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comparison: security/nss/lib/ssl/ssl3gthr.c

security/nss/lib/ssl/ssl3gthr.c

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1 /*
2 * Gather (Read) entire SSL3 records from socket into buffer.
3 *
4 * This Source Code Form is subject to the terms of the Mozilla Public
5 * License, v. 2.0. If a copy of the MPL was not distributed with this
6 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
7
8 #include "cert.h"
9 #include "ssl.h"
10 #include "sslimpl.h"
11 #include "ssl3prot.h"
12
13 /*
14 * Attempt to read in an entire SSL3 record.
15 * Blocks here for blocking sockets, otherwise returns -1 with
16 * PR_WOULD_BLOCK_ERROR when socket would block.
17 *
18 * returns 1 if received a complete SSL3 record.
19 * returns 0 if recv returns EOF
20 * returns -1 if recv returns < 0
21 * (The error value may have already been set to PR_WOULD_BLOCK_ERROR)
22 *
23 * Caller must hold the recv buf lock.
24 *
25 * The Gather state machine has 3 states: GS_INIT, GS_HEADER, GS_DATA.
26 * GS_HEADER: waiting for the 5-byte SSL3 record header to come in.
27 * GS_DATA: waiting for the body of the SSL3 record to come in.
28 *
29 * This loop returns when either
30 * (a) an error or EOF occurs,
31 * (b) PR_WOULD_BLOCK_ERROR,
32 * (c) data (entire SSL3 record) has been received.
33 */
34 static int
35 ssl3_GatherData(sslSocket *ss, sslGather *gs, int flags)
36 {
37 unsigned char *bp;
38 unsigned char *lbp;
39 int nb;
40 int err;
41 int rv = 1;
42
43 PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
44 if (gs->state == GS_INIT) {
45 gs->state = GS_HEADER;
46 gs->remainder = 5;
47 gs->offset = 0;
48 gs->writeOffset = 0;
49 gs->readOffset = 0;
50 gs->inbuf.len = 0;
51 }
52
53 lbp = gs->inbuf.buf;
54 for(;;) {
55 SSL_TRC(30, ("%d: SSL3[%d]: gather state %d (need %d more)",
56 SSL_GETPID(), ss->fd, gs->state, gs->remainder));
57 bp = ((gs->state != GS_HEADER) ? lbp : gs->hdr) + gs->offset;
58 nb = ssl_DefRecv(ss, bp, gs->remainder, flags);
59
60 if (nb > 0) {
61 PRINT_BUF(60, (ss, "raw gather data:", bp, nb));
62 } else if (nb == 0) {
63 /* EOF */
64 SSL_TRC(30, ("%d: SSL3[%d]: EOF", SSL_GETPID(), ss->fd));
65 rv = 0;
66 break;
67 } else /* if (nb < 0) */ {
68 SSL_DBG(("%d: SSL3[%d]: recv error %d", SSL_GETPID(), ss->fd,
69 PR_GetError()));
70 rv = SECFailure;
71 break;
72 }
73
74 PORT_Assert( nb <= gs->remainder );
75 if (nb > gs->remainder) {
76 /* ssl_DefRecv is misbehaving! this error is fatal to SSL. */
77 gs->state = GS_INIT; /* so we don't crash next time */
78 rv = SECFailure;
79 break;
80 }
81
82 gs->offset += nb;
83 gs->remainder -= nb;
84 if (gs->state == GS_DATA)
85 gs->inbuf.len += nb;
86
87 /* if there's more to go, read some more. */
88 if (gs->remainder > 0) {
89 continue;
90 }
91
92 /* have received entire record header, or entire record. */
93 switch (gs->state) {
94 case GS_HEADER:
95 /*
96 ** Have received SSL3 record header in gs->hdr.
97 ** Now extract the length of the following encrypted data,
98 ** and then read in the rest of the SSL3 record into gs->inbuf.
99 */
100 gs->remainder = (gs->hdr[3] << 8) | gs->hdr[4];
101
102 /* This is the max fragment length for an encrypted fragment
103 ** plus the size of the record header.
104 */
105 if(gs->remainder > (MAX_FRAGMENT_LENGTH + 2048 + 5)) {
106 SSL3_SendAlert(ss, alert_fatal, unexpected_message);
107 gs->state = GS_INIT;
108 PORT_SetError(SSL_ERROR_RX_RECORD_TOO_LONG);
109 return SECFailure;
110 }
111
112 gs->state = GS_DATA;
113 gs->offset = 0;
114 gs->inbuf.len = 0;
115
116 if (gs->remainder > gs->inbuf.space) {
117 err = sslBuffer_Grow(&gs->inbuf, gs->remainder);
118 if (err) { /* realloc has set error code to no mem. */
119 return err;
120 }
121 lbp = gs->inbuf.buf;
122 }
123 break; /* End this case. Continue around the loop. */
124
125
126 case GS_DATA:
127 /*
128 ** SSL3 record has been completely received.
