xref: /openbsd/lib/libcrypto/ocsp/ocsp_ht.c (revision 510d2225) 
1 /* $OpenBSD: ocsp_ht.c,v 1.27 2023/11/28 09:29:20 jsg 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 	BIO_free(rctx->mem);
115 	free(rctx->iobuf);
116 	free(rctx);
117 }
118 LCRYPTO_ALIAS(OCSP_REQ_CTX_free);
119 
120 int
121 OCSP_REQ_CTX_set1_req(OCSP_REQ_CTX *rctx, OCSP_REQUEST *req)
122 {
123 	if (BIO_printf(rctx->mem, "Content-Type: application/ocsp-request\r\n"
124 	    "Content-Length: %d\r\n\r\n", i2d_OCSP_REQUEST(req, NULL)) <= 0)
125 		return 0;
126 	if (i2d_OCSP_REQUEST_bio(rctx->mem, req) <= 0)
127 		return 0;
128 	rctx->state = OHS_ASN1_WRITE;
129 	rctx->asn1_len = BIO_get_mem_data(rctx->mem, NULL);
130 	return 1;
131 }
132 LCRYPTO_ALIAS(OCSP_REQ_CTX_set1_req);
133 
134 int
135 OCSP_REQ_CTX_add1_header(OCSP_REQ_CTX *rctx, const char *name,
136     const char *value)
137 {
138 	if (!name)
139 		return 0;
140 	if (BIO_puts(rctx->mem, name) <= 0)
141 		return 0;
142 	if (value) {
143 		if (BIO_write(rctx->mem, ": ", 2) != 2)
144 			return 0;
145 		if (BIO_puts(rctx->mem, value) <= 0)
146 			return 0;
147 	}
148 	if (BIO_write(rctx->mem, "\r\n", 2) != 2)
149 		return 0;
150 	return 1;
151 }
152 LCRYPTO_ALIAS(OCSP_REQ_CTX_add1_header);
153 
154 OCSP_REQ_CTX *
155 OCSP_sendreq_new(BIO *io, const char *path, OCSP_REQUEST *req, int maxline)
156 {
157 	OCSP_REQ_CTX *rctx;
158 
159 	rctx = malloc(sizeof(OCSP_REQ_CTX));
160 	if (rctx == NULL)
161 		return NULL;
162 	rctx->state = OHS_ERROR;
163 	if ((rctx->mem = BIO_new(BIO_s_mem())) == NULL) {
164 		free(rctx);
165 		return NULL;
166 	}
167 	rctx->io = io;
168 	rctx->asn1_len = 0;
169 	if (maxline > 0)
170 		rctx->iobuflen = maxline;
171 	else
172 		rctx->iobuflen = OCSP_MAX_LINE_LEN;
173 	rctx->iobuf = malloc(rctx->iobuflen);
174 	if (!rctx->iobuf) {
175 		BIO_free(rctx->mem);
176 		free(rctx);
177 		return NULL;
178 	}
179 	if (!path)
180 		path = "/";
181 
182 	if (BIO_printf(rctx->mem, "POST %s HTTP/1.0\r\n", path) <= 0) {
183 		free(rctx->iobuf);
184 		BIO_free(rctx->mem);
185 		free(rctx);
186 		return NULL;
187 	}
188 
189 	if (req && !OCSP_REQ_CTX_set1_req(rctx, req)) {
190 		free(rctx->iobuf);
191 		BIO_free(rctx->mem);
192 		free(rctx);
193 		return NULL;
194 	}
195 
196 	return rctx;
197 }
198 LCRYPTO_ALIAS(OCSP_sendreq_new);
199 
200 /* Parse the HTTP response. This will look like this:
201  * "HTTP/1.0 200 OK". We need to obtain the numeric code and
202  * (optional) informational message.
