| /* |
| * |
| * Copyright 2015 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| #include "src/core/lib/security/credentials/jwt/json_token.h" |
| |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/log.h> |
| #include <grpc/support/string_util.h> |
| #include <grpc/support/time.h> |
| |
| #include "src/core/lib/security/util/json_util.h" |
| #include "src/core/lib/slice/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. --- */ |
| |
| 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 = grpc_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 (!grpc_copy_json_string_property(json, "private_key_id", |
| &result.private_key_id) || |
| !grpc_copy_json_string_property(json, "client_id", &result.client_id) || |
| !grpc_copy_json_string_property(json, "client_email", |
| &result.client_email)) { |
| goto end; |
| } |
| |
| prop_value = grpc_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; |
| } |