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33 #include "krb5/gsskrb5_locl.h"
35 RCSID("$Id: cfx.c 19031 2006-11-13 18:02:57Z lha $");
38 * Implementation of draft-ietf-krb-wg-gssapi-cfx-06.txt
41 #define CFXSentByAcceptor (1 << 0)
42 #define CFXSealed (1 << 1)
43 #define CFXAcceptorSubkey (1 << 2)
46 _gsskrb5cfx_wrap_length_cfx(const gsskrb5_ctx context_handle,
51 size_t *output_length,
58 /* 16-byte header is always first */
59 *output_length = sizeof(gss_cfx_wrap_token_desc);
62 ret = krb5_crypto_get_checksum_type(context, crypto, &type);
66 ret = krb5_checksumsize(context, type, cksumsize);
73 /* Header is concatenated with data before encryption */
74 input_length += sizeof(gss_cfx_wrap_token_desc);
76 if (IS_DCE_STYLE(context_handle)) {
77 ret = krb5_crypto_getblocksize(context, crypto, &padsize);
79 ret = krb5_crypto_getpadsize(context, crypto, &padsize);
86 *padlength = padsize - (input_length % padsize);
88 /* We add the pad ourselves (noted here for completeness only) */
89 input_length += *padlength;
92 *output_length += krb5_get_wrapped_length(context,
93 crypto, input_length);
95 /* Checksum is concatenated with data */
96 *output_length += input_length + *cksumsize;
99 assert(*output_length > input_length);
105 _gsskrb5cfx_max_wrap_length_cfx(krb5_context context,
109 OM_uint32 *output_length)
115 /* 16-byte header is always first */
116 if (input_length < 16)
121 size_t wrapped_size, sz;
123 wrapped_size = input_length + 1;
126 sz = krb5_get_wrapped_length(context,
127 crypto, wrapped_size);
128 } while (wrapped_size && sz > input_length);
129 if (wrapped_size == 0) {
135 if (wrapped_size < 16) {
141 *output_length = wrapped_size;
146 ret = krb5_crypto_get_checksum_type(context, crypto, &type);
150 ret = krb5_checksumsize(context, type, &cksumsize);
154 if (input_length < cksumsize)
157 /* Checksum is concatenated with data */
158 *output_length = input_length - cksumsize;
165 OM_uint32 _gssapi_wrap_size_cfx(OM_uint32 *minor_status,
166 const gsskrb5_ctx context_handle,
167 krb5_context context,
170 OM_uint32 req_output_size,
171 OM_uint32 *max_input_size,
177 ret = krb5_crypto_init(context, key, 0, &crypto);
180 return GSS_S_FAILURE;
183 ret = _gsskrb5cfx_max_wrap_length_cfx(context, crypto, conf_req_flag,
184 req_output_size, max_input_size);
187 krb5_crypto_destroy(context, crypto);
188 return GSS_S_FAILURE;
191 krb5_crypto_destroy(context, crypto);
193 return GSS_S_COMPLETE;
197 * Rotate "rrc" bytes to the front or back
200 static krb5_error_code
201 rrc_rotate(void *data, size_t len, uint16_t rrc, krb5_boolean unrotate)
203 u_char *tmp, buf[256];
216 if (rrc <= sizeof(buf)) {
225 memcpy(tmp, data, rrc);
226 memmove(data, (u_char *)data + rrc, left);
227 memcpy((u_char *)data + left, tmp, rrc);
229 memcpy(tmp, (u_char *)data + left, rrc);
230 memmove((u_char *)data + rrc, data, left);
231 memcpy(data, tmp, rrc);
234 if (rrc > sizeof(buf))
240 OM_uint32 _gssapi_wrap_cfx(OM_uint32 *minor_status,
241 const gsskrb5_ctx context_handle,
242 krb5_context context,
245 const gss_buffer_t input_message_buffer,
247 gss_buffer_t output_message_buffer,
251 gss_cfx_wrap_token token;
255 size_t wrapped_len, cksumsize;
256 uint16_t padlength, rrc = 0;
260 ret = krb5_crypto_init(context, key, 0, &crypto);
263 return GSS_S_FAILURE;
266 ret = _gsskrb5cfx_wrap_length_cfx(context_handle, context,
267 crypto, conf_req_flag,
268 input_message_buffer->length,
269 &wrapped_len, &cksumsize, &padlength);
272 krb5_crypto_destroy(context, crypto);
273 return GSS_S_FAILURE;
276 /* Always rotate encrypted token (if any) and checksum to header */
277 rrc = (conf_req_flag ? sizeof(*token) : 0) + (uint16_t)cksumsize;
279 output_message_buffer->length = wrapped_len;
280 output_message_buffer->value = malloc(output_message_buffer->length);
281 if (output_message_buffer->value == NULL) {
282 *minor_status = ENOMEM;
283 krb5_crypto_destroy(context, crypto);
284 return GSS_S_FAILURE;
287 p = output_message_buffer->value;
288 token = (gss_cfx_wrap_token)p;
289 token->TOK_ID[0] = 0x05;
290 token->TOK_ID[1] = 0x04;
292 token->Filler = 0xFF;
293 if ((context_handle->more_flags & LOCAL) == 0)
294 token->Flags |= CFXSentByAcceptor;
295 if (context_handle->more_flags & ACCEPTOR_SUBKEY)
296 token->Flags |= CFXAcceptorSubkey;
299 * In Wrap tokens with confidentiality, the EC field is
300 * used to encode the size (in bytes) of the random filler.