203  */
204 static int
205 parse_http_line1(char *line)
206 {
207 	int retcode;
208 	char *p, *q, *r;
209 
210 	/* Skip to first white space (passed protocol info) */
211 	for (p = line; *p && !isspace((unsigned char)*p); p++)
212 		continue;
213 	if (!*p) {
214 		OCSPerror(OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
215 		return 0;
216 	}
217 
218 	/* Skip past white space to start of response code */
219 	while (*p && isspace((unsigned char)*p))
220 		p++;
221 	if (!*p) {
222 		OCSPerror(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 		OCSPerror(OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
231 		return 0;
232 	}
233 
234 	/* Set end of response code and start of message */
235 	*q++ = 0;
236 
237 	/* Attempt to parse numeric code */
238 	retcode = strtoul(p, &r, 10);
239 
240 	if (*r)
241 		return 0;
242 
243 	/* Skip over any leading white space in message */
244 	while (*q && isspace((unsigned char)*q))
245 		q++;
246 	if (*q) {
247 		/* Finally zap any trailing white space in message (include
248 		 * CRLF) */
249 
250 		/* We know q has a non white space character so this is OK */
251 		for (r = q + strlen(q) - 1; isspace((unsigned char)*r); r--)
252 			*r = 0;
253 	}
254 	if (retcode != 200) {
255 		OCSPerror(OCSP_R_SERVER_RESPONSE_ERROR);
256 		if (!*q)
257 			ERR_asprintf_error_data("Code=%s", p);
258 		else
259 			ERR_asprintf_error_data("Code=%s,Reason=%s", p, q);
260 		return 0;
261 	}
262 
263 	return 1;
264 }
265 
266 int
267 OCSP_sendreq_nbio(OCSP_RESPONSE **presp, OCSP_REQ_CTX *rctx)
268 {
269 	int i, n;
270 	const unsigned char *p;
271 
272 next_io:
273 	if (!(rctx->state & OHS_NOREAD)) {
274 		n = BIO_read(rctx->io, rctx->iobuf, rctx->iobuflen);
275 
276 		if (n <= 0) {
277 			if (BIO_should_retry(rctx->io))
278 				return -1;
279 			return 0;
280 		}
281 
282 		/* Write data to memory BIO */
283 		if (BIO_write(rctx->mem, rctx->iobuf, n) != n)
284 			return 0;
285 	}
286 
287 	switch (rctx->state) {
288 	case OHS_ASN1_WRITE:
289 		n = BIO_get_mem_data(rctx->mem, &p);
290 		i = BIO_write(rctx->io,
291 		    p + (n - rctx->asn1_len), rctx->asn1_len);
292 		if (i <= 0) {
293 			if (BIO_should_retry(rctx->io))
294 				return -1;
295 			rctx->state = OHS_ERROR;
296 			return 0;
297 		}
298 
299 		rctx->asn1_len -= i;
300 		if (rctx->asn1_len > 0)
301 			goto next_io;
302 
303 		rctx->state = OHS_ASN1_FLUSH;
304 
305 		(void)BIO_reset(rctx->mem);
306 		/* FALLTHROUGH */
307 
308 	case OHS_ASN1_FLUSH:
309 		i = BIO_flush(rctx->io);
310 		if (i > 0) {
311 			rctx->state = OHS_FIRSTLINE;
312 			goto next_io;
313 		}
314 
315 		if (BIO_should_retry(rctx->io))
316 			return -1;
317 
318 		rctx->state = OHS_ERROR;
319 		return 0;
320 
321 	case OHS_ERROR:
322 		return 0;
323 
324 	case OHS_FIRSTLINE:
325 	case OHS_HEADERS:
326 		/* Attempt to read a line in */
327 next_line:
328 		/* Due to &%^*$" memory BIO behaviour with BIO_gets we
329 		 * have to check there's a complete line in there before
330 		 * calling BIO_gets or we'll just get a partial read.
