3
* The Regents of the University of Michigan
6
* Permission is granted to use, copy, create derivative works
7
* and redistribute this software and such derivative works
8
* for any purpose, so long as the name of The University of
9
* Michigan is not used in any advertising or publicity
10
* pertaining to the use of distribution of this software
11
* without specific, written prior authorization. If the
12
* above copyright notice or any other identification of the
13
* University of Michigan is included in any copy of any
14
* portion of this software, then the disclaimer below must
17
* THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
18
* FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
19
* PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
20
* MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
21
* WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
22
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
23
* REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
24
* FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
25
* CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
26
* OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
27
* IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
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>
39
# define RPCDBG_FACILITY RPCDBG_AUTH
43
gss_krb5_padding(int blocksize, int length)
45
return blocksize - (length % blocksize);
49
gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
51
int padding = gss_krb5_padding(blocksize, buf->len - offset);
55
if (buf->page_len || buf->tail[0].iov_len)
59
p = iov->iov_base + iov->iov_len;
60
iov->iov_len += padding;
62
memset(p, padding, padding);
66
gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
70
size_t len = buf->len;
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)
76
buf->head[0].iov_len -= pad;
79
len -= buf->head[0].iov_len;
80
if (len <= buf->page_len) {
81
unsigned int last = (buf->page_base + len - 1)
83
unsigned int offset = (buf->page_base + len - 1)
84
& (PAGE_CACHE_SIZE - 1);
85
ptr = kmap_atomic(buf->pages[last], KM_USER0);
86
pad = *(ptr + offset);
87
kunmap_atomic(ptr, KM_USER0);
91
BUG_ON(len > buf->tail[0].iov_len);
92
pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
94
/* XXX: NOTE: we do not adjust the page lengths--they represent
95
* a range of data in the real filesystem page cache, and we need
96
* to know that range so the xdr code can properly place read data.
97
* However adjusting the head length, as we do above, is harmless.
98
* In the case of a request that fits into a single page, the server
99
* also uses length and head length together to determine the original
100
* start of the request to copy the request for deferal; so it's
101
* easier on the server if we adjust head and tail length in tandem.
102
* It's not really a problem that we don't fool with the page and
103
* tail lengths, though--at worst badly formed xdr might lead the
104
* server to attempt to parse the padding.
105
* XXX: Document all these weird requirements for gss mechanism
106
* wrap/unwrap functions. */
117
gss_krb5_make_confounder(char *p, u32 conflen)
122
/* rfc1964 claims this should be "random". But all that's really
123
* necessary is that it be unique. And not even that is necessary in
124
* our case since our "gssapi" implementation exists only to support
125
* rpcsec_gss, so we know that the only buffers we will ever encrypt
126
* already begin with a unique sequence number. Just to hedge my bets
127
* I'll make a half-hearted attempt at something unique, but ensuring
128
* uniqueness would mean worrying about atomicity and rollover, and I
129
* don't care enough. */
131
/* initialize to random value */
134
i = (i << 32) | random32();
149
/* Assumptions: the head and tail of inbuf are ours to play with.
