2 * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
28 * CCM initialisation. This does everything except setting the vtable,
29 * which depends on whether this is a context for encrypting or for
33 gen_ccm_init(br_sslrec_ccm_context *cc,
34 const br_block_ctrcbc_class *bc_impl,
35 const void *key, size_t key_len,
36 const void *iv, size_t tag_len)
39 bc_impl->init(&cc->bc.vtable, key, key_len);
40 memcpy(cc->iv, iv, sizeof cc->iv);
41 cc->tag_len = tag_len;
45 in_ccm_init(br_sslrec_ccm_context *cc,
46 const br_block_ctrcbc_class *bc_impl,
47 const void *key, size_t key_len,
48 const void *iv, size_t tag_len)
50 cc->vtable.in = &br_sslrec_in_ccm_vtable;
51 gen_ccm_init(cc, bc_impl, key, key_len, iv, tag_len);
55 ccm_check_length(const br_sslrec_ccm_context *cc, size_t rlen)
58 * CCM overhead is 8 bytes for nonce_explicit, and the tag
59 * (normally 8 or 16 bytes, depending on cipher suite).
63 over = 8 + cc->tag_len;
64 return rlen >= over && rlen <= (16384 + over);
67 static unsigned char *
68 ccm_decrypt(br_sslrec_ccm_context *cc,
69 int record_type, unsigned version, void *data, size_t *data_len)
73 unsigned char nonce[12], header[13];
76 buf = (unsigned char *)data + 8;
77 len = *data_len - (8 + cc->tag_len);
80 * Make nonce (implicit + explicit parts).
82 memcpy(nonce, cc->iv, sizeof cc->iv);
83 memcpy(nonce + 4, data, 8);
86 * Assemble synthetic header for the AAD.
88 br_enc64be(header, cc->seq ++);
89 header[8] = (unsigned char)record_type;
90 br_enc16be(header + 9, version);
91 br_enc16be(header + 11, len);
94 * Perform CCM decryption.
96 br_ccm_init(&zc, &cc->bc.vtable);
97 br_ccm_reset(&zc, nonce, sizeof nonce, sizeof header, len, cc->tag_len);
98 br_ccm_aad_inject(&zc, header, sizeof header);
100 br_ccm_run(&zc, 0, buf, len);
101 if (!br_ccm_check_tag(&zc, buf + len)) {
108 /* see bearssl_ssl.h */
109 const br_sslrec_in_ccm_class br_sslrec_in_ccm_vtable = {
111 sizeof(br_sslrec_ccm_context),
112 (int (*)(const br_sslrec_in_class *const *, size_t))
114 (unsigned char *(*)(const br_sslrec_in_class **,
115 int, unsigned, void *, size_t *))
118 (void (*)(const br_sslrec_in_ccm_class **,
119 const br_block_ctrcbc_class *, const void *, size_t,
120 const void *, size_t))
125 out_ccm_init(br_sslrec_ccm_context *cc,
126 const br_block_ctrcbc_class *bc_impl,
127 const void *key, size_t key_len,
128 const void *iv, size_t tag_len)
130 cc->vtable.out = &br_sslrec_out_ccm_vtable;
131 gen_ccm_init(cc, bc_impl, key, key_len, iv, tag_len);
135 ccm_max_plaintext(const br_sslrec_ccm_context *cc,
136 size_t *start, size_t *end)
141 len = *end - *start - cc->tag_len;
148 static unsigned char *
149 ccm_encrypt(br_sslrec_ccm_context *cc,
150 int record_type, unsigned version, void *data, size_t *data_len)
154 unsigned char nonce[12], header[13];
157 buf = (unsigned char *)data;
161 * Make nonce; the explicit part is an encoding of the sequence
164 memcpy(nonce, cc->iv, sizeof cc->iv);
165 br_enc64be(nonce + 4, cc->seq);
168 * Assemble synthetic header for the AAD.
170 br_enc64be(header, cc->seq ++);
171 header[8] = (unsigned char)record_type;
172 br_enc16be(header + 9, version);
173 br_enc16be(header + 11, len);
176 * Perform CCM encryption.
178 br_ccm_init(&zc, &cc->bc.vtable);
179 br_ccm_reset(&zc, nonce, sizeof nonce, sizeof header, len, cc->tag_len);
180 br_ccm_aad_inject(&zc, header, sizeof header);
182 br_ccm_run(&zc, 1, buf, len);
183 br_ccm_get_tag(&zc, buf + len);
186 * Assemble header and adjust pointer/length.
188 len += 8 + cc->tag_len;
190 memcpy(buf + 5, nonce + 4, 8);
191 buf[0] = (unsigned char)record_type;
192 br_enc16be(buf + 1, version);
193 br_enc16be(buf + 3, len);
198 /* see bearssl_ssl.h */
199 const br_sslrec_out_ccm_class br_sslrec_out_ccm_vtable = {
201 sizeof(br_sslrec_ccm_context),
202 (void (*)(const br_sslrec_out_class *const *,
205 (unsigned char *(*)(const br_sslrec_out_class **,
206 int, unsigned, void *, size_t *))
209 (void (*)(const br_sslrec_out_ccm_class **,
210 const br_block_ctrcbc_class *, const void *, size_t,
211 const void *, size_t))