2 * Copyright (c) 2003 - 2006 Kungliga Tekniska Högskolan
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34 #include "krb5/gsskrb5_locl.h"
36 RCSID("$Id: arcfour.c 19031 2006-11-13 18:02:57Z lha $");
39 * Implements draft-brezak-win2k-krb-rc4-hmac-04.txt
41 * The arcfour message have the following formats:
61 * WRAP in DCE-style have a fixed size header, the oid and length over
62 * the WRAP header is a total of
63 * GSS_ARCFOUR_WRAP_TOKEN_DCE_DER_HEADER_SIZE +
64 * GSS_ARCFOUR_WRAP_TOKEN_SIZE byte (ie total of 45 bytes overhead,
65 * remember the 2 bytes from APPL [0] SEQ).
68 #define GSS_ARCFOUR_WRAP_TOKEN_SIZE 32
69 #define GSS_ARCFOUR_WRAP_TOKEN_DCE_DER_HEADER_SIZE 13
72 static krb5_error_code
73 arcfour_mic_key(krb5_context context, krb5_keyblock *key,
74 void *cksum_data, size_t cksum_size,
75 void *key6_data, size_t key6_size)
88 cksum_k5.checksum.data = k5_data;
89 cksum_k5.checksum.length = sizeof(k5_data);
91 if (key->keytype == KEYTYPE_ARCFOUR_56) {
92 char L40[14] = "fortybits";
94 memcpy(L40 + 10, T, sizeof(T));
95 ret = krb5_hmac(context, CKSUMTYPE_RSA_MD5,
96 L40, 14, 0, key, &cksum_k5);
97 memset(&k5_data[7], 0xAB, 9);
99 ret = krb5_hmac(context, CKSUMTYPE_RSA_MD5,
100 T, 4, 0, key, &cksum_k5);
105 key5.keytype = KEYTYPE_ARCFOUR;
106 key5.keyvalue = cksum_k5.checksum;
108 cksum_k6.checksum.data = key6_data;
109 cksum_k6.checksum.length = key6_size;
111 return krb5_hmac(context, CKSUMTYPE_RSA_MD5,
112 cksum_data, cksum_size, 0, &key5, &cksum_k6);
116 static krb5_error_code
117 arcfour_mic_cksum(krb5_context context,
118 krb5_keyblock *key, unsigned usage,
119 u_char *sgn_cksum, size_t sgn_cksum_sz,
120 const u_char *v1, size_t l1,
121 const void *v2, size_t l2,
122 const void *v3, size_t l3)
130 assert(sgn_cksum_sz == 8);
139 memcpy(ptr + l1, v2, l2);
140 memcpy(ptr + l1 + l2, v3, l3);
142 ret = krb5_crypto_init(context, key, 0, &crypto);
148 ret = krb5_create_checksum(context,
156 memcpy(sgn_cksum, CKSUM.checksum.data, sgn_cksum_sz);
157 free_Checksum(&CKSUM);
159 krb5_crypto_destroy(context, crypto);
166 _gssapi_get_mic_arcfour(OM_uint32 * minor_status,
167 const gsskrb5_ctx context_handle,
168 krb5_context context,
170 const gss_buffer_t message_buffer,
171 gss_buffer_t message_token,
176 size_t len, total_len;
177 u_char k6_data[16], *p0, *p;
180 _gsskrb5_encap_length (22, &len, &total_len, GSS_KRB5_MECHANISM);
182 message_token->length = total_len;
183 message_token->value = malloc (total_len);
184 if (message_token->value == NULL) {
185 *minor_status = ENOMEM;
186 return GSS_S_FAILURE;
189 p0 = _gssapi_make_mech_header(message_token->value,
194 *p++ = 0x01; /* TOK_ID */
196 *p++ = 0x11; /* SGN_ALG */
198 *p++ = 0xff; /* Filler */
205 ret = arcfour_mic_cksum(context,
206 key, KRB5_KU_USAGE_SIGN,
207 p0 + 16, 8, /* SGN_CKSUM */
208 p0, 8, /* TOK_ID, SGN_ALG, Filer */
209 message_buffer->value, message_buffer->length,
212 _gsskrb5_release_buffer(minor_status, message_token);
214 return GSS_S_FAILURE;
217 ret = arcfour_mic_key(context, key,
218 p0 + 16, 8, /* SGN_CKSUM */
219 k6_data, sizeof(k6_data));
221 _gsskrb5_release_buffer(minor_status, message_token);
223 return GSS_S_FAILURE;
226 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
227 krb5_auth_con_getlocalseqnumber (context,
228 context_handle->auth_context,
230 p = p0 + 8; /* SND_SEQ */
231 _gsskrb5_encode_be_om_uint32(seq_number, p);
233 krb5_auth_con_setlocalseqnumber (context,
234 context_handle->auth_context,
