2 * Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
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
11 * See SP800-185 "Appendix A - KMAC, .... in Terms of Keccak[c]"
14 * K = Key (len(K) < 2^2040 bits)
16 * L = Output length (0 <= L < 2^2040 bits)
17 * S = Customization String Default="" (len(S) < 2^2040 bits)
21 * newX = bytepad(encode_string(K), 168) || X || right_encode(L).
22 * T = bytepad(encode_string("KMAC") || encode_string(S), 168).
23 * return KECCAK[256](T || newX || 00, L).
28 * newX = bytepad(encode_string(K), 136) || X || right_encode(L).
29 * T = bytepad(encode_string("KMAC") || encode_string(S), 136).
30 * return KECCAK[512](T || newX || 00, L).
33 * KMAC128XOF(K, X, L, S)
35 * newX = bytepad(encode_string(K), 168) || X || right_encode(0).
36 * T = bytepad(encode_string("KMAC") || encode_string(S), 168).
37 * return KECCAK[256](T || newX || 00, L).
40 * KMAC256XOF(K, X, L, S)
42 * newX = bytepad(encode_string(K), 136) || X || right_encode(0).
43 * T = bytepad(encode_string("KMAC") || encode_string(S), 136).
44 * return KECCAK[512](T || newX || 00, L).
51 #include <openssl/core_dispatch.h>
52 #include <openssl/core_names.h>
53 #include <openssl/params.h>
54 #include <openssl/evp.h>
55 #include <openssl/err.h>
56 #include <openssl/proverr.h>
58 #include "prov/implementations.h"
59 #include "prov/provider_ctx.h"
60 #include "prov/provider_util.h"
61 #include "prov/providercommon.h"
64 * Forward declaration of everything implemented here. This is not strictly
65 * necessary for the compiler, but provides an assurance that the signatures
66 * of the functions in the dispatch table are correct.
68 static OSSL_FUNC_mac_newctx_fn kmac128_new;
69 static OSSL_FUNC_mac_newctx_fn kmac256_new;
70 static OSSL_FUNC_mac_dupctx_fn kmac_dup;
71 static OSSL_FUNC_mac_freectx_fn kmac_free;
72 static OSSL_FUNC_mac_gettable_ctx_params_fn kmac_gettable_ctx_params;
73 static OSSL_FUNC_mac_get_ctx_params_fn kmac_get_ctx_params;
74 static OSSL_FUNC_mac_settable_ctx_params_fn kmac_settable_ctx_params;
75 static OSSL_FUNC_mac_set_ctx_params_fn kmac_set_ctx_params;
76 static OSSL_FUNC_mac_init_fn kmac_init;
77 static OSSL_FUNC_mac_update_fn kmac_update;
78 static OSSL_FUNC_mac_final_fn kmac_final;
80 #define KMAC_MAX_BLOCKSIZE ((1600 - 128*2) / 8) /* 168 */
81 #define KMAC_MIN_BLOCKSIZE ((1600 - 256*2) / 8) /* 136 */
83 /* Length encoding will be a 1 byte size + length in bits (2 bytes max) */
84 #define KMAC_MAX_ENCODED_HEADER_LEN 3
87 * Custom string max size is chosen such that:
88 * len(encoded_string(custom) + len(kmac_encoded_string) <= KMAC_MIN_BLOCKSIZE
89 * i.e: (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_LEN) + 6 <= 136
91 #define KMAC_MAX_CUSTOM 127
93 /* Maximum size of encoded custom string */
94 #define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)
96 /* Maximum key size in bytes = 2040 / 8 */
97 #define KMAC_MAX_KEY 255
100 * Maximum Encoded Key size will be padded to a multiple of the blocksize
101 * i.e KMAC_MAX_KEY + KMAC_MAX_ENCODED_LEN = 258
102 * Padded to a multiple of KMAC_MAX_BLOCKSIZE
104 #define KMAC_MAX_KEY_ENCODED (KMAC_MAX_BLOCKSIZE * 2)
106 /* Fixed value of encode_string("KMAC") */
107 static const unsigned char kmac_string[] = {
108 0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43
112 #define KMAC_FLAG_XOF_MODE 1
114 struct kmac_data_st {
121 /* If xof_mode = 1 then we use right_encode(0) */
123 /* key and custom are stored in encoded form */
124 unsigned char key[KMAC_MAX_KEY_ENCODED];
125 unsigned char custom[KMAC_MAX_CUSTOM_ENCODED];
128 static int encode_string(unsigned char *out, int *out_len,
129 const unsigned char *in, int in_len);
130 static int right_encode(unsigned char *out, int *out_len, size_t bits);
131 static int bytepad(unsigned char *out, int *out_len,
132 const unsigned char *in1, int in1_len,
133 const unsigned char *in2, int in2_len,
135 static int kmac_bytepad_encode_key(unsigned char *out, int *out_len,
136 const unsigned char *in, int in_len,
139 static void kmac_free(void *vmacctx)
141 struct kmac_data_st *kctx = vmacctx;
144 EVP_MD_CTX_free(kctx->ctx);
145 ossl_prov_digest_reset(&kctx->digest);
146 OPENSSL_cleanse(kctx->key, kctx->key_len);
147 OPENSSL_cleanse(kctx->custom, kctx->custom_len);
153 * We have KMAC implemented as a hash, which we can use instead of
154 * reimplementing the EVP functionality with direct use of
155 * keccak_mac_init() and friends.