331 		 */
332 		n = BIO_get_mem_data(rctx->mem, &p);
333 		if ((n <= 0) || !memchr(p, '\n', n)) {
334 			if (n >= rctx->iobuflen) {
335 				rctx->state = OHS_ERROR;
336 				return 0;
337 			}
338 			goto next_io;
339 		}
340 		n = BIO_gets(rctx->mem, (char *)rctx->iobuf, rctx->iobuflen);
341 		if (n <= 0) {
342 			if (BIO_should_retry(rctx->mem))
343 				goto next_io;
344 			rctx->state = OHS_ERROR;
345 			return 0;
346 		}
347 
348 		/* Don't allow excessive lines */
349 		if (n == rctx->iobuflen) {
350 			rctx->state = OHS_ERROR;
351 			return 0;
352 		}
353 
354 		/* First line */
355 		if (rctx->state == OHS_FIRSTLINE) {
356 			if (parse_http_line1((char *)rctx->iobuf)) {
357 				rctx->state = OHS_HEADERS;
358 				goto next_line;
359 			} else {
360 				rctx->state = OHS_ERROR;
361 				return 0;
362 			}
363 		} else {
364 			/* Look for blank line: end of headers */
365 			for (p = rctx->iobuf; *p; p++) {
366 				if ((*p != '\r') && (*p != '\n'))
367 					break;
368 			}
369 			if (*p)
370 				goto next_line;
371 
372 			rctx->state = OHS_ASN1_HEADER;
373 		}
374 		/* FALLTHROUGH */
375 
376 	case OHS_ASN1_HEADER:
377 		/* Now reading ASN1 header: can read at least 2 bytes which
378 		 * is enough for ASN1 SEQUENCE header and either length field
379 		 * or at least the length of the length field.
380 		 */
381 		n = BIO_get_mem_data(rctx->mem, &p);
382 		if (n < 2)
383 			goto next_io;
384 
385 		/* Check it is an ASN1 SEQUENCE */
386 		if (*p++ != (V_ASN1_SEQUENCE|V_ASN1_CONSTRUCTED)) {
387 			rctx->state = OHS_ERROR;
388 			return 0;
389 		}
390 
391 		/* Check out length field */
392 		if (*p & 0x80) {
393 			/* If MSB set on initial length octet we can now
394 			 * always read 6 octets: make sure we have them.
395 			 */
396 			if (n < 6)
397 				goto next_io;
398 			n = *p & 0x7F;
399 			/* Not NDEF or excessive length */
400 			if (!n || (n > 4)) {
401 				rctx->state = OHS_ERROR;
402 				return 0;
403 			}
404 			p++;
405 			rctx->asn1_len = 0;
406 			for (i = 0; i < n; i++) {
407 				rctx->asn1_len <<= 8;
408 				rctx->asn1_len |= *p++;
409 			}
410 
411 			if (rctx->asn1_len > OCSP_MAX_REQUEST_LENGTH) {
412 				rctx->state = OHS_ERROR;
413 				return 0;
414 			}
415 
416 			rctx->asn1_len += n + 2;
417 		} else
418 			rctx->asn1_len = *p + 2;
419 
420 		rctx->state = OHS_ASN1_CONTENT;
421 
422 		/* FALLTHROUGH */
423 
424 	case OHS_ASN1_CONTENT:
425 		n = BIO_get_mem_data(rctx->mem, &p);
426 		if (n < (int)rctx->asn1_len)
427 			goto next_io;
428 
429 		*presp = d2i_OCSP_RESPONSE(NULL, &p, rctx->asn1_len);
430 		if (*presp) {
431 			rctx->state = OHS_DONE;
432 			return 1;
433 		}
434 
435 		rctx->state = OHS_ERROR;
436 		return 0;
437 
438 	case OHS_DONE:
439 		return 1;
440 	}
441 
442 	return 0;
443 }
444 LCRYPTO_ALIAS(OCSP_sendreq_nbio);
445 
446 /* Blocking OCSP request handler: now a special case of non-blocking I/O */
447 OCSP_RESPONSE *
448 OCSP_sendreq_bio(BIO *b, const 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 LCRYPTO_ALIAS(OCSP_sendreq_bio);
470