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31#include <crypto/skcipher.h>
32#include <linux/types.h>
33#include <linux/jiffies.h>
34#include <linux/sunrpc/gss_krb5.h>
35#include <linux/random.h>
36#include <linux/pagemap.h>
37
38#if IS_ENABLED(CONFIG_SUNRPC_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_SHIFT;
83 unsigned int offset = (buf->page_base + len - 1)
84 & (PAGE_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_sync_skcipher_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
205
206
207
208
209 *(__le16 *)(ptr + 2) = cpu_to_le16(kctx->gk5e->signalg);
210 *(__le16 *)(ptr + 4) = cpu_to_le16(kctx->gk5e->sealalg);
211 ptr[6] = 0xff;
212 ptr[7] = 0xff;
213
214 gss_krb5_make_confounder(msg_start, conflen);
215
216 if (kctx->gk5e->keyed_cksum)
217 cksumkey = kctx->cksum;
218 else
219 cksumkey = NULL;
220
221
222 tmp_pages = buf->pages;
223 buf->pages = pages;
224 if (make_checksum(kctx, ptr, 8, buf, offset + headlen - conflen,
225 cksumkey, KG_USAGE_SEAL, &md5cksum))
226 return GSS_S_FAILURE;
227 buf->pages = tmp_pages;
228
229 memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
230
231 seq_send = atomic_fetch_inc(&kctx->seq_send);
232
233
234
235 if ((krb5_make_seq_num(kctx, kctx->seq, kctx->initiate ? 0 : 0xff,
236 seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
237 return GSS_S_FAILURE;
238
239 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
240 struct crypto_sync_skcipher *cipher;
241 int err;
242 cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
243 0, 0);
244 if (IS_ERR(cipher))
245 return GSS_S_FAILURE;
246
247 krb5_rc4_setup_enc_key(kctx, cipher, seq_send);
248
249 err = gss_encrypt_xdr_buf(cipher, buf,
250 offset + headlen - conflen, pages);
251 crypto_free_sync_skcipher(cipher);
252 if (err)
253 return GSS_S_FAILURE;
254 } else {
255 if (gss_encrypt_xdr_buf(kctx->enc, buf,
256 offset + headlen - conflen, pages))
257 return GSS_S_FAILURE;
258 }
259
260 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
261}
262
263static u32
264gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
265{
266 int signalg;
267 int sealalg;
268 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
269 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
270 .data = cksumdata};
271 s32 now;
272 int direction;
273 s32 seqnum;
274 unsigned char *ptr;
275 int bodysize;
276 void *data_start, *orig_start;
277 int data_len;
278 int blocksize;
279 u32 conflen = kctx->gk5e->conflen;
280 int crypt_offset;
281 u8 *cksumkey;
282
283 dprintk("RPC: gss_unwrap_kerberos\n");
284
285 ptr = (u8 *)buf->head[0].iov_base + offset;
286 if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
287 buf->len - offset))
288 return GSS_S_DEFECTIVE_TOKEN;
289
290 if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
291 (ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
292 return GSS_S_DEFECTIVE_TOKEN;
293
294
295
296
297
298 signalg = ptr[2] + (ptr[3] << 8);
299 if (signalg != kctx->gk5e->signalg)
300 return GSS_S_DEFECTIVE_TOKEN;
301
302 sealalg = ptr[4] + (ptr[5] << 8);
303 if (sealalg != kctx->gk5e->sealalg)
304 return GSS_S_DEFECTIVE_TOKEN;
305
306 if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
307 return GSS_S_DEFECTIVE_TOKEN;
308
309
310
311
312
313 crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
314 (unsigned char *)buf->head[0].iov_base;
315
316
317
318
319 if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
320 ptr + 8, &direction, &seqnum))
321 return GSS_S_BAD_SIG;
322
323 if ((kctx->initiate && direction != 0xff) ||
324 (!kctx->initiate && direction != 0))
325 return GSS_S_BAD_SIG;
326
327 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
328 struct crypto_sync_skcipher *cipher;
329 int err;
330
331 cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
332 0, 0);
333 if (IS_ERR(cipher))
334 return GSS_S_FAILURE;
335
336 krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
337
338 err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
339 crypto_free_sync_skcipher(cipher);
340 if (err)
341 return GSS_S_DEFECTIVE_TOKEN;
342 } else {
343 if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
344 return GSS_S_DEFECTIVE_TOKEN;
345 }
346
347 if (kctx->gk5e->keyed_cksum)
348 cksumkey = kctx->cksum;
349 else
350 cksumkey = NULL;
351
352 if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
353 cksumkey, KG_USAGE_SEAL, &md5cksum))
354 return GSS_S_FAILURE;
355
356 if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
357 kctx->gk5e->cksumlength))
358 return GSS_S_BAD_SIG;
359
360
361
362 now = get_seconds();
363
364 if (now > kctx->endtime)
365 return GSS_S_CONTEXT_EXPIRED;
366
367
368
369
370
371
372 blocksize = crypto_sync_skcipher_blocksize(kctx->enc);
373 data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
374 conflen;
375 orig_start = buf->head[0].iov_base + offset;
376 data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
377 memmove(orig_start, data_start, data_len);
378 buf->head[0].iov_len -= (data_start - orig_start);
379 buf->len -= (data_start - orig_start);
380
381 if (gss_krb5_remove_padding(buf, blocksize))
382 return GSS_S_DEFECTIVE_TOKEN;
383
384 return GSS_S_COMPLETE;
385}
386
387
388
389
390
391
392
393
394
395
396
397#define LOCAL_BUF_LEN 32u
398
399static void rotate_buf_a_little(struct xdr_buf *buf, unsigned int shift)
400{
401 char head[LOCAL_BUF_LEN];
402 char tmp[LOCAL_BUF_LEN];
403 unsigned int this_len, i;
404
405 BUG_ON(shift > LOCAL_BUF_LEN);
406
