1/*
2 * This file is part of the MicroPython project, http://micropython.org/
3 *
4 * The MIT License (MIT)
5 *
6 * Copyright (c) 2016 Linaro Ltd.
7 * Copyright (c) 2019 Paul Sokolovsky
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 * THE SOFTWARE.
26 */
27
28#include "py/mpconfig.h"
29#if MICROPY_PY_USSL && MICROPY_SSL_MBEDTLS
30
31#include <stdio.h>
32#include <string.h>
33#include <errno.h> // needed because mp_is_nonblocking_error uses system error codes
34
35#include "py/runtime.h"
36#include "py/stream.h"
37#include "py/objstr.h"
38
39// mbedtls_time_t
40#include "mbedtls/platform.h"
41#include "mbedtls/ssl.h"
42#include "mbedtls/x509_crt.h"
43#include "mbedtls/pk.h"
44#include "mbedtls/entropy.h"
45#include "mbedtls/ctr_drbg.h"
46#include "mbedtls/debug.h"
47#include "mbedtls/error.h"
48
49typedef struct _mp_obj_ssl_socket_t {
50 mp_obj_base_t base;
51 mp_obj_t sock;
52 mbedtls_entropy_context entropy;
53 mbedtls_ctr_drbg_context ctr_drbg;
54 mbedtls_ssl_context ssl;
55 mbedtls_ssl_config conf;
56 mbedtls_x509_crt cacert;
57 mbedtls_x509_crt cert;
58 mbedtls_pk_context pkey;
59} mp_obj_ssl_socket_t;
60
61struct ssl_args {
62 mp_arg_val_t key;
63 mp_arg_val_t cert;
64 mp_arg_val_t server_side;
65 mp_arg_val_t server_hostname;
66 mp_arg_val_t do_handshake;
67};
68
69STATIC const mp_obj_type_t ussl_socket_type;
70
71#ifdef MBEDTLS_DEBUG_C
72STATIC void mbedtls_debug(void *ctx, int level, const char *file, int line, const char *str) {
73 (void)ctx;
74 (void)level;
75 printf("DBG:%s:%04d: %s\n", file, line, str);
76}
77#endif
78
79STATIC NORETURN void mbedtls_raise_error(int err) {
80 // _mbedtls_ssl_send and _mbedtls_ssl_recv (below) turn positive error codes from the
81 // underlying socket into negative codes to pass them through mbedtls. Here we turn them
82 // positive again so they get interpreted as the OSError they really are. The
83 // cut-off of -256 is a bit hacky, sigh.
84 if (err < 0 && err > -256) {
85 mp_raise_OSError(-err);
86 }
87
88 #if defined(MBEDTLS_ERROR_C)
89 // Including mbedtls_strerror takes about 1.5KB due to the error strings.
90 // MBEDTLS_ERROR_C is the define used by mbedtls to conditionally include mbedtls_strerror.
91 // It is set/unset in the MBEDTLS_CONFIG_FILE which is defined in the Makefile.
92
93 // Try to allocate memory for the message
94 #define ERR_STR_MAX 80 // mbedtls_strerror truncates if it doesn't fit
95 mp_obj_str_t *o_str = m_new_obj_maybe(mp_obj_str_t);
96 byte *o_str_buf = m_new_maybe(byte, ERR_STR_MAX);
97 if (o_str == NULL || o_str_buf == NULL) {
98 mp_raise_OSError(err);
99 }
100
101 // print the error message into the allocated buffer
102 mbedtls_strerror(err, (char *)o_str_buf, ERR_STR_MAX);
103 size_t len = strlen((char *)o_str_buf);
104
105 // Put the exception object together
106 o_str->base.type = &mp_type_str;
107 o_str->data = o_str_buf;
108 o_str->len = len;
109 o_str->hash = qstr_compute_hash(o_str->data, o_str->len);
110 // raise
111 mp_obj_t args[2] = { MP_OBJ_NEW_SMALL_INT(err), MP_OBJ_FROM_PTR(o_str)};
112 nlr_raise(mp_obj_exception_make_new(&mp_type_OSError, 2, 0, args));
113 #else
114 // mbedtls is compiled without error strings so we simply return the err number
115 mp_raise_OSError(err); // err is typically a large negative number
116 #endif
117}
118
119STATIC int _mbedtls_ssl_send(void *ctx, const byte *buf, size_t len) {
