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31#include <linux/types.h>
32#include <linux/jiffies.h>
33#include <linux/sunrpc/gss_krb5.h>
34#include <linux/random.h>
35#include <linux/pagemap.h>
36#include <linux/crypto.h>
37
38#ifdef RPC_DEBUG
39# define RPCDBG_FACILITY RPCDBG_AUTH
40#endif
41
42static inline int
43gss_krb5_padding(int blocksize, int length)
44{
45 return blocksize - (length % blocksize);
46}
47
48static inline void
49gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
50{
51 int padding = gss_krb5_padding(blocksize, buf->len - offset);
52 char *p;
53 struct kvec *iov;
54
55 if (buf->page_len || buf->tail[0].iov_len)
56 iov = &buf->tail[0];
57 else
58 iov = &buf->head[0];
59 p = iov->iov_base + iov->iov_len;
60 iov->iov_len += padding;
61 buf->len += padding;
62 memset(p, padding, padding);
63}
64
65static inline int
66gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
67{
68 u8 *ptr;
69 u8 pad;
70 size_t len = buf->len;
71
72 if (len <= buf->head[0].iov_len) {
73 pad = *(u8 *)(buf->head[0].iov_base + len - 1);
74 if (pad > buf->head[0].iov_len)
75 return -EINVAL;
76 buf->head[0].iov_len -= pad;
77 goto out;
78 } else
79 len -= buf->head[0].iov_len;
80 if (len <= buf->page_len) {
81 unsigned int last = (buf->page_base + len - 1)
82 >>PAGE_CACHE_SHIFT;
83 unsigned int offset = (buf->page_base + len - 1)
84 & (PAGE_CACHE_SIZE - 1);
85 ptr = kmap_atomic(buf->pages[last]);
86 pad = *(ptr + offset);
87 kunmap_atomic(ptr);
88 goto out;
89 } else
90 len -= buf->page_len;
91 BUG_ON(len > buf->tail[0].iov_len);
92 pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
93out:
94
95
96
97
98
99
100
101
102
103
104
105
106
107 if (pad > blocksize)
108 return -EINVAL;
109 if (buf->len > pad)
110 buf->len -= pad;
111 else
112 return -EINVAL;
113 return 0;
114}
115
116void
117gss_krb5_make_confounder(char *p, u32 conflen)
118{
119 static u64 i = 0;
120 u64 *q = (u64 *)p;
121
122
123
124
125
126
127
128
129
130
131
132 if (i == 0) {
133 i = prandom_u32();
134 i = (i << 32) | prandom_u32();
135 }
136
137 switch (conflen) {
138 case 16:
139 *q++ = i++;
140
141 case 8:
142 *q++ = i++;
143 break;
144 default:
145 BUG();
146 }
147}
148
149
150
151
152
153
154
155
156
157static u32
158gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
159 struct xdr_buf *buf, struct page **pages)
160{
161 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
162 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
163 .data = cksumdata};
164 int blocksize = 0, plainlen;
165 unsigned char *ptr, *msg_start;
166 s32 now;
167 int headlen;
168 struct page **tmp_pages;
169 u32 seq_send;
170 u8 *cksumkey;
171 u32 conflen = kctx->gk5e->conflen;
172
173 dprintk("RPC: %s\n", __func__);
174
175 now = get_seconds();
176
177 blocksize = crypto_blkcipher_blocksize(kctx->enc);
178 gss_krb5_add_padding(buf, offset, blocksize);
179 BUG_ON((buf->len - offset) % blocksize);
180 plainlen = conflen + buf->len - offset;
181
182 headlen = g_token_size(&kctx->mech_used,
183 GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength + plainlen) -
184 (buf->len - offset);
185
186 ptr = buf->head[0].iov_base + offset;
187
188 xdr_extend_head(buf, offset, headlen);
189
190
191 BUG_ON((buf->len - offset - headlen) % blocksize);
192
193 g_make_token_header(&kctx->mech_used,
194 GSS_KRB5_TOK_HDR_LEN +
195 kctx->gk5e->cksumlength + plainlen, &ptr);
196
197
198
199 ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
200 ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
201
202 msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength;
203
