2 * linux/net/sunrpc/gss_krb5_crypto.c
4 * Copyright (c) 2000-2008 The Regents of the University of Michigan.
7 * Andy Adamson <andros@umich.edu>
8 * Bruce Fields <bfields@umich.edu>
12 * Copyright (C) 1998 by the FundsXpress, INC.
14 * All rights reserved.
16 * Export of this software from the United States of America may require
17 * a specific license from the United States Government. It is the
18 * responsibility of any person or organization contemplating export to
19 * obtain such a license before exporting.
21 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
22 * distribute this software and its documentation for any purpose and
23 * without fee is hereby granted, provided that the above copyright
24 * notice appear in all copies and that both that copyright notice and
25 * this permission notice appear in supporting documentation, and that
26 * the name of FundsXpress. not be used in advertising or publicity pertaining
27 * to distribution of the software without specific, written prior
28 * permission. FundsXpress makes no representations about the suitability of
29 * this software for any purpose. It is provided "as is" without express
30 * or implied warranty.
32 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
33 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
34 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
37 #include <crypto/hash.h>
38 #include <crypto/skcipher.h>
39 #include <linux/err.h>
40 #include <linux/types.h>
42 #include <linux/scatterlist.h>
43 #include <linux/highmem.h>
44 #include <linux/pagemap.h>
45 #include <linux/random.h>
46 #include <linux/sunrpc/gss_krb5.h>
47 #include <linux/sunrpc/xdr.h>
49 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
50 # define RPCDBG_FACILITY RPCDBG_AUTH
55 struct crypto_skcipher *tfm,
62 struct scatterlist sg[1];
63 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
64 SKCIPHER_REQUEST_ON_STACK(req, tfm);
66 if (length % crypto_skcipher_blocksize(tfm) != 0)
69 if (crypto_skcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
70 dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
71 crypto_skcipher_ivsize(tfm));
76 memcpy(local_iv, iv, crypto_skcipher_ivsize(tfm));
78 memcpy(out, in, length);
79 sg_init_one(sg, out, length);
81 skcipher_request_set_tfm(req, tfm);
82 skcipher_request_set_callback(req, 0, NULL, NULL);
83 skcipher_request_set_crypt(req, sg, sg, length, local_iv);
85 ret = crypto_skcipher_encrypt(req);
86 skcipher_request_zero(req);
88 dprintk("RPC: krb5_encrypt returns %d\n", ret);
94 struct crypto_skcipher *tfm,
101 struct scatterlist sg[1];
102 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
103 SKCIPHER_REQUEST_ON_STACK(req, tfm);
105 if (length % crypto_skcipher_blocksize(tfm) != 0)
108 if (crypto_skcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
109 dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
110 crypto_skcipher_ivsize(tfm));
114 memcpy(local_iv,iv, crypto_skcipher_ivsize(tfm));
116 memcpy(out, in, length);
117 sg_init_one(sg, out, length);
119 skcipher_request_set_tfm(req, tfm);
120 skcipher_request_set_callback(req, 0, NULL, NULL);
121 skcipher_request_set_crypt(req, sg, sg, length, local_iv);
123 ret = crypto_skcipher_decrypt(req);
124 skcipher_request_zero(req);
126 dprintk("RPC: gss_k5decrypt returns %d\n",ret);
131 checksummer(struct scatterlist *sg, void *data)
133 struct ahash_request *req = data;
135 ahash_request_set_crypt(req, sg, NULL, sg->length);
137 return crypto_ahash_update(req);
141 arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4])
143 unsigned int ms_usage;
155 salt[0] = (ms_usage >> 0) & 0xff;
156 salt[1] = (ms_usage >> 8) & 0xff;
157 salt[2] = (ms_usage >> 16) & 0xff;
158 salt[3] = (ms_usage >> 24) & 0xff;
164 make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
165 struct xdr_buf *body, int body_offset, u8 *cksumkey,
166 unsigned int usage, struct xdr_netobj *cksumout)
168 struct scatterlist sg[1];
170 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
172 struct crypto_ahash *md5;
173 struct crypto_ahash *hmac_md5;
174 struct ahash_request *req;
176 if (cksumkey == NULL)
177 return GSS_S_FAILURE;
179 if (cksumout->len < kctx->gk5e->cksumlength) {
180 dprintk("%s: checksum buffer length, %u, too small for %s\n",
