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 * [email protected].
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
51 #include <assert.h>
52 #include <limits.h>
53 #include <string.h>
54
55 #include <openssl/mem.h>
56
57 #include "../../internal.h"
58 #include "../service_indicator/internal.h"
59
60
61 // kDefaultIV is the default IV value given in RFC 3394, 2.2.3.1.
62 static const uint8_t kDefaultIV[] = {
63 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6,
64 };
65
66 static const unsigned kBound = 6;
67
AES_wrap_key(const AES_KEY * key,const uint8_t * iv,uint8_t * out,const uint8_t * in,size_t in_len)68 int AES_wrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out,
69 const uint8_t *in, size_t in_len) {
70 // See RFC 3394, section 2.2.1. Additionally, note that section 2 requires the
71 // plaintext be at least two 8-byte blocks.
72
73 if (in_len > INT_MAX - 8 || in_len < 16 || in_len % 8 != 0) {
74 return -1;
75 }
76
77 if (iv == NULL) {
78 iv = kDefaultIV;
79 }
80
81 OPENSSL_memmove(out + 8, in, in_len);
82 uint8_t A[AES_BLOCK_SIZE];
83 OPENSSL_memcpy(A, iv, 8);
84
85 size_t n = in_len / 8;
86
87 for (unsigned j = 0; j < kBound; j++) {
88 for (size_t i = 1; i <= n; i++) {
89 OPENSSL_memcpy(A + 8, out + 8 * i, 8);
90 AES_encrypt(A, A, key);
91
92 uint32_t t = (uint32_t)(n * j + i);
93 A[7] ^= t & 0xff;
94 A[6] ^= (t >> 8) & 0xff;
95 A[5] ^= (t >> 16) & 0xff;
96 A[4] ^= (t >> 24) & 0xff;
97 OPENSSL_memcpy(out + 8 * i, A + 8, 8);
98 }
99 }
100
101 OPENSSL_memcpy(out, A, 8);
102 FIPS_service_indicator_update_state();
103 return (int)in_len + 8;
104 }
105
106 // aes_unwrap_key_inner performs steps one and two from
107 // https://tools.ietf.org/html/rfc3394#section-2.2.2
aes_unwrap_key_inner(const AES_KEY * key,uint8_t * out,uint8_t out_iv[8],const uint8_t * in,size_t in_len)108 static int aes_unwrap_key_inner(const AES_KEY *key, uint8_t *out,
109 uint8_t out_iv[8], const uint8_t *in,
110 size_t in_len) {
111 // See RFC 3394, section 2.2.2. Additionally, note that section 2 requires the
112 // plaintext be at least two 8-byte blocks, so the ciphertext must be at least
113 // three blocks.
114
115 if (in_len > INT_MAX || in_len < 24 || in_len % 8 != 0) {
116 return 0;
117 }
118
119 uint8_t A[AES_BLOCK_SIZE];
120 OPENSSL_memcpy(A, in, 8);
121 OPENSSL_memmove(out, in + 8, in_len - 8);
122
123 size_t n = (in_len / 8) - 1;
124
125 for (unsigned j = kBound - 1; j < kBound; j--) {
126 for (size_t i = n; i > 0; i--) {
127 uint32_t t = (uint32_t)(n * j + i);
128 A[7] ^= t & 0xff;
129 A[6] ^= (t >> 8) & 0xff;
130 A[5] ^= (t >> 16) & 0xff;
131 A[4] ^= (t >> 24) & 0xff;
132 OPENSSL_memcpy(A + 8, out + 8 * (i - 1), 8);
133 AES_decrypt(A, A, key);
134 OPENSSL_memcpy(out + 8 * (i - 1), A + 8, 8);
135 }
136 }
137
138 memcpy(out_iv, A, 8);
139 return 1;
140 }
141
AES_unwrap_key(const AES_KEY * key,const uint8_t * iv,uint8_t * out,const uint8_t * in,size_t in_len)142 int AES_unwrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out,
143 const uint8_t *in, size_t in_len) {
144 uint8_t calculated_iv[8];
145 if (!aes_unwrap_key_inner(key, out, calculated_iv, in, in_len)) {
146 return -1;
147 }
148
