openssl/crypto/modes/xts128.c
Shane Lontis 459b15d451 Add Common shared code needed to move aes ciphers to providers
Custom aes ciphers will be placed into multiple new files
(instead of the monolithic setup used in the e_aes.c legacy code)
so it makes sense to have a header for the platform specific
code that needs to be shared between files.
modes_lcl.h has also moved to modes_int.h to allow sharing with the
provider source.
Code that will be common to AEAD ciphers has also been added. These
will be used by seperate PR's for GCM, CCM & OCB.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9301)
2019-07-16 09:46:14 +10:00

157 lines
4.4 KiB
C

/*
* Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <string.h>
#include <openssl/crypto.h>
#include "internal/modes_int.h"
int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
const unsigned char iv[16],
const unsigned char *inp, unsigned char *out,
size_t len, int enc)
{
const union {
long one;
char little;
} is_endian = {
1
};
union {
u64 u[2];
u32 d[4];
u8 c[16];
} tweak, scratch;
unsigned int i;
if (len < 16)
return -1;
memcpy(tweak.c, iv, 16);
(*ctx->block2) (tweak.c, tweak.c, ctx->key2);
if (!enc && (len % 16))
len -= 16;
while (len >= 16) {
#if defined(STRICT_ALIGNMENT)
memcpy(scratch.c, inp, 16);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
#else
scratch.u[0] = ((u64 *)inp)[0] ^ tweak.u[0];
scratch.u[1] = ((u64 *)inp)[1] ^ tweak.u[1];
#endif
(*ctx->block1) (scratch.c, scratch.c, ctx->key1);
#if defined(STRICT_ALIGNMENT)
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
memcpy(out, scratch.c, 16);
#else
((u64 *)out)[0] = scratch.u[0] ^= tweak.u[0];
((u64 *)out)[1] = scratch.u[1] ^= tweak.u[1];
#endif
inp += 16;
out += 16;
len -= 16;
if (len == 0)
return 0;
if (is_endian.little) {
unsigned int carry, res;
res = 0x87 & (((int)tweak.d[3]) >> 31);
carry = (unsigned int)(tweak.u[0] >> 63);
tweak.u[0] = (tweak.u[0] << 1) ^ res;
tweak.u[1] = (tweak.u[1] << 1) | carry;
} else {
size_t c;
for (c = 0, i = 0; i < 16; ++i) {
/*
* + substitutes for |, because c is 1 bit
*/
c += ((size_t)tweak.c[i]) << 1;
tweak.c[i] = (u8)c;
c = c >> 8;
}
tweak.c[0] ^= (u8)(0x87 & (0 - c));
}
}
if (enc) {
for (i = 0; i < len; ++i) {
u8 c = inp[i];
out[i] = scratch.c[i];
scratch.c[i] = c;
}
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1) (scratch.c, scratch.c, ctx->key1);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
memcpy(out - 16, scratch.c, 16);
} else {
union {
u64 u[2];
u8 c[16];
} tweak1;
if (is_endian.little) {
unsigned int carry, res;
res = 0x87 & (((int)tweak.d[3]) >> 31);
carry = (unsigned int)(tweak.u[0] >> 63);
tweak1.u[0] = (tweak.u[0] << 1) ^ res;
tweak1.u[1] = (tweak.u[1] << 1) | carry;
} else {
size_t c;
for (c = 0, i = 0; i < 16; ++i) {
/*
* + substitutes for |, because c is 1 bit
*/
c += ((size_t)tweak.c[i]) << 1;
tweak1.c[i] = (u8)c;
c = c >> 8;
}
tweak1.c[0] ^= (u8)(0x87 & (0 - c));
}
#if defined(STRICT_ALIGNMENT)
memcpy(scratch.c, inp, 16);
scratch.u[0] ^= tweak1.u[0];
scratch.u[1] ^= tweak1.u[1];
#else
scratch.u[0] = ((u64 *)inp)[0] ^ tweak1.u[0];
scratch.u[1] = ((u64 *)inp)[1] ^ tweak1.u[1];
#endif
(*ctx->block1) (scratch.c, scratch.c, ctx->key1);
scratch.u[0] ^= tweak1.u[0];
scratch.u[1] ^= tweak1.u[1];
for (i = 0; i < len; ++i) {
u8 c = inp[16 + i];
out[16 + i] = scratch.c[i];
scratch.c[i] = c;
}
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1) (scratch.c, scratch.c, ctx->key1);
#if defined(STRICT_ALIGNMENT)
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
memcpy(out, scratch.c, 16);
#else
((u64 *)out)[0] = scratch.u[0] ^ tweak.u[0];
((u64 *)out)[1] = scratch.u[1] ^ tweak.u[1];
#endif
}
return 0;
}