129 */
130 gs->state = GS_INIT;
131 return 1;
132 }
133 }
134
135 return rv;
136 }
137
138 /*
139 * Read in an entire DTLS record.
140 *
141 * Blocks here for blocking sockets, otherwise returns -1 with
142 * PR_WOULD_BLOCK_ERROR when socket would block.
143 *
144 * This is simpler than SSL because we are reading on a datagram socket
145 * and datagrams must contain >=1 complete records.
146 *
147 * returns 1 if received a complete DTLS record.
148 * returns 0 if recv returns EOF
149 * returns -1 if recv returns < 0
150 * (The error value may have already been set to PR_WOULD_BLOCK_ERROR)
151 *
152 * Caller must hold the recv buf lock.
153 *
154 * This loop returns when either
155 * (a) an error or EOF occurs,
156 * (b) PR_WOULD_BLOCK_ERROR,
157 * (c) data (entire DTLS record) has been received.
158 */
159 static int
160 dtls_GatherData(sslSocket *ss, sslGather *gs, int flags)
161 {
162 int nb;
163 int err;
164 int rv = 1;
165
166 SSL_TRC(30, ("dtls_GatherData"));
167
168 PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
169
170 gs->state = GS_HEADER;
171 gs->offset = 0;
172
173 if (gs->dtlsPacketOffset == gs->dtlsPacket.len) { /* No data left */
174 gs->dtlsPacketOffset = 0;
175 gs->dtlsPacket.len = 0;
176
177 /* Resize to the maximum possible size so we can fit a full datagram */
178 /* This is the max fragment length for an encrypted fragment
179 ** plus the size of the record header.
180 ** This magic constant is copied from ssl3_GatherData, with 5 changed
181 ** to 13 (the size of the record header).
182 */
183 if (gs->dtlsPacket.space < MAX_FRAGMENT_LENGTH + 2048 + 13) {
184 err = sslBuffer_Grow(&gs->dtlsPacket,
185 MAX_FRAGMENT_LENGTH + 2048 + 13);
186 if (err) { /* realloc has set error code to no mem. */
187 return err;
188 }
189 }
190
191 /* recv() needs to read a full datagram at a time */
192 nb = ssl_DefRecv(ss, gs->dtlsPacket.buf, gs->dtlsPacket.space, flags);
193
194 if (nb > 0) {
195 PRINT_BUF(60, (ss, "raw gather data:", gs->dtlsPacket.buf, nb));
196 } else if (nb == 0) {
197 /* EOF */
198 SSL_TRC(30, ("%d: SSL3[%d]: EOF", SSL_GETPID(), ss->fd));
199 rv = 0;
200 return rv;
201 } else /* if (nb < 0) */ {
202 SSL_DBG(("%d: SSL3[%d]: recv error %d", SSL_GETPID(), ss->fd,
203 PR_GetError()));
204 rv = SECFailure;
205 return rv;
206 }
207
208 gs->dtlsPacket.len = nb;
209 }
210
211 /* At this point we should have >=1 complete records lined up in
212 * dtlsPacket. Read off the header.
213 */
214 if ((gs->dtlsPacket.len - gs->dtlsPacketOffset) < 13) {
215 SSL_DBG(("%d: SSL3[%d]: rest of DTLS packet "
216 "too short to contain header", SSL_GETPID(), ss->fd));
217 PR_SetError(PR_WOULD_BLOCK_ERROR, 0);
218 gs->dtlsPacketOffset = 0;
219 gs->dtlsPacket.len = 0;
220 rv = SECFailure;
221 return rv;
222 }
223 memcpy(gs->hdr, gs->dtlsPacket.buf + gs->dtlsPacketOffset, 13);
224 gs->dtlsPacketOffset += 13;
225
226 /* Have received SSL3 record header in gs->hdr. */
227 gs->remainder = (gs->hdr[11] << 8) | gs->hdr[12];
228
229 if ((gs->dtlsPacket.len - gs->dtlsPacketOffset) < gs->remainder) {
230 SSL_DBG(("%d: SSL3[%d]: rest of DTLS packet too short "
231 "to contain rest of body", SSL_GETPID(), ss->fd));
232 PR_SetError(PR_WOULD_BLOCK_ERROR, 0);
233 gs->dtlsPacketOffset = 0;
234 gs->dtlsPacket.len = 0;
235 rv = SECFailure;
236 return rv;
237 }
238
239 /* OK, we have at least one complete packet, copy into inbuf */
240 if (gs->remainder > gs->inbuf.space) {
241 err = sslBuffer_Grow(&gs->inbuf, gs->remainder);
242 if (err) { /* realloc has set error code to no mem. */
243 return err;
244 }
245 }
246
247 memcpy(gs->inbuf.buf, gs->dtlsPacket.buf + gs->dtlsPacketOffset,
248 gs->remainder);
249 gs->inbuf.len = gs->remainder;
250 gs->offset = gs->remainder;
251 gs->dtlsPacketOffset += gs->remainder;
252 gs->state = GS_INIT;
253
254 return 1;
255 }
256
257 /* Gather in a record and when complete, Handle that record.
