json_key) {
if (json_key == NULL) return;
json_key->type = GRPC_AUTH_JSON_TYPE_INVALID;
if (json_key->client_id != NULL) {
gpr_free(json_key->client_id);
json_key->client_id = NULL;
}
if (json_key->private_key_id != NULL) {
gpr_free(json_key->private_key_id);
json_key->private_key_id = NULL;
}
if (json_key->client_email != NULL) {
gpr_free(json_key->client_email);
json_key->client_email = NULL;
}
if (json_key->private_key != NULL) {
RSA_free(json_key->private_key);
json_key->private_key = NULL;
}
}
/* --- jwt encoding and signature. --- */
static grpc_json *create_child(grpc_json *brother, grpc_json *parent,
const char *key, const char *value,
grpc_json_type type) {
grpc_json *child = grpc_json_create(type);
if (brother) brother->next = child;
if (!parent->child) parent->child = child;
child->parent = parent;
child->value = value;
child->key = key;
return child;
}
static char *encoded_jwt_header(const char *key_id, const char *algorithm) {
grpc_json *json = grpc_json_create(GRPC_JSON_OBJECT);
grpc_json *child = NULL;
char *json_str = NULL;
char *result = NULL;
child = create_child(NULL, json, "alg", algorithm, GRPC_JSON_STRING);
child = create_child(child, json, "typ", GRPC_JWT_TYPE, GRPC_JSON_STRING);
create_child(child, json, "kid", key_id, GRPC_JSON_STRING);
json_str = grpc_json_dump_to_string(json, 0);
result = grpc_base64_encode(json_str, strlen(json_str), 1, 0);
gpr_free(json_str);
grpc_json_destroy(json);
return result;
}
static char *encoded_jwt_claim(const grpc_auth_json_key *json_key,
const char *audience,
gpr_timespec token_lifetime, const char *scope) {
grpc_json *json = grpc_json_create(GRPC_JSON_OBJECT);
grpc_json *child = NULL;
char *json_str = NULL;
char *result = NULL;
gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
gpr_timespec expiration = gpr_time_add(now, token_lifetime);
char now_str[GPR_LTOA_MIN_BUFSIZE];
char expiration_str[GPR_LTOA_MIN_BUFSIZE];
if (gpr_time_cmp(token_lifetime, grpc_max_auth_token_lifetime()) > 0) {
gpr_log(GPR_INFO, "Cropping token lifetime to maximum allowed value.");
expiration = gpr_time_add(now, grpc_max_auth_token_lifetime());
}
int64_ttoa(now.tv_sec, now_str);
int64_ttoa(expiration.tv_sec, expiration_str);
child =
create_child(NULL, json, "iss", json_key->client_email, GRPC_JSON_STRING);
if (scope != NULL) {
child = create_child(child, json, "scope", scope, GRPC_JSON_STRING);
} else {
/* Unscoped JWTs need a sub field. */
child = create_child(child, json, "sub", json_key->client_email,
GRPC_JSON_STRING);
}
child = create_child(child, json, "aud", audience, GRPC_JSON_STRING);
child = create_child(child, json, "iat", now_str, GRPC_JSON_NUMBER);
create_child(child, json, "exp", expiration_str, GRPC_JSON_NUMBER);
json_str = grpc_json_dump_to_string(json, 0);
result = grpc_base64_encode(json_str, strlen(json_str), 1, 0);
gpr_free(json_str);
grpc_json_destroy(json);
return result;
}
static char *dot_concat_and_free_strings(char *str1, char *str2) {
size_t str1_len = strlen(str1);
size_t str2_len = strlen(str2);
size_t result_len = str1_len + 1 /* dot */ + str2_len;
char *result = gpr_malloc(result_len + 1 /* NULL terminated */);
char *current = result;
memcpy(current, str1, str1_len);
current += str1_len;
*(current++) = '.';
memcpy(current, str2, str2_len);
current += str2_len;
GPR_ASSERT(current >= result);
GPR_ASSERT((uintptr_t)(current - result) == result_len);
*current = '\0';
gpr_free(str1);
gpr_free(str2);
return result;
}
const EVP_MD *openssl_digest_from_algorithm(const char *algorithm) {
if (strcmp(algorithm, GRPC_JWT_RSA_SHA256_ALGORITHM) == 0) {
return EVP_sha256();
} else {
gpr_log(GPR_ERROR, "Unknown algorithm %s.", algorithm);
return NULL;
}
}
char *compute_and_encode_signature(const grpc_auth_json_key *json_key,
const char *signature_algorithm,
const char *to_sign) {