157 static struct kmac_data_st *kmac_new(void *provctx)
159 struct kmac_data_st *kctx;
161 if (!ossl_prov_is_running())
164 if ((kctx = OPENSSL_zalloc(sizeof(*kctx))) == NULL
165 || (kctx->ctx = EVP_MD_CTX_new()) == NULL) {
169 kctx->provctx = provctx;
173 static void *kmac_fetch_new(void *provctx, const OSSL_PARAM *params)
175 struct kmac_data_st *kctx = kmac_new(provctx);
179 if (!ossl_prov_digest_load_from_params(&kctx->digest, params,
180 PROV_LIBCTX_OF(provctx))) {
185 kctx->out_len = EVP_MD_size(ossl_prov_digest_md(&kctx->digest));
189 static void *kmac128_new(void *provctx)
191 static const OSSL_PARAM kmac128_params[] = {
192 OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC128,
193 sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC128)),
196 return kmac_fetch_new(provctx, kmac128_params);
199 static void *kmac256_new(void *provctx)
201 static const OSSL_PARAM kmac256_params[] = {
202 OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC256,
203 sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC256)),
206 return kmac_fetch_new(provctx, kmac256_params);
209 static void *kmac_dup(void *vsrc)
211 struct kmac_data_st *src = vsrc;
212 struct kmac_data_st *dst;
214 if (!ossl_prov_is_running())
217 dst = kmac_new(src->provctx);
221 if (!EVP_MD_CTX_copy(dst->ctx, src->ctx)
222 || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
227 dst->out_len = src->out_len;
228 dst->key_len = src->key_len;
229 dst->custom_len = src->custom_len;
230 dst->xof_mode = src->xof_mode;
231 memcpy(dst->key, src->key, src->key_len);
232 memcpy(dst->custom, src->custom, dst->custom_len);
237 static size_t kmac_size(void *vmacctx)
239 struct kmac_data_st *kctx = vmacctx;
241 return kctx->out_len;
244 static int kmac_setkey(struct kmac_data_st *kctx, const unsigned char *key,
247 const EVP_MD *digest = ossl_prov_digest_md(&kctx->digest);
249 if (keylen < 4 || keylen > KMAC_MAX_KEY) {
250 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
253 if (!kmac_bytepad_encode_key(kctx->key, &kctx->key_len,
254 key, keylen, EVP_MD_block_size(digest)))
260 * The init() assumes that any ctrl methods are set beforehand for
261 * md, key and custom. Setting the fields afterwards will have no
262 * effect on the output mac.
264 static int kmac_init(void *vmacctx, const unsigned char *key,
265 size_t keylen, const OSSL_PARAM params[])
267 struct kmac_data_st *kctx = vmacctx;
268 EVP_MD_CTX *ctx = kctx->ctx;
269 unsigned char out[KMAC_MAX_BLOCKSIZE];
270 int out_len, block_len;
272 if (!ossl_prov_is_running() || !kmac_set_ctx_params(kctx, params))
275 if (!kmac_setkey(kctx, key, keylen))
277 } else if (kctx->key_len == 0) {
278 /* Check key has been set */
279 ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
282 if (!EVP_DigestInit_ex(kctx->ctx, ossl_prov_digest_md(&kctx->digest),
286 block_len = EVP_MD_block_size(ossl_prov_digest_md(&kctx->digest));
290 /* Set default custom string if it is not already set */
291 if (kctx->custom_len == 0) {
292 const OSSL_PARAM cparams[] = {
293 OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, "", 0),
296 (void)kmac_set_ctx_params(kctx, cparams);
299 return bytepad(out, &out_len, kmac_string, sizeof(kmac_string),
300 kctx->custom, kctx->custom_len, block_len)
301 && EVP_DigestUpdate(ctx, out, out_len)
302 && EVP_DigestUpdate(ctx, kctx->key, kctx->key_len);
305 static int kmac_update(void *vmacctx, const unsigned char *data,
308 struct kmac_data_st *kctx = vmacctx;
310 return EVP_DigestUpdate(kctx->ctx, data, datalen);
313 static int kmac_final(void *vmacctx, unsigned char *out, size_t *outl,
316 struct kmac_data_st *kctx = vmacctx;
317 EVP_MD_CTX *ctx = kctx->ctx;
319 unsigned char encoded_outlen[KMAC_MAX_ENCODED_HEADER_LEN];
322 if (!ossl_prov_is_running())
325 /* KMAC XOF mode sets the encoded length to 0 */
326 lbits = (kctx->xof_mode ? 0 : (kctx->out_len * 8));
328 ok = right_encode(encoded_outlen, &len, lbits)
329 && EVP_DigestUpdate(ctx, encoded_outlen, len)
330 && EVP_DigestFinalXOF(ctx, out, kctx->out_len);
331 *outl = kctx->out_len;
335 static const OSSL_PARAM known_gettable_ctx_params[] = {
336 OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
339 static const OSSL_PARAM *kmac_gettable_ctx_params(ossl_unused void *ctx,
340 ossl_unused void *provctx)
342 return known_gettable_ctx_params;
345 static int kmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
349 if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL)
350 return OSSL_PARAM_set_size_t(p, kmac_size(vmacctx));
355 static const OSSL_PARAM known_settable_ctx_params[] = {
356 OSSL_PARAM_int(OSSL_MAC_PARAM_XOF, NULL),
357 OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
358 OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
359 OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, NULL, 0),
362 static const OSSL_PARAM *kmac_settable_ctx_params(ossl_unused void *ctx,
363 ossl_unused void *provctx)
365 return known_settable_ctx_params;
369 * The following params can be set any time before final():
370 * - "outlen" or "size": The requested output length.