204 *(__be16 *)(ptr + 2) = cpu_to_le16(kctx->gk5e->signalg);
205 memset(ptr + 4, 0xff, 4);
206 *(__be16 *)(ptr + 4) = cpu_to_le16(kctx->gk5e->sealalg);
207
208 gss_krb5_make_confounder(msg_start, conflen);
209
210 if (kctx->gk5e->keyed_cksum)
211 cksumkey = kctx->cksum;
212 else
213 cksumkey = NULL;
214
215
216 tmp_pages = buf->pages;
217 buf->pages = pages;
218 if (make_checksum(kctx, ptr, 8, buf, offset + headlen - conflen,
219 cksumkey, KG_USAGE_SEAL, &md5cksum))
220 return GSS_S_FAILURE;
221 buf->pages = tmp_pages;
222
223 memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
224
225 spin_lock(&krb5_seq_lock);
226 seq_send = kctx->seq_send++;
227 spin_unlock(&krb5_seq_lock);
228
229
230
231 if ((krb5_make_seq_num(kctx, kctx->seq, kctx->initiate ? 0 : 0xff,
232 seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
233 return GSS_S_FAILURE;
234
235 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
236 struct crypto_blkcipher *cipher;
237 int err;
238 cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
239 CRYPTO_ALG_ASYNC);
240 if (IS_ERR(cipher))
241 return GSS_S_FAILURE;
242
243 krb5_rc4_setup_enc_key(kctx, cipher, seq_send);
244
245 err = gss_encrypt_xdr_buf(cipher, buf,
246 offset + headlen - conflen, pages);
247 crypto_free_blkcipher(cipher);
248 if (err)
249 return GSS_S_FAILURE;
250 } else {
251 if (gss_encrypt_xdr_buf(kctx->enc, buf,
252 offset + headlen - conflen, pages))
253 return GSS_S_FAILURE;
254 }
255
256 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
257}
258
259static u32
260gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
261{
262 int signalg;
263 int sealalg;
264 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
265 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
266 .data = cksumdata};
267 s32 now;
268 int direction;
269 s32 seqnum;
270 unsigned char *ptr;
271 int bodysize;
272 void *data_start, *orig_start;
273 int data_len;
274 int blocksize;
275 u32 conflen = kctx->gk5e->conflen;
276 int crypt_offset;
277 u8 *cksumkey;
278
279 dprintk("RPC: gss_unwrap_kerberos\n");
280
281 ptr = (u8 *)buf->head[0].iov_base + offset;
282 if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
283 buf->len - offset))
284 return GSS_S_DEFECTIVE_TOKEN;
285
286 if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
287 (ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
288 return GSS_S_DEFECTIVE_TOKEN;
289
290
291
292
293
294 signalg = ptr[2] + (ptr[3] << 8);
295 if (signalg != kctx->gk5e->signalg)
296 return GSS_S_DEFECTIVE_TOKEN;
297
298 sealalg = ptr[4] + (ptr[5] << 8);
299 if (sealalg != kctx->gk5e->sealalg)
300 return GSS_S_DEFECTIVE_TOKEN;
301
302 if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
303 return GSS_S_DEFECTIVE_TOKEN;
304
305
306
307
308
309 crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
310 (unsigned char *)buf->head[0].iov_base;
311
312
313
314
315 if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
316 ptr + 8, &direction, &seqnum))
317 return GSS_S_BAD_SIG;
318
319 if ((kctx->initiate && direction != 0xff) ||
320 (!kctx->initiate && direction != 0))
321 return GSS_S_BAD_SIG;
322
323 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
324 struct crypto_blkcipher *cipher;
325 int err;
326
327 cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
328 CRYPTO_ALG_ASYNC);
329 if (IS_ERR(cipher))
330 return GSS_S_FAILURE;
331
332 krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
333
334 err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
335 crypto_free_blkcipher(cipher);
336 if (err)
337 return GSS_S_DEFECTIVE_TOKEN;
338 } else {