302 token->Flags |= CFXSealed;
303 token->EC[0] = (padlength >> 8) & 0xFF;
304 token->EC[1] = (padlength >> 0) & 0xFF;
307 * In Wrap tokens without confidentiality, the EC field is
308 * used to encode the size (in bytes) of the trailing
311 * This is not used in the checksum calcuation itself,
312 * because the checksum length could potentially vary
313 * depending on the data length.
320 * In Wrap tokens that provide for confidentiality, the RRC
321 * field in the header contains the hex value 00 00 before
324 * In Wrap tokens that do not provide for confidentiality,
325 * both the EC and RRC fields in the appended checksum
326 * contain the hex value 00 00 for the purpose of calculating
332 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
333 krb5_auth_con_getlocalseqnumber(context,
334 context_handle->auth_context,
336 _gsskrb5_encode_be_om_uint32(0, &token->SND_SEQ[0]);
337 _gsskrb5_encode_be_om_uint32(seq_number, &token->SND_SEQ[4]);
338 krb5_auth_con_setlocalseqnumber(context,
339 context_handle->auth_context,
341 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
344 * If confidentiality is requested, the token header is
345 * appended to the plaintext before encryption; the resulting
346 * token is {"header" | encrypt(plaintext | pad | "header")}.
348 * If no confidentiality is requested, the checksum is
349 * calculated over the plaintext concatenated with the
352 if (context_handle->more_flags & LOCAL) {
353 usage = KRB5_KU_USAGE_INITIATOR_SEAL;
355 usage = KRB5_KU_USAGE_ACCEPTOR_SEAL;
360 * Any necessary padding is added here to ensure that the
361 * encrypted token header is always at the end of the
364 * The specification does not require that the padding
365 * bytes are initialized.
368 memcpy(p, input_message_buffer->value, input_message_buffer->length);
369 memset(p + input_message_buffer->length, 0xFF, padlength);
370 memcpy(p + input_message_buffer->length + padlength,
371 token, sizeof(*token));
373 ret = krb5_encrypt(context, crypto,
375 input_message_buffer->length + padlength +
380 krb5_crypto_destroy(context, crypto);
381 _gsskrb5_release_buffer(minor_status, output_message_buffer);
382 return GSS_S_FAILURE;
384 assert(sizeof(*token) + cipher.length == wrapped_len);
385 token->RRC[0] = (rrc >> 8) & 0xFF;
386 token->RRC[1] = (rrc >> 0) & 0xFF;
389 * this is really ugly, but needed against windows
390 * for DCERPC, as windows rotates by EC+RRC.
