1 /*
2  * Copyright 2018-2024 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 #include <openssl/proverr.h>
24 #include <openssl/err.h>
25 
26 #include "internal/ssl3_cbc.h"
27 
28 #include "prov/implementations.h"
29 #include "prov/provider_ctx.h"
30 #include "prov/provider_util.h"
31 #include "prov/providercommon.h"
32 #include "prov/securitycheck.h"
33 
34 /*
35  * Forward declaration of everything implemented here.  This is not strictly
36  * necessary for the compiler, but provides an assurance that the signatures
37  * of the functions in the dispatch table are correct.
38  */
39 static OSSL_FUNC_mac_newctx_fn hmac_new;
40 static OSSL_FUNC_mac_dupctx_fn hmac_dup;
41 static OSSL_FUNC_mac_freectx_fn hmac_free;
42 static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
43 static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
44 static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
45 static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
46 static OSSL_FUNC_mac_init_fn hmac_init;
47 static OSSL_FUNC_mac_update_fn hmac_update;
48 static OSSL_FUNC_mac_final_fn hmac_final;
49 
50 /* local HMAC context structure */
51 
52 /* typedef EVP_MAC_IMPL */
53 struct hmac_data_st {
54     void *provctx;
55     HMAC_CTX *ctx;               /* HMAC context */
56     PROV_DIGEST digest;
57     unsigned char *key;
58     size_t keylen;
59     /* Length of full TLS record including the MAC and any padding */
60     size_t tls_data_size;
61     unsigned char tls_header[13];
62     int tls_header_set;
63     unsigned char tls_mac_out[EVP_MAX_MD_SIZE];
64     size_t tls_mac_out_size;
65 #ifdef FIPS_MODULE
66     /*
67      * 'internal' is set to 1 if HMAC is used inside another algorithm such as a
68      * KDF. In this case it is the parent algorithm that is responsible for
69      * performing any conditional FIPS indicator related checks for the HMAC.
70      */
71     int internal;
72 #endif
73     OSSL_FIPS_IND_DECLARE
74 };
75 
hmac_new(void * provctx)76 static void *hmac_new(void *provctx)
77 {
78     struct hmac_data_st *macctx;
79 
80     if (!ossl_prov_is_running())
81         return NULL;
82 
83     if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
84         || (macctx->ctx = HMAC_CTX_new()) == NULL) {
85         OPENSSL_free(macctx);
86         return NULL;
87     }
88     macctx->provctx = provctx;
89     OSSL_FIPS_IND_INIT(macctx)
90 
91     return macctx;
92 }
93 
hmac_free(void * vmacctx)94 static void hmac_free(void *vmacctx)
95 {
96     struct hmac_data_st *macctx = vmacctx;
97 
98     if (macctx != NULL) {
99         HMAC_CTX_free(macctx->ctx);
100         ossl_prov_digest_reset(&macctx->digest);
101         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
102         OPENSSL_free(macctx);
103     }
104 }
105 
hmac_dup(void * vsrc)106 static void *hmac_dup(void *vsrc)
107 {
108     struct hmac_data_st *src = vsrc;
109     struct hmac_data_st *dst;
110     HMAC_CTX *ctx;
111 
112     if (!ossl_prov_is_running())
113         return NULL;
114     dst = hmac_new(src->provctx);
115     if (dst == NULL)
116         return NULL;
117 
118     ctx = dst->ctx;
119     *dst = *src;
120     dst->ctx = ctx;
121     dst->key = NULL;
122     memset(&dst->digest, 0, sizeof(dst->digest));
123 
124     if (!HMAC_CTX_copy(dst->ctx, src->ctx)
125         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
126         hmac_free(dst);
127         return NULL;
128     }
129     if (src->key != NULL) {
130         /* There is no "secure" OPENSSL_memdup */
131         dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
132         if (dst->key == NULL) {
133             hmac_free(dst);
134             return 0;
135         }
136         memcpy(dst->key, src->key, src->keylen);
137     }
138     return dst;
139 }
140 
hmac_size(struct hmac_data_st * macctx)141 static size_t hmac_size(struct hmac_data_st *macctx)
142 {
143     return HMAC_size(macctx->ctx);
144 }
145 
hmac_block_size(struct hmac_data_st * macctx)146 static int hmac_block_size(struct hmac_data_st *macctx)
147 {
148     const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);
149 
150     if (md == NULL)
151         return 0;
152     return EVP_MD_block_size(md);
153 }
154 
hmac_setkey(struct hmac_data_st * macctx,const unsigned char * key,size_t keylen)155 static int hmac_setkey(struct hmac_data_st *macctx,
156                        const unsigned char *key, size_t keylen)
157 {
158     const EVP_MD *digest;
159 
160 #ifdef FIPS_MODULE
161     /*
162      * KDF's pass a salt rather than a key,
163      * which is why it skips the key check unless "HMAC" is fetched directly.
