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50c2f753 1/*
1da177e4
LT
2 * The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in
3 * turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich
50c2f753 4 *
1da177e4
LT
5 * Copyright (c) 2000 RP Internet (www.rpi.net.au).
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
1da177e4
LT
20#include <linux/module.h>
21#include <linux/types.h>
22#include <linux/kernel.h>
23#include <linux/mm.h>
24#include <linux/slab.h>
25#include "cifspdu.h"
26#include "cifsglob.h"
27#include "cifs_debug.h"
28#include "cifsproto.h"
29
30/*****************************************************************************
31 *
32 * Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse)
33 *
34 *****************************************************************************/
35
36/* Class */
37#define ASN1_UNI 0 /* Universal */
38#define ASN1_APL 1 /* Application */
39#define ASN1_CTX 2 /* Context */
40#define ASN1_PRV 3 /* Private */
41
42/* Tag */
43#define ASN1_EOC 0 /* End Of Contents or N/A */
44#define ASN1_BOL 1 /* Boolean */
45#define ASN1_INT 2 /* Integer */
46#define ASN1_BTS 3 /* Bit String */
47#define ASN1_OTS 4 /* Octet String */
48#define ASN1_NUL 5 /* Null */
49#define ASN1_OJI 6 /* Object Identifier */
50#define ASN1_OJD 7 /* Object Description */
51#define ASN1_EXT 8 /* External */
f46c7234 52#define ASN1_ENUM 10 /* Enumerated */
1da177e4
LT
53#define ASN1_SEQ 16 /* Sequence */
54#define ASN1_SET 17 /* Set */
55#define ASN1_NUMSTR 18 /* Numerical String */
56#define ASN1_PRNSTR 19 /* Printable String */
57#define ASN1_TEXSTR 20 /* Teletext String */
58#define ASN1_VIDSTR 21 /* Video String */
59#define ASN1_IA5STR 22 /* IA5 String */
60#define ASN1_UNITIM 23 /* Universal Time */
61#define ASN1_GENTIM 24 /* General Time */
62#define ASN1_GRASTR 25 /* Graphical String */
63#define ASN1_VISSTR 26 /* Visible String */
64#define ASN1_GENSTR 27 /* General String */
65
66/* Primitive / Constructed methods*/
67#define ASN1_PRI 0 /* Primitive */
68#define ASN1_CON 1 /* Constructed */
69
70/*
71 * Error codes.
72 */
73#define ASN1_ERR_NOERROR 0
74#define ASN1_ERR_DEC_EMPTY 2
75#define ASN1_ERR_DEC_EOC_MISMATCH 3
76#define ASN1_ERR_DEC_LENGTH_MISMATCH 4
77#define ASN1_ERR_DEC_BADVALUE 5
78
79#define SPNEGO_OID_LEN 7
80#define NTLMSSP_OID_LEN 10
e545937a 81#define KRB5_OID_LEN 7
f46c7234 82#define KRB5U2U_OID_LEN 8
e545937a 83#define MSKRB5_OID_LEN 7
1da177e4
LT
84static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
85static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
e545937a 86static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
f46c7234 87static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
e545937a 88static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
1da177e4 89
50c2f753 90/*
1da177e4
LT
91 * ASN.1 context.
