1: /*
2: * Copyright (c) 2007, Cameron Rich
3: *
4: * All rights reserved.
5: *
6: * Redistribution and use in source and binary forms, with or without
7: * modification, are permitted provided that the following conditions are met:
8: *
9: * * Redistributions of source code must retain the above copyright notice,
10: * this list of conditions and the following disclaimer.
11: * * Redistributions in binary form must reproduce the above copyright notice,
12: * this list of conditions and the following disclaimer in the documentation
13: * and/or other materials provided with the distribution.
14: * * Neither the name of the axTLS project nor the names of its contributors
15: * may be used to endorse or promote products derived from this software
16: * without specific prior written permission.
17: *
18: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21: * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
22: * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25: * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27: * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29: */
30:
31: #include <stdlib.h>
32: #include <string.h>
33: #include <time.h>
34: #include <stdio.h>
35: #include "os_port.h"
36: #include "ssl.h"
37:
38: #ifdef CONFIG_SSL_ENABLE_CLIENT /* all commented out if no client */
39:
40: static int send_client_hello(SSL *ssl);
41: static int process_server_hello(SSL *ssl);
42: static int process_server_hello_done(SSL *ssl);
43: static int send_client_key_xchg(SSL *ssl);
44: static int process_cert_req(SSL *ssl);
45: static int send_cert_verify(SSL *ssl);
46:
47: /*
48: * Establish a new SSL connection to an SSL server.
49: */
50: EXP_FUNC SSL * STDCALL ssl_client_new(SSL_CTX *ssl_ctx, int client_fd, const
51: uint8_t *session_id, uint8_t sess_id_size)
52: {
53: SSL *ssl = ssl_new(ssl_ctx, client_fd);
54: ssl->version = SSL_PROTOCOL_VERSION_MAX; /* try top version first */
55:
56: if (session_id && ssl_ctx->num_sessions)
57: {
58: if (sess_id_size > SSL_SESSION_ID_SIZE) /* validity check */
59: {
60: ssl_free(ssl);
61: return NULL;
62: }
63:
64: memcpy(ssl->session_id, session_id, sess_id_size);
65: ssl->sess_id_size = sess_id_size;
66: SET_SSL_FLAG(SSL_SESSION_RESUME); /* just flag for later */
67: }
68:
69: SET_SSL_FLAG(SSL_IS_CLIENT);
70: do_client_connect(ssl);
71: return ssl;
72: }
73:
74: /*
75: * Process the handshake record.
76: */
77: int do_clnt_handshake(SSL *ssl, int handshake_type, uint8_t *buf, int hs_len)
78: {
79: int ret;
80:
81: /* To get here the state must be valid */
82: switch (handshake_type)
83: {
84: case HS_SERVER_HELLO:
85: ret = process_server_hello(ssl);
86: break;
87:
88: case HS_CERTIFICATE:
89: ret = process_certificate(ssl, &ssl->x509_ctx);
90: break;
91:
92: case HS_SERVER_HELLO_DONE:
93: if ((ret = process_server_hello_done(ssl)) == SSL_OK)
94: {
95: if (IS_SET_SSL_FLAG(SSL_HAS_CERT_REQ))
96: {
97: if ((ret = send_certificate(ssl)) == SSL_OK &&
98: (ret = send_client_key_xchg(ssl)) == SSL_OK)
99: {
100: send_cert_verify(ssl);
101: }
102: }
103: else
104: {
105: ret = send_client_key_xchg(ssl);
106: }
107:
108: if (ret == SSL_OK &&
109: (ret = send_change_cipher_spec(ssl)) == SSL_OK)
110: {
111: ret = send_finished(ssl);
112: }
113: }
114: break;
115:
116: case HS_CERT_REQ:
117: ret = process_cert_req(ssl);
118: break;
119:
120: case HS_FINISHED:
121: ret = process_finished(ssl, buf, hs_len);
122: disposable_free(ssl); /* free up some memory */
123: /* note: client renegotiation is not allowed after this */
124: break;
125:
126: case HS_HELLO_REQUEST:
127: disposable_new(ssl);
128: ret = do_client_connect(ssl);
129: break;
130:
131: default:
132: ret = SSL_ERROR_INVALID_HANDSHAKE;
133: break;
134: }
135:
136: return ret;
137: }
138:
139: /*
140: * Do the handshaking from the beginning.