164      */
165     if (!macctx->internal) {
166         OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(macctx->provctx);
167         int approved = ossl_mac_check_key_size(keylen);
168 
169         if (!approved) {
170             if (!OSSL_FIPS_IND_ON_UNAPPROVED(macctx, OSSL_FIPS_IND_SETTABLE0,
171                                              libctx, "HMAC", "keysize",
172                                              ossl_fips_config_hmac_key_check)) {
173                 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
174                 return 0;
175             }
176         }
177     }
178 #endif
179 
180     if (macctx->key != NULL)
181         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
182     /* Keep a copy of the key in case we need it for TLS HMAC */
183     macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
184     if (macctx->key == NULL)
185         return 0;
186 
187     memcpy(macctx->key, key, keylen);
188     macctx->keylen = keylen;
189 
190     digest = ossl_prov_digest_md(&macctx->digest);
191     /* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
192     if (key != NULL || (macctx->tls_data_size == 0 && digest != NULL))
193         return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
194                             ossl_prov_digest_engine(&macctx->digest));
195     return 1;
196 }
197 
hmac_init(void * vmacctx,const unsigned char * key,size_t keylen,const OSSL_PARAM params[])198 static int hmac_init(void *vmacctx, const unsigned char *key,
199                      size_t keylen, const OSSL_PARAM params[])
200 {
201     struct hmac_data_st *macctx = vmacctx;
202 
203     if (!ossl_prov_is_running() || !hmac_set_ctx_params(macctx, params))
204         return 0;
205 
206     if (key != NULL)
207         return hmac_setkey(macctx, key, keylen);
208 
209     /* Just reinit the HMAC context */
210     return HMAC_Init_ex(macctx->ctx, NULL, 0, NULL, NULL);
211 }
212 
hmac_update(void * vmacctx,const unsigned char * data,size_t datalen)213 static int hmac_update(void *vmacctx, const unsigned char *data,
214                        size_t datalen)
215 {
216     struct hmac_data_st *macctx = vmacctx;
217 
218     if (macctx->tls_data_size > 0) {
219         /* We're doing a TLS HMAC */
220         if (!macctx->tls_header_set) {
221             /* We expect the first update call to contain the TLS header */
222             if (datalen != sizeof(macctx->tls_header))
223                 return 0;
224             memcpy(macctx->tls_header, data, datalen);
225             macctx->tls_header_set = 1;
226             return 1;
227         }
228         /* macctx->tls_data_size is datalen plus the padding length */
229         if (macctx->tls_data_size < datalen)
230             return 0;
231 
232         return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
233                                       macctx->tls_mac_out,
234                                       &macctx->tls_mac_out_size,
235                                       macctx->tls_header,
236                                       data,
237                                       datalen,
238                                       macctx->tls_data_size,
239                                       macctx->key,
240                                       macctx->keylen,
241                                       0);
242     }
243 
244     return HMAC_Update(macctx->ctx, data, datalen);
245 }
246 
hmac_final(void * vmacctx,unsigned char * out,size_t * outl,size_t outsize)247 static int hmac_final(void *vmacctx, unsigned char *out, size_t *outl,
248                       size_t outsize)
249 {
250     unsigned int hlen;
251     struct hmac_data_st *macctx = vmacctx;
252 
253     if (!ossl_prov_is_running())
254         return 0;
255     if (macctx->tls_data_size > 0) {
256         if (macctx->tls_mac_out_size == 0)
257             return 0;
258         if (outl != NULL)
259             *outl = macctx->tls_mac_out_size;
260         memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
261         return 1;
262     }
263     if (!HMAC_Final(macctx->ctx, out, &hlen))
264         return 0;
265     *outl = hlen;
266     return 1;
267 }
268 
269 static const OSSL_PARAM known_gettable_ctx_params[] = {
270     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
271     OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
272     OSSL_FIPS_IND_GETTABLE_CTX_PARAM()
273     OSSL_PARAM_END
274 };
hmac_gettable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)275 static const OSSL_PARAM *hmac_gettable_ctx_params(ossl_unused void *ctx,
276                                                   ossl_unused void *provctx)
277 {
278     return known_gettable_ctx_params;
279 }
280 
hmac_get_ctx_params(void * vmacctx,OSSL_PARAM params[])281 static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
