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  */
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 
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 
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 
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     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 
137 static size_t hmac_size(struct hmac_data_st *macctx)
138 {
139     return HMAC_size(macctx->ctx);
140 }
141 
142 static 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 
151 static 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 
173 static 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 
188 static 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 
222 static 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 
244 static 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 };
249 static 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 
255 static 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 
271 static 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 };
280 static 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 
286 static 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  */
306 static 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 
343 const 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