1 /*
2 * Copyright 2018-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /*
11 * DES low level APIs are deprecated for public use, but still ok for internal
12 * use. We access the DES_set_odd_parity(3) function here.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdlib.h>
17 #include <stdarg.h>
18 #include <string.h>
19
20 #include <openssl/core_names.h>
21 #include <openssl/des.h>
22 #include <openssl/evp.h>
23 #include <openssl/kdf.h>
24 #include <openssl/proverr.h>
25
26 #include "internal/cryptlib.h"
27 #include "crypto/evp.h"
28 #include "internal/numbers.h"
29 #include "prov/implementations.h"
30 #include "prov/provider_ctx.h"
31 #include "prov/provider_util.h"
32 #include "prov/providercommon.h"
33
34 /* KRB5 KDF defined in RFC 3961, Section 5.1 */
35
36 static OSSL_FUNC_kdf_newctx_fn krb5kdf_new;
37 static OSSL_FUNC_kdf_freectx_fn krb5kdf_free;
38 static OSSL_FUNC_kdf_reset_fn krb5kdf_reset;
39 static OSSL_FUNC_kdf_derive_fn krb5kdf_derive;
40 static OSSL_FUNC_kdf_settable_ctx_params_fn krb5kdf_settable_ctx_params;
41 static OSSL_FUNC_kdf_set_ctx_params_fn krb5kdf_set_ctx_params;
42 static OSSL_FUNC_kdf_gettable_ctx_params_fn krb5kdf_gettable_ctx_params;
43 static OSSL_FUNC_kdf_get_ctx_params_fn krb5kdf_get_ctx_params;
44
45 static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
46 const unsigned char *key, size_t key_len,
47 const unsigned char *constant, size_t constant_len,
48 unsigned char *okey, size_t okey_len);
49
50 typedef struct {
51 void *provctx;
52 PROV_CIPHER cipher;
53 unsigned char *key;
54 size_t key_len;
55 unsigned char *constant;
56 size_t constant_len;
57 } KRB5KDF_CTX;
58
krb5kdf_new(void * provctx)59 static void *krb5kdf_new(void *provctx)
60 {
61 KRB5KDF_CTX *ctx;
62
63 if (!ossl_prov_is_running())
64 return NULL;
65
66 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL) {
67 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
68 return NULL;
69 }
70 ctx->provctx = provctx;
71 return ctx;
72 }
73
krb5kdf_free(void * vctx)74 static void krb5kdf_free(void *vctx)
75 {
76 KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
77
78 if (ctx != NULL) {
79 krb5kdf_reset(ctx);
80 OPENSSL_free(ctx);
81 }
82 }
83
krb5kdf_reset(void * vctx)84 static void krb5kdf_reset(void *vctx)
85 {
86 KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
87 void *provctx = ctx->provctx;
88
89 ossl_prov_cipher_reset(&ctx->cipher);
90 OPENSSL_clear_free(ctx->key, ctx->key_len);
91 OPENSSL_clear_free(ctx->constant, ctx->constant_len);
92 memset(ctx, 0, sizeof(*ctx));
93 ctx->provctx = provctx;
94 }
95
krb5kdf_set_membuf(unsigned char ** dst,size_t * dst_len,const OSSL_PARAM * p)96 static int krb5kdf_set_membuf(unsigned char **dst, size_t *dst_len,
97 const OSSL_PARAM *p)
98 {
99 OPENSSL_clear_free(*dst, *dst_len);
100 *dst = NULL;
101 *dst_len = 0;
102 return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
103 }
104
krb5kdf_derive(void * vctx,unsigned char * key,size_t keylen,const OSSL_PARAM params[])105 static int krb5kdf_derive(void *vctx, unsigned char *key, size_t keylen,
106 const OSSL_PARAM params[])
107 {
108 KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
109 const EVP_CIPHER *cipher;
110 ENGINE *engine;
111
112 if (!ossl_prov_is_running() || !krb5kdf_set_ctx_params(ctx, params))
113 return 0;
114
115 cipher = ossl_prov_cipher_cipher(&ctx->cipher);
116 if (cipher == NULL) {
117 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CIPHER);
118 return 0;
119 }
120 if (ctx->key == NULL) {
