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 * 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 <string.h>
17
18#include <openssl/core_dispatch.h>
19#include <openssl/core_names.h>
20#include <openssl/params.h>
21#include <openssl/evp.h>
22#include <openssl/hmac.h>
23
24#include "prov/implementations.h"
25#include "prov/provider_ctx.h"
26#include "prov/provider_util.h"
27#include "prov/providercommon.h"
28
29/*
30 * Forward declaration of everything implemented here.  This is not strictly
31 * necessary for the compiler, but provides an assurance that the signatures
32 * of the functions in the dispatch table are correct.
33 */
34static OSSL_FUNC_mac_newctx_fn hmac_new;
35static OSSL_FUNC_mac_dupctx_fn hmac_dup;
36static OSSL_FUNC_mac_freectx_fn hmac_free;
37static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
38static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
39static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
40static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
41static OSSL_FUNC_mac_init_fn hmac_init;
42static OSSL_FUNC_mac_update_fn hmac_update;
43static OSSL_FUNC_mac_final_fn hmac_final;
44
45/* local HMAC context structure */
46
47/* typedef EVP_MAC_IMPL */
48struct hmac_data_st {
49    void *provctx;
50    HMAC_CTX *ctx;               /* HMAC context */
51    PROV_DIGEST digest;
52    unsigned char *key;
53    size_t keylen;
54    /* Length of full TLS record including the MAC and any padding */
55    size_t tls_data_size;
56    unsigned char tls_header[13];
57    int tls_header_set;
58    unsigned char tls_mac_out[EVP_MAX_MD_SIZE];
59    size_t tls_mac_out_size;
60};
61
62/* Defined in ssl/s3_cbc.c */
63int ssl3_cbc_digest_record(const EVP_MD *md,
64                           unsigned char *md_out,
65                           size_t *md_out_size,
66                           const unsigned char header[13],
67                           const unsigned char *data,
68                           size_t data_size,
69                           size_t data_plus_mac_plus_padding_size,
70                           const unsigned char *mac_secret,
71                           size_t mac_secret_length, char is_sslv3);
72
73static void *hmac_new(void *provctx)
74{
75    struct hmac_data_st *macctx;
76
77    if (!ossl_prov_is_running())
78        return NULL;
79
80    if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
81        || (macctx->ctx = HMAC_CTX_new()) == NULL) {
82        OPENSSL_free(macctx);
83        return NULL;
84    }
85    macctx->provctx = provctx;
86
87    return macctx;
88}
89
90static void hmac_free(void *vmacctx)
91{
92    struct hmac_data_st *macctx = vmacctx;
93
94    if (macctx != NULL) {
95        HMAC_CTX_free(macctx->ctx);
96        ossl_prov_digest_reset(&macctx->digest);
97        OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
98        OPENSSL_free(macctx);
99    }
100}
101
102static void *hmac_dup(void *vsrc)
103{
104    struct hmac_data_st *src = vsrc;
105    struct hmac_data_st *dst;
106    HMAC_CTX *ctx;
107
108    if (!ossl_prov_is_running())
109        return NULL;
110    dst = hmac_new(src->provctx);
111    if (dst == NULL)
112        return NULL;
113
114    ctx = dst->ctx;
115    *dst = *src;
116    dst->ctx = ctx;
117    dst->key = NULL;
118    memset(&dst->digest, 0, sizeof(dst->digest));
119
120    if (!HMAC_CTX_copy(dst->ctx, src->ctx)
121        || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
122        hmac_free(dst);
123        return NULL;
124    }
125    if (src->key != NULL) {
126        /* There is no "secure" OPENSSL_memdup */
127        dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
128        if (dst->key == NULL) {
129            hmac_free(dst);
130            return 0;
131        }
132        memcpy(dst->key, src->key, src->keylen);
133    }
134    return dst;
135}
136
137static size_t hmac_size(struct hmac_data_st *macctx)
138{
139    return HMAC_size(macctx->ctx);
140}
141
142static int hmac_block_size(struct hmac_data_st *macctx)
143{
144    const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);
145
146    if (md == NULL)
147        return 0;
148    return EVP_MD_block_size(md);
149}
150
151static int hmac_setkey(struct hmac_data_st *macctx,
152                       const unsigned char *key, size_t keylen)
153{
154    const EVP_MD *digest;
155
156    if (macctx->key != NULL)
157        OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
158    /* Keep a copy of the key in case we need it for TLS HMAC */
159    macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
160    if (macctx->key == NULL)
161        return 0;
162    memcpy(macctx->key, key, keylen);
163    macctx->keylen = keylen;
164
165    digest = ossl_prov_digest_md(&macctx->digest);
166    /* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
167    if (key != NULL || (macctx->tls_data_size == 0 && digest != NULL))
168        return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
169                            ossl_prov_digest_engine(&macctx->digest));
170    return 1;
171}
172
173static int hmac_init(void *vmacctx, const unsigned char *key,
174                     size_t keylen, const OSSL_PARAM params[])
175{
176    struct hmac_data_st *macctx = vmacctx;
177
178    if (!ossl_prov_is_running() || !hmac_set_ctx_params(macctx, params))
179        return 0;
180
181    if (key != NULL)
182        return hmac_setkey(macctx, key, keylen);
183
184    /* Just reinit the HMAC context */
185    return HMAC_Init_ex(macctx->ctx, NULL, 0, NULL, NULL);
186}
187
188static int hmac_update(void *vmacctx, const unsigned char *data,
189                       size_t datalen)
190{
191    struct hmac_data_st *macctx = vmacctx;
192
193    if (macctx->tls_data_size > 0) {
194        /* We're doing a TLS HMAC */
195        if (!macctx->tls_header_set) {
