1 /*
2 * Copyright 2018-2021 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 return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
102 }
103
krb5kdf_derive(void * vctx,unsigned char * key,size_t keylen,const OSSL_PARAM params[])104 static int krb5kdf_derive(void *vctx, unsigned char *key, size_t keylen,
105 const OSSL_PARAM params[])
106 {
107 KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
108 const EVP_CIPHER *cipher;
109 ENGINE *engine;
110
111 if (!ossl_prov_is_running() || !krb5kdf_set_ctx_params(ctx, params))
112 return 0;
113
114 cipher = ossl_prov_cipher_cipher(&ctx->cipher);
115 if (cipher == NULL) {
116 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CIPHER);
117 return 0;
118 }
119 if (ctx->key == NULL) {
120 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
121 return 0;
122 }
123 if (ctx->constant == NULL) {
124 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CONSTANT);
125 return 0;
126 }
127 engine = ossl_prov_cipher_engine(&ctx->cipher);
128 return KRB5KDF(cipher, engine, ctx->key, ctx->key_len,
129 ctx->constant, ctx->constant_len,
130 key, keylen);
131 }
132
krb5kdf_set_ctx_params(void * vctx,const OSSL_PARAM params[])133 static int krb5kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
134 {
135 const OSSL_PARAM *p;
136 KRB5KDF_CTX *ctx = vctx;
137 OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
138
139 if (params == NULL)
140 return 1;
141
142 if (!ossl_prov_cipher_load_from_params(&ctx->cipher, params, provctx))
143 return 0;
144
145 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
146 if (!krb5kdf_set_membuf(&ctx->key, &ctx->key_len, p))
147 return 0;
148
149 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CONSTANT))
150 != NULL)
151 if (!krb5kdf_set_membuf(&ctx->constant, &ctx->constant_len, p))
152 return 0;
153
154 return 1;
155 }
156
krb5kdf_settable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)157 static const OSSL_PARAM *krb5kdf_settable_ctx_params(ossl_unused void *ctx,
158 ossl_unused void *provctx)
159 {
160 static const OSSL_PARAM known_settable_ctx_params[] = {
161 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
162 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
163 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
164 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_CONSTANT, NULL, 0),
165 OSSL_PARAM_END
166 };
167 return known_settable_ctx_params;
168 }
169
krb5kdf_get_ctx_params(void * vctx,OSSL_PARAM params[])170 static int krb5kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
171 {
172 KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
173 const EVP_CIPHER *cipher;
174 size_t len;
175 OSSL_PARAM *p;
176
177 cipher = ossl_prov_cipher_cipher(&ctx->cipher);
178 if (cipher)
179 len = EVP_CIPHER_get_key_length(cipher);
180 else
181 len = EVP_MAX_KEY_LENGTH;
182
183 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
184 return OSSL_PARAM_set_size_t(p, len);
185 return -2;
186 }
187
krb5kdf_gettable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)188 static const OSSL_PARAM *krb5kdf_gettable_ctx_params(ossl_unused void *ctx,
189 ossl_unused void *provctx)
190 {
191 static const OSSL_PARAM known_gettable_ctx_params[] = {
192 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
193 OSSL_PARAM_END
194 };
195 return known_gettable_ctx_params;
196 }
197
198 const OSSL_DISPATCH ossl_kdf_krb5kdf_functions[] = {
199 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))krb5kdf_new },
200 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))krb5kdf_free },
201 { OSSL_FUNC_KDF_RESET, (void(*)(void))krb5kdf_reset },
202 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))krb5kdf_derive },
203 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
204 (void(*)(void))krb5kdf_settable_ctx_params },
205 { OSSL_FUNC_KDF_SET_CTX_PARAMS,
206 (void(*)(void))krb5kdf_set_ctx_params },
207 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
208 (void(*)(void))krb5kdf_gettable_ctx_params },
209 { OSSL_FUNC_KDF_GET_CTX_PARAMS,
210 (void(*)(void))krb5kdf_get_ctx_params },
211 { 0, NULL }
212 };
213
214 #ifndef OPENSSL_NO_DES
215 /*
216 * DES3 is a special case, it requires a random-to-key function and its
217 * input truncated to 21 bytes of the 24 produced by the cipher.