181 __func__, cksumout->len, kctx->gk5e->name);
182 return GSS_S_FAILURE;
185 if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) {
186 dprintk("%s: invalid usage value %u\n", __func__, usage);
187 return GSS_S_FAILURE;
190 md5 = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
192 return GSS_S_FAILURE;
194 hmac_md5 = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0,
196 if (IS_ERR(hmac_md5)) {
197 crypto_free_ahash(md5);
198 return GSS_S_FAILURE;
201 req = ahash_request_alloc(md5, GFP_KERNEL);
203 crypto_free_ahash(hmac_md5);
204 crypto_free_ahash(md5);
205 return GSS_S_FAILURE;
208 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
210 err = crypto_ahash_init(req);
213 sg_init_one(sg, rc4salt, 4);
214 ahash_request_set_crypt(req, sg, NULL, 4);
215 err = crypto_ahash_update(req);
219 sg_init_one(sg, header, hdrlen);
220 ahash_request_set_crypt(req, sg, NULL, hdrlen);
221 err = crypto_ahash_update(req);
224 err = xdr_process_buf(body, body_offset, body->len - body_offset,
228 ahash_request_set_crypt(req, NULL, checksumdata, 0);
229 err = crypto_ahash_final(req);
233 ahash_request_free(req);
234 req = ahash_request_alloc(hmac_md5, GFP_KERNEL);
236 crypto_free_ahash(hmac_md5);
237 crypto_free_ahash(md5);
238 return GSS_S_FAILURE;
241 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
243 err = crypto_ahash_init(req);
246 err = crypto_ahash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength);
250 sg_init_one(sg, checksumdata, crypto_ahash_digestsize(md5));
251 ahash_request_set_crypt(req, sg, checksumdata,
252 crypto_ahash_digestsize(md5));
253 err = crypto_ahash_digest(req);
257 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
258 cksumout->len = kctx->gk5e->cksumlength;
260 ahash_request_free(req);
261 crypto_free_ahash(md5);
262 crypto_free_ahash(hmac_md5);
263 return err ? GSS_S_FAILURE : 0;
267 * checksum the plaintext data and hdrlen bytes of the token header
268 * The checksum is performed over the first 8 bytes of the
269 * gss token header and then over the data body
272 make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
273 struct xdr_buf *body, int body_offset, u8 *cksumkey,
274 unsigned int usage, struct xdr_netobj *cksumout)
276 struct crypto_ahash *tfm;
277 struct ahash_request *req;
278 struct scatterlist sg[1];
280 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
281 unsigned int checksumlen;
283 if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR)
284 return make_checksum_hmac_md5(kctx, header, hdrlen,
286 cksumkey, usage, cksumout);
288 if (cksumout->len < kctx->gk5e->cksumlength) {
289 dprintk("%s: checksum buffer length, %u, too small for %s\n",
290 __func__, cksumout->len, kctx->gk5e->name);
291 return GSS_S_FAILURE;
294 tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
296 return GSS_S_FAILURE;
298 req = ahash_request_alloc(tfm, GFP_KERNEL);
300 crypto_free_ahash(tfm);
301 return GSS_S_FAILURE;
304 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
306 checksumlen = crypto_ahash_digestsize(tfm);
308 if (cksumkey != NULL) {
309 err = crypto_ahash_setkey(tfm, cksumkey,
310 kctx->gk5e->keylength);
315 err = crypto_ahash_init(req);
318 sg_init_one(sg, header, hdrlen);
319 ahash_request_set_crypt(req, sg, NULL, hdrlen);
320 err = crypto_ahash_update(req);
323 err = xdr_process_buf(body, body_offset, body->len - body_offset,
327 ahash_request_set_crypt(req, NULL, checksumdata, 0);
328 err = crypto_ahash_final(req);
332 switch (kctx->gk5e->ctype) {
333 case CKSUMTYPE_RSA_MD5:
334 err = kctx->gk5e->encrypt(kctx->seq, NULL, checksumdata,
335 checksumdata, checksumlen);
338 memcpy(cksumout->data,
339 checksumdata + checksumlen - kctx->gk5e->cksumlength,
340 kctx->gk5e->cksumlength);
342 case CKSUMTYPE_HMAC_SHA1_DES3:
343 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
349 cksumout->len = kctx->gk5e->cksumlength;
351 ahash_request_free(req);
352 crypto_free_ahash(tfm);
353 return err ? GSS_S_FAILURE : 0;
357 * checksum the plaintext data and hdrlen bytes of the token header
358 * Per rfc4121, sec. 4.2.4, the checksum is performed over the data
359 * body then over the first 16 octets of the MIC token
360 * Inclusion of the header data in the calculation of the
361 * checksum is optional.
364 make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
365 struct xdr_buf *body, int body_offset, u8 *cksumkey,
366 unsigned int usage, struct xdr_netobj *cksumout)
368 struct crypto_ahash *tfm;
369 struct ahash_request *req;
370 struct scatterlist sg[1];
372 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
373 unsigned int checksumlen;
375 if (kctx->gk5e->keyed_cksum == 0) {
376 dprintk("%s: expected keyed hash for %s\n",
377 __func__, kctx->gk5e->name);
378 return GSS_S_FAILURE;
380 if (cksumkey == NULL) {
381 dprintk("%s: no key supplied for %s\n",
382 __func__, kctx->gk5e->name);
383 return GSS_S_FAILURE;
386 tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
388 return GSS_S_FAILURE;
389 checksumlen = crypto_ahash_digestsize(tfm);
391 req = ahash_request_alloc(tfm, GFP_KERNEL);
393 crypto_free_ahash(tfm);
394 return GSS_S_FAILURE;
397 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
399 err = crypto_ahash_setkey(tfm, cksumkey, kctx->gk5e->keylength);
403 err = crypto_ahash_init(req);
406 err = xdr_process_buf(body, body_offset, body->len - body_offset,
410 if (header != NULL) {
411 sg_init_one(sg, header, hdrlen);
412 ahash_request_set_crypt(req, sg, NULL, hdrlen);
413 err = crypto_ahash_update(req);
417 ahash_request_set_crypt(req, NULL, checksumdata, 0);
418 err = crypto_ahash_final(req);
422 cksumout->len = kctx->gk5e->cksumlength;
424 switch (kctx->gk5e->ctype) {
425 case CKSUMTYPE_HMAC_SHA1_96_AES128:
426 case CKSUMTYPE_HMAC_SHA1_96_AES256:
427 /* note that this truncates the hash */
428 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
435 ahash_request_free(req);
436 crypto_free_ahash(tfm);
437 return err ? GSS_S_FAILURE : 0;
440 struct encryptor_desc {
441 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
442 struct skcipher_request *req;
444 struct xdr_buf *outbuf;
446 struct scatterlist infrags[4];
447 struct scatterlist outfrags[4];
453 encryptor(struct scatterlist *sg, void *data)
455 struct encryptor_desc *desc = data;
456 struct xdr_buf *outbuf = desc->outbuf;
457 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(desc->req);
458 struct page *in_page;
459 int thislen = desc->fraglen + sg->length;
463 /* Worst case is 4 fragments: head, end of page 1, start
464 * of page 2, tail. Anything more is a bug. */
465 BUG_ON(desc->fragno > 3);
467 page_pos = desc->pos - outbuf->head[0].iov_len;
468 if (page_pos >= 0 && page_pos < outbuf->page_len) {
469 /* pages are not in place: */
470 int i = (page_pos + outbuf->page_base) >> PAGE_SHIFT;
471 in_page = desc->pages[i];
473 in_page = sg_page(sg);
475 sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
477 sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
480 desc->fraglen += sg->length;
481 desc->pos += sg->length;
483 fraglen = thislen & (crypto_skcipher_blocksize(tfm) - 1);
489 sg_mark_end(&desc->infrags[desc->fragno - 1]);
490 sg_mark_end(&desc->outfrags[desc->fragno - 1]);
492 skcipher_request_set_crypt(desc->req, desc->infrags, desc->outfrags,
495 ret = crypto_skcipher_encrypt(desc->req);
499 sg_init_table(desc->infrags, 4);
500 sg_init_table(desc->outfrags, 4);
503 sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
504 sg->offset + sg->length - fraglen);
505 desc->infrags[0] = desc->outfrags[0];
506 sg_assign_page(&desc->infrags[0], in_page);
508 desc->fraglen = fraglen;
517 gss_encrypt_xdr_buf(struct crypto_skcipher *tfm, struct xdr_buf *buf,
518 int offset, struct page **pages)
