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4f22f405 RS |
1 | /* |
2 | * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved. | |
01be5db6 | 3 | * |
4f22f405 RS |
4 | * Licensed under the OpenSSL license (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 | |
01be5db6 AP |
8 | */ |
9 | ||
10 | #include <openssl/crypto.h> | |
11 | #include "modes_lcl.h" | |
12 | #include <string.h> | |
13 | ||
0f113f3e MC |
14 | int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx, |
15 | const unsigned char iv[16], | |
16 | const unsigned char *inp, unsigned char *out, | |
17 | size_t len, int enc) | |
01be5db6 | 18 | { |
0f113f3e MC |
19 | const union { |
20 | long one; | |
21 | char little; | |
22 | } is_endian = { | |
23 | 1 | |
24 | }; | |
25 | union { | |
26 | u64 u[2]; | |
27 | u32 d[4]; | |
28 | u8 c[16]; | |
29 | } tweak, scratch; | |
30 | unsigned int i; | |
31 | ||
32 | if (len < 16) | |
33 | return -1; | |
34 | ||
35 | memcpy(tweak.c, iv, 16); | |
36 | ||
37 | (*ctx->block2) (tweak.c, tweak.c, ctx->key2); | |
38 | ||
39 | if (!enc && (len % 16)) | |
40 | len -= 16; | |
41 | ||
42 | while (len >= 16) { | |
01be5db6 | 43 | #if defined(STRICT_ALIGNMENT) |
0f113f3e MC |
44 | memcpy(scratch.c, inp, 16); |
45 | scratch.u[0] ^= tweak.u[0]; | |
46 | scratch.u[1] ^= tweak.u[1]; | |
01be5db6 | 47 | #else |
0f113f3e MC |
48 | scratch.u[0] = ((u64 *)inp)[0] ^ tweak.u[0]; |
49 | scratch.u[1] = ((u64 *)inp)[1] ^ tweak.u[1]; | |
01be5db6 | 50 | #endif |
0f113f3e | 51 | (*ctx->block1) (scratch.c, scratch.c, ctx->key1); |
daaf5088 | 52 | #if defined(STRICT_ALIGNMENT) |
0f113f3e MC |
53 | scratch.u[0] ^= tweak.u[0]; |
54 | scratch.u[1] ^= tweak.u[1]; | |
55 | memcpy(out, scratch.c, 16); | |
daaf5088 | 56 | #else |
0f113f3e MC |
57 | ((u64 *)out)[0] = scratch.u[0] ^= tweak.u[0]; |
58 | ((u64 *)out)[1] = scratch.u[1] ^= tweak.u[1]; | |
daaf5088 | 59 | #endif |
0f113f3e MC |
60 | inp += 16; |
61 | out += 16; | |
62 | len -= 16; | |
63 | ||
64 | if (len == 0) | |
65 | return 0; | |
66 | ||
67 | if (is_endian.little) { | |
68 | unsigned int carry, res; | |
69 | ||
70 | res = 0x87 & (((int)tweak.d[3]) >> 31); | |
71 | carry = (unsigned int)(tweak.u[0] >> 63); | |
72 | tweak.u[0] = (tweak.u[0] << 1) ^ res; | |
73 | tweak.u[1] = (tweak.u[1] << 1) | carry; | |
74 | } else { | |
75 | size_t c; | |
76 | ||
77 | for (c = 0, i = 0; i < 16; ++i) { | |
78 | /* | |
79 | * + substitutes for |, because c is 1 bit | |
80 | */ | |
81 | c += ((size_t)tweak.c[i]) << 1; | |
82 | tweak.c[i] = (u8)c; | |
83 | c = c >> 8; | |
84 | } | |
85 | tweak.c[0] ^= (u8)(0x87 & (0 - c)); | |
86 | } | |
87 | } | |
88 | if (enc) { | |
89 | for (i = 0; i < len; ++i) { | |
90 | u8 c = inp[i]; | |
91 | out[i] = scratch.c[i]; | |
92 | scratch.c[i] = c; | |
93 | } | |
94 | scratch.u[0] ^= tweak.u[0]; | |
95 | scratch.u[1] ^= tweak.u[1]; | |
96 | (*ctx->block1) (scratch.c, scratch.c, ctx->key1); | |
97 | scratch.u[0] ^= tweak.u[0]; | |
98 | scratch.u[1] ^= tweak.u[1]; | |
99 | memcpy(out - 16, scratch.c, 16); | |
100 | } else { | |
101 | union { | |
102 | u64 u[2]; | |
103 | u8 c[16]; | |
104 | } tweak1; | |
105 | ||
106 | if (is_endian.little) { | |
107 | unsigned int carry, res; | |
108 | ||
109 | res = 0x87 & (((int)tweak.d[3]) >> 31); | |
110 | carry = (unsigned int)(tweak.u[0] >> 63); | |
111 | tweak1.u[0] = (tweak.u[0] << 1) ^ res; | |
112 | tweak1.u[1] = (tweak.u[1] << 1) | carry; | |
113 | } else { | |
114 | size_t c; | |
115 | ||
116 | for (c = 0, i = 0; i < 16; ++i) { | |
117 | /* | |
118 | * + substitutes for |, because c is 1 bit | |
119 | */ | |
120 | c += ((size_t)tweak.c[i]) << 1; | |
121 | tweak1.c[i] = (u8)c; | |
122 | c = c >> 8; | |
123 | } | |
124 | tweak1.c[0] ^= (u8)(0x87 & (0 - c)); | |
125 | } | |
01be5db6 | 126 | #if defined(STRICT_ALIGNMENT) |
0f113f3e MC |
127 | memcpy(scratch.c, inp, 16); |
128 | scratch.u[0] ^= tweak1.u[0]; | |
129 | scratch.u[1] ^= tweak1.u[1]; | |
01be5db6 | 130 | #else |
0f113f3e MC |
131 | scratch.u[0] = ((u64 *)inp)[0] ^ tweak1.u[0]; |
132 | scratch.u[1] = ((u64 *)inp)[1] ^ tweak1.u[1]; | |
01be5db6 | 133 | #endif |
0f113f3e MC |
134 | (*ctx->block1) (scratch.c, scratch.c, ctx->key1); |
135 | scratch.u[0] ^= tweak1.u[0]; | |
136 | scratch.u[1] ^= tweak1.u[1]; | |
137 | ||
138 | for (i = 0; i < len; ++i) { | |
139 | u8 c = inp[16 + i]; | |
140 | out[16 + i] = scratch.c[i]; | |
141 | scratch.c[i] = c; | |
142 | } | |
143 | scratch.u[0] ^= tweak.u[0]; | |
144 | scratch.u[1] ^= tweak.u[1]; | |
145 | (*ctx->block1) (scratch.c, scratch.c, ctx->key1); | |
daaf5088 | 146 | #if defined(STRICT_ALIGNMENT) |
0f113f3e MC |
147 | scratch.u[0] ^= tweak.u[0]; |
148 | scratch.u[1] ^= tweak.u[1]; | |
149 | memcpy(out, scratch.c, 16); | |
daaf5088 | 150 | #else |
0f113f3e MC |
151 | ((u64 *)out)[0] = scratch.u[0] ^ tweak.u[0]; |
152 | ((u64 *)out)[1] = scratch.u[1] ^ tweak.u[1]; | |
daaf5088 | 153 | #endif |
0f113f3e | 154 | } |
01be5db6 | 155 | |
0f113f3e | 156 | return 0; |
01be5db6 | 157 | } |