Srinivas Paladugu | dd42a61 | 2019-08-09 19:30:39 +0000 | [diff] [blame^] | 1 | /* ==================================================================== |
| 2 | * Copyright (c) 2011 The OpenSSL Project. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in |
| 13 | * the documentation and/or other materials provided with the |
| 14 | * distribution. |
| 15 | * |
| 16 | * 3. All advertising materials mentioning features or use of this |
| 17 | * software must display the following acknowledgment: |
| 18 | * "This product includes software developed by the OpenSSL Project |
| 19 | * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
| 20 | * |
| 21 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
| 22 | * endorse or promote products derived from this software without |
| 23 | * prior written permission. For written permission, please contact |
| 24 | * openssl-core@openssl.org. |
| 25 | * |
| 26 | * 5. Products derived from this software may not be called "OpenSSL" |
| 27 | * nor may "OpenSSL" appear in their names without prior written |
| 28 | * permission of the OpenSSL Project. |
| 29 | * |
| 30 | * 6. Redistributions of any form whatsoever must retain the following |
| 31 | * acknowledgment: |
| 32 | * "This product includes software developed by the OpenSSL Project |
| 33 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
| 34 | * |
| 35 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
| 36 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 37 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 38 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
| 39 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 40 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 41 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| 42 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 43 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 44 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 45 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| 46 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
| 47 | * ==================================================================== |
| 48 | */ |
| 49 | |
| 50 | #include <assert.h> |
| 51 | #include <string.h> |
| 52 | |
| 53 | #include <openssl/cpu.h> |
| 54 | #include <openssl/mem.h> |
| 55 | |
| 56 | #include "../../internal.h" |
| 57 | #include "internal.h" |
| 58 | |
| 59 | |
| 60 | struct ccm128_state { |
| 61 | union { |
| 62 | uint64_t u[2]; |
| 63 | uint8_t c[16]; |
| 64 | } nonce, cmac; |
| 65 | }; |
| 66 | |
| 67 | int CRYPTO_ccm128_init(CCM128_CONTEXT *ctx, const AES_KEY *key, |
| 68 | block128_f block, ctr128_f ctr, unsigned M, unsigned L) { |
| 69 | if (M < 4 || M > 16 || (M & 1) != 0 || L < 2 || L > 8) { |
| 70 | return 0; |
| 71 | } |
| 72 | ctx->block = block; |
| 73 | ctx->ctr = ctr; |
| 74 | ctx->M = M; |
| 75 | ctx->L = L; |
| 76 | return 1; |
| 77 | } |
| 78 | |
| 79 | size_t CRYPTO_ccm128_max_input(const CCM128_CONTEXT *ctx) { |
| 80 | return ctx->L >= sizeof(size_t) ? (size_t)-1 |
| 81 | : (((size_t)1) << (ctx->L * 8)) - 1; |
| 82 | } |
| 83 | |
| 84 | static int ccm128_init_state(const CCM128_CONTEXT *ctx, |
| 85 | struct ccm128_state *state, const AES_KEY *key, |
| 86 | const uint8_t *nonce, size_t nonce_len, |
| 87 | const uint8_t *aad, size_t aad_len, |
