1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
*
* Copyright 2015, 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/security/credentials.h"
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include "src/core/httpcli/httpcli.h"
#include "src/core/support/env.h"
#include "src/core/support/file.h"
/* -- Constants. -- */
#define GRPC_COMPUTE_ENGINE_DETECTION_HOST "metadata.google.internal"
#define GRPC_GOOGLE_CREDENTIALS_ENV_VAR "GOOGLE_APPLICATION_CREDENTIALS"
/* -- Default credentials. -- */
static grpc_credentials *default_credentials = NULL;
static int compute_engine_detection_done = 0;
static gpr_mu g_mu;
static gpr_once g_once = GPR_ONCE_INIT;
static void init_default_credentials(void) { gpr_mu_init(&g_mu); }
typedef struct {
grpc_pollset pollset;
int is_done;
int success;
} compute_engine_detector;
static void on_compute_engine_detection_http_response(
void *user_data, const grpc_httpcli_response *response) {
compute_engine_detector *detector = (compute_engine_detector *)user_data;
if (response != NULL && response->status == 200 && response->hdr_count > 0) {
/* Internet providers can return a generic response to all requests, so
it is necessary to check that metadata header is present also. */
size_t i;
for (i = 0; i < response->hdr_count; i++) {
grpc_httpcli_header *header = &response->hdrs[i];
if (strcmp(header->key, "Metadata-Flavor") == 0 &&
strcmp(header->value, "Google") == 0) {
detector->success = 1;
break;
}
}
}
gpr_mu_lock(GRPC_POLLSET_MU(&detector->pollset));
detector->is_done = 1;
grpc_pollset_kick(&detector->pollset);
gpr_mu_unlock(GRPC_POLLSET_MU(&detector->pollset));
}
static int is_stack_running_on_compute_engine(void) {
compute_engine_detector detector;
grpc_httpcli_request request;
grpc_httpcli_context context;
/* The http call is local. If it takes more than one sec, it is for sure not
on compute engine. */
gpr_timespec max_detection_delay = {1, 0};
grpc_pollset_init(&detector.pollset);
detector.is_done = 0;
detector.success = 0;
memset(&request, 0, sizeof(grpc_httpcli_request));
request.host = GRPC_COMPUTE_ENGINE_DETECTION_HOST;
request.path = "/";
grpc_httpcli_context_init(&context);
grpc_httpcli_get(&context, &detector.pollset, &request,
gpr_time_add(gpr_now(), max_detection_delay),
on_compute_engine_detection_http_response, &detector);
/* Block until we get the response. This is not ideal but this should only be
called once for the lifetime of the process by the default credentials. */
gpr_mu_lock(GRPC_POLLSET_MU(&detector.pollset));
while (!detector.is_done) {
grpc_pollset_work(&detector.pollset, gpr_inf_future);
}
gpr_mu_unlock(GRPC_POLLSET_MU(&detector.pollset));
grpc_httpcli_context_destroy(&context);
grpc_pollset_destroy(&detector.pollset);
return detector.success;
}
/* Takes ownership of creds_path if not NULL. */
static grpc_credentials *create_jwt_creds_from_path(char *creds_path) {
grpc_credentials *result = NULL;
gpr_slice creds_data;
int file_ok = 0;
if (creds_path == NULL) return NULL;
creds_data = gpr_load_file(creds_path, 1, &file_ok);
gpr_free(creds_path);
if (file_ok) {
result = grpc_jwt_credentials_create(
(const char *)GPR_SLICE_START_PTR(creds_data),
grpc_max_auth_token_lifetime);
gpr_slice_unref(creds_data);
}
return result;
}
/* Takes ownership of creds_path if not NULL. */
static grpc_credentials *create_refresh_token_creds_from_path(
char *creds_path) {
grpc_credentials *result = NULL;
gpr_slice creds_data;
int file_ok = 0;
if (creds_path == NULL) return NULL;
creds_data = gpr_load_file(creds_path, 1, &file_ok);
gpr_free(creds_path);
if (file_ok) {
result = grpc_refresh_token_credentials_create(
(const char *)GPR_SLICE_START_PTR(creds_data));
gpr_slice_unref(creds_data);
}
return result;
}
grpc_credentials *grpc_google_default_credentials_create(void) {
grpc_credentials *result = NULL;
int serving_cached_credentials = 0;
gpr_once_init(&g_once, init_default_credentials);
gpr_mu_lock(&g_mu);
if (default_credentials != NULL) {
result = grpc_credentials_ref(default_credentials);
serving_cached_credentials = 1;
goto end;
}
/* First, try the environment variable. */
result =
create_jwt_creds_from_path(gpr_getenv(GRPC_GOOGLE_CREDENTIALS_ENV_VAR));
if (result != NULL) goto end;
/* Then the well-known file. */
result = create_refresh_token_creds_from_path(
grpc_get_well_known_google_credentials_file_path());
if (result != NULL) goto end;
/* At last try to see if we're on compute engine (do the detection only once
since it requires a network test). */
if (!compute_engine_detection_done) {
int need_compute_engine_creds = is_stack_running_on_compute_engine();
compute_engine_detection_done = 1;
if (need_compute_engine_creds) {
result = grpc_compute_engine_credentials_create();
}
}
end:
if (!serving_cached_credentials && result != NULL) {
/* Blend with default ssl credentials and add a global reference so that it
can be cached and re-served. */
result = grpc_composite_credentials_create(
grpc_ssl_credentials_create(NULL, NULL), result);
GPR_ASSERT(result != NULL);
default_credentials = grpc_credentials_ref(result);
}
gpr_mu_unlock(&g_mu);
return result;
}
|
