xref: /openbsd-src/lib/libcrypto/ocsp/ocsp_ht.c (revision 50b7afb2c2c0993b0894d4e34bf857cb13ed9c80) 
1 /* $OpenBSD: ocsp_ht.c,v 1.20 2014/07/12 14:58:32 miod Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3  * project 2006.
4  */
5 /* ====================================================================
6  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    licensing@OpenSSL.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58 
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <ctype.h>
62 #include <string.h>
63 #include <openssl/asn1.h>
64 #include <openssl/ocsp.h>
65 #include <openssl/err.h>
66 #include <openssl/buffer.h>
67 
68 /* Stateful OCSP request code, supporting non-blocking I/O */
69 
70 /* Opaque OCSP request status structure */
71 
72 struct ocsp_req_ctx_st {
73 	int state;		/* Current I/O state */
74 	unsigned char *iobuf;	/* Line buffer */
75 	int iobuflen;		/* Line buffer length */
76 	BIO *io;		/* BIO to perform I/O with */
77 	BIO *mem;		/* Memory BIO response is built into */
78 	unsigned long asn1_len;	/* ASN1 length of response */
79 };
80 
81 #define OCSP_MAX_REQUEST_LENGTH	(100 * 1024)
82 #define OCSP_MAX_LINE_LEN	4096;
83 
84 /* OCSP states */
85 
86 /* If set no reading should be performed */
87 #define OHS_NOREAD		0x1000
88 /* Error condition */
89 #define OHS_ERROR		(0 | OHS_NOREAD)
90 /* First line being read */
91 #define OHS_FIRSTLINE		1
92 /* MIME headers being read */
93 #define OHS_HEADERS		2
94 /* OCSP initial header (tag + length) being read */
95 #define OHS_ASN1_HEADER		3
96 /* OCSP content octets being read */
97 #define OHS_ASN1_CONTENT	4
98 /* Request being sent */
99 #define OHS_ASN1_WRITE		(6 | OHS_NOREAD)
100 /* Request being flushed */
101 #define OHS_ASN1_FLUSH		(7 | OHS_NOREAD)
102 /* Completed */
103 #define OHS_DONE		(8 | OHS_NOREAD)
104 
105 
106 static int parse_http_line1(char *line);
107 
108 void
109 OCSP_REQ_CTX_free(OCSP_REQ_CTX *rctx)
110 {
111 	if (rctx == NULL)
112 		return;
113 
114 	if (rctx->mem)
115 		BIO_free(rctx->mem);
116 	free(rctx->iobuf);
117 	free(rctx);
118 }
119 
120 int
121 OCSP_REQ_CTX_set1_req(OCSP_REQ_CTX *rctx, OCSP_REQUEST *req)
122 {
123 	static const char req_hdr[] =
124 	    "Content-Type: application/ocsp-request\r\n"
125 	    "Content-Length: %d\r\n\r\n";
126 
127 	if (BIO_printf(rctx->mem, req_hdr, i2d_OCSP_REQUEST(req, NULL)) <= 0)
128 		return 0;
129 	if (i2d_OCSP_REQUEST_bio(rctx->mem, req) <= 0)
130 		return 0;
131 	rctx->state = OHS_ASN1_WRITE;
132 	rctx->asn1_len = BIO_get_mem_data(rctx->mem, NULL);
133 	return 1;
134 }
135 
136 int
137 OCSP_REQ_CTX_add1_header(OCSP_REQ_CTX *rctx, const char *name,
138     const char *value)
139 {
140 	if (!name)
141 		return 0;
142 	if (BIO_puts(rctx->mem, name) <= 0)
143 		return 0;
144 	if (value) {
145 		if (BIO_write(rctx->mem, ": ", 2) != 2)
146 			return 0;
147 		if (BIO_puts(rctx->mem, value) <= 0)
148 			return 0;
149 	}
150 	if (BIO_write(rctx->mem, "\r\n", 2) != 2)
151 		return 0;
152 	return 1;
153 }
154 
155 OCSP_REQ_CTX *
156 OCSP_sendreq_new(BIO *io, char *path, OCSP_REQUEST *req, int maxline)
157 {
158 	static const char post_hdr[] = "POST %s HTTP/1.0\r\n";
159 	OCSP_REQ_CTX *rctx;
160 
161 	rctx = malloc(sizeof(OCSP_REQ_CTX));
162 	if (rctx == NULL)
163 		return NULL;
164 	rctx->state = OHS_ERROR;
165 	rctx->mem = BIO_new(BIO_s_mem());
166 	rctx->io = io;
167 	rctx->asn1_len = 0;
168 	if (maxline > 0)
169 		rctx->iobuflen = maxline;
170 	else
171 		rctx->iobuflen = OCSP_MAX_LINE_LEN;
172 	rctx->iobuf = malloc(rctx->iobuflen);
173 	if (!rctx->iobuf) {
174 		BIO_free(rctx->mem);
175 		free(rctx);
176 		return NULL;
177 	}
178 	if (!path)
179 		path = "/";
180 
181 	if (BIO_printf(rctx->mem, post_hdr, path) <= 0) {
182 		free(rctx->iobuf);
183 		BIO_free(rctx->mem);
184 		free(rctx);
185 		return NULL;
186 	}
187 
188 	if (req && !OCSP_REQ_CTX_set1_req(rctx, req)) {
189 		free(rctx->iobuf);
190 		BIO_free(rctx->mem);
191 		free(rctx);
192 		return NULL;
193 	}
194 
195 	return rctx;
196 }
197 
198 /* Parse the HTTP response. This will look like this:
199  * "HTTP/1.0 200 OK". We need to obtain the numeric code and
200  * (optional) informational message.