282 {
283     struct hmac_data_st *macctx = vmacctx;
284     OSSL_PARAM *p;
285 
286     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
287             && !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
288         return 0;
289 
290     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
291             && !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
292         return 0;
293 
294 #ifdef FIPS_MODULE
295     p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_FIPS_APPROVED_INDICATOR);
296     if (p != NULL) {
297         int approved = 0;
298 
299         if (!macctx->internal)
300             approved = OSSL_FIPS_IND_GET(macctx)->approved;
301         if (!OSSL_PARAM_set_int(p, approved))
302             return 0;
303     }
304 #endif
305     return 1;
306 }
307 
308 static const OSSL_PARAM known_settable_ctx_params[] = {
309     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
310     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
311     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
312     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
313     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
314     OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
315     OSSL_FIPS_IND_SETTABLE_CTX_PARAM(OSSL_MAC_PARAM_FIPS_KEY_CHECK)
316     OSSL_PARAM_END
317 };
hmac_settable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)318 static const OSSL_PARAM *hmac_settable_ctx_params(ossl_unused void *ctx,
319                                                   ossl_unused void *provctx)
320 {
321     return known_settable_ctx_params;
322 }
323 
324 /*
325  * ALL parameters should be set before init().
326  */
hmac_set_ctx_params(void * vmacctx,const OSSL_PARAM params[])327 static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
328 {
329     struct hmac_data_st *macctx = vmacctx;
330     OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
331     const OSSL_PARAM *p;
332 
333     if (ossl_param_is_empty(params))
334         return 1;
335 
336     if (!OSSL_FIPS_IND_SET_CTX_PARAM(macctx, OSSL_FIPS_IND_SETTABLE0, params,
337                                      OSSL_MAC_PARAM_FIPS_KEY_CHECK))
338         return 0;
339 
340     if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
341         return 0;
342 
343     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
344         if (p->data_type != OSSL_PARAM_OCTET_STRING)
345             return 0;
346 
347         if (!hmac_setkey(macctx, p->data, p->data_size))
348             return 0;
349     }
350 
351     if ((p = OSSL_PARAM_locate_const(params,
352                                      OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
353         if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
354             return 0;
355     }
356     return 1;
357 }
358 
359 const OSSL_DISPATCH ossl_hmac_functions[] = {
360     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
361     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
362     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
363     { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
364     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
365     { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
366     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
367       (void (*)(void))hmac_gettable_ctx_params },
368     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
369     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
370       (void (*)(void))hmac_settable_ctx_params },
371     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
372     OSSL_DISPATCH_END
373 };
374 
375 #ifdef FIPS_MODULE
376 static OSSL_FUNC_mac_newctx_fn hmac_internal_new;
377 
hmac_internal_new(void * provctx)378 static void *hmac_internal_new(void *provctx)
379 {
380     struct hmac_data_st *macctx = hmac_new(provctx);
381 
382     if (macctx != NULL)
383         macctx->internal = 1;
384     return macctx;
385 }
386 
387 const OSSL_DISPATCH ossl_hmac_internal_functions[] = {
388     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_internal_new },
389     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
390     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
391     { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
392     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
393     { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
394     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
395       (void (*)(void))hmac_gettable_ctx_params },
396     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
397     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
398       (void (*)(void))hmac_settable_ctx_params },
399     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
400     OSSL_DISPATCH_END
401 };
402 
403 #endif /* FIPS_MODULE */
404