521 struct encryptor_desc desc;
522 SKCIPHER_REQUEST_ON_STACK(req, tfm);
524 BUG_ON((buf->len - offset) % crypto_skcipher_blocksize(tfm) != 0);
526 skcipher_request_set_tfm(req, tfm);
527 skcipher_request_set_callback(req, 0, NULL, NULL);
529 memset(desc.iv, 0, sizeof(desc.iv));
537 sg_init_table(desc.infrags, 4);
538 sg_init_table(desc.outfrags, 4);
540 ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
541 skcipher_request_zero(req);
545 struct decryptor_desc {
546 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
547 struct skcipher_request *req;
548 struct scatterlist frags[4];
554 decryptor(struct scatterlist *sg, void *data)
556 struct decryptor_desc *desc = data;
557 int thislen = desc->fraglen + sg->length;
558 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(desc->req);
561 /* Worst case is 4 fragments: head, end of page 1, start
562 * of page 2, tail. Anything more is a bug. */
563 BUG_ON(desc->fragno > 3);
564 sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
567 desc->fraglen += sg->length;
569 fraglen = thislen & (crypto_skcipher_blocksize(tfm) - 1);
575 sg_mark_end(&desc->frags[desc->fragno - 1]);
577 skcipher_request_set_crypt(desc->req, desc->frags, desc->frags,
580 ret = crypto_skcipher_decrypt(desc->req);
584 sg_init_table(desc->frags, 4);
587 sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
588 sg->offset + sg->length - fraglen);
590 desc->fraglen = fraglen;
599 gss_decrypt_xdr_buf(struct crypto_skcipher *tfm, struct xdr_buf *buf,
603 struct decryptor_desc desc;
604 SKCIPHER_REQUEST_ON_STACK(req, tfm);
607 BUG_ON((buf->len - offset) % crypto_skcipher_blocksize(tfm) != 0);
609 skcipher_request_set_tfm(req, tfm);
610 skcipher_request_set_callback(req, 0, NULL, NULL);
612 memset(desc.iv, 0, sizeof(desc.iv));
617 sg_init_table(desc.frags, 4);
619 ret = xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
620 skcipher_request_zero(req);
625 * This function makes the assumption that it was ultimately called
628 * The client auth_gss code moves any existing tail data into a
629 * separate page before calling gss_wrap.
630 * The server svcauth_gss code ensures that both the head and the
631 * tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap.
633 * Even with that guarantee, this function may be called more than
634 * once in the processing of gss_wrap(). The best we can do is
635 * verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the
636 * largest expected shift will fit within RPC_MAX_AUTH_SIZE.
637 * At run-time we can verify that a single invocation of this
638 * function doesn't attempt to use more the RPC_MAX_AUTH_SIZE.
642 xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
649 BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
650 BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE);
652 p = buf->head[0].iov_base + base;
654 memmove(p + shiftlen, p, buf->head[0].iov_len - base);
656 buf->head[0].iov_len += shiftlen;
657 buf->len += shiftlen;
663 gss_krb5_cts_crypt(struct crypto_skcipher *cipher, struct xdr_buf *buf,
664 u32 offset, u8 *iv, struct page **pages, int encrypt)
667 struct scatterlist sg[1];
668 SKCIPHER_REQUEST_ON_STACK(req, cipher);
669 u8 data[GSS_KRB5_MAX_BLOCKSIZE * 2];
670 struct page **save_pages;
671 u32 len = buf->len - offset;
673 if (len > ARRAY_SIZE(data)) {
679 * For encryption, we want to read from the cleartext
680 * page cache pages, and write the encrypted data to
681 * the supplied xdr_buf pages.
