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 "crypto/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
24struct 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
62static int parse_http_line1(char *line);
63
64OCSP_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
86void 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
95BIO *OCSP_REQ_CTX_get0_mem_bio(OCSP_REQ_CTX *rctx)
96{
97    return rctx->mem;
98}
99
100void 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
108int 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
122int 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
141int 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
154int 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
160int 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
179OCSP_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
206static 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
272int 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
472int 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
481OCSP_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