150
* The pages, however, may be real pages in the page cache and we replace
151
* them with scratch pages from **pages before writing to them. */
152
/* XXX: obviously the above should be documentation of wrap interface,
153
* and shouldn't be in this kerberos-specific file. */
155
/* XXX factor out common code with seal/unseal. */
158
gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
159
struct xdr_buf *buf, struct page **pages)
161
char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
162
struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
164
int blocksize = 0, plainlen;
165
unsigned char *ptr, *msg_start;
168
struct page **tmp_pages;
171
u32 conflen = kctx->gk5e->conflen;
173
dprintk("RPC: %s\n", __func__);
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;
182
headlen = g_token_size(&kctx->mech_used,
183
GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength + plainlen) -
186
ptr = buf->head[0].iov_base + offset;
187
/* shift data to make room for header. */
188
xdr_extend_head(buf, offset, headlen);
190
/* XXX Would be cleverer to encrypt while copying. */
191
BUG_ON((buf->len - offset - headlen) % blocksize);
193
g_make_token_header(&kctx->mech_used,
194
GSS_KRB5_TOK_HDR_LEN +
195
kctx->gk5e->cksumlength + plainlen, &ptr);
198
/* ptr now at header described in rfc 1964, section 1.2.1: */
199
ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
200
ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
202
msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength;
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);
208
gss_krb5_make_confounder(msg_start, conflen);
210
if (kctx->gk5e->keyed_cksum)
211
cksumkey = kctx->cksum;
216
tmp_pages = buf->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;
223
memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
225
spin_lock(&krb5_seq_lock);
226
seq_send = kctx->seq_send++;
227
spin_unlock(&krb5_seq_lock);
229
/* XXX would probably be more efficient to compute checksum
230
* and encrypt at the same time: */
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;
235
if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
236
struct crypto_blkcipher *cipher;
238
cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
241
return GSS_S_FAILURE;
243
krb5_rc4_setup_enc_key(kctx, cipher, seq_send);
245
err = gss_encrypt_xdr_buf(cipher, buf,
246
offset + headlen - conflen, pages);
247
crypto_free_blkcipher(cipher);
249
return GSS_S_FAILURE;
251
if (gss_encrypt_xdr_buf(kctx->enc, buf,
252
offset + headlen - conflen, pages))
253
return GSS_S_FAILURE;
256
return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
260
gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
264
char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
265
struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
272
void *data_start, *orig_start;
275
u32 conflen = kctx->gk5e->conflen;
279
dprintk("RPC: gss_unwrap_kerberos\n");
281
ptr = (u8 *)buf->head[0].iov_base + offset;
282
if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
284
return GSS_S_DEFECTIVE_TOKEN;
286
if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
287
(ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
288
return GSS_S_DEFECTIVE_TOKEN;
290
/* XXX sanity-check bodysize?? */
292
/* get the sign and seal algorithms */
294
signalg = ptr[2] + (ptr[3] << 8);
295
if (signalg != kctx->gk5e->signalg)
296
return GSS_S_DEFECTIVE_TOKEN;
298
sealalg = ptr[4] + (ptr[5] << 8);
299
if (sealalg != kctx->gk5e->sealalg)
300
return GSS_S_DEFECTIVE_TOKEN;
302
if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
303
return GSS_S_DEFECTIVE_TOKEN;
306
* Data starts after token header and checksum. ptr points
307
* to the beginning of the token header
309
crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
310
(unsigned char *)buf->head[0].iov_base;
313
* Need plaintext seqnum to derive encryption key for arcfour-hmac
315
if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
316
ptr + 8, &direction, &seqnum))
317
return GSS_S_BAD_SIG;
319
if ((kctx->initiate && direction != 0xff) ||
320
(!kctx->initiate && direction != 0))
321
return GSS_S_BAD_SIG;
323
if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
324
struct crypto_blkcipher *cipher;
327
cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
330
return GSS_S_FAILURE;
332
krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
334
err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
335
crypto_free_blkcipher(cipher);
337
return GSS_S_DEFECTIVE_TOKEN;
339
if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
340
return GSS_S_DEFECTIVE_TOKEN;
343
if (kctx->gk5e->keyed_cksum)
344
cksumkey = kctx->cksum;
348
if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
349
cksumkey, KG_USAGE_SEAL, &md5cksum))
350
return GSS_S_FAILURE;
352
if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
353
kctx->gk5e->cksumlength))
354
return GSS_S_BAD_SIG;
356
/* it got through unscathed. Make sure the context is unexpired */
360
if (now > kctx->endtime)
361
return GSS_S_CONTEXT_EXPIRED;
363
/* do sequencing checks */
365
/* Copy the data back to the right position. XXX: Would probably be
366
* better to copy and encrypt at the same time. */
368
blocksize = crypto_blkcipher_blocksize(kctx->enc);
369
data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
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);
377
if (gss_krb5_remove_padding(buf, blocksize))
378
return GSS_S_DEFECTIVE_TOKEN;
380
return GSS_S_COMPLETE;
384
* We cannot currently handle tokens with rotated data. We need a
385
* generalized routine to rotate the data in place. It is anticipated
386
* that we won't encounter rotated data in the general case.