236 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
238 memset (p + 4, (context_handle->more_flags & LOCAL) ? 0 : 0xff, 4);
240 RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
241 RC4 (&rc4_key, 8, p, p);
243 memset(&rc4_key, 0, sizeof(rc4_key));
244 memset(k6_data, 0, sizeof(k6_data));
247 return GSS_S_COMPLETE;
252 _gssapi_verify_mic_arcfour(OM_uint32 * minor_status,
253 const gsskrb5_ctx context_handle,
254 krb5_context context,
255 const gss_buffer_t message_buffer,
256 const gss_buffer_t token_buffer,
257 gss_qop_t * qop_state,
264 u_char SND_SEQ[8], cksum_data[8], *p;
271 p = token_buffer->value;
272 omret = _gsskrb5_verify_header (&p,
273 token_buffer->length,
279 if (memcmp(p, "\x11\x00", 2) != 0) /* SGN_ALG = HMAC MD5 ARCFOUR */
280 return GSS_S_BAD_SIG;
282 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
283 return GSS_S_BAD_MIC;
286 ret = arcfour_mic_cksum(context,
287 key, KRB5_KU_USAGE_SIGN,
288 cksum_data, sizeof(cksum_data),
290 message_buffer->value, message_buffer->length,
294 return GSS_S_FAILURE;
297 ret = arcfour_mic_key(context, key,
298 cksum_data, sizeof(cksum_data),
299 k6_data, sizeof(k6_data));
302 return GSS_S_FAILURE;
305 cmp = memcmp(cksum_data, p + 8, 8);
308 return GSS_S_BAD_MIC;
314 RC4_set_key (&rc4_key, sizeof(k6_data), (void*)k6_data);
315 RC4 (&rc4_key, 8, p, SND_SEQ);
317 memset(&rc4_key, 0, sizeof(rc4_key));
318 memset(k6_data, 0, sizeof(k6_data));
321 _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
323 if (context_handle->more_flags & LOCAL)
324 cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
326 cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
328 memset(SND_SEQ, 0, sizeof(SND_SEQ));
331 return GSS_S_BAD_MIC;
334 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
335 omret = _gssapi_msg_order_check(context_handle->order, seq_number);
336 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
341 return GSS_S_COMPLETE;
345 _gssapi_wrap_arcfour(OM_uint32 * minor_status,
346 const gsskrb5_ctx context_handle,
347 krb5_context context,
350 const gss_buffer_t input_message_buffer,
352 gss_buffer_t output_message_buffer,
355 u_char Klocaldata[16], k6_data[16], *p, *p0;
356 size_t len, total_len, datalen;
357 krb5_keyblock Klocal;
364 datalen = input_message_buffer->length;
366 if (IS_DCE_STYLE(context_handle)) {
367 len = GSS_ARCFOUR_WRAP_TOKEN_SIZE;
368 _gssapi_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
369 total_len += datalen;
371 datalen += 1; /* padding */
372 len = datalen + GSS_ARCFOUR_WRAP_TOKEN_SIZE;
373 _gssapi_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
376 output_message_buffer->length = total_len;
377 output_message_buffer->value = malloc (total_len);
378 if (output_message_buffer->value == NULL) {
379 *minor_status = ENOMEM;
380 return GSS_S_FAILURE;
383 p0 = _gssapi_make_mech_header(output_message_buffer->value,
388 *p++ = 0x02; /* TOK_ID */
390 *p++ = 0x11; /* SGN_ALG */
393 *p++ = 0x10; /* SEAL_ALG */
396 *p++ = 0xff; /* SEAL_ALG */
399 *p++ = 0xff; /* Filler */
404 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
405 krb5_auth_con_getlocalseqnumber (context,
406 context_handle->auth_context,
409 _gsskrb5_encode_be_om_uint32(seq_number, p0 + 8);
411 krb5_auth_con_setlocalseqnumber (context,
412 context_handle->auth_context,
414 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
417 (context_handle->more_flags & LOCAL) ? 0 : 0xff,
420 krb5_generate_random_block(p0 + 24, 8); /* fill in Confounder */
