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 <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  */
34 static OSSL_FUNC_mac_newctx_fn hmac_new;
35 static OSSL_FUNC_mac_dupctx_fn hmac_dup;
36 static OSSL_FUNC_mac_freectx_fn hmac_free;
37 static OSSL_FUNC_mac_gettable_ctx_params_fn hmac_gettable_ctx_params;
38 static OSSL_FUNC_mac_get_ctx_params_fn hmac_get_ctx_params;
39 static OSSL_FUNC_mac_settable_ctx_params_fn hmac_settable_ctx_params;
40 static OSSL_FUNC_mac_set_ctx_params_fn hmac_set_ctx_params;
41 static OSSL_FUNC_mac_init_fn hmac_init;
42 static OSSL_FUNC_mac_update_fn hmac_update;
43 static OSSL_FUNC_mac_final_fn hmac_final;
44 
45 /* local HMAC context structure */
46 
47 /* typedef EVP_MAC_IMPL */
48 struct 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 */
63 int 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 
hmac_new(void * provctx)73 static 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 
hmac_free(void * vmacctx)90 static 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 
hmac_dup(void * vsrc)102 static 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 
119     if (!HMAC_CTX_copy(dst->ctx, src->ctx)
120         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
121         hmac_free(dst);
122         return NULL;
123     }
124     if (src->key != NULL) {
125         /* There is no "secure" OPENSSL_memdup */
126         dst->key = OPENSSL_secure_malloc(src->keylen > 0 ? src->keylen : 1);
127         if (dst->key == NULL) {
128             hmac_free(dst);
129             return 0;
130         }
131         memcpy(dst->key, src->key, src->keylen);
132     }
133     return dst;
134 }
135 
hmac_size(struct hmac_data_st * macctx)136 static size_t hmac_size(struct hmac_data_st *macctx)
137 {
138     return HMAC_size(macctx->ctx);
139 }
140 
hmac_block_size(struct hmac_data_st * macctx)141 static int hmac_block_size(struct hmac_data_st *macctx)
142 {
143     const EVP_MD *md = ossl_prov_digest_md(&macctx->digest);
144 
145     if (md == NULL)
146         return 0;
147     return EVP_MD_block_size(md);
148 }
149 
hmac_setkey(struct hmac_data_st * macctx,const unsigned char * key,size_t keylen)150 static int hmac_setkey(struct hmac_data_st *macctx,
151                        const unsigned char *key, size_t keylen)
152 {
153     const EVP_MD *digest;
154 
155     if (macctx->keylen > 0)
156         OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
157     /* Keep a copy of the key in case we need it for TLS HMAC */
158     macctx->key = OPENSSL_secure_malloc(keylen > 0 ? keylen : 1);
159     if (macctx->key == NULL)
160         return 0;
161     memcpy(macctx->key, key, keylen);
162     macctx->keylen = keylen;
163 
164     digest = ossl_prov_digest_md(&macctx->digest);
165     /* HMAC_Init_ex doesn't tolerate all zero params, so we must be careful */
166     if (key != NULL || (macctx->tls_data_size == 0 && digest != NULL))
167         return HMAC_Init_ex(macctx->ctx, key, keylen, digest,
168                             ossl_prov_digest_engine(&macctx->digest));
169     return 1;
170 }
171 
hmac_init(void * vmacctx,const unsigned char * key,size_t keylen,const OSSL_PARAM params[])172 static int hmac_init(void *vmacctx, const unsigned char *key,
173                      size_t keylen, const OSSL_PARAM params[])
174 {
175     struct hmac_data_st *macctx = vmacctx;
176 
177     if (!ossl_prov_is_running() || !hmac_set_ctx_params(macctx, params))
178         return 0;
179 
180     if (key != NULL && !hmac_setkey(macctx, key, keylen))
181         return 0;
182     return 1;
183 }
184 
hmac_update(void * vmacctx,const unsigned char * data,size_t datalen)185 static int hmac_update(void *vmacctx, const unsigned char *data,
186                        size_t datalen)
187 {
188     struct hmac_data_st *macctx = vmacctx;
189 
190     if (macctx->tls_data_size > 0) {
191         /* We're doing a TLS HMAC */
192         if (!macctx->tls_header_set) {
193             /* We expect the first update call to contain the TLS header */
194             if (datalen != sizeof(macctx->tls_header))
195                 return 0;
196             memcpy(macctx->tls_header, data, datalen);
197             macctx->tls_header_set = 1;
198             return 1;
199         }
200         /* macctx->tls_data_size is datalen plus the padding length */
201         if (macctx->tls_data_size < datalen)
202             return 0;
203 
204         return ssl3_cbc_digest_record(ossl_prov_digest_md(&macctx->digest),
205                                       macctx->tls_mac_out,
206                                       &macctx->tls_mac_out_size,
207                                       macctx->tls_header,
208                                       data,
209                                       datalen,
210                                       macctx->tls_data_size,
211                                       macctx->key,
212                                       macctx->keylen,
213                                       0);
214     }
215 
216     return HMAC_Update(macctx->ctx, data, datalen);
217 }
218 
hmac_final(void * vmacctx,unsigned char * out,size_t * outl,size_t outsize)219 static int hmac_final(void *vmacctx, unsigned char *out, size_t *outl,
220                       size_t outsize)
221 {
222     unsigned int hlen;
223     struct hmac_data_st *macctx = vmacctx;
224 
225     if (!ossl_prov_is_running())
226         return 0;
227     if (macctx->tls_data_size > 0) {
228         if (macctx->tls_mac_out_size == 0)
229             return 0;