92 */
93struct asn1_ctx {
94 int error; /* Error condition */
95 unsigned char *pointer; /* Octet just to be decoded */
96 unsigned char *begin; /* First octet */
97 unsigned char *end; /* Octet after last octet */
98};
99
100/*
101 * Octet string (not null terminated)
102 */
103struct asn1_octstr {
104 unsigned char *data;
105 unsigned int len;
106};
107
108static void
109asn1_open(struct asn1_ctx *ctx, unsigned char *buf, unsigned int len)
110{
111 ctx->begin = buf;
112 ctx->end = buf + len;
113 ctx->pointer = buf;
114 ctx->error = ASN1_ERR_NOERROR;
115}
116
117static unsigned char
118asn1_octet_decode(struct asn1_ctx *ctx, unsigned char *ch)
119{
120 if (ctx->pointer >= ctx->end) {
121 ctx->error = ASN1_ERR_DEC_EMPTY;
122 return 0;
123 }
124 *ch = *(ctx->pointer)++;
125 return 1;
126}
127
f46c7234
SF
128#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
129static unsigned char
130asn1_enum_decode(struct asn1_ctx *ctx, __le32 *val)
131{
132 unsigned char ch;
133
134 if (ctx->pointer >= ctx->end) {
135 ctx->error = ASN1_ERR_DEC_EMPTY;
136 return 0;
137 }
138
1537a363 139 ch = *(ctx->pointer)++; /* ch has 0xa, ptr points to length octet */
f46c7234
SF
140 if ((ch) == ASN1_ENUM) /* if ch value is ENUM, 0xa */
141 *val = *(++(ctx->pointer)); /* value has enum value */
142 else
143 return 0;
144
145 ctx->pointer++;
146 return 1;
147}
148#endif
149
1da177e4
LT
150static unsigned char
151asn1_tag_decode(struct asn1_ctx *ctx, unsigned int *tag)
152{
153 unsigned char ch;
154
155 *tag = 0;
156
157 do {
158 if (!asn1_octet_decode(ctx, &ch))
159 return 0;
160 *tag <<= 7;
161 *tag |= ch & 0x7F;
162 } while ((ch & 0x80) == 0x80);
163 return 1;
164}
165
166static unsigned char
167asn1_id_decode(struct asn1_ctx *ctx,
168 unsigned int *cls, unsigned int *con, unsigned int *tag)
169{
170 unsigned char ch;
171
172 if (!asn1_octet_decode(ctx, &ch))
173 return 0;
174
175 *cls = (ch & 0xC0) >> 6;
176 *con = (ch & 0x20) >> 5;
177 *tag = (ch & 0x1F);
178
179 if (*tag == 0x1F) {
180 if (!asn1_tag_decode(ctx, tag))
181 return 0;
182 }
183 return 1;
184}
185
186static unsigned char
187asn1_length_decode(struct asn1_ctx *ctx, unsigned int *def, unsigned int *len)
188{
189 unsigned char ch, cnt;
190
191 if (!asn1_octet_decode(ctx, &ch))
192 return 0;
193
194 if (ch == 0x80)
195 *def = 0;
196 else {
197 *def = 1;
198
199 if (ch < 0x80)
200 *len = ch;
201 else {
202 cnt = (unsigned char) (ch & 0x7F);
203 *len = 0;
204
205 while (cnt > 0) {
206 if (!asn1_octet_decode(ctx, &ch))
207 return 0;
208 *len <<= 8;
209 *len |= ch;
210 cnt--;
211 }
212 }
213 }
ddb2c435
CW
214
215 /* don't trust len bigger than ctx buffer */
216 if (*len > ctx->end - ctx->pointer)
217 return 0;
218
1da177e4
LT
219 return 1;
220}
221
222static unsigned char
223asn1_header_decode(struct asn1_ctx *ctx,
224 unsigned char **eoc,
225 unsigned int *cls, unsigned int *con, unsigned int *tag)
226{
50c2f753 227 unsigned int def = 0;
ab2f218f 228 unsigned int len = 0;
1da177e4
LT
229
230 if (!asn1_id_decode(ctx, cls, con, tag))
231 return 0;
232
233 if (!asn1_length_decode(ctx, &def, &len))
234 return 0;
235
ddb2c435
CW
236 /* primitive shall be definite, indefinite shall be constructed */