389
rotate_left(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, u16 rrc)
391
unsigned int realrrc = rrc % (buf->len - offset - GSS_KRB5_TOK_HDR_LEN);
396
dprintk("%s: cannot process token with rotated data: "
397
"rrc %u, realrrc %u\n", __func__, rrc, realrrc);
402
gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
403
struct xdr_buf *buf, struct page **pages)
409
__be16 *be16ptr, ec = 0;
413
dprintk("RPC: %s\n", __func__);
415
if (kctx->gk5e->encrypt_v2 == NULL)
416
return GSS_S_FAILURE;
418
/* make room for gss token header */
419
if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
420
return GSS_S_FAILURE;
422
/* construct gss token header */
423
ptr = plainhdr = buf->head[0].iov_base + offset;
424
*ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
425
*ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
427
if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
428
flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
429
if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
430
flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
431
/* We always do confidentiality in wrap tokens */
432
flags |= KG2_TOKEN_FLAG_SEALED;
436
be16ptr = (__be16 *)ptr;
438
blocksize = crypto_blkcipher_blocksize(kctx->acceptor_enc);
439
*be16ptr++ = cpu_to_be16(ec);
440
/* "inner" token header always uses 0 for RRC */
441
*be16ptr++ = cpu_to_be16(0);
443
be64ptr = (__be64 *)be16ptr;
444
spin_lock(&krb5_seq_lock);
445
*be64ptr = cpu_to_be64(kctx->seq_send64++);
446
spin_unlock(&krb5_seq_lock);
448
err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, ec, pages);
453
return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
457
gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
465
u32 headskip, tailskip;
466
u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
467
unsigned int movelen;
470
dprintk("RPC: %s\n", __func__);
472
if (kctx->gk5e->decrypt_v2 == NULL)
473
return GSS_S_FAILURE;
475
ptr = buf->head[0].iov_base + offset;
477
if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
478
return GSS_S_DEFECTIVE_TOKEN;
481
if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
482
(kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
483
return GSS_S_BAD_SIG;
485
if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
486
dprintk("%s: token missing expected sealed flag\n", __func__);
487
return GSS_S_DEFECTIVE_TOKEN;
491
return GSS_S_DEFECTIVE_TOKEN;
493
ec = be16_to_cpup((__be16 *)(ptr + 4));
494
rrc = be16_to_cpup((__be16 *)(ptr + 6));
496
seqnum = be64_to_cpup((__be64 *)(ptr + 8));
499
err = rotate_left(kctx, offset, buf, rrc);
501
return GSS_S_FAILURE;
504
err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
505
&headskip, &tailskip);
507
return GSS_S_FAILURE;
510
* Retrieve the decrypted gss token header and verify
511
* it against the original
513
err = read_bytes_from_xdr_buf(buf,
514
buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
515
decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
517
dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
518
return GSS_S_FAILURE;
520
if (memcmp(ptr, decrypted_hdr, 6)
521
|| memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
522
dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
523
return GSS_S_FAILURE;
526
/* do sequencing checks */
528
/* it got through unscathed. Make sure the context is unexpired */
530
if (now > kctx->endtime)
531
return GSS_S_CONTEXT_EXPIRED;
534
* Move the head data back to the right position in xdr_buf.
535
* We ignore any "ec" data since it might be in the head or
536
* the tail, and we really don't need to deal with it.
537
* Note that buf->head[0].iov_len may indicate the available
538
* head buffer space rather than that actually occupied.
540
movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len);
541
movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
542
BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
543
buf->head[0].iov_len);
544
memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
545
buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
546
buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
548
return GSS_S_COMPLETE;
552
gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
553
struct xdr_buf *buf, struct page **pages)
555
struct krb5_ctx *kctx = gctx->internal_ctx_id;
557
switch (kctx->enctype) {
560
case ENCTYPE_DES_CBC_RAW:
561
case ENCTYPE_DES3_CBC_RAW:
562
case ENCTYPE_ARCFOUR_HMAC:
563
return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
564
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
565
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
566
return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
571
gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
573
struct krb5_ctx *kctx = gctx->internal_ctx_id;
575
switch (kctx->enctype) {
578
case ENCTYPE_DES_CBC_RAW:
579
case ENCTYPE_DES3_CBC_RAW:
580
case ENCTYPE_ARCFOUR_HMAC:
581
return gss_unwrap_kerberos_v1(kctx, offset, buf);
582
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
583
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
584
return gss_unwrap_kerberos_v2(kctx, offset, buf);