Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 1 | /* ==================================================================== |
| 2 | * Copyright (c) 2001-2011 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 | #include <openssl/aes.h> |
| 50 | |
Pete Bentley | 0c61efe | 2019-08-13 09:32:23 +0100 | [diff] [blame^] | 51 | #include <assert.h> |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 52 | #include <limits.h> |
| 53 | #include <string.h> |
| 54 | |
| 55 | #include <openssl/mem.h> |
| 56 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 57 | #include "../../internal.h" |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 58 | |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 59 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 60 | // kDefaultIV is the default IV value given in RFC 3394, 2.2.3.1. |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 61 | static const uint8_t kDefaultIV[] = { |
| 62 | 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, |
| 63 | }; |
| 64 | |
Steven Valdez | 909b19f | 2016-11-21 15:35:44 -0500 | [diff] [blame] | 65 | static const unsigned kBound = 6; |
| 66 | |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 67 | int AES_wrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out, |
| 68 | const uint8_t *in, size_t in_len) { |
Adam Vartanian | bfcf3a7 | 2018-08-10 14:55:24 +0100 | [diff] [blame] | 69 | // See RFC 3394, section 2.2.1. Additionally, note that section 2 requires the |
| 70 | // plaintext be at least two 8-byte blocks. |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 71 | |
Adam Vartanian | bfcf3a7 | 2018-08-10 14:55:24 +0100 | [diff] [blame] | 72 | if (in_len > INT_MAX - 8 || in_len < 16 || in_len % 8 != 0) { |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 73 | return -1; |
| 74 | } |
| 75 | |
| 76 | if (iv == NULL) { |
| 77 | iv = kDefaultIV; |
| 78 | } |
| 79 | |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 80 | OPENSSL_memmove(out + 8, in, in_len); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 81 | uint8_t A[AES_BLOCK_SIZE]; |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 82 | OPENSSL_memcpy(A, iv, 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 83 | |
| 84 | size_t n = in_len / 8; |
| 85 | |
Steven Valdez | 909b19f | 2016-11-21 15:35:44 -0500 | [diff] [blame] | 86 | for (unsigned j = 0; j < kBound; j++) { |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 87 | for (size_t i = 1; i <= n; i++) { |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 88 | OPENSSL_memcpy(A + 8, out + 8 * i, 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 89 | AES_encrypt(A, A, key); |
| 90 | |
| 91 | uint32_t t = (uint32_t)(n * j + i); |
| 92 | A[7] ^= t & 0xff; |
| 93 | A[6] ^= (t >> 8) & 0xff; |
| 94 | A[5] ^= (t >> 16) & 0xff; |
| 95 | A[4] ^= (t >> 24) & 0xff; |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 96 | OPENSSL_memcpy(out + 8 * i, A + 8, 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 97 | } |
| 98 | } |
| 99 | |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 100 | OPENSSL_memcpy(out, A, 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 101 | return (int)in_len + 8; |
| 102 | } |
| 103 | |
Pete Bentley | 0c61efe | 2019-08-13 09:32:23 +0100 | [diff] [blame^] | 104 | // aes_unwrap_key_inner performs steps one and two from |
| 105 | // https://tools.ietf.org/html/rfc3394#section-2.2.2 |
| 106 | static int aes_unwrap_key_inner(const AES_KEY *key, uint8_t *out, |
| 107 | uint8_t out_iv[8], const uint8_t *in, |
| 108 | size_t in_len) { |
Adam Vartanian | bfcf3a7 | 2018-08-10 14:55:24 +0100 | [diff] [blame] | 109 | // See RFC 3394, section 2.2.2. Additionally, note that section 2 requires the |
| 110 | // plaintext be at least two 8-byte blocks, so the ciphertext must be at least |
| 111 | // three blocks. |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 112 | |
Adam Vartanian | bfcf3a7 | 2018-08-10 14:55:24 +0100 | [diff] [blame] | 113 | if (in_len > INT_MAX || in_len < 24 || in_len % 8 != 0) { |
Pete Bentley | 0c61efe | 2019-08-13 09:32:23 +0100 | [diff] [blame^] | 114 | return 0; |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 115 | } |
| 116 | |
| 117 | uint8_t A[AES_BLOCK_SIZE]; |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 118 | OPENSSL_memcpy(A, in, 8); |
| 119 | OPENSSL_memmove(out, in + 8, in_len - 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 120 | |
| 121 | size_t n = (in_len / 8) - 1; |
| 122 | |
Steven Valdez | 909b19f | 2016-11-21 15:35:44 -0500 | [diff] [blame] | 123 | for (unsigned j = kBound - 1; j < kBound; j--) { |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 124 | for (size_t i = n; i > 0; i--) { |