121 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
122 return 0;
123 }
124 if (ctx->constant == NULL) {
125 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CONSTANT);
126 return 0;
127 }
128 engine = ossl_prov_cipher_engine(&ctx->cipher);
129 return KRB5KDF(cipher, engine, ctx->key, ctx->key_len,
130 ctx->constant, ctx->constant_len,
131 key, keylen);
132 }
133
krb5kdf_set_ctx_params(void * vctx,const OSSL_PARAM params[])134 static int krb5kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
135 {
136 const OSSL_PARAM *p;
137 KRB5KDF_CTX *ctx = vctx;
138 OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
139
140 if (params == NULL)
141 return 1;
142
143 if (!ossl_prov_cipher_load_from_params(&ctx->cipher, params, provctx))
144 return 0;
145
146 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
147 if (!krb5kdf_set_membuf(&ctx->key, &ctx->key_len, p))
148 return 0;
149
150 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CONSTANT))
151 != NULL)
152 if (!krb5kdf_set_membuf(&ctx->constant, &ctx->constant_len, p))
153 return 0;
154
155 return 1;
156 }
157
krb5kdf_settable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)158 static const OSSL_PARAM *krb5kdf_settable_ctx_params(ossl_unused void *ctx,
159 ossl_unused void *provctx)
160 {
161 static const OSSL_PARAM known_settable_ctx_params[] = {
162 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
163 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
164 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
165 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_CONSTANT, NULL, 0),
166 OSSL_PARAM_END
167 };
168 return known_settable_ctx_params;
169 }
170
krb5kdf_get_ctx_params(void * vctx,OSSL_PARAM params[])171 static int krb5kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
172 {
173 KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
174 const EVP_CIPHER *cipher;
175 size_t len;
176 OSSL_PARAM *p;
177
178 cipher = ossl_prov_cipher_cipher(&ctx->cipher);
179 if (cipher)
180 len = EVP_CIPHER_get_key_length(cipher);
181 else
182 len = EVP_MAX_KEY_LENGTH;
183
184 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
185 return OSSL_PARAM_set_size_t(p, len);
186 return -2;
187 }
188
krb5kdf_gettable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)189 static const OSSL_PARAM *krb5kdf_gettable_ctx_params(ossl_unused void *ctx,
190 ossl_unused void *provctx)
191 {
192 static const OSSL_PARAM known_gettable_ctx_params[] = {
193 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
194 OSSL_PARAM_END
195 };
196 return known_gettable_ctx_params;
197 }
198
199 const OSSL_DISPATCH ossl_kdf_krb5kdf_functions[] = {
200 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))krb5kdf_new },
201 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))krb5kdf_free },
202 { OSSL_FUNC_KDF_RESET, (void(*)(void))krb5kdf_reset },
203 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))krb5kdf_derive },
204 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
205 (void(*)(void))krb5kdf_settable_ctx_params },
206 { OSSL_FUNC_KDF_SET_CTX_PARAMS,
207 (void(*)(void))krb5kdf_set_ctx_params },
208 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
209 (void(*)(void))krb5kdf_gettable_ctx_params },
210 { OSSL_FUNC_KDF_GET_CTX_PARAMS,
211 (void(*)(void))krb5kdf_get_ctx_params },
212 { 0, NULL }
213 };
214
215 #ifndef OPENSSL_NO_DES
216 /*
217 * DES3 is a special case, it requires a random-to-key function and its
218 * input truncated to 21 bytes of the 24 produced by the cipher.
