aboutsummaryrefslogtreecommitdiff
path: root/lib/http_digest.c
blob: bc8e23d43d8f0fc2452013246072f0038bf215fb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_CRYPTO_AUTH)

#include "urldata.h"
#include "sendf.h"
#include "rawstr.h"
#include "curl_base64.h"
#include "curl_md5.h"
#include "http_digest.h"
#include "strtok.h"
#include "url.h" /* for Curl_safefree() */
#include "curl_memory.h"
#include "sslgen.h" /* for Curl_rand() */
#include "non-ascii.h" /* included for Curl_convert_... prototypes */
#include "warnless.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

/* The last #include file should be: */
#include "memdebug.h"

#define MAX_VALUE_LENGTH 256
#define MAX_CONTENT_LENGTH 1024

static void digest_cleanup_one(struct digestdata *dig);

/*
 * Return 0 on success and then the buffers are filled in fine.
 *
 * Non-zero means failure to parse.
 */
static int get_pair(const char *str, char *value, char *content,
                    const char **endptr)
{
  int c;
  bool starts_with_quote = FALSE;
  bool escape = FALSE;

  for(c=MAX_VALUE_LENGTH-1; (*str && (*str != '=') && c--); )
    *value++ = *str++;
  *value=0;

  if('=' != *str++)
    /* eek, no match */
    return 1;

  if('\"' == *str) {
    /* this starts with a quote so it must end with one as well! */
    str++;
    starts_with_quote = TRUE;
  }

  for(c=MAX_CONTENT_LENGTH-1; *str && c--; str++) {
    switch(*str) {
    case '\\':
      if(!escape) {
        /* possibly the start of an escaped quote */
        escape = TRUE;
        *content++ = '\\'; /* even though this is an escape character, we still
                              store it as-is in the target buffer */
        continue;
      }
      break;
    case ',':
      if(!starts_with_quote) {
        /* this signals the end of the content if we didn't get a starting
           quote and then we do "sloppy" parsing */
        c=0; /* the end */
        continue;
      }
      break;
    case '\r':
    case '\n':
      /* end of string */
      c=0;
      continue;
    case '\"':
      if(!escape && starts_with_quote) {
        /* end of string */
        c=0;
        continue;
      }
      break;
    }
    escape = FALSE;
    *content++ = *str;
  }
  *content=0;

  *endptr = str;

  return 0; /* all is fine! */
}

/* Test example headers:

WWW-Authenticate: Digest realm="testrealm", nonce="1053604598"
Proxy-Authenticate: Digest realm="testrealm", nonce="1053604598"

*/

CURLdigest Curl_input_digest(struct connectdata *conn,
                             bool proxy,
                             const char *header) /* rest of the *-authenticate:
                                                    header */
{
  char *token = NULL;
  char *tmp = NULL;
  bool foundAuth = FALSE;
  bool foundAuthInt = FALSE;
  struct SessionHandle *data=conn->data;
  bool before = FALSE; /* got a nonce before */
  struct digestdata *d;

  if(proxy) {
    d = &data->state.proxydigest;
  }
  else {
    d = &data->state.digest;
  }

  /* skip initial whitespaces */
  while(*header && ISSPACE(*header))
    header++;

  if(checkprefix("Digest", header)) {
    header += strlen("Digest");

    /* If we already have received a nonce, keep that in mind */
    if(d->nonce)
      before = TRUE;

    /* clear off any former leftovers and init to defaults */
    digest_cleanup_one(d);

    for(;;) {
      char value[MAX_VALUE_LENGTH];
      char content[MAX_CONTENT_LENGTH];

      while(*header && ISSPACE(*header))
        header++;