| 125 | uint32_t t = (uint32_t)(n * j + i); |
| 126 | A[7] ^= t & 0xff; |
| 127 | A[6] ^= (t >> 8) & 0xff; |
| 128 | A[5] ^= (t >> 16) & 0xff; |
| 129 | A[4] ^= (t >> 24) & 0xff; |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 130 | OPENSSL_memcpy(A + 8, out + 8 * (i - 1), 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 131 | AES_decrypt(A, A, key); |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 132 | OPENSSL_memcpy(out + 8 * (i - 1), A + 8, 8); |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 133 | } |
| 134 | } |
| 135 | |
Pete Bentley | 0c61efe | 2019-08-13 09:32:23 +0100 | [diff] [blame^] | 136 | memcpy(out_iv, A, 8); |
| 137 | return 1; |
| 138 | } |
| 139 | |
| 140 | int AES_unwrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out, |
| 141 | const uint8_t *in, size_t in_len) { |
| 142 | uint8_t calculated_iv[8]; |
| 143 | if (!aes_unwrap_key_inner(key, out, calculated_iv, in, in_len)) { |
| 144 | return -1; |
| 145 | } |
| 146 | |
| 147 | if (iv == NULL) { |
| 148 | iv = kDefaultIV; |
| 149 | } |
| 150 | if (CRYPTO_memcmp(calculated_iv, iv, 8) != 0) { |
Steven Valdez | bb1ceac | 2016-10-07 10:34:51 -0400 | [diff] [blame] | 151 | return -1; |
| 152 | } |
| 153 | |
| 154 | return (int)in_len - 8; |
| 155 | } |
Pete Bentley | 0c61efe | 2019-08-13 09:32:23 +0100 | [diff] [blame^] | 156 | |
| 157 | // kPaddingConstant is used in Key Wrap with Padding. See |
| 158 | // https://tools.ietf.org/html/rfc5649#section-3 |
| 159 | static const uint8_t kPaddingConstant[4] = {0xa6, 0x59, 0x59, 0xa6}; |
| 160 | |
| 161 | int AES_wrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len, |
| 162 | size_t max_out, const uint8_t *in, size_t in_len) { |
| 163 | // See https://tools.ietf.org/html/rfc5649#section-4.1 |
| 164 | const uint32_t in_len32_be = CRYPTO_bswap4(in_len); |
| 165 | const uint64_t in_len64 = in_len; |
| 166 | const size_t padded_len = (in_len + 7) & ~7; |
| 167 | |
| 168 | *out_len = 0; |
| 169 | if (in_len == 0 || in_len64 > 0xffffffffu || in_len + 7 < in_len || |
| 170 | padded_len + 8 < padded_len || max_out < padded_len + 8) { |
| 171 | return 0; |
| 172 | } |
| 173 | |
| 174 | uint8_t block[AES_BLOCK_SIZE]; |
| 175 | memcpy(block, kPaddingConstant, sizeof(kPaddingConstant)); |
| 176 | memcpy(block + 4, &in_len32_be, sizeof(in_len32_be)); |
| 177 | |
| 178 | if (in_len <= 8) { |
| 179 | memset(block + 8, 0, 8); |
| 180 | memcpy(block + 8, in, in_len); |
| 181 | AES_encrypt(block, out, key); |
| 182 | *out_len = AES_BLOCK_SIZE; |
| 183 | return 1; |
| 184 | } |
| 185 | |
| 186 | uint8_t *padded_in = OPENSSL_malloc(padded_len); |
| 187 | if (padded_in == NULL) { |
| 188 | return 0; |
| 189 | } |
| 190 | assert(padded_len >= 8); |
| 191 | memset(padded_in + padded_len - 8, 0, 8); |
| 192 | memcpy(padded_in, in, in_len); |
| 193 | const int ret = AES_wrap_key(key, block, out, padded_in, padded_len); |
| 194 | OPENSSL_free(padded_in); |
| 195 | if (ret < 0) { |
| 196 | return 0; |
| 197 | } |
| 198 | *out_len = ret; |
| 199 | return 1; |
| 200 | } |
| 201 | |
| 202 | int AES_unwrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len, |
| 203 | size_t max_out, const uint8_t *in, size_t in_len) { |
| 204 | *out_len = 0; |
| 205 | if (in_len < AES_BLOCK_SIZE || max_out < in_len - 8) { |
| 206 | return 0; |
| 207 | } |
| 208 | |
| 209 | uint8_t iv[8]; |
| 210 | if (in_len == AES_BLOCK_SIZE) { |
| 211 | uint8_t block[AES_BLOCK_SIZE]; |
| 212 | AES_decrypt(in, block, key); |
| 213 | memcpy(iv, block, sizeof(iv)); |
| 214 | memcpy(out, block + 8, 8); |
| 215 | } else if (!aes_unwrap_key_inner(key, out, iv, in, in_len)) { |
| 216 | return 0; |
| 217 | } |
| 218 | assert(in_len % 8 == 0); |
| 219 | |
| 220 | crypto_word_t ok = constant_time_eq_int( |
| 221 | CRYPTO_memcmp(iv, kPaddingConstant, sizeof(kPaddingConstant)), 0); |
| 222 | |
| 223 | uint32_t claimed_len32; |
| 224 | memcpy(&claimed_len32, iv + 4, sizeof(claimed_len32)); |
| 225 | const size_t claimed_len = CRYPTO_bswap4(claimed_len32); |
| 226 | ok &= ~constant_time_is_zero_w(claimed_len); |
| 227 | ok &= constant_time_eq_w((claimed_len - 1) >> 3, (in_len - 9) >> 3); |
| 228 | |
| 229 | // Check that padding bytes are all zero. |
| 230 | for (size_t i = in_len - 15; i < in_len - 8; i++) { |
| 231 | ok &= constant_time_is_zero_w(constant_time_ge_8(i, claimed_len) & out[i]); |
| 232 | } |
| 233 | |
| 234 | *out_len = constant_time_select_w(ok, claimed_len, 0); |
| 235 | return ok & 1; |
| 236 | } |