1 /*
2  * Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 #include "e_os.h"
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include "internal/ctype.h"
14 #include <string.h>
15 #include <openssl/asn1.h>
16 #include <openssl/ocsp.h>
17 #include <openssl/err.h>
18 #include <openssl/buffer.h>
19 
20 /* Stateful OCSP request code, supporting non-blocking I/O */
21 
22 /* Opaque OCSP request status structure */
23 
24 struct ocsp_req_ctx_st {
25     int state;                  /* Current I/O state */
26     unsigned char *iobuf;       /* Line buffer */
27     int iobuflen;               /* Line buffer length */
28     BIO *io;                    /* BIO to perform I/O with */
29     BIO *mem;                   /* Memory BIO response is built into */
30     unsigned long asn1_len;     /* ASN1 length of response */
31     unsigned long max_resp_len; /* Maximum length of response */
32 };
33 
34 #define OCSP_MAX_RESP_LENGTH    (100 * 1024)
35 #define OCSP_MAX_LINE_LEN       4096;
36 
37 /* OCSP states */
38 
39 /* If set no reading should be performed */
40 #define OHS_NOREAD              0x1000
41 /* Error condition */
42 #define OHS_ERROR               (0 | OHS_NOREAD)
43 /* First line being read */
44 #define OHS_FIRSTLINE           1
45 /* MIME headers being read */
46 #define OHS_HEADERS             2
47 /* OCSP initial header (tag + length) being read */
48 #define OHS_ASN1_HEADER         3
49 /* OCSP content octets being read */
50 #define OHS_ASN1_CONTENT        4
51 /* First call: ready to start I/O */
52 #define OHS_ASN1_WRITE_INIT     (5 | OHS_NOREAD)
53 /* Request being sent */
54 #define OHS_ASN1_WRITE          (6 | OHS_NOREAD)
55 /* Request being flushed */
56 #define OHS_ASN1_FLUSH          (7 | OHS_NOREAD)
57 /* Completed */
58 #define OHS_DONE                (8 | OHS_NOREAD)
59 /* Headers set, no final \r\n included */
60 #define OHS_HTTP_HEADER         (9 | OHS_NOREAD)
61 
62 static int parse_http_line1(char *line);
63 
OCSP_REQ_CTX_new(BIO * io,int maxline)64 OCSP_REQ_CTX *OCSP_REQ_CTX_new(BIO *io, int maxline)
65 {
66     OCSP_REQ_CTX *rctx = OPENSSL_zalloc(sizeof(*rctx));
67 
68     if (rctx == NULL)
69         return NULL;
70     rctx->state = OHS_ERROR;
71     rctx->max_resp_len = OCSP_MAX_RESP_LENGTH;
72     rctx->mem = BIO_new(BIO_s_mem());
73     rctx->io = io;
74     if (maxline > 0)
75         rctx->iobuflen = maxline;
76     else
77         rctx->iobuflen = OCSP_MAX_LINE_LEN;
78     rctx->iobuf = OPENSSL_malloc(rctx->iobuflen);
79     if (rctx->iobuf == NULL || rctx->mem == NULL) {
80         OCSP_REQ_CTX_free(rctx);
81         return NULL;
82     }
83     return rctx;
84 }
85 
OCSP_REQ_CTX_free(OCSP_REQ_CTX * rctx)86 void OCSP_REQ_CTX_free(OCSP_REQ_CTX *rctx)
87 {
88     if (!rctx)
89         return;
90     BIO_free(rctx->mem);
91     OPENSSL_free(rctx->iobuf);
92     OPENSSL_free(rctx);
93 }
94 
OCSP_REQ_CTX_get0_mem_bio(OCSP_REQ_CTX * rctx)95 BIO *OCSP_REQ_CTX_get0_mem_bio(OCSP_REQ_CTX *rctx)
96 {
97     return rctx->mem;
98 }
99 
OCSP_set_max_response_length(OCSP_REQ_CTX * rctx,unsigned long len)100 void OCSP_set_max_response_length(OCSP_REQ_CTX *rctx, unsigned long len)
101 {
102     if (len == 0)
103         rctx->max_resp_len = OCSP_MAX_RESP_LENGTH;
104     else
105         rctx->max_resp_len = len;