258 * Repeat this until the handshake is complete,
259 * or until application data is available.
260 *
261 * Returns 1 when the handshake is completed without error, or
262 * application data is available.
263 * Returns 0 if ssl3_GatherData hits EOF.
264 * Returns -1 on read error, or PR_WOULD_BLOCK_ERROR, or handleRecord error.
265 * Returns -2 on SECWouldBlock return from ssl3_HandleRecord.
266 *
267 * Called from ssl_GatherRecord1stHandshake in sslcon.c,
268 * and from SSL_ForceHandshake in sslsecur.c
269 * and from ssl3_GatherAppDataRecord below (<- DoRecv in sslsecur.c).
270 *
271 * Caller must hold the recv buf lock.
272 */
273 int
274 ssl3_GatherCompleteHandshake(sslSocket *ss, int flags)
275 {
276 SSL3Ciphertext cText;
277 int rv;
278 PRBool keepGoing = PR_TRUE;
279
280 SSL_TRC(30, ("ssl3_GatherCompleteHandshake"));
281
282 /* ssl3_HandleRecord may end up eventually calling ssl_FinishHandshake,
283 * which requires the 1stHandshakeLock, which must be acquired before the
284 * RecvBufLock.
285 */
286 PORT_Assert( ss->opt.noLocks || ssl_Have1stHandshakeLock(ss) );
287 PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
288
289 do {
290 PRBool handleRecordNow = PR_FALSE;
291
292 ssl_GetSSL3HandshakeLock(ss);
293
294 /* Without this, we may end up wrongly reporting
295 * SSL_ERROR_RX_UNEXPECTED_* errors if we receive any records from the
296 * peer while we are waiting to be restarted.
297 */
298 if (ss->ssl3.hs.restartTarget) {
299 ssl_ReleaseSSL3HandshakeLock(ss);
300 PORT_SetError(PR_WOULD_BLOCK_ERROR);
301 return (int) SECFailure;
302 }
303
304 /* Treat an empty msgState like a NULL msgState. (Most of the time
305 * when ssl3_HandleHandshake returns SECWouldBlock, it leaves
306 * behind a non-NULL but zero-length msgState).
307 * Test: async_cert_restart_server_sends_hello_request_first_in_separate_record
308 */
309 if (ss->ssl3.hs.msgState.buf) {
310 if (ss->ssl3.hs.msgState.len == 0) {
311 ss->ssl3.hs.msgState.buf = NULL;
312 } else {
313 handleRecordNow = PR_TRUE;
314 }
315 }
316
317 ssl_ReleaseSSL3HandshakeLock(ss);
318
319 if (handleRecordNow) {
320 /* ssl3_HandleHandshake previously returned SECWouldBlock and the
321 * as-yet-unprocessed plaintext of that previous handshake record.
322 * We need to process it now before we overwrite it with the next
323 * handshake record.
324 */
325 rv = ssl3_HandleRecord(ss, NULL, &ss->gs.buf);
326 } else {
327 /* bring in the next sslv3 record. */
328 if (ss->recvdCloseNotify) {
329 /* RFC 5246 Section 7.2.1:
330 * Any data received after a closure alert is ignored.
331 */
332 return 0;
333 }
334 if (!IS_DTLS(ss)) {
335 rv = ssl3_GatherData(ss, &ss->gs, flags);
336 } else {
337 rv = dtls_GatherData(ss, &ss->gs, flags);
338
339 /* If we got a would block error, that means that no data was
340 * available, so we check the timer to see if it's time to
341 * retransmit */
342 if (rv == SECFailure &&
343 (PORT_GetError() == PR_WOULD_BLOCK_ERROR)) {
344 ssl_GetSSL3HandshakeLock(ss);
345 dtls_CheckTimer(ss);
346 ssl_ReleaseSSL3HandshakeLock(ss);
347 /* Restore the error in case something succeeded */
348 PORT_SetError(PR_WOULD_BLOCK_ERROR);
349 }
350 }
351
352 if (rv <= 0) {
353 return rv;
354 }
355
356 /* decipher it, and handle it if it's a handshake.