237 if (*con == ASN1_PRI && !def)
238 return 0;
239
1da177e4
LT
240 if (def)
241 *eoc = ctx->pointer + len;
242 else
243 *eoc = NULL;
244 return 1;
245}
246
247static unsigned char
248asn1_eoc_decode(struct asn1_ctx *ctx, unsigned char *eoc)
249{
250 unsigned char ch;
251
252 if (eoc == NULL) {
253 if (!asn1_octet_decode(ctx, &ch))
254 return 0;
255
256 if (ch != 0x00) {
257 ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
258 return 0;
259 }
260
261 if (!asn1_octet_decode(ctx, &ch))
262 return 0;
263
264 if (ch != 0x00) {
265 ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
266 return 0;
267 }
268 return 1;
269 } else {
270 if (ctx->pointer != eoc) {
271 ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH;
272 return 0;
273 }
274 return 1;
275 }
276}
277
278/* static unsigned char asn1_null_decode(struct asn1_ctx *ctx,
279 unsigned char *eoc)
280{
281 ctx->pointer = eoc;
282 return 1;
283}
284
285static unsigned char asn1_long_decode(struct asn1_ctx *ctx,
286 unsigned char *eoc, long *integer)
287{
288 unsigned char ch;
289 unsigned int len;
290
291 if (!asn1_octet_decode(ctx, &ch))
292 return 0;
293
294 *integer = (signed char) ch;
295 len = 1;
296
297 while (ctx->pointer < eoc) {
298 if (++len > sizeof(long)) {
299 ctx->error = ASN1_ERR_DEC_BADVALUE;
300 return 0;
301 }
302
303 if (!asn1_octet_decode(ctx, &ch))
304 return 0;
305
306 *integer <<= 8;
307 *integer |= ch;
308 }
309 return 1;
310}
311
312static unsigned char asn1_uint_decode(struct asn1_ctx *ctx,
313 unsigned char *eoc,
314 unsigned int *integer)
315{
316 unsigned char ch;
317 unsigned int len;
318
319 if (!asn1_octet_decode(ctx, &ch))
320 return 0;
321
322 *integer = ch;
323 if (ch == 0)
324 len = 0;
325 else
326 len = 1;
327
328 while (ctx->pointer < eoc) {
329 if (++len > sizeof(unsigned int)) {
330 ctx->error = ASN1_ERR_DEC_BADVALUE;
331 return 0;
332 }
333
334 if (!asn1_octet_decode(ctx, &ch))
335 return 0;
336
337 *integer <<= 8;
338 *integer |= ch;
339 }
340 return 1;
341}
342
343static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx,
344 unsigned char *eoc,
345 unsigned long *integer)
346{
347 unsigned char ch;
348 unsigned int len;
349
350 if (!asn1_octet_decode(ctx, &ch))
351 return 0;
352
353 *integer = ch;
354 if (ch == 0)
355 len = 0;
356 else
357 len = 1;
358
359 while (ctx->pointer < eoc) {
360 if (++len > sizeof(unsigned long)) {
361 ctx->error = ASN1_ERR_DEC_BADVALUE;
362 return 0;
363 }
364
365 if (!asn1_octet_decode(ctx, &ch))
366 return 0;
367
368 *integer <<= 8;
369 *integer |= ch;
370 }
371 return 1;
50c2f753 372}
1da177e4
LT
373
374static unsigned char
375asn1_octets_decode(struct asn1_ctx *ctx,
376 unsigned char *eoc,
377 unsigned char **octets, unsigned int *len)
378{
379 unsigned char *ptr;
380
381 *len = 0;
382
383 *octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC);
384 if (*octets == NULL) {
385 return 0;
386 }
387
388 ptr = *octets;
389 while (ctx->pointer < eoc) {
390 if (!asn1_octet_decode(ctx, (unsigned char *) ptr++)) {
391 kfree(*octets);
392 *octets = NULL;
393 return 0;
394 }
395 (*len)++;
396 }
397 return 1;
398} */
399
400static unsigned char
401asn1_subid_decode(struct asn1_ctx *ctx, unsigned long *subid)
402{