219 * See RFC3961 6.3.1
220 */
fixup_des3_key(unsigned char * key)221 static int fixup_des3_key(unsigned char *key)
222 {
223 unsigned char *cblock;
224 int i, j;
225
226 for (i = 2; i >= 0; i--) {
227 cblock = &key[i * 8];
228 memmove(cblock, &key[i * 7], 7);
229 cblock[7] = 0;
230 for (j = 0; j < 7; j++)
231 cblock[7] |= (cblock[j] & 1) << (j + 1);
232 DES_set_odd_parity((DES_cblock *)cblock);
233 }
234
235 /* fail if keys are such that triple des degrades to single des */
236 if (CRYPTO_memcmp(&key[0], &key[8], 8) == 0 ||
237 CRYPTO_memcmp(&key[8], &key[16], 8) == 0) {
238 return 0;
239 }
240
241 return 1;
242 }
243 #endif
244
245 /*
246 * N-fold(K) where blocksize is N, and constant_len is K
247 * Note: Here |= denotes concatenation
248 *
249 * L = lcm(N,K)
250 * R = L/K
251 *
252 * for r: 1 -> R
253 * s |= constant rot 13*(r-1))
254 *
255 * block = 0
256 * for k: 1 -> K
257 * block += s[N(k-1)..(N-1)k] (one's complement addition)
258 *
259 * Optimizing for space we compute:
260 * for each l in L-1 -> 0:
261 * s[l] = (constant rot 13*(l/K))[l%k]
262 * block[l % N] += s[l] (with carry)
263 * finally add carry if any
264 */
n_fold(unsigned char * block,unsigned int blocksize,const unsigned char * constant,size_t constant_len)265 static void n_fold(unsigned char *block, unsigned int blocksize,
266 const unsigned char *constant, size_t constant_len)
267 {
268 unsigned int tmp, gcd, remainder, lcm, carry;
269 int b, l;
270
271 if (constant_len == blocksize) {
272 memcpy(block, constant, constant_len);
273 return;
274 }
275
276 /* Least Common Multiple of lengths: LCM(a,b)*/
277 gcd = blocksize;
278 remainder = constant_len;
279 /* Calculate Great Common Divisor first GCD(a,b) */
280 while (remainder != 0) {
281 tmp = gcd % remainder;
282 gcd = remainder;
283 remainder = tmp;
284 }
285 /* resulting a is the GCD, LCM(a,b) = |a*b|/GCD(a,b) */
286 lcm = blocksize * constant_len / gcd;
287
288 /* now spread out the bits */
289 memset(block, 0, blocksize);
290
291 /* last to first to be able to bring carry forward */
292 carry = 0;
293 for (l = lcm - 1; l >= 0; l--) {
294 unsigned int rotbits, rshift, rbyte;
295
296 /* destination byte in block is l % N */
297 b = l % blocksize;
298 /* Our virtual s buffer is R = L/K long (K = constant_len) */
299 /* So we rotate backwards from R-1 to 0 (none) rotations */
300 rotbits = 13 * (l / constant_len);
301 /* find the byte on s where rotbits falls onto */
302 rbyte = l - (rotbits / 8);
303 /* calculate how much shift on that byte */
304 rshift = rotbits & 0x07;
305 /* rbyte % constant_len gives us the unrotated byte in the
306 * constant buffer, get also the previous byte then
307 * appropriately shift them to get the rotated byte we need */
308 tmp = (constant[(rbyte-1) % constant_len] << (8 - rshift)
309 | constant[rbyte % constant_len] >> rshift)
310 & 0xff;
311 /* add with carry to any value placed by previous passes */
312 tmp += carry + block[b];
313 block[b] = tmp & 0xff;
314 /* save any carry that may be left */
315 carry = tmp >> 8;
316 }
317
318 /* if any carry is left at the end, add it through the number */
319 for (b = blocksize - 1; b >= 0 && carry != 0; b--) {
320 carry += block[b];
321 block[b] = carry & 0xff;
322 carry >>= 8;
323 }
324 }
325
cipher_init(EVP_CIPHER_CTX * ctx,const EVP_CIPHER * cipher,ENGINE * engine,const unsigned char * key,size_t key_len)326 static int cipher_init(EVP_CIPHER_CTX *ctx,
327 const EVP_CIPHER *cipher, ENGINE *engine,
328 const unsigned char *key, size_t key_len)
329 {
330 int klen, ret;
331
332 ret = EVP_EncryptInit_ex(ctx, cipher, engine, key, NULL);
333 if (!ret)
334 goto out;
335 /* set the key len for the odd variable key len cipher */