371 * - "xof": If set, this indicates that right_encoded(0)
372 * is part of the digested data, otherwise it
373 * uses right_encoded(requested output length).
375 * All other params should be set before init().
377 static int kmac_set_ctx_params(void *vmacctx, const OSSL_PARAM *params)
379 struct kmac_data_st *kctx = vmacctx;
385 if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_XOF)) != NULL
386 && !OSSL_PARAM_get_int(p, &kctx->xof_mode))
388 if (((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_SIZE)) != NULL)
389 && !OSSL_PARAM_get_size_t(p, &kctx->out_len))
391 if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL
392 && !kmac_setkey(kctx, p->data, p->data_size))
394 if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_CUSTOM))
396 if (p->data_size > KMAC_MAX_CUSTOM) {
397 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CUSTOM_LENGTH);
400 if (!encode_string(kctx->custom, &kctx->custom_len,
401 p->data, p->data_size))
408 * Encoding/Padding Methods.
411 /* Returns the number of bytes required to store 'bits' into a byte array */
412 static unsigned int get_encode_size(size_t bits)
414 unsigned int cnt = 0, sz = sizeof(size_t);
416 while (bits && (cnt < sz)) {
420 /* If bits is zero 1 byte is required */
427 * Convert an integer into bytes . The number of bytes is appended
428 * to the end of the buffer. Returns an array of bytes 'out' of size
431 * e.g if bits = 32, out[2] = { 0x20, 0x01 }
434 static int right_encode(unsigned char *out, int *out_len, size_t bits)
436 unsigned int len = get_encode_size(bits);
439 /* The length is constrained to a single byte: 2040/8 = 255 */
443 /* MSB's are at the start of the bytes array */
444 for (i = len - 1; i >= 0; --i) {
445 out[i] = (unsigned char)(bits & 0xFF);
448 /* Tack the length onto the end */
449 out[len] = (unsigned char)len;
451 /* The Returned length includes the tacked on byte */
457 * Encodes a string with a left encoded length added. Note that the
458 * in_len is converted to bits (*8).
460 * e.g- in="KMAC" gives out[6] = { 0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43 }
463 static int encode_string(unsigned char *out, int *out_len,
464 const unsigned char *in, int in_len)
472 len = get_encode_size(bits);
477 for (i = len; i > 0; --i) {
478 out[i] = (bits & 0xFF);
481 memcpy(out + len + 1, in, in_len);
482 *out_len = (1 + len + in_len);
488 * Returns a zero padded encoding of the inputs in1 and an optional
489 * in2 (can be NULL). The padded output must be a multiple of the blocksize 'w'.
490 * The value of w is in bytes (< 256).
492 * The returned output is:
493 * zero_padded(multiple of w, (left_encode(w) || in1 [|| in2])
495 static int bytepad(unsigned char *out, int *out_len,
496 const unsigned char *in1, int in1_len,
497 const unsigned char *in2, int in2_len, int w)
500 unsigned char *p = out;
507 memcpy(p, in1, in1_len);
510 if (in2 != NULL && in2_len > 0) {
511 memcpy(p, in2, in2_len);
514 /* Figure out the pad size (divisible by w) */
519 /* zero pad the end of the buffer */
520 memset(p, 0, sz - len);
526 * Returns out = bytepad(encode_string(in), w)
528 static int kmac_bytepad_encode_key(unsigned char *out, int *out_len,
529 const unsigned char *in, int in_len,
532 unsigned char tmp[KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN];
535 if (!encode_string(tmp, &tmp_len, in, in_len))
538 return bytepad(out, out_len, tmp, tmp_len, NULL, 0, w);
541 const OSSL_DISPATCH ossl_kmac128_functions[] = {
542 { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac128_new },
543 { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
544 { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
545 { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
546 { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
547 { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
548 { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
549 (void (*)(void))kmac_gettable_ctx_params },
550 { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
551 { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
552 (void (*)(void))kmac_settable_ctx_params },
553 { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
557 const OSSL_DISPATCH ossl_kmac256_functions[] = {
558 { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac256_new },
559 { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
560 { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
561 { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
562 { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
563 { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
564 { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
565 (void (*)(void))kmac_gettable_ctx_params },
566 { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
567 { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
568 (void (*)(void))kmac_settable_ctx_params },
569 { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },