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 * HMAC low level APIs are deprecated for public use, but still ok for internal
12 * use.
13 */
14#include "internal/deprecated.h"
15
16#include <stdlib.h>
17#include <stdarg.h>
18#include <string.h>
19#include <openssl/hmac.h>
20#include <openssl/evp.h>
21#include <openssl/kdf.h>
22#include <openssl/core_names.h>
23#include <openssl/proverr.h>
24#include "internal/cryptlib.h"
25#include "internal/numbers.h"
26#include "crypto/evp.h"
27#include "prov/provider_ctx.h"
28#include "prov/providercommon.h"
29#include "prov/implementations.h"
30#include "prov/provider_util.h"
31#include "pbkdf2.h"
32
33/* Constants specified in SP800-132 */
34#define KDF_PBKDF2_MIN_KEY_LEN_BITS  112
35#define KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO 0xFFFFFFFF
36#define KDF_PBKDF2_MIN_ITERATIONS 1000
37#define KDF_PBKDF2_MIN_SALT_LEN   (128 / 8)
38
39static OSSL_FUNC_kdf_newctx_fn kdf_pbkdf2_new;
40static OSSL_FUNC_kdf_freectx_fn kdf_pbkdf2_free;
41static OSSL_FUNC_kdf_reset_fn kdf_pbkdf2_reset;
42static OSSL_FUNC_kdf_derive_fn kdf_pbkdf2_derive;
43static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_pbkdf2_settable_ctx_params;
44static OSSL_FUNC_kdf_set_ctx_params_fn kdf_pbkdf2_set_ctx_params;
45static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_pbkdf2_gettable_ctx_params;
46static OSSL_FUNC_kdf_get_ctx_params_fn kdf_pbkdf2_get_ctx_params;
47
48static int  pbkdf2_derive(const char *pass, size_t passlen,
49                          const unsigned char *salt, int saltlen, uint64_t iter,
50                          const EVP_MD *digest, unsigned char *key,
51                          size_t keylen, int extra_checks);
52
53typedef struct {
54    void *provctx;
55    unsigned char *pass;
56    size_t pass_len;
57    unsigned char *salt;
58    size_t salt_len;
59    uint64_t iter;
60    PROV_DIGEST digest;
61    int lower_bound_checks;
62} KDF_PBKDF2;
63
64static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx);
65
66static void *kdf_pbkdf2_new(void *provctx)
67{
68    KDF_PBKDF2 *ctx;
69
70    if (!ossl_prov_is_running())
71        return NULL;
72
73    ctx = OPENSSL_zalloc(sizeof(*ctx));
74    if (ctx == NULL) {
75        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
76        return NULL;
77    }
78    ctx->provctx = provctx;
79    kdf_pbkdf2_init(ctx);
80    return ctx;
81}
82
83static void kdf_pbkdf2_cleanup(KDF_PBKDF2 *ctx)
84{
85    ossl_prov_digest_reset(&ctx->digest);
86    OPENSSL_free(ctx->salt);
87    OPENSSL_clear_free(ctx->pass, ctx->pass_len);
88    memset(ctx, 0, sizeof(*ctx));
89}
90
91static void kdf_pbkdf2_free(void *vctx)
92{
93    KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
94
95    if (ctx != NULL) {
96        kdf_pbkdf2_cleanup(ctx);
97        OPENSSL_free(ctx);
98    }
99}
100
101static void kdf_pbkdf2_reset(void *vctx)
102{
103    KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
104    void *provctx = ctx->provctx;
105
106    kdf_pbkdf2_cleanup(ctx);
107    ctx->provctx = provctx;
108    kdf_pbkdf2_init(ctx);
109}
110
111static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx)
112{
113    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
114    OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
115
116    params[0] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
117                                                 SN_sha1, 0);
118    if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
119        /* This is an error, but there is no way to indicate such directly */
120        ossl_prov_digest_reset(&ctx->digest);
121    ctx->iter = PKCS5_DEFAULT_ITER;
122    ctx->lower_bound_checks = ossl_kdf_pbkdf2_default_checks;
123}
124
125static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,
126                             const OSSL_PARAM *p)
127{
128    OPENSSL_clear_free(*buffer, *buflen);
129    *buffer = NULL;
130    *buflen = 0;
131
132    if (p->data_size == 0) {
133        if ((*buffer = OPENSSL_malloc(1)) == NULL) {
134            ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
135            return 0;
136        }
137    } else if (p->data != NULL) {
138        if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
139            return 0;
140    }
141    return 1;
142}
143
144static int kdf_pbkdf2_derive(void *vctx, unsigned char *key, size_t keylen,
145                             const OSSL_PARAM params[])
146{
147    KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
148    const EVP_MD *md;
149
150    if (!ossl_prov_is_running() || !kdf_pbkdf2_set_ctx_params(ctx, params))
151        return 0;
152
153    if (ctx->pass == NULL) {
154        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
155        return 0;
156    }
157
158    if (ctx->salt == NULL) {
159        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
160        return 0;
161    }
162
163    md = ossl_prov_digest_md(&ctx->digest);
164    return pbkdf2_derive((char *)ctx->pass, ctx->pass_len,
165                         ctx->salt, ctx->salt_len, ctx->iter,
166                         md, key, keylen, ctx->lower_bound_checks);
167}
168
169static int kdf_pbkdf2_set_ctx_params(void *vctx, const OSSL_PARAM params[])
170{
171    const OSSL_PARAM *p;
172    KDF_PBKDF2 *ctx = vctx;
173    OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
174    int pkcs5;
175    uint64_t iter, min_iter;
176
177    if (params == NULL)
178        return 1;
179
180    if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
181        return 0;
182
183    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PKCS5)) != NULL) {
184        if (!OSSL_PARAM_get_int(p, &pkcs5))
185            return 0;
186        ctx->lower_bound_checks = pkcs5 == 0;
187    }
188
189    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
190        if (!pbkdf2_set_membuf(&ctx->pass, &ctx->pass_len, p))
191            return 0;
192
193    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL) {
194        if (ctx->lower_bound_checks != 0
195            && p->data_size < KDF_PBKDF2_MIN_SALT_LEN) {
196            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
197            return 0;
198        }
199        if (!pbkdf2_set_membuf(&ctx->salt, &ctx->salt_len,p))
200            return 0;
201    }
202
203    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_ITER)) != NULL) {
204        if (!OSSL_PARAM_get_uint64(p, &iter))
205            return 0;
206        min_iter = ctx->lower_bound_checks != 0 ? KDF_PBKDF2_MIN_ITERATIONS : 1;
207        if (iter < min_iter) {
208            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
209            return 0;
210        }
211        ctx->iter = iter;
212    }
213    return 1;
214}
215
216static const OSSL_PARAM *kdf_pbkdf2_settable_ctx_params(ossl_unused void *ctx,
217                                                        ossl_unused void *p_ctx)
218{
219    static const OSSL_PARAM known_settable_ctx_params[] = {
220        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
221        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
222        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
223        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
224        OSSL_PARAM_uint64(OSSL_KDF_PARAM_ITER, NULL),
225        OSSL_PARAM_int(OSSL_KDF_PARAM_PKCS5, NULL),
226        OSSL_PARAM_END
227    };
228    return known_settable_ctx_params;
229}
230
231static int kdf_pbkdf2_get_ctx_params(void *vctx, OSSL_PARAM params[])
232{
233    OSSL_PARAM *p;
234
235    if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
236        return OSSL_PARAM_set_size_t(p, SIZE_MAX);
237    return -2;
238}
239
240static const OSSL_PARAM *kdf_pbkdf2_gettable_ctx_params(ossl_unused void *ctx,
241                                                        ossl_unused void *p_ctx)
242{
243    static const OSSL_PARAM known_gettable_ctx_params[] = {
244        OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
245        OSSL_PARAM_END
246    };
247    return known_gettable_ctx_params;
248}
249
250const OSSL_DISPATCH ossl_kdf_pbkdf2_functions[] = {
251    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_pbkdf2_new },
252    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_pbkdf2_free },
253    { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_pbkdf2_reset },
254    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_pbkdf2_derive },
255    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
256      (void(*)(void))kdf_pbkdf2_settable_ctx_params },
257    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_set_ctx_params },
258    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
259      (void(*)(void))kdf_pbkdf2_gettable_ctx_params },
260    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_get_ctx_params },
261    { 0, NULL }
262};
263
264/*
265 * This is an implementation of PKCS#5 v2.0 password based encryption key
266 * derivation function PBKDF2. SHA1 version verified against test vectors
267 * posted by Peter Gutmann to the PKCS-TNG mailing list.
268 *
269 * The constraints specified by SP800-132 have been added i.e.
270 *  - Check the range of the key length.
271 *  - Minimum iteration count of 1000.
272 *  - Randomly-generated portion of the salt shall be at least 128 bits.
273 */
274static int pbkdf2_derive(const char *pass, size_t passlen,
275                         const unsigned char *salt, int saltlen, uint64_t iter,
276                         const EVP_MD *digest, unsigned char *key,
277                         size_t keylen, int lower_bound_checks)
278{
279    int ret = 0;
280    unsigned char digtmp[EVP_MAX_MD_SIZE], *p, itmp[4];
281    int cplen, k, tkeylen, mdlen;
282    uint64_t j;
283    unsigned long i = 1;
284    HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;
285
286    mdlen = EVP_MD_get_size(digest);
287    if (mdlen <= 0)
288        return 0;
289
290    /*
291     * This check should always be done because keylen / mdlen >= (2^32 - 1)
292     * results in an overflow of the loop counter 'i'.
293     */
294    if ((keylen / mdlen) >= KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO) {
295        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
296        return 0;
297    }
298
299    if (lower_bound_checks) {
300        if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {
301            ERR_raise(ERR_LIB_PROV, PROV_R_KEY_SIZE_TOO_SMALL);
302            return 0;
303        }
304        if (saltlen < KDF_PBKDF2_MIN_SALT_LEN) {
305            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
306            return 0;
307        }
308        if (iter < KDF_PBKDF2_MIN_ITERATIONS) {
309            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
310            return 0;
311        }
312    }
313
314    hctx_tpl = HMAC_CTX_new();
315    if (hctx_tpl == NULL)
316        return 0;
317    p = key;
318    tkeylen = keylen;
319    if (!HMAC_Init_ex(hctx_tpl, pass, passlen, digest, NULL))
320        goto err;
321    hctx = HMAC_CTX_new();
322    if (hctx == NULL)
323        goto err;
324    while (tkeylen) {
325        if (tkeylen > mdlen)
326            cplen = mdlen;
327        else
328            cplen = tkeylen;
329        /*
330         * We are unlikely to ever use more than 256 blocks (5120 bits!) but
331         * just in case...
332         */
333        itmp[0] = (unsigned char)((i >> 24) & 0xff);
334        itmp[1] = (unsigned char)((i >> 16) & 0xff);
335        itmp[2] = (unsigned char)((i >> 8) & 0xff);
336        itmp[3] = (unsigned char)(i & 0xff);
337        if (!HMAC_CTX_copy(hctx, hctx_tpl))
338            goto err;
339        if (!HMAC_Update(hctx, salt, saltlen)
340                || !HMAC_Update(hctx, itmp, 4)
341                || !HMAC_Final(hctx, digtmp, NULL))
342            goto err;
343        memcpy(p, digtmp, cplen);
344        for (j = 1; j < iter; j++) {
345            if (!HMAC_CTX_copy(hctx, hctx_tpl))
346                goto err;
347            if (!HMAC_Update(hctx, digtmp, mdlen)
348                    || !HMAC_Final(hctx, digtmp, NULL))
349                goto err;
350            for (k = 0; k < cplen; k++)
351                p[k] ^= digtmp[k];
352        }
353        tkeylen -= cplen;
354        i++;
355        p += cplen;
356    }
357    ret = 1;
358
359err:
360    HMAC_CTX_free(hctx);
361    HMAC_CTX_free(hctx_tpl);
362    return ret;
363}
364