336 klen = EVP_CIPHER_CTX_get_key_length(ctx);
337 if (key_len != (size_t)klen) {
338 ret = EVP_CIPHER_CTX_set_key_length(ctx, key_len);
339 if (ret <= 0) {
340 ret = 0;
341 goto out;
342 }
343 }
344 /* we never want padding, either the length requested is a multiple of
345 * the cipher block size or we are passed a cipher that can cope with
346 * partial blocks via techniques like cipher text stealing */
347 ret = EVP_CIPHER_CTX_set_padding(ctx, 0);
348 if (!ret)
349 goto out;
350
351 out:
352 return ret;
353 }
354
KRB5KDF(const EVP_CIPHER * cipher,ENGINE * engine,const unsigned char * key,size_t key_len,const unsigned char * constant,size_t constant_len,unsigned char * okey,size_t okey_len)355 static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
356 const unsigned char *key, size_t key_len,
357 const unsigned char *constant, size_t constant_len,
358 unsigned char *okey, size_t okey_len)
359 {
360 EVP_CIPHER_CTX *ctx = NULL;
361 unsigned char block[EVP_MAX_BLOCK_LENGTH * 2];
362 unsigned char *plainblock, *cipherblock;
363 size_t blocksize;
364 size_t cipherlen;
365 size_t osize;
366 #ifndef OPENSSL_NO_DES
367 int des3_no_fixup = 0;
368 #endif
369 int ret;
370
371 if (key_len != okey_len) {
372 #ifndef OPENSSL_NO_DES
373 /* special case for 3des, where the caller may be requesting
374 * the random raw key, instead of the fixed up key */
375 if (EVP_CIPHER_get_nid(cipher) == NID_des_ede3_cbc &&
376 key_len == 24 && okey_len == 21) {
377 des3_no_fixup = 1;
378 } else {
379 #endif
380 ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_OUTPUT_BUFFER_SIZE);
381 return 0;
382 #ifndef OPENSSL_NO_DES
383 }
384 #endif
385 }
386
387 ctx = EVP_CIPHER_CTX_new();
388 if (ctx == NULL)
389 return 0;
390
391 ret = cipher_init(ctx, cipher, engine, key, key_len);
392 if (!ret)
393 goto out;
394
395 /* Initialize input block */
396 blocksize = EVP_CIPHER_CTX_get_block_size(ctx);
397
398 if (constant_len > blocksize) {
399 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CONSTANT_LENGTH);
400 ret = 0;
401 goto out;
402 }
403
404 n_fold(block, blocksize, constant, constant_len);
405 plainblock = block;
406 cipherblock = block + EVP_MAX_BLOCK_LENGTH;
407
408 for (osize = 0; osize < okey_len; osize += cipherlen) {
409 int olen;
410
411 ret = EVP_EncryptUpdate(ctx, cipherblock, &olen,
412 plainblock, blocksize);
413 if (!ret)
414 goto out;
415 cipherlen = olen;
416 ret = EVP_EncryptFinal_ex(ctx, cipherblock, &olen);
417 if (!ret)
418 goto out;
419 if (olen != 0) {
420 ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_FINAL_BLOCK_LENGTH);
421 ret = 0;
422 goto out;
423 }
424
425 /* write cipherblock out */
426 if (cipherlen > okey_len - osize)
427 cipherlen = okey_len - osize;
428 memcpy(okey + osize, cipherblock, cipherlen);
429
430 if (okey_len > osize + cipherlen) {
431 /* we need to reinitialize cipher context per spec */
432 ret = EVP_CIPHER_CTX_reset(ctx);
433 if (!ret)
434 goto out;
435 ret = cipher_init(ctx, cipher, engine, key, key_len);
436 if (!ret)
437 goto out;
438
439 /* also swap block offsets so last ciphertext becomes new
440 * plaintext */
441 plainblock = cipherblock;
442 if (cipherblock == block) {
443 cipherblock += EVP_MAX_BLOCK_LENGTH;
444 } else {
445 cipherblock = block;
446 }
447 }
448 }
449
450 #ifndef OPENSSL_NO_DES
451 if (EVP_CIPHER_get_nid(cipher) == NID_des_ede3_cbc && !des3_no_fixup) {
452 ret = fixup_des3_key(okey);
453 if (!ret) {
454 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GENERATE_KEY);
455 goto out;
456 }
457 }
458 #endif
459
460 ret = 1;
461
462 out:
463 EVP_CIPHER_CTX_free(ctx);
464 OPENSSL_cleanse(block, EVP_MAX_BLOCK_LENGTH * 2);
465 return ret;
466 }
467
468