149 if (iv == NULL) {
150 iv = kDefaultIV;
151 }
152 if (CRYPTO_memcmp(calculated_iv, iv, 8) != 0) {
153 return -1;
154 }
155
156 FIPS_service_indicator_update_state();
157 return (int)in_len - 8;
158 }
159
160 // kPaddingConstant is used in Key Wrap with Padding. See
161 // https://tools.ietf.org/html/rfc5649#section-3
162 static const uint8_t kPaddingConstant[4] = {0xa6, 0x59, 0x59, 0xa6};
163
AES_wrap_key_padded(const AES_KEY * key,uint8_t * out,size_t * out_len,size_t max_out,const uint8_t * in,size_t in_len)164 int AES_wrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len,
165 size_t max_out, const uint8_t *in, size_t in_len) {
166 // See https://tools.ietf.org/html/rfc5649#section-4.1
167 const uint64_t in_len64 = in_len;
168 const size_t padded_len = (in_len + 7) & ~7;
169 *out_len = 0;
170 if (in_len == 0 || in_len64 > 0xffffffffu || in_len + 7 < in_len ||
171 padded_len + 8 < padded_len || max_out < padded_len + 8) {
172 return 0;
173 }
174
175 uint8_t block[AES_BLOCK_SIZE];
176 memcpy(block, kPaddingConstant, sizeof(kPaddingConstant));
177 CRYPTO_store_u32_be(block + 4, (uint32_t)in_len);
178
179 if (in_len <= 8) {
180 memset(block + 8, 0, 8);
181 memcpy(block + 8, in, in_len);
182 AES_encrypt(block, out, key);
183 *out_len = AES_BLOCK_SIZE;
184 return 1;
185 }
186
187 uint8_t *padded_in = OPENSSL_malloc(padded_len);
188 if (padded_in == NULL) {
189 return 0;
190 }
191 assert(padded_len >= 8);
192 memset(padded_in + padded_len - 8, 0, 8);
193 memcpy(padded_in, in, in_len);
194 FIPS_service_indicator_lock_state();
195 const int ret = AES_wrap_key(key, block, out, padded_in, padded_len);
196 FIPS_service_indicator_unlock_state();
197 OPENSSL_free(padded_in);
198 if (ret < 0) {
199 return 0;
200 }
201 *out_len = ret;
202 FIPS_service_indicator_update_state();
203 return 1;
204 }
205
AES_unwrap_key_padded(const AES_KEY * key,uint8_t * out,size_t * out_len,size_t max_out,const uint8_t * in,size_t in_len)206 int AES_unwrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len,
207 size_t max_out, const uint8_t *in, size_t in_len) {
208 *out_len = 0;
209 if (in_len < AES_BLOCK_SIZE || max_out < in_len - 8) {
210 return 0;
211 }
212
213 uint8_t iv[8];
214 if (in_len == AES_BLOCK_SIZE) {
215 uint8_t block[AES_BLOCK_SIZE];
216 AES_decrypt(in, block, key);
217 memcpy(iv, block, sizeof(iv));
218 memcpy(out, block + 8, 8);
219 } else if (!aes_unwrap_key_inner(key, out, iv, in, in_len)) {
220 return 0;
221 }
222 assert(in_len % 8 == 0);
223
224 crypto_word_t ok = constant_time_eq_int(
225 CRYPTO_memcmp(iv, kPaddingConstant, sizeof(kPaddingConstant)), 0);
226
227 const size_t claimed_len = CRYPTO_load_u32_be(iv + 4);
228 ok &= ~constant_time_is_zero_w(claimed_len);
229 ok &= constant_time_eq_w((claimed_len - 1) >> 3, (in_len - 9) >> 3);
230
231 // Check that padding bytes are all zero.
232 for (size_t i = in_len - 15; i < in_len - 8; i++) {
233 ok &= constant_time_is_zero_w(constant_time_ge_8(i, claimed_len) & out[i]);
234 }
235
236 *out_len = constant_time_select_w(ok, claimed_len, 0);
237 const int ret = ok & 1;
238 if (ret) {
239 FIPS_service_indicator_update_state();
240 }
241 return ret;
242 }
243