201  */
202 static int
203 parse_http_line1(char *line)
204 {
205 	int retcode;
206 	char *p, *q, *r;
207 
208 	/* Skip to first white space (passed protocol info) */
209 	for (p = line; *p && !isspace((unsigned char)*p); p++)
210 		continue;
211 	if (!*p) {
212 		OCSPerr(OCSP_F_PARSE_HTTP_LINE1,
213 		    OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
214 		return 0;
215 	}
216 
217 	/* Skip past white space to start of response code */
218 	while (*p && isspace((unsigned char)*p))
219 		p++;
220 	if (!*p) {
221 		OCSPerr(OCSP_F_PARSE_HTTP_LINE1,
222 		    OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
223 		return 0;
224 	}
225 
226 	/* Find end of response code: first whitespace after start of code */
227 	for (q = p; *q && !isspace((unsigned char)*q); q++)
228 		continue;
229 	if (!*q) {
230 		OCSPerr(OCSP_F_PARSE_HTTP_LINE1,
231 		    OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
232 		return 0;
233 	}
234 
235 	/* Set end of response code and start of message */
236 	*q++ = 0;
237 
238 	/* Attempt to parse numeric code */
239 	retcode = strtoul(p, &r, 10);
240 
241 	if (*r)
242 		return 0;
243 
244 	/* Skip over any leading white space in message */
245 	while (*q && isspace((unsigned char)*q))
246 		q++;
247 	if (*q) {
248 		/* Finally zap any trailing white space in message (include
249 		 * CRLF) */
250 
251 		/* We know q has a non white space character so this is OK */
252 		for (r = q + strlen(q) - 1; isspace((unsigned char)*r); r--)
253 			*r = 0;
254 	}
255 	if (retcode != 200) {
256 		OCSPerr(OCSP_F_PARSE_HTTP_LINE1, OCSP_R_SERVER_RESPONSE_ERROR);
257 		if (!*q)
258 			ERR_asprintf_error_data("Code=%s", p);
259 		else
260 			ERR_asprintf_error_data("Code=%s,Reason=%s", p, q);
261 		return 0;
262 	}
263 
264 	return 1;
265 }
266 
267 int
268 OCSP_sendreq_nbio(OCSP_RESPONSE **presp, OCSP_REQ_CTX *rctx)
269 {
270 	int i, n;
271 	const unsigned char *p;
272 
273 next_io:
274 	if (!(rctx->state & OHS_NOREAD)) {
275 		n = BIO_read(rctx->io, rctx->iobuf, rctx->iobuflen);
276 
277 		if (n <= 0) {
278 			if (BIO_should_retry(rctx->io))
279 				return -1;
280 			return 0;
281 		}
282 
283 		/* Write data to memory BIO */
284 		if (BIO_write(rctx->mem, rctx->iobuf, n) != n)
285 			return 0;
286 	}
287 
288 	switch (rctx->state) {
289 	case OHS_ASN1_WRITE:
290 		n = BIO_get_mem_data(rctx->mem, &p);
291 		i = BIO_write(rctx->io,
292 		    p + (n - rctx->asn1_len), rctx->asn1_len);
293 		if (i <= 0) {
294 			if (BIO_should_retry(rctx->io))
295 				return -1;
296 			rctx->state = OHS_ERROR;
297 			return 0;
298 		}
299 
300 		rctx->asn1_len -= i;
301 		if (rctx->asn1_len > 0)
302 			goto next_io;
303 
304 		rctx->state = OHS_ASN1_FLUSH;
305 
306 		(void)BIO_reset(rctx->mem);
307 		/* FALLTHROUGH */
308 
309 	case OHS_ASN1_FLUSH:
310 		i = BIO_flush(rctx->io);
311 		if (i > 0) {
312 			rctx->state = OHS_FIRSTLINE;
313 			goto next_io;
314 		}
315 
316 		if (BIO_should_retry(rctx->io))
317 			return -1;
318 
319 		rctx->state = OHS_ERROR;
320 		return 0;
321 
322 	case OHS_ERROR:
323 		return 0;
324 
325 	case OHS_FIRSTLINE:
326 	case OHS_HEADERS:
327 		/* Attempt to read a line in */
328 next_line:
329 		/* Due to &%^*$" memory BIO behaviour with BIO_gets we
330 		 * have to check there's a complete line in there before
331 		 * calling BIO_gets or we'll just get a partial read.