392 if (IS_DCE_STYLE(context_handle)) {
393 ret = rrc_rotate(cipher.data, cipher.length, rrc+padlength, FALSE);
395 ret = rrc_rotate(cipher.data, cipher.length, rrc, FALSE);
399 krb5_crypto_destroy(context, crypto);
400 _gsskrb5_release_buffer(minor_status, output_message_buffer);
401 return GSS_S_FAILURE;
403 memcpy(p, cipher.data, cipher.length);
404 krb5_data_free(&cipher);
409 buf = malloc(input_message_buffer->length + sizeof(*token));
411 *minor_status = ENOMEM;
412 krb5_crypto_destroy(context, crypto);
413 _gsskrb5_release_buffer(minor_status, output_message_buffer);
414 return GSS_S_FAILURE;
416 memcpy(buf, input_message_buffer->value, input_message_buffer->length);
417 memcpy(buf + input_message_buffer->length, token, sizeof(*token));
419 ret = krb5_create_checksum(context, crypto,
421 input_message_buffer->length +
426 krb5_crypto_destroy(context, crypto);
427 _gsskrb5_release_buffer(minor_status, output_message_buffer);
429 return GSS_S_FAILURE;
434 assert(cksum.checksum.length == cksumsize);
435 token->EC[0] = (cksum.checksum.length >> 8) & 0xFF;
436 token->EC[1] = (cksum.checksum.length >> 0) & 0xFF;
437 token->RRC[0] = (rrc >> 8) & 0xFF;
438 token->RRC[1] = (rrc >> 0) & 0xFF;
441 memcpy(p, input_message_buffer->value, input_message_buffer->length);
442 memcpy(p + input_message_buffer->length,
443 cksum.checksum.data, cksum.checksum.length);
446 input_message_buffer->length + cksum.checksum.length, rrc, FALSE);
449 krb5_crypto_destroy(context, crypto);
450 _gsskrb5_release_buffer(minor_status, output_message_buffer);
451 free_Checksum(&cksum);
452 return GSS_S_FAILURE;
454 free_Checksum(&cksum);
457 krb5_crypto_destroy(context, crypto);
459 if (conf_state != NULL) {
460 *conf_state = conf_req_flag;
464 return GSS_S_COMPLETE;
467 OM_uint32 _gssapi_unwrap_cfx(OM_uint32 *minor_status,
468 const gsskrb5_ctx context_handle,
469 krb5_context context,
470 const gss_buffer_t input_message_buffer,
471 gss_buffer_t output_message_buffer,
473 gss_qop_t *qop_state,
477 gss_cfx_wrap_token token;
483 OM_uint32 seq_number_lo, seq_number_hi;
489 if (input_message_buffer->length < sizeof(*token)) {
490 return GSS_S_DEFECTIVE_TOKEN;
493 p = input_message_buffer->value;
495 token = (gss_cfx_wrap_token)p;
497 if (token->TOK_ID[0] != 0x05 || token->TOK_ID[1] != 0x04) {
498 return GSS_S_DEFECTIVE_TOKEN;
501 /* Ignore unknown flags */
502 token_flags = token->Flags &
503 (CFXSentByAcceptor | CFXSealed | CFXAcceptorSubkey);
505 if (token_flags & CFXSentByAcceptor) {
506 if ((context_handle->more_flags & LOCAL) == 0)
507 return GSS_S_DEFECTIVE_TOKEN;
510 if (context_handle->more_flags & ACCEPTOR_SUBKEY) {
511 if ((token_flags & CFXAcceptorSubkey) == 0)
512 return GSS_S_DEFECTIVE_TOKEN;
514 if (token_flags & CFXAcceptorSubkey)
515 return GSS_S_DEFECTIVE_TOKEN;
518 if (token->Filler != 0xFF) {
519 return GSS_S_DEFECTIVE_TOKEN;
522 if (conf_state != NULL) {
523 *conf_state = (token_flags & CFXSealed) ? 1 : 0;
526 ec = (token->EC[0] << 8) | token->EC[1];
527 rrc = (token->RRC[0] << 8) | token->RRC[1];
530 * Check sequence number
532 _gsskrb5_decode_be_om_uint32(&token->SND_SEQ[0], &seq_number_hi);
533 _gsskrb5_decode_be_om_uint32(&token->SND_SEQ[4], &seq_number_lo);
535 /* no support for 64-bit sequence numbers */
536 *minor_status = ERANGE;
537 return GSS_S_UNSEQ_TOKEN;
540 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
541 ret = _gssapi_msg_order_check(context_handle->order, seq_number_lo);
544 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
545 _gsskrb5_release_buffer(minor_status, output_message_buffer);
548 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
551 * Decrypt and/or verify checksum
553 ret = krb5_crypto_init(context, key, 0, &crypto);
556 return GSS_S_FAILURE;
559 if (context_handle->more_flags & LOCAL) {
560 usage = KRB5_KU_USAGE_ACCEPTOR_SEAL;
562 usage = KRB5_KU_USAGE_INITIATOR_SEAL;
566 len = input_message_buffer->length;
567 len -= (p - (u_char *)input_message_buffer->value);
569 if (token_flags & CFXSealed) {
571 * this is really ugly, but needed against windows
572 * for DCERPC, as windows rotates by EC+RRC.