196            /* We expect the first update call to contain the TLS header */
197            if (datalen != sizeof(macctx->tls_header))
198                return 0;
199            memcpy(macctx->tls_header, data, datalen);
200            macctx->tls_header_set = 1;
201            return 1;
202        }
203        /* macctx->tls_data_size is datalen plus the padding length */
204        if (macctx->tls_data_size < datalen)
205            return 0;
206
207        return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
208                                      macctx->tls_mac_out,
209                                      &macctx->tls_mac_out_size,
210                                      macctx->tls_header,
211                                      data,
212                                      datalen,
213                                      macctx->tls_data_size,
214                                      macctx->key,
215                                      macctx->keylen,
216                                      0);
217    }
218
219    return HMAC_Update(macctx->ctx, data, datalen);
220}
221
222static int hmac_final(void *vmacctx, unsigned char *out, size_t *outl,
223                      size_t outsize)
224{
225    unsigned int hlen;
226    struct hmac_data_st *macctx = vmacctx;
227
228    if (!ossl_prov_is_running())
229        return 0;
230    if (macctx->tls_data_size > 0) {
231        if (macctx->tls_mac_out_size == 0)
232            return 0;
233        if (outl != NULL)
234            *outl = macctx->tls_mac_out_size;
235        memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
236        return 1;
237    }
238    if (!HMAC_Final(macctx->ctx, out, &hlen))
239        return 0;
240    *outl = hlen;
241    return 1;
242}
243
244static const OSSL_PARAM known_gettable_ctx_params[] = {
245    OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
246    OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
247    OSSL_PARAM_END
248};
249static const OSSL_PARAM *hmac_gettable_ctx_params(ossl_unused void *ctx,
250                                                  ossl_unused void *provctx)
251{
252    return known_gettable_ctx_params;
253}
254
255static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
256{
257    struct hmac_data_st *macctx = vmacctx;
258    OSSL_PARAM *p;
259
260    if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
261            && !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
262        return 0;
263
264    if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
265            && !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
266        return 0;
267
268    return 1;
269}
270
271static const OSSL_PARAM known_settable_ctx_params[] = {
272    OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
273    OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
274    OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
275    OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
276    OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
277    OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
278    OSSL_PARAM_END
279};
280static const OSSL_PARAM *hmac_settable_ctx_params(ossl_unused void *ctx,
281                                                  ossl_unused void *provctx)
282{
283    return known_settable_ctx_params;
284}
285
286static int set_flag(const OSSL_PARAM params[], const char *key, int mask,
287                    int *flags)
288{
289    const OSSL_PARAM *p = OSSL_PARAM_locate_const(params, key);
290    int flag = 0;
291
292    if (p != NULL) {
293        if (!OSSL_PARAM_get_int(p, &flag))
294            return 0;
295        if (flag == 0)
296            *flags &= ~mask;
297        else
298            *flags |= mask;
299    }
300    return 1;
301}
302
303/*
304 * ALL parameters should be set before init().
305 */
306static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
307{
308    struct hmac_data_st *macctx = vmacctx;
309    OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
310    const OSSL_PARAM *p;
311    int flags = 0;
312
313    if (params == NULL)
314        return 1;
315
316    if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
317        return 0;
318
319    if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_NOINIT, EVP_MD_CTX_FLAG_NO_INIT,
320                  &flags))
321        return 0;
322    if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_ONESHOT, EVP_MD_CTX_FLAG_ONESHOT,
323                  &flags))
324        return 0;
325    if (flags)
326        HMAC_CTX_set_flags(macctx->ctx, flags);
327
328    if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
329        if (p->data_type != OSSL_PARAM_OCTET_STRING)
330            return 0;
331        if (!hmac_setkey(macctx, p->data, p->data_size))
332            return 0;
333    }
334
335    if ((p = OSSL_PARAM_locate_const(params,
336                                     OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
337        if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
338            return 0;
339    }
340    return 1;
341}
342
343const OSSL_DISPATCH ossl_hmac_functions[] = {
344    { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
345    { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
346    { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
347    { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
348    { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
349    { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
350    { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
351      (void (*)(void))hmac_gettable_ctx_params },
352    { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
353    { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
354      (void (*)(void))hmac_settable_ctx_params },
355    { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
356    { 0, NULL }
357};
358