| 88 | size_t plaintext_len) { |
| 89 | const block128_f block = ctx->block; |
| 90 | const unsigned M = ctx->M; |
| 91 | const unsigned L = ctx->L; |
| 92 | |
| 93 | // |L| determines the expected |nonce_len| and the limit for |plaintext_len|. |
| 94 | if (plaintext_len > CRYPTO_ccm128_max_input(ctx) || |
| 95 | nonce_len != 15 - L) { |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | // Assemble the first block for computing the MAC. |
| 100 | OPENSSL_memset(state, 0, sizeof(*state)); |
| 101 | state->nonce.c[0] = (uint8_t)((L - 1) | ((M - 2) / 2) << 3); |
| 102 | if (aad_len != 0) { |
| 103 | state->nonce.c[0] |= 0x40; // Set AAD Flag |
| 104 | } |
| 105 | OPENSSL_memcpy(&state->nonce.c[1], nonce, nonce_len); |
| 106 | for (unsigned i = 0; i < L; i++) { |
| 107 | state->nonce.c[15 - i] = (uint8_t)(plaintext_len >> (8 * i)); |
| 108 | } |
| 109 | |
| 110 | (*block)(state->nonce.c, state->cmac.c, key); |
| 111 | size_t blocks = 1; |
| 112 | |
| 113 | if (aad_len != 0) { |
| 114 | unsigned i; |
| 115 | // Cast to u64 to avoid the compiler complaining about invalid shifts. |
| 116 | uint64_t aad_len_u64 = aad_len; |
| 117 | if (aad_len_u64 < 0x10000 - 0x100) { |
| 118 | state->cmac.c[0] ^= (uint8_t)(aad_len_u64 >> 8); |
| 119 | state->cmac.c[1] ^= (uint8_t)aad_len_u64; |
| 120 | i = 2; |
| 121 | } else if (aad_len_u64 <= 0xffffffff) { |
| 122 | state->cmac.c[0] ^= 0xff; |
| 123 | state->cmac.c[1] ^= 0xfe; |
| 124 | state->cmac.c[2] ^= (uint8_t)(aad_len_u64 >> 24); |
| 125 | state->cmac.c[3] ^= (uint8_t)(aad_len_u64 >> 16); |
| 126 | state->cmac.c[4] ^= (uint8_t)(aad_len_u64 >> 8); |
| 127 | state->cmac.c[5] ^= (uint8_t)aad_len_u64; |
| 128 | i = 6; |
| 129 | } else { |
| 130 | state->cmac.c[0] ^= 0xff; |
| 131 | state->cmac.c[1] ^= 0xff; |
| 132 | state->cmac.c[2] ^= (uint8_t)(aad_len_u64 >> 56); |
| 133 | state->cmac.c[3] ^= (uint8_t)(aad_len_u64 >> 48); |
| 134 | state->cmac.c[4] ^= (uint8_t)(aad_len_u64 >> 40); |
| 135 | state->cmac.c[5] ^= (uint8_t)(aad_len_u64 >> 32); |
| 136 | state->cmac.c[6] ^= (uint8_t)(aad_len_u64 >> 24); |
| 137 | state->cmac.c[7] ^= (uint8_t)(aad_len_u64 >> 16); |
| 138 | state->cmac.c[8] ^= (uint8_t)(aad_len_u64 >> 8); |
| 139 | state->cmac.c[9] ^= (uint8_t)aad_len_u64; |
| 140 | i = 10; |
| 141 | } |
| 142 | |
| 143 | do { |
| 144 | for (; i < 16 && aad_len != 0; i++) { |
| 145 | state->cmac.c[i] ^= *aad; |
| 146 | aad++; |
| 147 | aad_len--; |
| 148 | } |
| 149 | (*block)(state->cmac.c, state->cmac.c, key); |
| 150 | blocks++; |
| 151 | i = 0; |
| 152 | } while (aad_len != 0); |
| 153 | } |
| 154 | |
| 155 | // Per RFC 3610, section 2.6, the total number of block cipher operations done |
| 156 | // must not exceed 2^61. There are two block cipher operations remaining per |
| 157 | // message block, plus one block at the end to encrypt the MAC. |
| 158 | size_t remaining_blocks = 2 * ((plaintext_len + 15) / 16) + 1; |
| 159 | if (plaintext_len + 15 < plaintext_len || |
| 160 | remaining_blocks + blocks < blocks || |
| 161 | (uint64_t) remaining_blocks + blocks > UINT64_C(1) << 61) { |
| 162 | return 0; |
| 163 | } |
| 164 | |
| 165 | // Assemble the first block for encrypting and decrypting. The bottom |L| |
| 166 | // bytes are replaced with a counter and all bit the encoding of |L| is |
| 167 | // cleared in the first byte. |