422 /* p points to data */
423 p = p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE;
424 memcpy(p, input_message_buffer->value, input_message_buffer->length);
426 if (!IS_DCE_STYLE(context_handle))
427 p[input_message_buffer->length] = 1; /* padding */
429 ret = arcfour_mic_cksum(context,
430 key, KRB5_KU_USAGE_SEAL,
431 p0 + 16, 8, /* SGN_CKSUM */
432 p0, 8, /* TOK_ID, SGN_ALG, SEAL_ALG, Filler */
433 p0 + 24, 8, /* Confounder */
434 p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE,
438 _gsskrb5_release_buffer(minor_status, output_message_buffer);
439 return GSS_S_FAILURE;
445 Klocal.keytype = key->keytype;
446 Klocal.keyvalue.data = Klocaldata;
447 Klocal.keyvalue.length = sizeof(Klocaldata);
449 for (i = 0; i < 16; i++)
450 Klocaldata[i] = ((u_char *)key->keyvalue.data)[i] ^ 0xF0;
452 ret = arcfour_mic_key(context, &Klocal,
453 p0 + 8, 4, /* SND_SEQ */
454 k6_data, sizeof(k6_data));
455 memset(Klocaldata, 0, sizeof(Klocaldata));
457 _gsskrb5_release_buffer(minor_status, output_message_buffer);
459 return GSS_S_FAILURE;
466 RC4_set_key (&rc4_key, sizeof(k6_data), (void *)k6_data);
468 RC4 (&rc4_key, 8 + datalen, p0 + 24, p0 + 24); /* Confounder + data */
469 memset(&rc4_key, 0, sizeof(rc4_key));
471 memset(k6_data, 0, sizeof(k6_data));
473 ret = arcfour_mic_key(context, key,
474 p0 + 16, 8, /* SGN_CKSUM */
475 k6_data, sizeof(k6_data));
477 _gsskrb5_release_buffer(minor_status, output_message_buffer);
479 return GSS_S_FAILURE;
485 RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
486 RC4 (&rc4_key, 8, p0 + 8, p0 + 8); /* SND_SEQ */
487 memset(&rc4_key, 0, sizeof(rc4_key));
488 memset(k6_data, 0, sizeof(k6_data));
492 *conf_state = conf_req_flag;
495 return GSS_S_COMPLETE;
498 OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status,
499 const gsskrb5_ctx context_handle,
500 krb5_context context,
501 const gss_buffer_t input_message_buffer,
502 gss_buffer_t output_message_buffer,
504 gss_qop_t *qop_state,
507 u_char Klocaldata[16];
508 krb5_keyblock Klocal;
513 u_char k6_data[16], SND_SEQ[8], Confounder[8];
514 u_char cksum_data[8];
518 size_t padlen = 0, len;
525 p0 = input_message_buffer->value;
527 if (IS_DCE_STYLE(context_handle)) {
528 len = GSS_ARCFOUR_WRAP_TOKEN_SIZE +
529 GSS_ARCFOUR_WRAP_TOKEN_DCE_DER_HEADER_SIZE;
530 if (input_message_buffer->length < len)
531 return GSS_S_BAD_MECH;
533 len = input_message_buffer->length;
536 omret = _gssapi_verify_mech_header(&p0,
542 /* length of mech header */
543 len = (p0 - (u_char *)input_message_buffer->value) +
544 GSS_ARCFOUR_WRAP_TOKEN_SIZE;
546 if (len > input_message_buffer->length)
547 return GSS_S_BAD_MECH;
550 datalen = input_message_buffer->length - len;
554 if (memcmp(p, "\x02\x01", 2) != 0)
555 return GSS_S_BAD_SIG;
557 if (memcmp(p, "\x11\x00", 2) != 0) /* SGN_ALG = HMAC MD5 ARCFOUR */
558 return GSS_S_BAD_SIG;
561 if (memcmp (p, "\x10\x00", 2) == 0)
563 else if (memcmp (p, "\xff\xff", 2) == 0)
566 return GSS_S_BAD_SIG;
569 if (memcmp (p, "\xff\xff", 2) != 0)
570 return GSS_S_BAD_MIC;
573 ret = arcfour_mic_key(context, key,
574 p0 + 16, 8, /* SGN_CKSUM */
575 k6_data, sizeof(k6_data));
578 return GSS_S_FAILURE;
584 RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
585 RC4 (&rc4_key, 8, p0 + 8, SND_SEQ); /* SND_SEQ */
586 memset(&rc4_key, 0, sizeof(rc4_key));
587 memset(k6_data, 0, sizeof(k6_data));
590 _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
592 if (context_handle->more_flags & LOCAL)