141: */
142: int do_client_connect(SSL *ssl)
143: {
144: int ret = SSL_OK;
145:
146: send_client_hello(ssl); /* send the client hello */
147: ssl->bm_read_index = 0;
148: ssl->next_state = HS_SERVER_HELLO;
149: ssl->hs_status = SSL_NOT_OK; /* not connected */
150:
151: /* sit in a loop until it all looks good */
152: if (!IS_SET_SSL_FLAG(SSL_CONNECT_IN_PARTS))
153: {
154: while (ssl->hs_status != SSL_OK)
155: {
156: ret = ssl_read(ssl, NULL);
157:
158: if (ret < SSL_OK)
159: break;
160: }
161:
162: ssl->hs_status = ret; /* connected? */
163: }
164:
165: return ret;
166: }
167:
168: /*
169: * Send the initial client hello.
170: */
171: static int send_client_hello(SSL *ssl)
172: {
173: uint8_t *buf = ssl->bm_data;
174: time_t tm = time(NULL);
175: uint8_t *tm_ptr = &buf[6]; /* time will go here */
176: int i, offset;
177:
178: buf[0] = HS_CLIENT_HELLO;
179: buf[1] = 0;
180: buf[2] = 0;
181: /* byte 3 is calculated later */
182: buf[4] = 0x03;
183: buf[5] = ssl->version & 0x0f;
184:
185: /* client random value - spec says that 1st 4 bytes are big endian time */
186: *tm_ptr++ = (uint8_t)(((long)tm & 0xff000000) >> 24);
187: *tm_ptr++ = (uint8_t)(((long)tm & 0x00ff0000) >> 16);
188: *tm_ptr++ = (uint8_t)(((long)tm & 0x0000ff00) >> 8);
189: *tm_ptr++ = (uint8_t)(((long)tm & 0x000000ff));
190: get_random(SSL_RANDOM_SIZE-4, &buf[10]);
191: memcpy(ssl->dc->client_random, &buf[6], SSL_RANDOM_SIZE);
192: offset = 6 + SSL_RANDOM_SIZE;
193:
194: /* give session resumption a go */
195: if (IS_SET_SSL_FLAG(SSL_SESSION_RESUME)) /* set initially by user */
196: {
197: buf[offset++] = ssl->sess_id_size;
198: memcpy(&buf[offset], ssl->session_id, ssl->sess_id_size);
199: offset += ssl->sess_id_size;
200: CLR_SSL_FLAG(SSL_SESSION_RESUME); /* clear so we can set later */
201: }
202: else
203: {
204: /* no session id - because no session resumption just yet */
205: buf[offset++] = 0;
206: }
207:
208: buf[offset++] = 0; /* number of ciphers */
209: buf[offset++] = NUM_PROTOCOLS*2;/* number of ciphers */
210:
211: /* put all our supported protocols in our request */
212: for (i = 0; i < NUM_PROTOCOLS; i++)
213: {
214: buf[offset++] = 0; /* cipher we are using */
215: buf[offset++] = ssl_prot_prefs[i];
216: }
217:
218: buf[offset++] = 1; /* no compression */
219: buf[offset++] = 0;
220: buf[3] = offset - 4; /* handshake size */
221:
222: return send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, offset);
223: }
224:
225: /*
226: * Process the server hello.
227: */
228: static int process_server_hello(SSL *ssl)
229: {
230: uint8_t *buf = ssl->bm_data;
231: int pkt_size = ssl->bm_index;
232: int num_sessions = ssl->ssl_ctx->num_sessions;
233: uint8_t sess_id_size;
234: int offset, ret = SSL_OK;
235:
236: /* check that we are talking to a TLSv1 server */
237: uint8_t version = (buf[4] << 4) + buf[5];
238: if (version > SSL_PROTOCOL_VERSION_MAX)
239: {
240: version = SSL_PROTOCOL_VERSION_MAX;
241: }
242: else if (ssl->version < SSL_PROTOCOL_MIN_VERSION)
243: {
244: ret = SSL_ERROR_INVALID_VERSION;
245: ssl_display_error(ret);
246: goto error;
247: }
248:
249: ssl->version = version;
250:
251: /* get the server random value */
252: memcpy(ssl->dc->server_random, &buf[6], SSL_RANDOM_SIZE);
253: offset = 6 + SSL_RANDOM_SIZE; /* skip of session id size */
254: sess_id_size = buf[offset++];
255:
256: if (sess_id_size > SSL_SESSION_ID_SIZE)
257: {
258: ret = SSL_ERROR_INVALID_SESSION;
259: goto error;
260: }
261:
262: if (num_sessions)
263: {
264: ssl->session = ssl_session_update(num_sessions,
265: ssl->ssl_ctx->ssl_sessions, ssl, &buf[offset]);
266: memcpy(ssl->session->session_id, &buf[offset], sess_id_size);
267:
268: /* pad the rest with 0's */
269: if (sess_id_size < SSL_SESSION_ID_SIZE)
270: {
271: memset(&ssl->session->session_id[sess_id_size], 0,
272: SSL_SESSION_ID_SIZE-sess_id_size);
273: }
274: }
275:
276: memcpy(ssl->session_id, &buf[offset], sess_id_size);
277: ssl->sess_id_size = sess_id_size;
278: offset += sess_id_size;
279:
280: /* get the real cipher we are using */
281: ssl->cipher = buf[++offset];
282: ssl->next_state = IS_SET_SSL_FLAG(SSL_SESSION_RESUME) ?