106 }
107 
OCSP_REQ_CTX_i2d(OCSP_REQ_CTX * rctx,const ASN1_ITEM * it,ASN1_VALUE * val)108 int OCSP_REQ_CTX_i2d(OCSP_REQ_CTX *rctx, const ASN1_ITEM *it, ASN1_VALUE *val)
109 {
110     static const char req_hdr[] =
111         "Content-Type: application/ocsp-request\r\n"
112         "Content-Length: %d\r\n\r\n";
113     int reqlen = ASN1_item_i2d(val, NULL, it);
114     if (BIO_printf(rctx->mem, req_hdr, reqlen) <= 0)
115         return 0;
116     if (ASN1_item_i2d_bio(it, rctx->mem, val) <= 0)
117         return 0;
118     rctx->state = OHS_ASN1_WRITE_INIT;
119     return 1;
120 }
121 
OCSP_REQ_CTX_nbio_d2i(OCSP_REQ_CTX * rctx,ASN1_VALUE ** pval,const ASN1_ITEM * it)122 int OCSP_REQ_CTX_nbio_d2i(OCSP_REQ_CTX *rctx,
123                           ASN1_VALUE **pval, const ASN1_ITEM *it)
124 {
125     int rv, len;
126     const unsigned char *p;
127 
128     rv = OCSP_REQ_CTX_nbio(rctx);
129     if (rv != 1)
130         return rv;
131 
132     len = BIO_get_mem_data(rctx->mem, &p);
133     *pval = ASN1_item_d2i(NULL, &p, len, it);
134     if (*pval == NULL) {
135         rctx->state = OHS_ERROR;
136         return 0;
137     }
138     return 1;
139 }
140 
OCSP_REQ_CTX_http(OCSP_REQ_CTX * rctx,const char * op,const char * path)141 int OCSP_REQ_CTX_http(OCSP_REQ_CTX *rctx, const char *op, const char *path)
142 {
143     static const char http_hdr[] = "%s %s HTTP/1.0\r\n";
144 
145     if (!path)
146         path = "/";
147 
148     if (BIO_printf(rctx->mem, http_hdr, op, path) <= 0)
149         return 0;
150     rctx->state = OHS_HTTP_HEADER;
151     return 1;
152 }
153 
OCSP_REQ_CTX_set1_req(OCSP_REQ_CTX * rctx,OCSP_REQUEST * req)154 int OCSP_REQ_CTX_set1_req(OCSP_REQ_CTX *rctx, OCSP_REQUEST *req)
155 {
156     return OCSP_REQ_CTX_i2d(rctx, ASN1_ITEM_rptr(OCSP_REQUEST),
157                             (ASN1_VALUE *)req);
158 }
159 
OCSP_REQ_CTX_add1_header(OCSP_REQ_CTX * rctx,const char * name,const char * value)160 int OCSP_REQ_CTX_add1_header(OCSP_REQ_CTX *rctx,
161                              const char *name, const char *value)
162 {
163     if (!name)
164         return 0;
165     if (BIO_puts(rctx->mem, name) <= 0)
166         return 0;
167     if (value) {
168         if (BIO_write(rctx->mem, ": ", 2) != 2)
169             return 0;
170         if (BIO_puts(rctx->mem, value) <= 0)
171             return 0;
172     }
173     if (BIO_write(rctx->mem, "\r\n", 2) != 2)
174         return 0;
175     rctx->state = OHS_HTTP_HEADER;
176     return 1;
177 }
178 
OCSP_sendreq_new(BIO * io,const char * path,OCSP_REQUEST * req,int maxline)179 OCSP_REQ_CTX *OCSP_sendreq_new(BIO *io, const char *path, OCSP_REQUEST *req,
180                                int maxline)
181 {
182 
183     OCSP_REQ_CTX *rctx = NULL;
184     rctx = OCSP_REQ_CTX_new(io, maxline);
185     if (rctx == NULL)
186         return NULL;
187 
188     if (!OCSP_REQ_CTX_http(rctx, "POST", path))
189         goto err;
190 
191     if (req && !OCSP_REQ_CTX_set1_req(rctx, req))
192         goto err;
193 
194     return rctx;
195 
196  err:
197     OCSP_REQ_CTX_free(rctx);
198     return NULL;
199 }
200 
201 /*
202  * Parse the HTTP response. This will look like this: "HTTP/1.0 200 OK". We
203  * need to obtain the numeric code and (optional) informational message.