683 save_pages = buf->pages;
687 ret = read_bytes_from_xdr_buf(buf, offset, data, len);
688 buf->pages = save_pages;
692 sg_init_one(sg, data, len);
694 skcipher_request_set_tfm(req, cipher);
695 skcipher_request_set_callback(req, 0, NULL, NULL);
696 skcipher_request_set_crypt(req, sg, sg, len, iv);
699 ret = crypto_skcipher_encrypt(req);
701 ret = crypto_skcipher_decrypt(req);
703 skcipher_request_zero(req);
708 ret = write_bytes_to_xdr_buf(buf, offset, data, len);
715 gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
716 struct xdr_buf *buf, struct page **pages)
719 struct xdr_netobj hmac;
722 struct crypto_skcipher *cipher, *aux_cipher;
724 struct page **save_pages;
726 struct encryptor_desc desc;
730 if (kctx->initiate) {
731 cipher = kctx->initiator_enc;
732 aux_cipher = kctx->initiator_enc_aux;
733 cksumkey = kctx->initiator_integ;
734 usage = KG_USAGE_INITIATOR_SEAL;
736 cipher = kctx->acceptor_enc;
737 aux_cipher = kctx->acceptor_enc_aux;
738 cksumkey = kctx->acceptor_integ;
739 usage = KG_USAGE_ACCEPTOR_SEAL;
741 blocksize = crypto_skcipher_blocksize(cipher);
743 /* hide the gss token header and insert the confounder */
744 offset += GSS_KRB5_TOK_HDR_LEN;
745 if (xdr_extend_head(buf, offset, kctx->gk5e->conflen))
746 return GSS_S_FAILURE;
747 gss_krb5_make_confounder(buf->head[0].iov_base + offset, kctx->gk5e->conflen);
748 offset -= GSS_KRB5_TOK_HDR_LEN;
750 if (buf->tail[0].iov_base != NULL) {
751 ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
753 buf->tail[0].iov_base = buf->head[0].iov_base
754 + buf->head[0].iov_len;
755 buf->tail[0].iov_len = 0;
756 ecptr = buf->tail[0].iov_base;
759 /* copy plaintext gss token header after filler (if any) */
760 memcpy(ecptr, buf->head[0].iov_base + offset, GSS_KRB5_TOK_HDR_LEN);
761 buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
762 buf->len += GSS_KRB5_TOK_HDR_LEN;
765 hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
766 hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
769 * When we are called, pages points to the real page cache
770 * data -- which we can't go and encrypt! buf->pages points
771 * to scratch pages which we are going to send off to the
772 * client/server. Swap in the plaintext pages to calculate
775 save_pages = buf->pages;
778 err = make_checksum_v2(kctx, NULL, 0, buf,
779 offset + GSS_KRB5_TOK_HDR_LEN,
780 cksumkey, usage, &hmac);
781 buf->pages = save_pages;
783 return GSS_S_FAILURE;
785 nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
786 nblocks = (nbytes + blocksize - 1) / blocksize;
789 cbcbytes = (nblocks - 2) * blocksize;
791 memset(desc.iv, 0, sizeof(desc.iv));
794 SKCIPHER_REQUEST_ON_STACK(req, aux_cipher);
796 desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
803 skcipher_request_set_tfm(req, aux_cipher);
804 skcipher_request_set_callback(req, 0, NULL, NULL);
806 sg_init_table(desc.infrags, 4);
807 sg_init_table(desc.outfrags, 4);
809 err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
810 cbcbytes, encryptor, &desc);
811 skcipher_request_zero(req);
816 /* Make sure IV carries forward from any CBC results. */
817 err = gss_krb5_cts_crypt(cipher, buf,
818 offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
825 /* Now update buf to account for HMAC */
826 buf->tail[0].iov_len += kctx->gk5e->cksumlength;
827 buf->len += kctx->gk5e->cksumlength;
836 gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
837 u32 *headskip, u32 *tailskip)
839 struct xdr_buf subbuf;
842 struct crypto_skcipher *cipher, *aux_cipher;
843 struct xdr_netobj our_hmac_obj;
844 u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
845 u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
846 int nblocks, blocksize, cbcbytes;
847 struct decryptor_desc desc;
850 if (kctx->initiate) {
851 cipher = kctx->acceptor_enc;
852 aux_cipher = kctx->acceptor_enc_aux;
853 cksum_key = kctx->acceptor_integ;
854 usage = KG_USAGE_ACCEPTOR_SEAL;
856 cipher = kctx->initiator_enc;
857 aux_cipher = kctx->initiator_enc_aux;
858 cksum_key = kctx->initiator_integ;
859 usage = KG_USAGE_INITIATOR_SEAL;
861 blocksize = crypto_skcipher_blocksize(cipher);
864 /* create a segment skipping the header and leaving out the checksum */