      /* extract a value=content pair */
      if(!get_pair(header, value, content, &header)) {
        if(Curl_raw_equal(value, "nonce")) {
          d->nonce = strdup(content);
          if(!d->nonce)
            return CURLDIGEST_NOMEM;
        }
        else if(Curl_raw_equal(value, "stale")) {
          if(Curl_raw_equal(content, "true")) {
            d->stale = TRUE;
            d->nc = 1; /* we make a new nonce now */
          }
        }
        else if(Curl_raw_equal(value, "realm")) {
          d->realm = strdup(content);
          if(!d->realm)
            return CURLDIGEST_NOMEM;
        }
        else if(Curl_raw_equal(value, "opaque")) {
          d->opaque = strdup(content);
          if(!d->opaque)
            return CURLDIGEST_NOMEM;
        }
        else if(Curl_raw_equal(value, "qop")) {
          char *tok_buf;
          /* tokenize the list and choose auth if possible, use a temporary
             clone of the buffer since strtok_r() ruins it */
          tmp = strdup(content);
          if(!tmp)
            return CURLDIGEST_NOMEM;
          token = strtok_r(tmp, ",", &tok_buf);
          while(token != NULL) {
            if(Curl_raw_equal(token, "auth")) {
              foundAuth = TRUE;
            }
            else if(Curl_raw_equal(token, "auth-int")) {
              foundAuthInt = TRUE;
            }
            token = strtok_r(NULL, ",", &tok_buf);
          }
          free(tmp);
          /*select only auth o auth-int. Otherwise, ignore*/
          if(foundAuth) {
            d->qop = strdup("auth");
            if(!d->qop)
              return CURLDIGEST_NOMEM;
          }
          else if(foundAuthInt) {
            d->qop = strdup("auth-int");
            if(!d->qop)
              return CURLDIGEST_NOMEM;
          }
        }
        else if(Curl_raw_equal(value, "algorithm")) {
          d->algorithm = strdup(content);
          if(!d->algorithm)
            return CURLDIGEST_NOMEM;
          if(Curl_raw_equal(content, "MD5-sess"))
            d->algo = CURLDIGESTALGO_MD5SESS;
          else if(Curl_raw_equal(content, "MD5"))
            d->algo = CURLDIGESTALGO_MD5;
          else
            return CURLDIGEST_BADALGO;
        }
        else {
          /* unknown specifier, ignore it! */
        }
      }
      else
        break; /* we're done here */

      /* pass all additional spaces here */
      while(*header && ISSPACE(*header))
        header++;
      if(',' == *header)
        /* allow the list to be comma-separated */
        header++;
    }
    /* We had a nonce since before, and we got another one now without
       'stale=true'. This means we provided bad credentials in the previous
       request */
    if(before && !d->stale)
      return CURLDIGEST_BAD;

    /* We got this header without a nonce, that's a bad Digest line! */
    if(!d->nonce)
      return CURLDIGEST_BAD;
  }
  else
    /* else not a digest, get out */
    return CURLDIGEST_NONE;

  return CURLDIGEST_FINE;
}

/* convert md5 chunk to RFC2617 (section 3.1.3) -suitable ascii string*/
static void md5_to_ascii(unsigned char *source, /* 16 bytes */
                         unsigned char *dest) /* 33 bytes */
{
  int i;
  for(i=0; i<16; i++)
    snprintf((char *)&dest[i*2], 3, "%02x", source[i]);
}

/* Perform quoted-string escaping as described in RFC2616 and its errata */
static char *string_quoted(const char *source)
{
  char *dest, *d;
  const char *s = source;
  size_t n = 1; /* null terminator */

  /* Calculate size needed */
  while(*s) {
    ++n;
    if(*s == '"' || *s == '\\') {
      ++n;
    }
    ++s;
  }

  dest = (char *)malloc(n);
  if(dest) {
    s = source;
    d = dest;
    while(*s) {
      if(*s == '"' || *s == '\\') {
        *d++ = '\\';
      }
      *d++ = *s++;
    }
    *d = 0;
  }

  return dest;
}

CURLcode Curl_output_digest(struct connectdata *conn,
                            bool proxy,
                            const unsigned char *request,
                            const unsigned char *uripath)
{
  /* We have a Digest setup for this, use it!  Now, to get all the details for
     this sorted out, I must urge you dear friend to read up on the RFC2617
     section 3.2.2, */
  unsigned char md5buf[16]; /* 16 bytes/128 bits */
  unsigned char request_digest[33];
  unsigned char *md5this;
  unsigned char *ha1;
  unsigned char ha2[33];/* 32 digits and 1 zero byte */
  char cnoncebuf[33];
  char *cnonce = NULL;
  size_t cnonce_sz = 0;
  char *tmp = NULL;
  char **allocuserpwd;
  size_t userlen;
  const char *userp;
  char *userp_quoted;
  const char *passwdp;
  struct auth *authp;

  struct SessionHandle *data = conn->data;
  struct digestdata *d;
  CURLcode rc;
/* The CURL_OUTPUT_DIGEST_CONV macro below is for non-ASCII machines.
   It converts digest text to ASCII so the MD5 will be correct for
   what ultimately goes over the network.
*/
#define CURL_OUTPUT_DIGEST_CONV(a, b) \
  rc = Curl_convert_to_network(a, (char *)b, strlen((const char*)b)); \
  if(rc != CURLE_OK) { \
    free(b); \
    return rc; \
  }

  if(proxy) {
    d = &data->state.proxydigest;
    allocuserpwd = &conn->allocptr.proxyuserpwd;
    userp = conn->proxyuser;
    passwdp = conn->proxypasswd;
    authp = &data->state.authproxy;
  }
  else {
    d = &data->state.digest;
    allocuserpwd = &conn->allocptr.userpwd;
    userp = conn->user;
    passwdp = conn->passwd;
    authp = &data->state.authhost;
  }

  if(*allocuserpwd) {
    Curl_safefree(*allocuserpwd);
    *allocuserpwd = NULL;
  }