204  */
205 
parse_http_line1(char * line)206 static int parse_http_line1(char *line)
207 {
208     int retcode;
209     char *p, *q, *r;
210     /* Skip to first white space (passed protocol info) */
211 
212     for (p = line; *p && !ossl_isspace(*p); p++)
213         continue;
214     if (!*p) {
215         OCSPerr(OCSP_F_PARSE_HTTP_LINE1, OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
216         return 0;
217     }
218 
219     /* Skip past white space to start of response code */
220     while (*p && ossl_isspace(*p))
221         p++;
222 
223     if (!*p) {
224         OCSPerr(OCSP_F_PARSE_HTTP_LINE1, OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
225         return 0;
226     }
227 
228     /* Find end of response code: first whitespace after start of code */
229     for (q = p; *q && !ossl_isspace(*q); q++)
230         continue;
231 
232     if (!*q) {
233         OCSPerr(OCSP_F_PARSE_HTTP_LINE1, OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
234         return 0;
235     }
236 
237     /* Set end of response code and start of message */
238     *q++ = 0;
239 
240     /* Attempt to parse numeric code */
241     retcode = strtoul(p, &r, 10);
242 
243     if (*r)
244         return 0;
245 
246     /* Skip over any leading white space in message */
247     while (*q && ossl_isspace(*q))
248         q++;
249 
250     if (*q) {
251         /*
252          * Finally zap any trailing white space in message (include CRLF)
253          */
254 
255         /* We know q has a non white space character so this is OK */
256         for (r = q + strlen(q) - 1; ossl_isspace(*r); r--)
257             *r = 0;
258     }
259     if (retcode != 200) {
260         OCSPerr(OCSP_F_PARSE_HTTP_LINE1, OCSP_R_SERVER_RESPONSE_ERROR);
261         if (!*q)
262             ERR_add_error_data(2, "Code=", p);
263         else
264             ERR_add_error_data(4, "Code=", p, ",Reason=", q);
265         return 0;
266     }
267 
268     return 1;
269 
270 }
271 
OCSP_REQ_CTX_nbio(OCSP_REQ_CTX * rctx)272 int OCSP_REQ_CTX_nbio(OCSP_REQ_CTX *rctx)
273 {
274     int i, n;
275     const unsigned char *p;
276  next_io:
277     if (!(rctx->state & OHS_NOREAD)) {
278         n = BIO_read(rctx->io, rctx->iobuf, rctx->iobuflen);
279 
280         if (n <= 0) {
281             if (BIO_should_retry(rctx->io))
282                 return -1;
283             return 0;
284         }
285 
286         /* Write data to memory BIO */
287 
288         if (BIO_write(rctx->mem, rctx->iobuf, n) != n)
289             return 0;
290     }
291 
292     switch (rctx->state) {
293     case OHS_HTTP_HEADER:
294         /* Last operation was adding headers: need a final \r\n */
295         if (BIO_write(rctx->mem, "\r\n", 2) != 2) {
296             rctx->state = OHS_ERROR;
297             return 0;
298         }
299         rctx->state = OHS_ASN1_WRITE_INIT;
300 
301         /* fall thru */
302     case OHS_ASN1_WRITE_INIT:
303         rctx->asn1_len = BIO_get_mem_data(rctx->mem, NULL);
304         rctx->state = OHS_ASN1_WRITE;
305 
306         /* fall thru */
307     case OHS_ASN1_WRITE:
308         n = BIO_get_mem_data(rctx->mem, &p);
309 
310         i = BIO_write(rctx->io, p + (n - rctx->asn1_len), rctx->asn1_len);
311 
312         if (i <= 0) {
313             if (BIO_should_retry(rctx->io))
314                 return -1;
315             rctx->state = OHS_ERROR;
316             return 0;
317         }
318 
319         rctx->asn1_len -= i;
320 
321         if (rctx->asn1_len > 0)
322             goto next_io;
323 
324         rctx->state = OHS_ASN1_FLUSH;
325 
326         (void)BIO_reset(rctx->mem);
327 
328         /* fall thru */
329     case OHS_ASN1_FLUSH:
330 
331         i = BIO_flush(rctx->io);
332 
333         if (i > 0) {
334             rctx->state = OHS_FIRSTLINE;
335             goto next_io;
336         }
337 
338         if (BIO_should_retry(rctx->io))
339             return -1;
340 
341         rctx->state = OHS_ERROR;
342         return 0;
343 
344     case OHS_ERROR:
345         return 0;
346 
347     case OHS_FIRSTLINE:
348     case OHS_HEADERS:
349 
350         /* Attempt to read a line in */
351 
352  next_line:
353         /*
354          * Due to &%^*$" memory BIO behaviour with BIO_gets we have to check
355          * there's a complete line in there before calling BIO_gets or we'll
356          * just get a partial read.