574 if (IS_DCE_STYLE(context_handle)) {
575 *minor_status = rrc_rotate(p, len, rrc+ec, TRUE);
577 *minor_status = rrc_rotate(p, len, rrc, TRUE);
579 if (*minor_status != 0) {
580 krb5_crypto_destroy(context, crypto);
581 return GSS_S_FAILURE;
584 ret = krb5_decrypt(context, crypto, usage,
588 krb5_crypto_destroy(context, crypto);
589 return GSS_S_BAD_MIC;
592 /* Check that there is room for the pad and token header */
593 if (data.length < ec + sizeof(*token)) {
594 krb5_crypto_destroy(context, crypto);
595 krb5_data_free(&data);
596 return GSS_S_DEFECTIVE_TOKEN;
599 p += data.length - sizeof(*token);
601 /* RRC is unprotected; don't modify input buffer */
602 ((gss_cfx_wrap_token)p)->RRC[0] = token->RRC[0];
603 ((gss_cfx_wrap_token)p)->RRC[1] = token->RRC[1];
605 /* Check the integrity of the header */
606 if (memcmp(p, token, sizeof(*token)) != 0) {
607 krb5_crypto_destroy(context, crypto);
608 krb5_data_free(&data);
609 return GSS_S_BAD_MIC;
612 output_message_buffer->value = data.data;
613 output_message_buffer->length = data.length - ec - sizeof(*token);
617 /* Rotate by RRC; bogus to do this in-place XXX */
618 *minor_status = rrc_rotate(p, len, rrc, TRUE);
619 if (*minor_status != 0) {
620 krb5_crypto_destroy(context, crypto);
621 return GSS_S_FAILURE;
624 /* Determine checksum type */
625 ret = krb5_crypto_get_checksum_type(context,
626 crypto, &cksum.cksumtype);
629 krb5_crypto_destroy(context, crypto);
630 return GSS_S_FAILURE;
633 cksum.checksum.length = ec;
635 /* Check we have at least as much data as the checksum */
636 if (len < cksum.checksum.length) {
637 *minor_status = ERANGE;
638 krb5_crypto_destroy(context, crypto);
639 return GSS_S_BAD_MIC;
642 /* Length now is of the plaintext only, no checksum */
643 len -= cksum.checksum.length;
644 cksum.checksum.data = p + len;
646 output_message_buffer->length = len; /* for later */
647 output_message_buffer->value = malloc(len + sizeof(*token));
648 if (output_message_buffer->value == NULL) {
649 *minor_status = ENOMEM;
650 krb5_crypto_destroy(context, crypto);
651 return GSS_S_FAILURE;
654 /* Checksum is over (plaintext-data | "header") */
655 memcpy(output_message_buffer->value, p, len);
656 memcpy((u_char *)output_message_buffer->value + len,
657 token, sizeof(*token));
659 /* EC is not included in checksum calculation */
660 token = (gss_cfx_wrap_token)((u_char *)output_message_buffer->value +
667 ret = krb5_verify_checksum(context, crypto,
669 output_message_buffer->value,
670 len + sizeof(*token),
674 krb5_crypto_destroy(context, crypto);
675 _gsskrb5_release_buffer(minor_status, output_message_buffer);
676 return GSS_S_BAD_MIC;
680 krb5_crypto_destroy(context, crypto);
682 if (qop_state != NULL) {
683 *qop_state = GSS_C_QOP_DEFAULT;
687 return GSS_S_COMPLETE;
690 OM_uint32 _gssapi_mic_cfx(OM_uint32 *minor_status,
691 const gsskrb5_ctx context_handle,
692 krb5_context context,
694 const gss_buffer_t message_buffer,
695 gss_buffer_t message_token,
699 gss_cfx_mic_token token;
707 ret = krb5_crypto_init(context, key, 0, &crypto);
710 return GSS_S_FAILURE;
713 len = message_buffer->length + sizeof(*token);
716 *minor_status = ENOMEM;
717 krb5_crypto_destroy(context, crypto);
718 return GSS_S_FAILURE;
721 memcpy(buf, message_buffer->value, message_buffer->length);
723 token = (gss_cfx_mic_token)(buf + message_buffer->length);
724 token->TOK_ID[0] = 0x04;
725 token->TOK_ID[1] = 0x04;
727 if ((context_handle->more_flags & LOCAL) == 0)
728 token->Flags |= CFXSentByAcceptor;
729 if (context_handle->more_flags & ACCEPTOR_SUBKEY)
730 token->Flags |= CFXAcceptorSubkey;
731 memset(token->Filler, 0xFF, 5);
733 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
734 krb5_auth_con_getlocalseqnumber(context,