230         if (outl != NULL)
231             *outl = macctx->tls_mac_out_size;
232         memcpy(out, macctx->tls_mac_out, macctx->tls_mac_out_size);
233         return 1;
234     }
235     if (!HMAC_Final(macctx->ctx, out, &hlen))
236         return 0;
237     *outl = hlen;
238     return 1;
239 }
240 
241 static const OSSL_PARAM known_gettable_ctx_params[] = {
242     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
243     OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
244     OSSL_PARAM_END
245 };
hmac_gettable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)246 static const OSSL_PARAM *hmac_gettable_ctx_params(ossl_unused void *ctx,
247                                                   ossl_unused void *provctx)
248 {
249     return known_gettable_ctx_params;
250 }
251 
hmac_get_ctx_params(void * vmacctx,OSSL_PARAM params[])252 static int hmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
253 {
254     struct hmac_data_st *macctx = vmacctx;
255     OSSL_PARAM *p;
256 
257     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
258             && !OSSL_PARAM_set_size_t(p, hmac_size(macctx)))
259         return 0;
260 
261     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
262             && !OSSL_PARAM_set_int(p, hmac_block_size(macctx)))
263         return 0;
264 
265     return 1;
266 }
267 
268 static const OSSL_PARAM known_settable_ctx_params[] = {
269     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_DIGEST, NULL, 0),
270     OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
271     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
272     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_NOINIT, NULL),
273     OSSL_PARAM_int(OSSL_MAC_PARAM_DIGEST_ONESHOT, NULL),
274     OSSL_PARAM_size_t(OSSL_MAC_PARAM_TLS_DATA_SIZE, NULL),
275     OSSL_PARAM_END
276 };
hmac_settable_ctx_params(ossl_unused void * ctx,ossl_unused void * provctx)277 static const OSSL_PARAM *hmac_settable_ctx_params(ossl_unused void *ctx,
278                                                   ossl_unused void *provctx)
279 {
280     return known_settable_ctx_params;
281 }
282 
set_flag(const OSSL_PARAM params[],const char * key,int mask,int * flags)283 static int set_flag(const OSSL_PARAM params[], const char *key, int mask,
284                     int *flags)
285 {
286     const OSSL_PARAM *p = OSSL_PARAM_locate_const(params, key);
287     int flag = 0;
288 
289     if (p != NULL) {
290         if (!OSSL_PARAM_get_int(p, &flag))
291             return 0;
292         if (flag == 0)
293             *flags &= ~mask;
294         else
295             *flags |= mask;
296     }
297     return 1;
298 }
299 
300 /*
301  * ALL parameters should be set before init().
302  */
hmac_set_ctx_params(void * vmacctx,const OSSL_PARAM params[])303 static int hmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
304 {
305     struct hmac_data_st *macctx = vmacctx;
306     OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
307     const OSSL_PARAM *p;
308     int flags = 0;
309 
310     if (params == NULL)
311         return 1;
312 
313     if (!ossl_prov_digest_load_from_params(&macctx->digest, params, ctx))
314         return 0;
315 
316     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_NOINIT, EVP_MD_CTX_FLAG_NO_INIT,
317                   &flags))
318         return 0;
319     if (!set_flag(params, OSSL_MAC_PARAM_DIGEST_ONESHOT, EVP_MD_CTX_FLAG_ONESHOT,
320                   &flags))
321         return 0;
322     if (flags)
323         HMAC_CTX_set_flags(macctx->ctx, flags);
324 
325     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
326         if (p->data_type != OSSL_PARAM_OCTET_STRING)
327             return 0;
328 
329         if (macctx->keylen > 0)
330             OPENSSL_secure_clear_free(macctx->key, macctx->keylen);
331         /* Keep a copy of the key if we need it for TLS HMAC */
332         macctx->key = OPENSSL_secure_malloc(p->data_size > 0 ? p->data_size : 1);
333         if (macctx->key == NULL)
334             return 0;
335         memcpy(macctx->key, p->data, p->data_size);
336         macctx->keylen = p->data_size;
337 
338         if (!HMAC_Init_ex(macctx->ctx, p->data, p->data_size,
339                           ossl_prov_digest_md(&macctx->digest),
340                           NULL /* ENGINE */))
341             return 0;
342 
343     }
344     if ((p = OSSL_PARAM_locate_const(params,
345                                      OSSL_MAC_PARAM_TLS_DATA_SIZE)) != NULL) {
346         if (!OSSL_PARAM_get_size_t(p, &macctx->tls_data_size))
347             return 0;
348     }
349     return 1;
350 }
351 
352 const OSSL_DISPATCH ossl_hmac_functions[] = {
353     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))hmac_new },
354     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))hmac_dup },
355     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))hmac_free },
356     { OSSL_FUNC_MAC_INIT, (void (*)(void))hmac_init },
357     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))hmac_update },
358     { OSSL_FUNC_MAC_FINAL, (void (*)(void))hmac_final },
359     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
360       (void (*)(void))hmac_gettable_ctx_params },
361     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))hmac_get_ctx_params },
362     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
363       (void (*)(void))hmac_settable_ctx_params },
364     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))hmac_set_ctx_params },
365     { 0, NULL }
366 };
367