357          */
358         n = BIO_get_mem_data(rctx->mem, &p);
359         if ((n <= 0) || !memchr(p, '\n', n)) {
360             if (n >= rctx->iobuflen) {
361                 rctx->state = OHS_ERROR;
362                 return 0;
363             }
364             goto next_io;
365         }
366         n = BIO_gets(rctx->mem, (char *)rctx->iobuf, rctx->iobuflen);
367 
368         if (n <= 0) {
369             if (BIO_should_retry(rctx->mem))
370                 goto next_io;
371             rctx->state = OHS_ERROR;
372             return 0;
373         }
374 
375         /* Don't allow excessive lines */
376         if (n == rctx->iobuflen) {
377             rctx->state = OHS_ERROR;
378             return 0;
379         }
380 
381         /* First line */
382         if (rctx->state == OHS_FIRSTLINE) {
383             if (parse_http_line1((char *)rctx->iobuf)) {
384                 rctx->state = OHS_HEADERS;
385                 goto next_line;
386             } else {
387                 rctx->state = OHS_ERROR;
388                 return 0;
389             }
390         } else {
391             /* Look for blank line: end of headers */
392             for (p = rctx->iobuf; *p; p++) {
393                 if ((*p != '\r') && (*p != '\n'))
394                     break;
395             }
396             if (*p)
397                 goto next_line;
398 
399             rctx->state = OHS_ASN1_HEADER;
400 
401         }
402 
403         /* Fall thru */
404 
405     case OHS_ASN1_HEADER:
406         /*
407          * Now reading ASN1 header: can read at least 2 bytes which is enough
408          * for ASN1 SEQUENCE header and either length field or at least the
409          * length of the length field.
410          */
411         n = BIO_get_mem_data(rctx->mem, &p);
412         if (n < 2)
413             goto next_io;
414 
415         /* Check it is an ASN1 SEQUENCE */
416         if (*p++ != (V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)) {
417             rctx->state = OHS_ERROR;
418             return 0;
419         }
420 
421         /* Check out length field */
422         if (*p & 0x80) {
423             /*
424              * If MSB set on initial length octet we can now always read 6
425              * octets: make sure we have them.
426              */
427             if (n < 6)
428                 goto next_io;
429             n = *p & 0x7F;
430             /* Not NDEF or excessive length */
431             if (!n || (n > 4)) {
432                 rctx->state = OHS_ERROR;
433                 return 0;
434             }
435             p++;
436             rctx->asn1_len = 0;
437             for (i = 0; i < n; i++) {
438                 rctx->asn1_len <<= 8;
439                 rctx->asn1_len |= *p++;
440             }
441 
442             if (rctx->asn1_len > rctx->max_resp_len) {
443                 rctx->state = OHS_ERROR;
444                 return 0;
445             }
446 
447             rctx->asn1_len += n + 2;
448         } else
449             rctx->asn1_len = *p + 2;
450 
451         rctx->state = OHS_ASN1_CONTENT;
452 
453         /* Fall thru */
454 
455     case OHS_ASN1_CONTENT:
456         n = BIO_get_mem_data(rctx->mem, NULL);
457         if (n < (int)rctx->asn1_len)
458             goto next_io;
459 
460         rctx->state = OHS_DONE;
461         return 1;
462 
463     case OHS_DONE:
464         return 1;
465 
466     }
467 
468     return 0;
469 
470 }
471 
OCSP_sendreq_nbio(OCSP_RESPONSE ** presp,OCSP_REQ_CTX * rctx)472 int OCSP_sendreq_nbio(OCSP_RESPONSE **presp, OCSP_REQ_CTX *rctx)
473 {
474     return OCSP_REQ_CTX_nbio_d2i(rctx,
475                                  (ASN1_VALUE **)presp,
476                                  ASN1_ITEM_rptr(OCSP_RESPONSE));
477 }
478 
479 /* Blocking OCSP request handler: now a special case of non-blocking I/O */
480 
OCSP_sendreq_bio(BIO * b,const char * path,OCSP_REQUEST * req)481 OCSP_RESPONSE *OCSP_sendreq_bio(BIO *b, const char *path, OCSP_REQUEST *req)
482 {
483     OCSP_RESPONSE *resp = NULL;
484     OCSP_REQ_CTX *ctx;
485     int rv;
486 
487     ctx = OCSP_sendreq_new(b, path, req, -1);
488 
489     if (ctx == NULL)
490         return NULL;
491 
492     do {
493         rv = OCSP_sendreq_nbio(&resp, ctx);
494     } while ((rv == -1) && BIO_should_retry(b));
495 
496     OCSP_REQ_CTX_free(ctx);
497 
498     if (rv)
499         return resp;
500 
501     return NULL;
502 }
503