339 if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
340 return GSS_S_DEFECTIVE_TOKEN;
341 }
342
343 if (kctx->gk5e->keyed_cksum)
344 cksumkey = kctx->cksum;
345 else
346 cksumkey = NULL;
347
348 if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
349 cksumkey, KG_USAGE_SEAL, &md5cksum))
350 return GSS_S_FAILURE;
351
352 if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
353 kctx->gk5e->cksumlength))
354 return GSS_S_BAD_SIG;
355
356
357
358 now = get_seconds();
359
360 if (now > kctx->endtime)
361 return GSS_S_CONTEXT_EXPIRED;
362
363
364
365
366
367
368 blocksize = crypto_blkcipher_blocksize(kctx->enc);
369 data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
370 conflen;
371 orig_start = buf->head[0].iov_base + offset;
372 data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
373 memmove(orig_start, data_start, data_len);
374 buf->head[0].iov_len -= (data_start - orig_start);
375 buf->len -= (data_start - orig_start);
376
377 if (gss_krb5_remove_padding(buf, blocksize))
378 return GSS_S_DEFECTIVE_TOKEN;
379
380 return GSS_S_COMPLETE;
381}
382
383
384
385
386
387
388
389
390
391
392
393#define LOCAL_BUF_LEN 32u
394
395static void rotate_buf_a_little(struct xdr_buf *buf, unsigned int shift)
396{
397 char head[LOCAL_BUF_LEN];
398 char tmp[LOCAL_BUF_LEN];
399 unsigned int this_len, i;
400
401 BUG_ON(shift > LOCAL_BUF_LEN);
402
403 read_bytes_from_xdr_buf(buf, 0, head, shift);
404 for (i = 0; i + shift < buf->len; i += LOCAL_BUF_LEN) {
405 this_len = min(LOCAL_BUF_LEN, buf->len - (i + shift));
406 read_bytes_from_xdr_buf(buf, i+shift, tmp, this_len);
407 write_bytes_to_xdr_buf(buf, i, tmp, this_len);
408 }
409 write_bytes_to_xdr_buf(buf, buf->len - shift, head, shift);
410}
411
412static void _rotate_left(struct xdr_buf *buf, unsigned int shift)
413{
414 int shifted = 0;
415 int this_shift;
416
417 shift %= buf->len;
418 while (shifted < shift) {
419 this_shift = min(shift - shifted, LOCAL_BUF_LEN);
420 rotate_buf_a_little(buf, this_shift);
421 shifted += this_shift;
422 }
423}
424
425static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift)
426{
427 struct xdr_buf subbuf;
428
429 xdr_buf_subsegment(buf, &subbuf, base, buf->len - base);
430 _rotate_left(&subbuf, shift);
431}
432
433static u32
434gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
435 struct xdr_buf *buf, struct page **pages)
436{
437 int blocksize;
438 u8 *ptr, *plainhdr;
439 s32 now;
440 u8 flags = 0x00;
441 __be16 *be16ptr, ec = 0;
442 __be64 *be64ptr;
443 u32 err;
444
445 dprintk("RPC: %s\n", __func__);
446
447 if (kctx->gk5e->encrypt_v2 == NULL)
448 return GSS_S_FAILURE;
449
450
451 if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
452 return GSS_S_FAILURE;
453
454
455 ptr = plainhdr = buf->head[0].iov_base + offset;
456 *ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
457 *ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
458
459 if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
460 flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
461 if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
462 flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
463
464 flags |= KG2_TOKEN_FLAG_SEALED;
465
466 *ptr++ = flags;
467 *ptr++ = 0xff;
468 be16ptr = (__be16 *)ptr;
469
470 blocksize = crypto_blkcipher_blocksize(kctx->acceptor_enc);
471 *be16ptr++ = cpu_to_be16(ec);
472
473 *be16ptr++ = cpu_to_be16(0);
474
475 be64ptr = (__be64 *)be16ptr;
476 spin_lock(&krb5_seq_lock);
477 *be64ptr = cpu_to_be64(kctx->seq_send64++);
478 spin_unlock(&krb5_seq_lock);
479
480 err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, ec, pages);
481 if (err)