865 xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
866 (buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
867 kctx->gk5e->cksumlength));
869 nblocks = (subbuf.len + blocksize - 1) / blocksize;
873 cbcbytes = (nblocks - 2) * blocksize;
875 memset(desc.iv, 0, sizeof(desc.iv));
878 SKCIPHER_REQUEST_ON_STACK(req, aux_cipher);
884 skcipher_request_set_tfm(req, aux_cipher);
885 skcipher_request_set_callback(req, 0, NULL, NULL);
887 sg_init_table(desc.frags, 4);
889 ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
890 skcipher_request_zero(req);
895 /* Make sure IV carries forward from any CBC results. */
896 ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
901 /* Calculate our hmac over the plaintext data */
902 our_hmac_obj.len = sizeof(our_hmac);
903 our_hmac_obj.data = our_hmac;
905 ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
906 cksum_key, usage, &our_hmac_obj);
910 /* Get the packet's hmac value */
911 ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
912 pkt_hmac, kctx->gk5e->cksumlength);
916 if (memcmp(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
920 *headskip = kctx->gk5e->conflen;
921 *tailskip = kctx->gk5e->cksumlength;
923 if (ret && ret != GSS_S_BAD_SIG)
929 * Compute Kseq given the initial session key and the checksum.
930 * Set the key of the given cipher.
933 krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
934 unsigned char *cksum)
936 struct crypto_shash *hmac;
937 struct shash_desc *desc;
938 u8 Kseq[GSS_KRB5_MAX_KEYLEN];
939 u32 zeroconstant = 0;
942 dprintk("%s: entered\n", __func__);
944 hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
946 dprintk("%s: error %ld, allocating hash '%s'\n",
947 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
948 return PTR_ERR(hmac);
951 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
954 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
955 __func__, kctx->gk5e->cksum_name);
956 crypto_free_shash(hmac);
963 /* Compute intermediate Kseq from session key */
964 err = crypto_shash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength);
968 err = crypto_shash_digest(desc, (u8 *)&zeroconstant, 4, Kseq);
972 /* Compute final Kseq from the checksum and intermediate Kseq */
973 err = crypto_shash_setkey(hmac, Kseq, kctx->gk5e->keylength);
977 err = crypto_shash_digest(desc, cksum, 8, Kseq);
981 err = crypto_skcipher_setkey(cipher, Kseq, kctx->gk5e->keylength);
989 crypto_free_shash(hmac);
990 dprintk("%s: returning %d\n", __func__, err);
995 * Compute Kcrypt given the initial session key and the plaintext seqnum.
996 * Set the key of cipher kctx->enc.
999 krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
1002 struct crypto_shash *hmac;
1003 struct shash_desc *desc;
1004 u8 Kcrypt[GSS_KRB5_MAX_KEYLEN];
1005 u8 zeroconstant[4] = {0};
1009 dprintk("%s: entered, seqnum %u\n", __func__, seqnum);
1011 hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
1013 dprintk("%s: error %ld, allocating hash '%s'\n",
1014 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
1015 return PTR_ERR(hmac);
1018 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
1021 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
1022 __func__, kctx->gk5e->cksum_name);
1023 crypto_free_shash(hmac);
1030 /* Compute intermediate Kcrypt from session key */
1031 for (i = 0; i < kctx->gk5e->keylength; i++)
1032 Kcrypt[i] = kctx->Ksess[i] ^ 0xf0;
1034 err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
1038 err = crypto_shash_digest(desc, zeroconstant, 4, Kcrypt);
1042 /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */
1043 err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
1047 seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff);
1048 seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff);
1049 seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff);
1050 seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff);
1052 err = crypto_shash_digest(desc, seqnumarray, 4, Kcrypt);
1056 err = crypto_skcipher_setkey(cipher, Kcrypt, kctx->gk5e->keylength);
1064 crypto_free_shash(hmac);
1065 dprintk("%s: returning %d\n", __func__, err);