407 read_bytes_from_xdr_buf(buf, 0, head, shift);
408 for (i = 0; i + shift < buf->len; i += LOCAL_BUF_LEN) {
409 this_len = min(LOCAL_BUF_LEN, buf->len - (i + shift));
410 read_bytes_from_xdr_buf(buf, i+shift, tmp, this_len);
411 write_bytes_to_xdr_buf(buf, i, tmp, this_len);
412 }
413 write_bytes_to_xdr_buf(buf, buf->len - shift, head, shift);
414}
415
416static void _rotate_left(struct xdr_buf *buf, unsigned int shift)
417{
418 int shifted = 0;
419 int this_shift;
420
421 shift %= buf->len;
422 while (shifted < shift) {
423 this_shift = min(shift - shifted, LOCAL_BUF_LEN);
424 rotate_buf_a_little(buf, this_shift);
425 shifted += this_shift;
426 }
427}
428
429static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift)
430{
431 struct xdr_buf subbuf;
432
433 xdr_buf_subsegment(buf, &subbuf, base, buf->len - base);
434 _rotate_left(&subbuf, shift);
435}
436
437static u32
438gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
439 struct xdr_buf *buf, struct page **pages)
440{
441 u8 *ptr, *plainhdr;
442 s32 now;
443 u8 flags = 0x00;
444 __be16 *be16ptr;
445 __be64 *be64ptr;
446 u32 err;
447
448 dprintk("RPC: %s\n", __func__);
449
450 if (kctx->gk5e->encrypt_v2 == NULL)
451 return GSS_S_FAILURE;
452
453
454 if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
455 return GSS_S_FAILURE;
456
457
458 ptr = plainhdr = buf->head[0].iov_base + offset;
459 *ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
460 *ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
461
462 if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
463 flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
464 if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
465 flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
466
467 flags |= KG2_TOKEN_FLAG_SEALED;
468
469 *ptr++ = flags;
470 *ptr++ = 0xff;
471 be16ptr = (__be16 *)ptr;
472
473 *be16ptr++ = 0;
474
475 *be16ptr++ = 0;
476
477 be64ptr = (__be64 *)be16ptr;
478 *be64ptr = cpu_to_be64(atomic64_fetch_inc(&kctx->seq_send64));
479
480 err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, 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 u8 *ptr;
493 u8 flags = 0x00;
494 u16 ec, rrc;
495 int err;
496 u32 headskip, tailskip;
497 u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
498 unsigned int movelen;
499
500
501 dprintk("RPC: %s\n", __func__);
502
503 if (kctx->gk5e->decrypt_v2 == NULL)
504 return GSS_S_FAILURE;
505
506 ptr = buf->head[0].iov_base + offset;
507
508 if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
509 return GSS_S_DEFECTIVE_TOKEN;
510
511 flags = ptr[2];
512 if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
513 (kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
514 return GSS_S_BAD_SIG;
515
516 if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
517 dprintk("%s: token missing expected sealed flag\n", __func__);
518 return GSS_S_DEFECTIVE_TOKEN;
519 }
520
521 if (ptr[3] != 0xff)
522 return GSS_S_DEFECTIVE_TOKEN;
523
524 ec = be16_to_cpup((__be16 *)(ptr + 4));
525 rrc = be16_to_cpup((__be16 *)(ptr + 6));
526
527
528
529
530
531
532 if (rrc != 0)
533 rotate_left(offset + 16, buf, rrc);
534
535 err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
536 &headskip, &tailskip);
537 if (err)
538 return GSS_S_FAILURE;
539
540
541
542
543
544 err = read_bytes_from_xdr_buf(buf,
545 buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
546 decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
547 if (err) {
548 dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
549 return GSS_S_FAILURE;
550 }
551 if (memcmp(ptr, decrypted_hdr, 6)
552 || memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
553 dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
554 return GSS_S_FAILURE;
555 }
556
557
558
559
560 now = get_seconds();
561 if (now > kctx->endtime)
562 return GSS_S_CONTEXT_EXPIRED;
563
564
565
566
567
568
569
570
571 movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len);
572 movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
573 BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
574 buf->head[0].iov_len);
575 memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
576 buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
577 buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
578
579
580 xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
581 return GSS_S_COMPLETE;
582}
583
584u32
585gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
586 struct xdr_buf *buf, struct page **pages)
587{
588 struct krb5_ctx *kctx = gctx->internal_ctx_id;
589
590 switch (kctx->enctype) {
591 default:
592 BUG();
593 case ENCTYPE_DES_CBC_RAW:
594 case ENCTYPE_DES3_CBC_RAW:
595 case ENCTYPE_ARCFOUR_HMAC:
596 return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
597 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
598 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
599 return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
600 }
601}
602
603u32
604gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
605{
606 struct krb5_ctx *kctx = gctx->internal_ctx_id;
607
608 switch (kctx->enctype) {
609 default:
610 BUG();
611 case ENCTYPE_DES_CBC_RAW:
612 case ENCTYPE_DES3_CBC_RAW:
613 case ENCTYPE_ARCFOUR_HMAC:
614 return gss_unwrap_kerberos_v1(kctx, offset, buf);
615 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
616 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
617 return gss_unwrap_kerberos_v2(kctx, offset, buf);
618 }
619}
620