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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>
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]);
86 pad = *(ptr + offset);
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);