403 unsigned char ch;
404
405 *subid = 0;
406
407 do {
408 if (!asn1_octet_decode(ctx, &ch))
409 return 0;
410
411 *subid <<= 7;
412 *subid |= ch & 0x7F;
413 } while ((ch & 0x80) == 0x80);
414 return 1;
415}
416
50c2f753 417static int
1da177e4
LT
418asn1_oid_decode(struct asn1_ctx *ctx,
419 unsigned char *eoc, unsigned long **oid, unsigned int *len)
420{
421 unsigned long subid;
422 unsigned int size;
423 unsigned long *optr;
424
425 size = eoc - ctx->pointer + 1;
ddb2c435
CW
426
427 /* first subid actually encodes first two subids */
04e1e0cc 428 if (size < 2 || size > UINT_MAX/sizeof(unsigned long))
ddb2c435
CW
429 return 0;
430
26f57364
SF
431 *oid = kmalloc(size * sizeof(unsigned long), GFP_ATOMIC);
432 if (*oid == NULL)
1da177e4 433 return 0;
1da177e4
LT
434
435 optr = *oid;
436
437 if (!asn1_subid_decode(ctx, &subid)) {
438 kfree(*oid);
439 *oid = NULL;
440 return 0;
441 }
442
443 if (subid < 40) {
444 optr[0] = 0;
445 optr[1] = subid;
446 } else if (subid < 80) {
447 optr[0] = 1;
448 optr[1] = subid - 40;
449 } else {
450 optr[0] = 2;
451 optr[1] = subid - 80;
452 }
453
454 *len = 2;
455 optr += 2;
456
457 while (ctx->pointer < eoc) {
458 if (++(*len) > size) {
459 ctx->error = ASN1_ERR_DEC_BADVALUE;
460 kfree(*oid);
461 *oid = NULL;
462 return 0;
463 }
464
465 if (!asn1_subid_decode(ctx, optr++)) {
466 kfree(*oid);
467 *oid = NULL;
468 return 0;
469 }
470 }
471 return 1;
472}
473
474static int
475compare_oid(unsigned long *oid1, unsigned int oid1len,
476 unsigned long *oid2, unsigned int oid2len)
477{
478 unsigned int i;
479
480 if (oid1len != oid2len)
481 return 0;
482 else {
483 for (i = 0; i < oid1len; i++) {
484 if (oid1[i] != oid2[i])
485 return 0;
486 }
487 return 1;
488 }
489}
490
491 /* BB check for endian conversion issues here */
492
493int
494decode_negTokenInit(unsigned char *security_blob, int length,
26efa0ba 495 struct TCP_Server_Info *server)
1da177e4
LT
496{
497 struct asn1_ctx ctx;
498 unsigned char *end;
499 unsigned char *sequence_end;
500 unsigned long *oid = NULL;
501 unsigned int cls, con, tag, oidlen, rc;
1da177e4 502
1da177e4
LT
503 /* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
504
505 asn1_open(&ctx, security_blob, length);
506
2f0e58ac 507 /* GSSAPI header */
1da177e4 508 if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be 509 cifs_dbg(FYI, "Error decoding negTokenInit header\n");
1da177e4
LT
510 return 0;
511 } else if ((cls != ASN1_APL) || (con != ASN1_CON)
512 || (tag != ASN1_EOC)) {
f96637be 513 cifs_dbg(FYI, "cls = %d con = %d tag = %d\n", cls, con, tag);
1da177e4 514 return 0;
2f0e58ac 515 }
1da177e4 516
2f0e58ac
JL
517 /* Check for SPNEGO OID -- remember to free obj->oid */
518 rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
519 if (rc) {
520 if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
521 (cls == ASN1_UNI)) {
522 rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
523 if (rc) {
524 rc = compare_oid(oid, oidlen, SPNEGO_OID,
525 SPNEGO_OID_LEN);
526 kfree(oid);
527 }
528 } else
529 rc = 0;
530 }
1da177e4 531
2f0e58ac
JL
532 /* SPNEGO OID not present or garbled -- bail out */
533 if (!rc) {
f96637be 534 cifs_dbg(FYI, "Error decoding negTokenInit header\n");