const EVP_MD *md = openssl_digest_from_algorithm(signature_algorithm);
EVP_MD_CTX *md_ctx = NULL;
EVP_PKEY *key = EVP_PKEY_new();
size_t sig_len = 0;
unsigned char *sig = NULL;
char *result = NULL;
if (md == NULL) return NULL;
md_ctx = EVP_MD_CTX_create();
if (md_ctx == NULL) {
gpr_log(GPR_ERROR, "Could not create MD_CTX");
goto end;
}
EVP_PKEY_set1_RSA(key, json_key->private_key);
if (EVP_DigestSignInit(md_ctx, NULL, md, NULL, key) != 1) {
gpr_log(GPR_ERROR, "DigestInit failed.");
goto end;
}
if (EVP_DigestSignUpdate(md_ctx, to_sign, strlen(to_sign)) != 1) {
gpr_log(GPR_ERROR, "DigestUpdate failed.");
goto end;
}
if (EVP_DigestSignFinal(md_ctx, NULL, &sig_len) != 1) {
gpr_log(GPR_ERROR, "DigestFinal (get signature length) failed.");
goto end;
}
sig = gpr_malloc(sig_len);
if (EVP_DigestSignFinal(md_ctx, sig, &sig_len) != 1) {
gpr_log(GPR_ERROR, "DigestFinal (signature compute) failed.");
goto end;
}
result = grpc_base64_encode(sig, sig_len, 1, 0);
end:
if (key != NULL) EVP_PKEY_free(key);
if (md_ctx != NULL) EVP_MD_CTX_destroy(md_ctx);
if (sig != NULL) gpr_free(sig);
return result;
}
char *grpc_jwt_encode_and_sign(const grpc_auth_json_key *json_key,
const char *audience,
gpr_timespec token_lifetime, const char *scope) {
if (g_jwt_encode_and_sign_override != NULL) {
return g_jwt_encode_and_sign_override(json_key, audience, token_lifetime,
scope);
} else {
const char *sig_algo = GRPC_JWT_RSA_SHA256_ALGORITHM;
char *to_sign = dot_concat_and_free_strings(
encoded_jwt_header(json_key->private_key_id, sig_algo),
encoded_jwt_claim(json_key, audience, token_lifetime, scope));
char *sig = compute_and_encode_signature(json_key, sig_algo, to_sign);
if (sig == NULL) {
gpr_free(to_sign);
return NULL;
}
return dot_concat_and_free_strings(to_sign, sig);
}
}
void grpc_jwt_encode_and_sign_set_override(
grpc_jwt_encode_and_sign_override func) {
g_jwt_encode_and_sign_override = func;
}
/* --- grpc_auth_refresh_token --- */
int grpc_auth_refresh_token_is_valid(
const grpc_auth_refresh_token *refresh_token) {
return (refresh_token != NULL) &&
strcmp(refresh_token->type, GRPC_AUTH_JSON_TYPE_INVALID);
}
grpc_auth_refresh_token grpc_auth_refresh_token_create_from_json(
const grpc_json *json) {
grpc_auth_refresh_token result;
const char *prop_value;
int success = 0;
memset(&result, 0, sizeof(grpc_auth_refresh_token));
result.type = GRPC_AUTH_JSON_TYPE_INVALID;
if (json == NULL) {
gpr_log(GPR_ERROR, "Invalid json.");
goto end;
}
prop_value = json_get_string_property(json, "type");
if (prop_value == NULL ||
strcmp(prop_value, GRPC_AUTH_JSON_TYPE_AUTHORIZED_USER)) {
goto end;
}
result.type = GRPC_AUTH_JSON_TYPE_AUTHORIZED_USER;
if (!set_json_key_string_property(json, "client_secret",
&result.client_secret) ||
!set_json_key_string_property(json, "client_id", &result.client_id) ||
!set_json_key_string_property(json, "refresh_token",
&result.refresh_token)) {
goto end;
}
success = 1;
end:
if (!success) grpc_auth_refresh_token_destruct(&result);
return result;
}
grpc_auth_refresh_token grpc_auth_refresh_token_create_from_string(
const char *json_string) {
char *scratchpad = gpr_strdup(json_string);
grpc_json *json = grpc_json_parse_string(scratchpad);
grpc_auth_refresh_token result =
grpc_auth_refresh_token_create_from_json(json);
if (json != NULL) grpc_json_destroy(json);
gpr_free(scratchpad);
return result;
}
void grpc_auth_refresh_token_destruct(grpc_auth_refresh_token *refresh_token) {
if (refresh_token == NULL) return;
refresh_token->type = GRPC_AUTH_JSON_TYPE_INVALID;
if (refresh_token->client_id != NULL) {
gpr_free(refresh_token->client_id);
refresh_token->client_id = NULL;
}
if (refresh_token->client_secret != NULL) {
gpr_free(refresh_token->client_secret);
refresh_token->client_secret = NULL;
}
if (refresh_token->refresh_token != NULL) {
gpr_free(refresh_token->refresh_token);
refresh_token->refresh_token = NULL;
}
}
|