  /* not set means empty */
  if(!userp)
    userp="";

  if(!passwdp)
    passwdp="";

  if(!d->nonce) {
    authp->done = FALSE;
    return CURLE_OK;
  }
  authp->done = TRUE;

  if(!d->nc)
    d->nc = 1;

  if(!d->cnonce) {
    struct timeval now = Curl_tvnow();
    snprintf(cnoncebuf, sizeof(cnoncebuf), "%08x%08x%08x%08x",
             Curl_rand(data), Curl_rand(data),
             (unsigned int)now.tv_sec,
             (unsigned int)now.tv_usec);

    rc = Curl_base64_encode(data, cnoncebuf, strlen(cnoncebuf),
                            &cnonce, &cnonce_sz);
    if(rc)
      return rc;
    d->cnonce = cnonce;
  }

  /*
    if the algorithm is "MD5" or unspecified (which then defaults to MD5):

    A1 = unq(username-value) ":" unq(realm-value) ":" passwd

    if the algorithm is "MD5-sess" then:

    A1 = H( unq(username-value) ":" unq(realm-value) ":" passwd )
         ":" unq(nonce-value) ":" unq(cnonce-value)
  */

  md5this = (unsigned char *)
    aprintf("%s:%s:%s", userp, d->realm, passwdp);
  if(!md5this)
    return CURLE_OUT_OF_MEMORY;

  CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */
  Curl_md5it(md5buf, md5this);
  free(md5this); /* free this again */

  ha1 = malloc(33); /* 32 digits and 1 zero byte */
  if(!ha1)
    return CURLE_OUT_OF_MEMORY;

  md5_to_ascii(md5buf, ha1);

  if(d->algo == CURLDIGESTALGO_MD5SESS) {
    /* nonce and cnonce are OUTSIDE the hash */
    tmp = aprintf("%s:%s:%s", ha1, d->nonce, d->cnonce);
    if(!tmp)
      return CURLE_OUT_OF_MEMORY;
    CURL_OUTPUT_DIGEST_CONV(data, tmp); /* convert on non-ASCII machines */
    Curl_md5it(md5buf, (unsigned char *)tmp);
    free(tmp); /* free this again */
    md5_to_ascii(md5buf, ha1);
  }

  /*
    If the "qop" directive's value is "auth" or is unspecified, then A2 is:

      A2       = Method ":" digest-uri-value

          If the "qop" value is "auth-int", then A2 is:

      A2       = Method ":" digest-uri-value ":" H(entity-body)

    (The "Method" value is the HTTP request method as specified in section
    5.1.1 of RFC 2616)
  */

  /* So IE browsers < v7 cut off the URI part at the query part when they
     evaluate the MD5 and some (IIS?) servers work with them so we may need to
     do the Digest IE-style. Note that the different ways cause different MD5
     sums to get sent.

     Apache servers can be set to do the Digest IE-style automatically using
     the BrowserMatch feature:
     http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html#msie

     Further details on Digest implementation differences:
     http://www.fngtps.com/2006/09/http-authentication
  */
  if(authp->iestyle && ((tmp = strchr((char *)uripath, '?')) != NULL)) {
    md5this = (unsigned char *)aprintf("%s:%.*s", request,
                                       curlx_sztosi(tmp - (char *)uripath),
                                       uripath);
  }
  else
    md5this = (unsigned char *)aprintf("%s:%s", request, uripath);

  if(d->qop && Curl_raw_equal(d->qop, "auth-int")) {
    /* We don't support auth-int for PUT or POST at the moment.
       TODO: replace md5 of empty string with entity-body for PUT/POST */
    unsigned char *md5this2 = (unsigned char *)
      aprintf("%s:%s", md5this, "d41d8cd98f00b204e9800998ecf8427e");
    free(md5this);
    md5this = md5this2;
  }

  if(!md5this) {
    free(ha1);
    return CURLE_OUT_OF_MEMORY;
  }

  CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */
  Curl_md5it(md5buf, md5this);
  free(md5this); /* free this again */
  md5_to_ascii(md5buf, ha2);

  if(d->qop) {
    md5this = (unsigned char *)aprintf("%s:%s:%08x:%s:%s:%s",
                                       ha1,
                                       d->nonce,
                                       d->nc,
                                       d->cnonce,
                                       d->qop,
                                       ha2);
  }
  else {
    md5this = (unsigned char *)aprintf("%s:%s:%s",
                                       ha1,
                                       d->nonce,
                                       ha2);
  }
  free(ha1);
  if(!md5this)
    return CURLE_OUT_OF_MEMORY;

  CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */
  Curl_md5it(md5buf, md5this);
  free(md5this); /* free this again */
  md5_to_ascii(md5buf, request_digest);

  /* for test case 64 (snooped from a Mozilla 1.3a request)

    Authorization: Digest username="testuser", realm="testrealm", \
    nonce="1053604145", uri="/64", response="c55f7f30d83d774a3d2dcacf725abaca"

    Digest parameters are all quoted strings.  Username which is provided by
    the user will need double quotes and backslashes within it escaped.  For
    the other fields, this shouldn't be an issue.  realm, nonce, and opaque
    are copied as is from the server, escapes and all.  cnonce is generated
    with web-safe characters.  uri is already percent encoded.  nc is 8 hex
    characters.  algorithm and qop with standard values only contain web-safe
    chracters.
  */
  userp_quoted = string_quoted(userp);
  if(!*userp_quoted)
    return CURLE_OUT_OF_MEMORY;

  if(d->qop) {
    *allocuserpwd =
      aprintf( "%sAuthorization: Digest "
               "username=\"%s\", "
               "realm=\"%s\", "
               "nonce=\"%s\", "
               "uri=\"%s\", "
               "cnonce=\"%s\", "
               "nc=%08x, "
               "qop=%s, "
               "response=\"%s\"",
               proxy?"Proxy-":"",
               userp_quoted,
               d->realm,
               d->nonce,
               uripath, /* this is the PATH part of the URL */
               d->cnonce,
               d->nc,
               d->qop,
               request_digest);

    if(Curl_raw_equal(d->qop, "auth"))
      d->nc++; /* The nc (from RFC) has to be a 8 hex digit number 0 padded
                  which tells to the server how many times you are using the
                  same nonce in the qop=auth mode. */
  }
  else {
    *allocuserpwd =
      aprintf( "%sAuthorization: Digest "
               "username=\"%s\", "
               "realm=\"%s\", "
               "nonce=\"%s\", "
               "uri=\"%s\", "
               "response=\"%s\"",
               proxy?"Proxy-":"",
               userp_quoted,
               d->realm,
               d->nonce,
               uripath, /* this is the PATH part of the URL */
               request_digest);
  }
  free(userp_quoted);
  if(!*allocuserpwd)
    return CURLE_OUT_OF_MEMORY;

  /* Add optional fields */
  if(d->opaque) {
    /* append opaque */
    tmp = aprintf("%s, opaque=\"%s\"", *allocuserpwd, d->opaque);
    if(!tmp)
      return CURLE_OUT_OF_MEMORY;
    free(*allocuserpwd);
    *allocuserpwd = tmp;
  }

  if(d->algorithm) {
    /* append algorithm */
    tmp = aprintf("%s, algorithm=\"%s\"", *allocuserpwd, d->algorithm);
    if(!tmp)
      return CURLE_OUT_OF_MEMORY;
    free(*allocuserpwd);
    *allocuserpwd = tmp;
  }

  /* append CRLF + zero (3 bytes) to the userpwd header */
  userlen = strlen(*allocuserpwd);
  tmp = realloc(*allocuserpwd, userlen + 3);
  if(!tmp)
    return CURLE_OUT_OF_MEMORY;
  strcpy(&tmp[userlen], "\r\n"); /* append the data */
  *allocuserpwd = tmp;

  return CURLE_OK;
}

static void digest_cleanup_one(struct digestdata *d)
{
  if(d->nonce)
    free(d->nonce);
  d->nonce = NULL;

  if(d->cnonce)
    free(d->cnonce);
  d->cnonce = NULL;

  if(d->realm)
    free(d->realm);
  d->realm = NULL;

  if(d->opaque)
    free(d->opaque);
  d->opaque = NULL;

  if(d->qop)
    free(d->qop);
  d->qop = NULL;

  if(d->algorithm)
    free(d->algorithm);
  d->algorithm = NULL;

  d->nc = 0;
  d->algo = CURLDIGESTALGO_MD5; /* default algorithm */
  d->stale = FALSE; /* default means normal, not stale */
}


void Curl_digest_cleanup(struct SessionHandle *data)
{
  digest_cleanup_one(&data->state.digest);
  digest_cleanup_one(&data->state.proxydigest);
}

#endif