283: HS_FINISHED : HS_CERTIFICATE;
284:
285: offset++; // skip the compr
286: PARANOIA_CHECK(pkt_size, offset);
287: ssl->dc->bm_proc_index = offset+1;
288:
289: error:
290: return ret;
291: }
292:
293: /**
294: * Process the server hello done message.
295: */
296: static int process_server_hello_done(SSL *ssl)
297: {
298: ssl->next_state = HS_FINISHED;
299: return SSL_OK;
300: }
301:
302: /*
303: * Send a client key exchange message.
304: */
305: static int send_client_key_xchg(SSL *ssl)
306: {
307: uint8_t *buf = ssl->bm_data;
308: uint8_t premaster_secret[SSL_SECRET_SIZE];
309: int enc_secret_size = -1;
310:
311: buf[0] = HS_CLIENT_KEY_XCHG;
312: buf[1] = 0;
313:
314: premaster_secret[0] = 0x03; /* encode the version number */
315: premaster_secret[1] = SSL_PROTOCOL_MINOR_VERSION; /* must be TLS 1.1 */
316: get_random(SSL_SECRET_SIZE-2, &premaster_secret[2]);
317: DISPLAY_RSA(ssl, ssl->x509_ctx->rsa_ctx);
318:
319: /* rsa_ctx->bi_ctx is not thread-safe */
320: SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
321: enc_secret_size = RSA_encrypt(ssl->x509_ctx->rsa_ctx, premaster_secret,
322: SSL_SECRET_SIZE, &buf[6], 0);
323: SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
324:
325: buf[2] = (enc_secret_size + 2) >> 8;
326: buf[3] = (enc_secret_size + 2) & 0xff;
327: buf[4] = enc_secret_size >> 8;
328: buf[5] = enc_secret_size & 0xff;
329:
330: generate_master_secret(ssl, premaster_secret);
331: return send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, enc_secret_size+6);
332: }
333:
334: /*
335: * Process the certificate request.
336: */
337: static int process_cert_req(SSL *ssl)
338: {
339: uint8_t *buf = &ssl->bm_data[ssl->dc->bm_proc_index];
340: int ret = SSL_OK;
341: int offset = (buf[2] << 4) + buf[3];
342: int pkt_size = ssl->bm_index;
343:
344: /* don't do any processing - we will send back an RSA certificate anyway */
345: ssl->next_state = HS_SERVER_HELLO_DONE;
346: SET_SSL_FLAG(SSL_HAS_CERT_REQ);
347: ssl->dc->bm_proc_index += offset;
348: PARANOIA_CHECK(pkt_size, offset);
349: error:
350: return ret;
351: }
352:
353: /*
354: * Send a certificate verify message.
355: */
356: static int send_cert_verify(SSL *ssl)
357: {
358: uint8_t *buf = ssl->bm_data;
359: uint8_t dgst[MD5_SIZE+SHA1_SIZE];
360: RSA_CTX *rsa_ctx = ssl->ssl_ctx->rsa_ctx;
361: int n = 0, ret;
362:
363: DISPLAY_RSA(ssl, rsa_ctx);
364:
365: buf[0] = HS_CERT_VERIFY;
366: buf[1] = 0;
367:
368: finished_digest(ssl, NULL, dgst); /* calculate the digest */
369:
370: /* rsa_ctx->bi_ctx is not thread-safe */
371: if (rsa_ctx)
372: {
373: SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
374: n = RSA_encrypt(rsa_ctx, dgst, sizeof(dgst), &buf[6], 1);
375: SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
376:
377: if (n == 0)
378: {
379: ret = SSL_ERROR_INVALID_KEY;
380: goto error;
381: }
382: }
383:
384: buf[4] = n >> 8; /* add the RSA size (not officially documented) */
385: buf[5] = n & 0xff;
386: n += 2;
387: buf[2] = n >> 8;
388: buf[3] = n & 0xff;
389: ret = send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, n+4);
390:
391: error:
392: return ret;
393: }
394:
395: #endif /* CONFIG_SSL_ENABLE_CLIENT */
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