218 * See RFC3961 6.3.1
219 */
fixup_des3_key(unsigned char * key)220 static int fixup_des3_key(unsigned char *key)
221 {
222 unsigned char *cblock;
223 int i, j;
224
225 for (i = 2; i >= 0; i--) {
226 cblock = &key[i * 8];
227 memmove(cblock, &key[i * 7], 7);
228 cblock[7] = 0;
229 for (j = 0; j < 7; j++)
230 cblock[7] |= (cblock[j] & 1) << (j + 1);
231 DES_set_odd_parity((DES_cblock *)cblock);
232 }
233
234 /* fail if keys are such that triple des degrades to single des */
235 if (CRYPTO_memcmp(&key[0], &key[8], 8) == 0 ||
236 CRYPTO_memcmp(&key[8], &key[16], 8) == 0) {
237 return 0;
238 }
239
240 return 1;
241 }
242 #endif
243
244 /*
245 * N-fold(K) where blocksize is N, and constant_len is K
246 * Note: Here |= denotes concatenation
247 *
248 * L = lcm(N,K)
249 * R = L/K
250 *
251 * for r: 1 -> R
252 * s |= constant rot 13*(r-1))
253 *
254 * block = 0
255 * for k: 1 -> K
256 * block += s[N(k-1)..(N-1)k] (one's complement addition)
257 *
258 * Optimizing for space we compute:
259 * for each l in L-1 -> 0:
260 * s[l] = (constant rot 13*(l/K))[l%k]
261 * block[l % N] += s[l] (with carry)
262 * finally add carry if any
263 */
n_fold(unsigned char * block,unsigned int blocksize,const unsigned char * constant,size_t constant_len)264 static void n_fold(unsigned char *block, unsigned int blocksize,
265 const unsigned char *constant, size_t constant_len)
266 {
267 unsigned int tmp, gcd, remainder, lcm, carry;
268 int b, l;
269
270 if (constant_len == blocksize) {
271 memcpy(block, constant, constant_len);
272 return;
273 }
274
275 /* Least Common Multiple of lengths: LCM(a,b)*/
276 gcd = blocksize;
277 remainder = constant_len;
278 /* Calculate Great Common Divisor first GCD(a,b) */
279 while (remainder != 0) {
280 tmp = gcd % remainder;
281 gcd = remainder;
282 remainder = tmp;
283 }
284 /* resulting a is the GCD, LCM(a,b) = |a*b|/GCD(a,b) */
285 lcm = blocksize * constant_len / gcd;
286
287 /* now spread out the bits */
288 memset(block, 0, blocksize);
289
290 /* last to first to be able to bring carry forward */
291 carry = 0;
292 for (l = lcm - 1; l >= 0; l--) {
293 unsigned int rotbits, rshift, rbyte;
294
295 /* destination byte in block is l % N */
296 b = l % blocksize;
297 /* Our virtual s buffer is R = L/K long (K = constant_len) */
298 /* So we rotate backwards from R-1 to 0 (none) rotations */
299 rotbits = 13 * (l / constant_len);
300 /* find the byte on s where rotbits falls onto */
301 rbyte = l - (rotbits / 8);
302 /* calculate how much shift on that byte */
303 rshift = rotbits & 0x07;
304 /* rbyte % constant_len gives us the unrotated byte in the
305 * constant buffer, get also the previous byte then
306 * appropriately shift them to get the rotated byte we need */
307 tmp = (constant[(rbyte-1) % constant_len] << (8 - rshift)
308 | constant[rbyte % constant_len] >> rshift)
309 & 0xff;
310 /* add with carry to any value placed by previous passes */
311 tmp += carry + block[b];
312 block[b] = tmp & 0xff;
313 /* save any carry that may be left */
314 carry = tmp >> 8;
315 }
316
317 /* if any carry is left at the end, add it through the number */
318 for (b = blocksize - 1; b >= 0 && carry != 0; b--) {
319 carry += block[b];
320 block[b] = carry & 0xff;
321 carry >>= 8;
322 }
323 }
324
cipher_init(EVP_CIPHER_CTX * ctx,const EVP_CIPHER * cipher,ENGINE * engine,const unsigned char * key,size_t key_len)325 static int cipher_init(EVP_CIPHER_CTX *ctx,
326 const EVP_CIPHER *cipher, ENGINE *engine,
327 const unsigned char *key, size_t key_len)
328 {
329 int klen, ret;
330
331 ret = EVP_EncryptInit_ex(ctx, cipher, engine, key, NULL);