593 cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
595 cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
599 return GSS_S_BAD_MIC;
605 Klocal.keytype = key->keytype;
606 Klocal.keyvalue.data = Klocaldata;
607 Klocal.keyvalue.length = sizeof(Klocaldata);
609 for (i = 0; i < 16; i++)
610 Klocaldata[i] = ((u_char *)key->keyvalue.data)[i] ^ 0xF0;
612 ret = arcfour_mic_key(context, &Klocal,
614 k6_data, sizeof(k6_data));
615 memset(Klocaldata, 0, sizeof(Klocaldata));
618 return GSS_S_FAILURE;
621 output_message_buffer->value = malloc(datalen);
622 if (output_message_buffer->value == NULL) {
623 *minor_status = ENOMEM;
624 return GSS_S_FAILURE;
626 output_message_buffer->length = datalen;
631 RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
632 RC4 (&rc4_key, 8, p0 + 24, Confounder); /* Confounder */
633 RC4 (&rc4_key, datalen, p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE,
634 output_message_buffer->value);
635 memset(&rc4_key, 0, sizeof(rc4_key));
637 memcpy(Confounder, p0 + 24, 8); /* Confounder */
638 memcpy(output_message_buffer->value,
639 p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE,
642 memset(k6_data, 0, sizeof(k6_data));
644 if (!IS_DCE_STYLE(context_handle)) {
645 ret = _gssapi_verify_pad(output_message_buffer, datalen, &padlen);
647 _gsskrb5_release_buffer(minor_status, output_message_buffer);
651 output_message_buffer->length -= padlen;
654 ret = arcfour_mic_cksum(context,
655 key, KRB5_KU_USAGE_SEAL,
656 cksum_data, sizeof(cksum_data),
658 Confounder, sizeof(Confounder),
659 output_message_buffer->value,
660 output_message_buffer->length + padlen);
662 _gsskrb5_release_buffer(minor_status, output_message_buffer);
664 return GSS_S_FAILURE;
667 cmp = memcmp(cksum_data, p0 + 16, 8); /* SGN_CKSUM */
669 _gsskrb5_release_buffer(minor_status, output_message_buffer);
671 return GSS_S_BAD_MIC;
674 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
675 omret = _gssapi_msg_order_check(context_handle->order, seq_number);
676 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
681 *conf_state = conf_flag;
684 return GSS_S_COMPLETE;
688 max_wrap_length_arcfour(const gsskrb5_ctx ctx,
691 OM_uint32 *max_input_size)
694 * if GSS_C_DCE_STYLE is in use:
695 * - we only need to encapsulate the WRAP token
696 * However, since this is a fixed since, we just
698 if (IS_DCE_STYLE(ctx)) {
699 size_t len, total_len;
701 len = GSS_ARCFOUR_WRAP_TOKEN_SIZE;
702 _gssapi_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
704 if (input_length < len)
707 *max_input_size = input_length - len;
710 size_t extrasize = GSS_ARCFOUR_WRAP_TOKEN_SIZE;
711 size_t blocksize = 8;
712 size_t len, total_len;
714 len = 8 + input_length + blocksize + extrasize;
716 _gsskrb5_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
718 total_len -= input_length; /* token length */
719 if (total_len < input_length) {
720 *max_input_size = (input_length - total_len);
721 (*max_input_size) &= (~(OM_uint32)(blocksize - 1));
727 return GSS_S_COMPLETE;
731 _gssapi_wrap_size_arcfour(OM_uint32 *minor_status,
732 const gsskrb5_ctx ctx,
733 krb5_context context,
736 OM_uint32 req_output_size,
737 OM_uint32 *max_input_size,
743 ret = krb5_crypto_init(context, key, 0, &crypto);
746 return GSS_S_FAILURE;
749 ret = max_wrap_length_arcfour(ctx, crypto,
750 req_output_size, max_input_size);
753 krb5_crypto_destroy(context, crypto);
754 return GSS_S_FAILURE;
757 krb5_crypto_destroy(context, crypto);
759 return GSS_S_COMPLETE;