482 return err;
483
484 now = get_seconds();
485 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
486}
487
488static u32
489gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
490{
491 s32 now;
492 u64 seqnum;
493 u8 *ptr;
494 u8 flags = 0x00;
495 u16 ec, rrc;
496 int err;
497 u32 headskip, tailskip;
498 u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
499 unsigned int movelen;
500
501
502 dprintk("RPC: %s\n", __func__);
503
504 if (kctx->gk5e->decrypt_v2 == NULL)
505 return GSS_S_FAILURE;
506
507 ptr = buf->head[0].iov_base + offset;
508
509 if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
510 return GSS_S_DEFECTIVE_TOKEN;
511
512 flags = ptr[2];
513 if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
514 (kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
515 return GSS_S_BAD_SIG;
516
517 if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
518 dprintk("%s: token missing expected sealed flag\n", __func__);
519 return GSS_S_DEFECTIVE_TOKEN;
520 }
521
522 if (ptr[3] != 0xff)
523 return GSS_S_DEFECTIVE_TOKEN;
524
525 ec = be16_to_cpup((__be16 *)(ptr + 4));
526 rrc = be16_to_cpup((__be16 *)(ptr + 6));
527
528 seqnum = be64_to_cpup((__be64 *)(ptr + 8));
529
530 if (rrc != 0)
531 rotate_left(offset + 16, buf, rrc);
532
533 err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
534 &headskip, &tailskip);
535 if (err)
536 return GSS_S_FAILURE;
537
538
539
540
541
542 err = read_bytes_from_xdr_buf(buf,
543 buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
544 decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
545 if (err) {
546 dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
547 return GSS_S_FAILURE;
548 }
549 if (memcmp(ptr, decrypted_hdr, 6)
550 || memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
551 dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
552 return GSS_S_FAILURE;
553 }
554
555
556
557
558 now = get_seconds();
559 if (now > kctx->endtime)
560 return GSS_S_CONTEXT_EXPIRED;
561
562
563
564
565
566
567
568
569 movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len);
570 movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
571 BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
572 buf->head[0].iov_len);
573 memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
574 buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
575 buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
576
577
578 xdr_buf_trim(buf, GSS_KRB5_TOK_HDR_LEN + tailskip);
579 return GSS_S_COMPLETE;
580}
581
582u32
583gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
584 struct xdr_buf *buf, struct page **pages)
585{
586 struct krb5_ctx *kctx = gctx->internal_ctx_id;
587
588 switch (kctx->enctype) {
589 default:
590 BUG();
591 case ENCTYPE_DES_CBC_RAW:
592 case ENCTYPE_DES3_CBC_RAW:
593 case ENCTYPE_ARCFOUR_HMAC:
594 return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
595 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
596 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
597 return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
598 }
599}
600
601u32
602gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
603{
604 struct krb5_ctx *kctx = gctx->internal_ctx_id;
605
606 switch (kctx->enctype) {
607 default:
608 BUG();
609 case ENCTYPE_DES_CBC_RAW:
610 case ENCTYPE_DES3_CBC_RAW:
611 case ENCTYPE_ARCFOUR_HMAC:
612 return gss_unwrap_kerberos_v1(kctx, offset, buf);
613 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
614 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
615 return gss_unwrap_kerberos_v2(kctx, offset, buf);
616 }
617}
618
619