332 if (!ret)
333 goto out;
334 /* set the key len for the odd variable key len cipher */
335 klen = EVP_CIPHER_CTX_get_key_length(ctx);
336 if (key_len != (size_t)klen) {
337 ret = EVP_CIPHER_CTX_set_key_length(ctx, key_len);
338 if (!ret)
339 goto out;
340 }
341 /* we never want padding, either the length requested is a multiple of
342 * the cipher block size or we are passed a cipher that can cope with
343 * partial blocks via techniques like cipher text stealing */
344 ret = EVP_CIPHER_CTX_set_padding(ctx, 0);
345 if (!ret)
346 goto out;
347
348 out:
349 return ret;
350 }
351
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)352 static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
353 const unsigned char *key, size_t key_len,
354 const unsigned char *constant, size_t constant_len,
355 unsigned char *okey, size_t okey_len)
356 {
357 EVP_CIPHER_CTX *ctx = NULL;
358 unsigned char block[EVP_MAX_BLOCK_LENGTH * 2];
359 unsigned char *plainblock, *cipherblock;
360 size_t blocksize;
361 size_t cipherlen;
362 size_t osize;
363 #ifndef OPENSSL_NO_DES
364 int des3_no_fixup = 0;
365 #endif
366 int ret;
367
368 if (key_len != okey_len) {
369 #ifndef OPENSSL_NO_DES
370 /* special case for 3des, where the caller may be requesting
371 * the random raw key, instead of the fixed up key */
372 if (EVP_CIPHER_get_nid(cipher) == NID_des_ede3_cbc &&
373 key_len == 24 && okey_len == 21) {
374 des3_no_fixup = 1;
375 } else {
376 #endif
377 ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_OUTPUT_BUFFER_SIZE);
378 return 0;
379 #ifndef OPENSSL_NO_DES
380 }
381 #endif
382 }
383
384 ctx = EVP_CIPHER_CTX_new();
385 if (ctx == NULL)
386 return 0;
387
388 ret = cipher_init(ctx, cipher, engine, key, key_len);
389 if (!ret)
390 goto out;
391
392 /* Initialize input block */
393 blocksize = EVP_CIPHER_CTX_get_block_size(ctx);
394
395 if (constant_len > blocksize) {
396 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CONSTANT_LENGTH);
397 ret = 0;
398 goto out;
399 }
400
401 n_fold(block, blocksize, constant, constant_len);
402 plainblock = block;
403 cipherblock = block + EVP_MAX_BLOCK_LENGTH;
404
405 for (osize = 0; osize < okey_len; osize += cipherlen) {
406 int olen;
407
408 ret = EVP_EncryptUpdate(ctx, cipherblock, &olen,
409 plainblock, blocksize);
410 if (!ret)
411 goto out;
412 cipherlen = olen;
413 ret = EVP_EncryptFinal_ex(ctx, cipherblock, &olen);
414 if (!ret)
415 goto out;
416 if (olen != 0) {
417 ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_FINAL_BLOCK_LENGTH);
418 ret = 0;
419 goto out;
420 }
421
422 /* write cipherblock out */
423 if (cipherlen > okey_len - osize)
424 cipherlen = okey_len - osize;
425 memcpy(okey + osize, cipherblock, cipherlen);
426
427 if (okey_len > osize + cipherlen) {
428 /* we need to reinitialize cipher context per spec */
429 ret = EVP_CIPHER_CTX_reset(ctx);
430 if (!ret)
431 goto out;
432 ret = cipher_init(ctx, cipher, engine, key, key_len);
433 if (!ret)
434 goto out;
435
436 /* also swap block offsets so last ciphertext becomes new
437 * plaintext */
438 plainblock = cipherblock;
439 if (cipherblock == block) {
440 cipherblock += EVP_MAX_BLOCK_LENGTH;
441 } else {
442 cipherblock = block;
443 }
444 }
445 }
446
447 #ifndef OPENSSL_NO_DES
448 if (EVP_CIPHER_get_nid(cipher) == NID_des_ede3_cbc && !des3_no_fixup) {
449 ret = fixup_des3_key(okey);
450 if (!ret) {
451 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GENERATE_KEY);
452 goto out;
453 }
454 }
455 #endif
456
457 ret = 1;
458
459 out:
460 EVP_CIPHER_CTX_free(ctx);
461 OPENSSL_cleanse(block, EVP_MAX_BLOCK_LENGTH * 2);
462 return ret;
463 }
464
465