357 * If it's application data, ss->gs.buf will not be empty upon return.
358 * If it's a change cipher spec, alert, or handshake message,
359 * ss->gs.buf.len will be 0 when ssl3_HandleRecord returns SECSuccess.
360 */
361 cText.type = (SSL3ContentType)ss->gs.hdr[0];
362 cText.version = (ss->gs.hdr[1] << 8) | ss->gs.hdr[2];
363
364 if (IS_DTLS(ss)) {
365 int i;
366
367 cText.version = dtls_DTLSVersionToTLSVersion(cText.version);
368 /* DTLS sequence number */
369 cText.seq_num.high = 0; cText.seq_num.low = 0;
370 for (i = 0; i < 4; i++) {
371 cText.seq_num.high <<= 8; cText.seq_num.low <<= 8;
372 cText.seq_num.high |= ss->gs.hdr[3 + i];
373 cText.seq_num.low |= ss->gs.hdr[7 + i];
374 }
375 }
376
377 cText.buf = &ss->gs.inbuf;
378 rv = ssl3_HandleRecord(ss, &cText, &ss->gs.buf);
379 }
380 if (rv < 0) {
381 return ss->recvdCloseNotify ? 0 : rv;
382 }
383 if (ss->gs.buf.len > 0) {
384 /* We have application data to return to the application. This
385 * prioritizes returning application data to the application over
386 * completing any renegotiation handshake we may be doing.
387 */
388 PORT_Assert(ss->firstHsDone);
389 PORT_Assert(cText.type == content_application_data);
390 break;
391 }
392
393 PORT_Assert(keepGoing);
394 ssl_GetSSL3HandshakeLock(ss);
395 if (ss->ssl3.hs.ws == idle_handshake) {
396 /* We are done with the current handshake so stop trying to
397 * handshake. Note that it would be safe to test ss->firstHsDone
398 * instead of ss->ssl3.hs.ws. By testing ss->ssl3.hs.ws instead,
399 * we prioritize completing a renegotiation handshake over sending
400 * application data.
401 */
402 PORT_Assert(ss->firstHsDone);
403 PORT_Assert(!ss->ssl3.hs.canFalseStart);
404 keepGoing = PR_FALSE;
405 } else if (ss->ssl3.hs.canFalseStart) {
406 /* Prioritize sending application data over trying to complete
407 * the handshake if we're false starting.
408 *
409 * If we were to do this check at the beginning of the loop instead
410 * of here, then this function would become be a no-op after
411 * receiving the ServerHelloDone in the false start case, and we
412 * would never complete the handshake.
413 */
414 PORT_Assert(!ss->firstHsDone);
415
416 if (ssl3_WaitingForStartOfServerSecondRound(ss)) {
417 keepGoing = PR_FALSE;
418 } else {
419 ss->ssl3.hs.canFalseStart = PR_FALSE;
420 }
421 }
422 ssl_ReleaseSSL3HandshakeLock(ss);
423 } while (keepGoing);
424
425 ss->gs.readOffset = 0;
426 ss->gs.writeOffset = ss->gs.buf.len;
427 return 1;
428 }
429
430 /* Repeatedly gather in a record and when complete, Handle that record.
431 * Repeat this until some application data is received.
432 *
433 * Returns 1 when application data is available.
434 * Returns 0 if ssl3_GatherData hits EOF.
435 * Returns -1 on read error, or PR_WOULD_BLOCK_ERROR, or handleRecord error.
436 * Returns -2 on SECWouldBlock return from ssl3_HandleRecord.
437 *
438 * Called from DoRecv in sslsecur.c
439 * Caller must hold the recv buf lock.
440 */
441 int
442 ssl3_GatherAppDataRecord(sslSocket *ss, int flags)
443 {
444 int rv;
445
446 /* ssl3_GatherCompleteHandshake requires both of these locks. */
447 PORT_Assert( ss->opt.noLocks || ssl_Have1stHandshakeLock(ss) );
448 PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
449
450 do {
451 rv = ssl3_GatherCompleteHandshake(ss, flags);
452 } while (rv > 0 && ss->gs.buf.len == 0);
453
454 return rv;
455 }

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