2f0e58ac
JL
535 return 0;
536 }
1da177e4 537
f46c7234 538 /* SPNEGO */
2f0e58ac 539 if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be 540 cifs_dbg(FYI, "Error decoding negTokenInit\n");
2f0e58ac
JL
541 return 0;
542 } else if ((cls != ASN1_CTX) || (con != ASN1_CON)
543 || (tag != ASN1_EOC)) {
f96637be
JP
544 cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 0\n",
545 cls, con, tag, end, *end);
2f0e58ac
JL
546 return 0;
547 }
1da177e4 548
f46c7234 549 /* negTokenInit */
2f0e58ac 550 if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be 551 cifs_dbg(FYI, "Error decoding negTokenInit\n");
2f0e58ac
JL
552 return 0;
553 } else if ((cls != ASN1_UNI) || (con != ASN1_CON)
554 || (tag != ASN1_SEQ)) {
f96637be
JP
555 cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 1\n",
556 cls, con, tag, end, *end);
2f0e58ac
JL
557 return 0;
558 }
1da177e4 559
f46c7234 560 /* sequence */
2f0e58ac 561 if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be 562 cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
2f0e58ac
JL
563 return 0;
564 } else if ((cls != ASN1_CTX) || (con != ASN1_CON)
565 || (tag != ASN1_EOC)) {
f96637be
JP
566 cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 0\n",
567 cls, con, tag, end, *end);
2f0e58ac
JL
568 return 0;
569 }
1da177e4 570
f46c7234 571 /* sequence of */
2f0e58ac
JL
572 if (asn1_header_decode
573 (&ctx, &sequence_end, &cls, &con, &tag) == 0) {
f96637be 574 cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
2f0e58ac
JL
575 return 0;
576 } else if ((cls != ASN1_UNI) || (con != ASN1_CON)
577 || (tag != ASN1_SEQ)) {
f96637be
JP
578 cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 1\n",
579 cls, con, tag, end, *end);
2f0e58ac
JL
580 return 0;
581 }
1da177e4 582
f46c7234 583 /* list of security mechanisms */
2f0e58ac
JL
584 while (!asn1_eoc_decode(&ctx, sequence_end)) {
585 rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
586 if (!rc) {
f96637be 587 cifs_dbg(FYI, "Error decoding negTokenInit hdr exit2\n");
1da177e4
LT
588 return 0;
589 }
2f0e58ac
JL
590 if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
591 if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {
592
f96637be
JP
593 cifs_dbg(FYI, "OID len = %d oid = 0x%lx 0x%lx 0x%lx 0x%lx\n",
594 oidlen, *oid, *(oid + 1), *(oid + 2),
595 *(oid + 3));
2f0e58ac
JL
596
597 if (compare_oid(oid, oidlen, MSKRB5_OID,
26efa0ba
JL
598 MSKRB5_OID_LEN))
599 server->sec_mskerberos = true;
c8e56f1f 600 else if (compare_oid(oid, oidlen, KRB5U2U_OID,
26efa0ba
JL
601 KRB5U2U_OID_LEN))
602 server->sec_kerberosu2u = true;
c8e56f1f 603 else if (compare_oid(oid, oidlen, KRB5_OID,
26efa0ba
JL
604 KRB5_OID_LEN))
605 server->sec_kerberos = true;
c8e56f1f 606 else if (compare_oid(oid, oidlen, NTLMSSP_OID,
2f0e58ac 607 NTLMSSP_OID_LEN))
26efa0ba 608 server->sec_ntlmssp = true;
2f0e58ac
JL
609
610 kfree(oid);
611 }
612 } else {
f96637be 613 cifs_dbg(FYI, "Should be an oid what is going on?\n");
1da177e4 614 }
2f0e58ac 615 }
1da177e4 616
f853c616
JL
617 /*
618 * We currently ignore anything at the end of the SPNEGO blob after
619 * the mechTypes have been parsed, since none of that info is
620 * used at the moment.
621 */
1da177e4
LT
622 return 1;
623}