| 168 | state->nonce.c[0] &= 7; |
| 169 | return 1; |
| 170 | } |
| 171 | |
| 172 | static int ccm128_encrypt(const CCM128_CONTEXT *ctx, struct ccm128_state *state, |
| 173 | const AES_KEY *key, uint8_t *out, const uint8_t *in, |
| 174 | size_t len) { |
| 175 | // The counter for encryption begins at one. |
| 176 | for (unsigned i = 0; i < ctx->L; i++) { |
| 177 | state->nonce.c[15 - i] = 0; |
| 178 | } |
| 179 | state->nonce.c[15] = 1; |
| 180 | |
| 181 | uint8_t partial_buf[16]; |
| 182 | unsigned num = 0; |
| 183 | if (ctx->ctr != NULL) { |
| 184 | CRYPTO_ctr128_encrypt_ctr32(in, out, len, key, state->nonce.c, partial_buf, |
| 185 | &num, ctx->ctr); |
| 186 | } else { |
| 187 | CRYPTO_ctr128_encrypt(in, out, len, key, state->nonce.c, partial_buf, &num, |
| 188 | ctx->block); |
| 189 | } |
| 190 | return 1; |
| 191 | } |
| 192 | |
| 193 | static int ccm128_compute_mac(const CCM128_CONTEXT *ctx, |
| 194 | struct ccm128_state *state, const AES_KEY *key, |
| 195 | uint8_t *out_tag, size_t tag_len, |
| 196 | const uint8_t *in, size_t len) { |
| 197 | block128_f block = ctx->block; |
| 198 | if (tag_len != ctx->M) { |
| 199 | return 0; |
| 200 | } |
| 201 | |
| 202 | // Incorporate |in| into the MAC. |
| 203 | union { |
| 204 | uint64_t u[2]; |
| 205 | uint8_t c[16]; |
| 206 | } tmp; |
| 207 | while (len >= 16) { |
| 208 | OPENSSL_memcpy(tmp.c, in, 16); |
| 209 | state->cmac.u[0] ^= tmp.u[0]; |
| 210 | state->cmac.u[1] ^= tmp.u[1]; |
| 211 | (*block)(state->cmac.c, state->cmac.c, key); |
| 212 | in += 16; |
| 213 | len -= 16; |
| 214 | } |
| 215 | if (len > 0) { |
| 216 | for (size_t i = 0; i < len; i++) { |
| 217 | state->cmac.c[i] ^= in[i]; |
| 218 | } |
| 219 | (*block)(state->cmac.c, state->cmac.c, key); |
| 220 | } |
| 221 | |
| 222 | // Encrypt the MAC with counter zero. |
| 223 | for (unsigned i = 0; i < ctx->L; i++) { |
| 224 | state->nonce.c[15 - i] = 0; |
| 225 | } |
| 226 | (*block)(state->nonce.c, tmp.c, key); |
| 227 | state->cmac.u[0] ^= tmp.u[0]; |
| 228 | state->cmac.u[1] ^= tmp.u[1]; |
| 229 | |
| 230 | OPENSSL_memcpy(out_tag, state->cmac.c, tag_len); |
| 231 | return 1; |
| 232 | } |
| 233 | |
| 234 | int CRYPTO_ccm128_encrypt(const CCM128_CONTEXT *ctx, const AES_KEY *key, |
| 235 | uint8_t *out, uint8_t *out_tag, size_t tag_len, |
| 236 | const uint8_t *nonce, size_t nonce_len, |
| 237 | const uint8_t *in, size_t len, const uint8_t *aad, |
| 238 | size_t aad_len) { |
| 239 | struct ccm128_state state; |
| 240 | return ccm128_init_state(ctx, &state, key, nonce, nonce_len, aad, aad_len, |
| 241 | len) && |
| 242 | ccm128_compute_mac(ctx, &state, key, out_tag, tag_len, in, len) && |
| 243 | ccm128_encrypt(ctx, &state, key, out, in, len); |
| 244 | } |
| 245 | |
| 246 | int CRYPTO_ccm128_decrypt(const CCM128_CONTEXT *ctx, const AES_KEY *key, |
| 247 | uint8_t *out, uint8_t *out_tag, size_t tag_len, |
| 248 | const uint8_t *nonce, size_t nonce_len, |
| 249 | const uint8_t *in, size_t len, const uint8_t *aad, |
| 250 | size_t aad_len) { |
| 251 | struct ccm128_state state; |
| 252 | return ccm128_init_state(ctx, &state, key, nonce, nonce_len, aad, aad_len, |
| 253 | len) && |
| 254 | ccm128_encrypt(ctx, &state, key, out, in, len) && |
| 255 | ccm128_compute_mac(ctx, &state, key, out_tag, tag_len, out, len); |
| 256 | } |