332 		 */
333 		n = BIO_get_mem_data(rctx->mem, &p);
334 		if ((n <= 0) || !memchr(p, '\n', n)) {
335 			if (n >= rctx->iobuflen) {
336 				rctx->state = OHS_ERROR;
337 				return 0;
338 			}
339 			goto next_io;
340 		}
341 		n = BIO_gets(rctx->mem, (char *)rctx->iobuf, rctx->iobuflen);
342 		if (n <= 0) {
343 			if (BIO_should_retry(rctx->mem))
344 				goto next_io;
345 			rctx->state = OHS_ERROR;
346 			return 0;
347 		}
348 
349 		/* Don't allow excessive lines */
350 		if (n == rctx->iobuflen) {
351 			rctx->state = OHS_ERROR;
352 			return 0;
353 		}
354 
355 		/* First line */
356 		if (rctx->state == OHS_FIRSTLINE) {
357 			if (parse_http_line1((char *)rctx->iobuf)) {
358 				rctx->state = OHS_HEADERS;
359 				goto next_line;
360 			} else {
361 				rctx->state = OHS_ERROR;
362 				return 0;
363 			}
364 		} else {
365 			/* Look for blank line: end of headers */
366 			for (p = rctx->iobuf; *p; p++) {
367 				if ((*p != '\r') && (*p != '\n'))
368 					break;
369 			}
370 			if (*p)
371 				goto next_line;
372 
373 			rctx->state = OHS_ASN1_HEADER;
374 		}
375 		/* FALLTRHOUGH */
376 
377 	case OHS_ASN1_HEADER:
378 		/* Now reading ASN1 header: can read at least 2 bytes which
379 		 * is enough for ASN1 SEQUENCE header and either length field
380 		 * or at least the length of the length field.
381 		 */
382 		n = BIO_get_mem_data(rctx->mem, &p);
383 		if (n < 2)
384 			goto next_io;
385 
386 		/* Check it is an ASN1 SEQUENCE */
387 		if (*p++ != (V_ASN1_SEQUENCE|V_ASN1_CONSTRUCTED)) {
388 			rctx->state = OHS_ERROR;
389 			return 0;
390 		}
391 
392 		/* Check out length field */
393 		if (*p & 0x80) {
394 			/* If MSB set on initial length octet we can now
395 			 * always read 6 octets: make sure we have them.
396 			 */
397 			if (n < 6)
398 				goto next_io;
399 			n = *p & 0x7F;
400 			/* Not NDEF or excessive length */
401 			if (!n || (n > 4)) {
402 				rctx->state = OHS_ERROR;
403 				return 0;
404 			}
405 			p++;
406 			rctx->asn1_len = 0;
407 			for (i = 0; i < n; i++) {
408 				rctx->asn1_len <<= 8;
409 				rctx->asn1_len |= *p++;
410 			}
411 
412 			if (rctx->asn1_len > OCSP_MAX_REQUEST_LENGTH) {
413 				rctx->state = OHS_ERROR;
414 				return 0;
415 			}
416 
417 			rctx->asn1_len += n + 2;
418 		} else
419 			rctx->asn1_len = *p + 2;
420 
421 		rctx->state = OHS_ASN1_CONTENT;
422 
423 		/* FALLTHROUGH */
424 
425 	case OHS_ASN1_CONTENT:
426 		n = BIO_get_mem_data(rctx->mem, &p);
427 		if (n < (int)rctx->asn1_len)
428 			goto next_io;
429 
430 		*presp = d2i_OCSP_RESPONSE(NULL, &p, rctx->asn1_len);
431 		if (*presp) {
432 			rctx->state = OHS_DONE;
433 			return 1;
434 		}
435 
436 		rctx->state = OHS_ERROR;
437 		return 0;
438 
439 	case OHS_DONE:
440 		return 1;
441 	}
442 
443 	return 0;
444 }
445 
446 /* Blocking OCSP request handler: now a special case of non-blocking I/O */
447 OCSP_RESPONSE *
448 OCSP_sendreq_bio(BIO *b, char *path, OCSP_REQUEST *req)
449 {
450 	OCSP_RESPONSE *resp = NULL;
451 	OCSP_REQ_CTX *ctx;
452 	int rv;
453 
454 	ctx = OCSP_sendreq_new(b, path, req, -1);
455 	if (ctx == NULL)
456 		return NULL;
457 
458 	do {
459 		rv = OCSP_sendreq_nbio(&resp, ctx);
460 	} while ((rv == -1) && BIO_should_retry(b));
461 
462 	OCSP_REQ_CTX_free(ctx);
463 
464 	if (rv)
465 		return resp;
466 
467 	return NULL;
468 }
469