735 context_handle->auth_context,
737 _gsskrb5_encode_be_om_uint32(0, &token->SND_SEQ[0]);
738 _gsskrb5_encode_be_om_uint32(seq_number, &token->SND_SEQ[4]);
739 krb5_auth_con_setlocalseqnumber(context,
740 context_handle->auth_context,
742 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
744 if (context_handle->more_flags & LOCAL) {
745 usage = KRB5_KU_USAGE_INITIATOR_SIGN;
747 usage = KRB5_KU_USAGE_ACCEPTOR_SIGN;
750 ret = krb5_create_checksum(context, crypto,
751 usage, 0, buf, len, &cksum);
754 krb5_crypto_destroy(context, crypto);
756 return GSS_S_FAILURE;
758 krb5_crypto_destroy(context, crypto);
760 /* Determine MIC length */
761 message_token->length = sizeof(*token) + cksum.checksum.length;
762 message_token->value = malloc(message_token->length);
763 if (message_token->value == NULL) {
764 *minor_status = ENOMEM;
765 free_Checksum(&cksum);
767 return GSS_S_FAILURE;
770 /* Token is { "header" | get_mic("header" | plaintext-data) } */
771 memcpy(message_token->value, token, sizeof(*token));
772 memcpy((u_char *)message_token->value + sizeof(*token),
773 cksum.checksum.data, cksum.checksum.length);
775 free_Checksum(&cksum);
779 return GSS_S_COMPLETE;
782 OM_uint32 _gssapi_verify_mic_cfx(OM_uint32 *minor_status,
783 const gsskrb5_ctx context_handle,
784 krb5_context context,
785 const gss_buffer_t message_buffer,
786 const gss_buffer_t token_buffer,
787 gss_qop_t *qop_state,
791 gss_cfx_mic_token token;
795 OM_uint32 seq_number_lo, seq_number_hi;
801 if (token_buffer->length < sizeof(*token)) {
802 return GSS_S_DEFECTIVE_TOKEN;
805 p = token_buffer->value;
807 token = (gss_cfx_mic_token)p;
809 if (token->TOK_ID[0] != 0x04 || token->TOK_ID[1] != 0x04) {
810 return GSS_S_DEFECTIVE_TOKEN;
813 /* Ignore unknown flags */
814 token_flags = token->Flags & (CFXSentByAcceptor | CFXAcceptorSubkey);
816 if (token_flags & CFXSentByAcceptor) {
817 if ((context_handle->more_flags & LOCAL) == 0)
818 return GSS_S_DEFECTIVE_TOKEN;
820 if (context_handle->more_flags & ACCEPTOR_SUBKEY) {
821 if ((token_flags & CFXAcceptorSubkey) == 0)
822 return GSS_S_DEFECTIVE_TOKEN;
824 if (token_flags & CFXAcceptorSubkey)
825 return GSS_S_DEFECTIVE_TOKEN;
828 if (memcmp(token->Filler, "\xff\xff\xff\xff\xff", 5) != 0) {
829 return GSS_S_DEFECTIVE_TOKEN;
833 * Check sequence number
835 _gsskrb5_decode_be_om_uint32(&token->SND_SEQ[0], &seq_number_hi);
836 _gsskrb5_decode_be_om_uint32(&token->SND_SEQ[4], &seq_number_lo);
838 *minor_status = ERANGE;
839 return GSS_S_UNSEQ_TOKEN;
842 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
843 ret = _gssapi_msg_order_check(context_handle->order, seq_number_lo);
846 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
849 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
854 ret = krb5_crypto_init(context, key, 0, &crypto);
857 return GSS_S_FAILURE;
860 ret = krb5_crypto_get_checksum_type(context, crypto,
864 krb5_crypto_destroy(context, crypto);
865 return GSS_S_FAILURE;
868 cksum.checksum.data = p + sizeof(*token);
869 cksum.checksum.length = token_buffer->length - sizeof(*token);
871 if (context_handle->more_flags & LOCAL) {
872 usage = KRB5_KU_USAGE_ACCEPTOR_SIGN;
874 usage = KRB5_KU_USAGE_INITIATOR_SIGN;
877 buf = malloc(message_buffer->length + sizeof(*token));
879 *minor_status = ENOMEM;
880 krb5_crypto_destroy(context, crypto);
881 return GSS_S_FAILURE;
883 memcpy(buf, message_buffer->value, message_buffer->length);
884 memcpy(buf + message_buffer->length, token, sizeof(*token));
886 ret = krb5_verify_checksum(context, crypto,
889 sizeof(*token) + message_buffer->length,
891 krb5_crypto_destroy(context, crypto);
895 return GSS_S_BAD_MIC;
900 if (qop_state != NULL) {
901 *qop_state = GSS_C_QOP_DEFAULT;
904 return GSS_S_COMPLETE;