120 mp_obj_t sock = *(mp_obj_t *)ctx;
121
122 const mp_stream_p_t *sock_stream = mp_get_stream(sock);
123 int err;
124
125 mp_uint_t out_sz = sock_stream->write(sock, buf, len, &err);
126 if (out_sz == MP_STREAM_ERROR) {
127 if (mp_is_nonblocking_error(err)) {
128 return MBEDTLS_ERR_SSL_WANT_WRITE;
129 }
130 return -err; // convert an MP_ERRNO to something mbedtls passes through as error
131 } else {
132 return out_sz;
133 }
134}
135
136// _mbedtls_ssl_recv is called by mbedtls to receive bytes from the underlying socket
137STATIC int _mbedtls_ssl_recv(void *ctx, byte *buf, size_t len) {
138 mp_obj_t sock = *(mp_obj_t *)ctx;
139
140 const mp_stream_p_t *sock_stream = mp_get_stream(sock);
141 int err;
142
143 mp_uint_t out_sz = sock_stream->read(sock, buf, len, &err);
144 if (out_sz == MP_STREAM_ERROR) {
145 if (mp_is_nonblocking_error(err)) {
146 return MBEDTLS_ERR_SSL_WANT_READ;
147 }
148 return -err;
149 } else {
150 return out_sz;
151 }
152}
153
154
155STATIC mp_obj_ssl_socket_t *socket_new(mp_obj_t sock, struct ssl_args *args) {
156 // Verify the socket object has the full stream protocol
157 mp_get_stream_raise(sock, MP_STREAM_OP_READ | MP_STREAM_OP_WRITE | MP_STREAM_OP_IOCTL);
158
159 #if MICROPY_PY_USSL_FINALISER
160 mp_obj_ssl_socket_t *o = m_new_obj_with_finaliser(mp_obj_ssl_socket_t);
161 #else
162 mp_obj_ssl_socket_t *o = m_new_obj(mp_obj_ssl_socket_t);
163 #endif
164 o->base.type = &ussl_socket_type;
165 o->sock = sock;
166
167 int ret;
168 mbedtls_ssl_init(&o->ssl);
169 mbedtls_ssl_config_init(&o->conf);
170 mbedtls_x509_crt_init(&o->cacert);
171 mbedtls_x509_crt_init(&o->cert);
172 mbedtls_pk_init(&o->pkey);
173 mbedtls_ctr_drbg_init(&o->ctr_drbg);
174 #ifdef MBEDTLS_DEBUG_C
175 // Debug level (0-4) 1=warning, 2=info, 3=debug, 4=verbose
176 mbedtls_debug_set_threshold(0);
177 #endif
178
179 mbedtls_entropy_init(&o->entropy);
180 const byte seed[] = "upy";
181 ret = mbedtls_ctr_drbg_seed(&o->ctr_drbg, mbedtls_entropy_func, &o->entropy, seed, sizeof(seed));
182 if (ret != 0) {
183 goto cleanup;
184 }
185
186 ret = mbedtls_ssl_config_defaults(&o->conf,
187 args->server_side.u_bool ? MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT,
188 MBEDTLS_SSL_TRANSPORT_STREAM,
189 MBEDTLS_SSL_PRESET_DEFAULT);
190 if (ret != 0) {
191 goto cleanup;
192 }
193
194 mbedtls_ssl_conf_authmode(&o->conf, MBEDTLS_SSL_VERIFY_NONE);
195 mbedtls_ssl_conf_rng(&o->conf, mbedtls_ctr_drbg_random, &o->ctr_drbg);
196 #ifdef MBEDTLS_DEBUG_C
197 mbedtls_ssl_conf_dbg(&o->conf, mbedtls_debug, NULL);
198 #endif
199
200 ret = mbedtls_ssl_setup(&o->ssl, &o->conf);
201 if (ret != 0) {
202 goto cleanup;
203 }
204
205 if (args->server_hostname.u_obj != mp_const_none) {
206 const char *sni = mp_obj_str_get_str(args->server_hostname.u_obj);
207 ret = mbedtls_ssl_set_hostname(&o->ssl, sni);
208 if (ret != 0) {
209 goto cleanup;
210 }
211 }
212
213 mbedtls_ssl_set_bio(&o->ssl, &o->sock, _mbedtls_ssl_send, _mbedtls_ssl_recv, NULL);
214
215 if (args->key.u_obj != mp_const_none) {
216 size_t key_len;
217 const byte *key = (const byte *)mp_obj_str_get_data(args->key.u_obj, &key_len);
218 // len should include terminating null
219 ret = mbedtls_pk_parse_key(&o->pkey, key, key_len + 1, NULL, 0);
220 if (ret != 0) {
221 ret = MBEDTLS_ERR_PK_BAD_INPUT_DATA; // use general error for all key errors
222 goto cleanup;
223 }
224
225 size_t cert_len;
226 const byte *cert = (const byte *)mp_obj_str_get_data(args->cert.u_obj, &cert_len);
227 // len should include terminating null
228 ret = mbedtls_x509_crt_parse(&o->cert, cert, cert_len + 1);
229 if (ret != 0) {
230 ret = MBEDTLS_ERR_X509_BAD_INPUT_DATA; // use general error for all cert errors
231 goto cleanup;
232 }
233
234 ret = mbedtls_ssl_conf_own_cert(&o->conf, &o->cert, &o->pkey);
235 if (ret != 0) {
236 goto cleanup;
237 }
238 }
239
240 if (args->do_handshake.u_bool) {
241 while ((ret = mbedtls_ssl_handshake(&o->ssl)) != 0) {
242 if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
243 goto cleanup;
244 }
245 }
246 }
247
248 return o;
249
250cleanup:
251 mbedtls_pk_free(&o->pkey);
252 mbedtls_x509_crt_free(&o->cert);
253 mbedtls_x509_crt_free(&o->cacert);
254 mbedtls_ssl_free(&o->ssl);
255 mbedtls_ssl_config_free(&o->conf);
256 mbedtls_ctr_drbg_free(&o->ctr_drbg);
257 mbedtls_entropy_free(&o->entropy);
258
259 if (ret == MBEDTLS_ERR_SSL_ALLOC_FAILED) {
260 mp_raise_OSError(MP_ENOMEM);
261 } else if (ret == MBEDTLS_ERR_PK_BAD_INPUT_DATA) {
262 mp_raise_ValueError(MP_ERROR_TEXT("invalid key"));
263 } else if (ret == MBEDTLS_ERR_X509_BAD_INPUT_DATA) {
264 mp_raise_ValueError(MP_ERROR_TEXT("invalid cert"));
265 } else {
266 mbedtls_raise_error(ret);
267 }
268}
269
270STATIC mp_obj_t mod_ssl_getpeercert(mp_obj_t o_in, mp_obj_t binary_form) {
271 mp_obj_ssl_socket_t *o = MP_OBJ_TO_PTR(o_in);
272 if (!mp_obj_is_true(binary_form)) {
273 mp_raise_NotImplementedError(NULL);
274 }
275 const mbedtls_x509_crt *peer_cert = mbedtls_ssl_get_peer_cert(&o->ssl);
276 if (peer_cert == NULL) {
277 return mp_const_none;
278 }
279 return mp_obj_new_bytes(peer_cert->raw.p, peer_cert->raw.len);
280}
281STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_ssl_getpeercert_obj, mod_ssl_getpeercert);
282
283STATIC void socket_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
284 (void)kind;
285 mp_obj_ssl_socket_t *self = MP_OBJ_TO_PTR(self_in);
286 mp_printf(print, "<_SSLSocket %p>", self);
287}
288
289STATIC mp_uint_t socket_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
290 mp_obj_ssl_socket_t *o = MP_OBJ_TO_PTR(o_in);
291
292 int ret = mbedtls_ssl_read(&o->ssl, buf, size);
293 if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) {
294 // end of stream
295 return 0;
296 }
297 if (ret >= 0) {
298 return ret;
299 }
300 if (ret == MBEDTLS_ERR_SSL_WANT_READ) {
301 ret = MP_EWOULDBLOCK;
302 } else if (ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
303 // If handshake is not finished, read attempt may end up in protocol
304 // wanting to write next handshake message. The same may happen with
305 // renegotation.
306 ret = MP_EWOULDBLOCK;
307 }
308 *errcode = ret;
309 return MP_STREAM_ERROR;
310}
311
312STATIC mp_uint_t socket_write(mp_obj_t o_in, const void *buf, mp_uint_t size, int *errcode) {
313 mp_obj_ssl_socket_t *o = MP_OBJ_TO_PTR(o_in);
314
315 int ret = mbedtls_ssl_write(&o->ssl, buf, size);
316 if (ret >= 0) {
317 return ret;
318 }
319 if (ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
320 ret = MP_EWOULDBLOCK;
321 } else if (ret == MBEDTLS_ERR_SSL_WANT_READ) {
322 // If handshake is not finished, write attempt may end up in protocol
323 // wanting to read next handshake message. The same may happen with
324 // renegotation.
325 ret = MP_EWOULDBLOCK;
326 }
327 *errcode = ret;
328 return MP_STREAM_ERROR;
329}
330
331STATIC mp_obj_t socket_setblocking(mp_obj_t self_in, mp_obj_t flag_in) {
332 mp_obj_ssl_socket_t *o = MP_OBJ_TO_PTR(self_in);
333 mp_obj_t sock = o->sock;
334 mp_obj_t dest[3];
335 mp_load_method(sock, MP_QSTR_setblocking, dest);
336 dest[2] = flag_in;
337 return mp_call_method_n_kw(1, 0, dest);
338}
339STATIC MP_DEFINE_CONST_FUN_OBJ_2(socket_setblocking_obj, socket_setblocking);
340
341STATIC mp_uint_t socket_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, int *errcode) {
342 mp_obj_ssl_socket_t *self = MP_OBJ_TO_PTR(o_in);
343 if (request == MP_STREAM_CLOSE) {
344 mbedtls_pk_free(&self->pkey);
345 mbedtls_x509_crt_free(&self->cert);
346 mbedtls_x509_crt_free(&self->cacert);
347 mbedtls_ssl_free(&self->ssl);
348 mbedtls_ssl_config_free(&self->conf);
349 mbedtls_ctr_drbg_free(&self->ctr_drbg);
350 mbedtls_entropy_free(&self->entropy);
351 }
352 // Pass all requests down to the underlying socket
353 return mp_get_stream(self->sock)->ioctl(self->sock, request, arg, errcode);
354}
355
356STATIC const mp_rom_map_elem_t ussl_socket_locals_dict_table[] = {
357 { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
358 { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
359 { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
360 { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
361 { MP_ROM_QSTR(MP_QSTR_setblocking), MP_ROM_PTR(&socket_setblocking_obj) },
362 { MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&mp_stream_close_obj) },
363 #if MICROPY_PY_USSL_FINALISER
364 { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&mp_stream_close_obj) },
365 #endif
366 { MP_ROM_QSTR(MP_QSTR_getpeercert), MP_ROM_PTR(&mod_ssl_getpeercert_obj) },
367};
368
369STATIC MP_DEFINE_CONST_DICT(ussl_socket_locals_dict, ussl_socket_locals_dict_table);
370
371STATIC const mp_stream_p_t ussl_socket_stream_p = {
372 .read = socket_read,
373 .write = socket_write,
374 .ioctl = socket_ioctl,
375};
376
377STATIC const mp_obj_type_t ussl_socket_type = {
378 { &mp_type_type },
379 // Save on qstr's, reuse same as for module
380 .name = MP_QSTR_ussl,
381 .print = socket_print,
382 .getiter = NULL,
383 .iternext = NULL,
384 .protocol = &ussl_socket_stream_p,
385 .locals_dict = (void *)&ussl_socket_locals_dict,
386};
387
388STATIC mp_obj_t mod_ssl_wrap_socket(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
389 // TODO: Implement more args
390 static const mp_arg_t allowed_args[] = {
391 { MP_QSTR_key, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
392 { MP_QSTR_cert, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
393 { MP_QSTR_server_side, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
394 { MP_QSTR_server_hostname, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
395 { MP_QSTR_do_handshake, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = true} },
396 };
397
398 // TODO: Check that sock implements stream protocol
399 mp_obj_t sock = pos_args[0];
400
401 struct ssl_args args;
402 mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args,
403 MP_ARRAY_SIZE(allowed_args), allowed_args, (mp_arg_val_t *)&args);
404
405 return MP_OBJ_FROM_PTR(socket_new(sock, &args));
406}
407STATIC MP_DEFINE_CONST_FUN_OBJ_KW(mod_ssl_wrap_socket_obj, 1, mod_ssl_wrap_socket);
408
409STATIC const mp_rom_map_elem_t mp_module_ssl_globals_table[] = {
410 { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_ussl) },
411 { MP_ROM_QSTR(MP_QSTR_wrap_socket), MP_ROM_PTR(&mod_ssl_wrap_socket_obj) },
412};
413
414STATIC MP_DEFINE_CONST_DICT(mp_module_ssl_globals, mp_module_ssl_globals_table);
415
416const mp_obj_module_t mp_module_ussl = {
417 .base = { &mp_type_module },
418 .globals = (mp_obj_dict_t *)&mp_module_ssl_globals,
419};
420
421#endif // MICROPY_PY_USSL
422