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linux/crypto/cast6_generic.c
Ard Biesheuvel 80879dd9de crypto: cast6 - use unaligned accessors instead of alignmask 
Instead of using an alignmask of 0x3 to ensure 32-bit alignment of the
CAST6 input and output blocks, which propagates to mode drivers, and
results in pointless copying on architectures that don't care about
alignment, use the unaligned accessors, which will do the right thing on
each respective architecture, avoiding the need for double buffering.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-02-10 17:55:56 +11:00

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9.1 KiB
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// SPDX-License-Identifier: GPL-2.0-or-later
/* Kernel cryptographic api.
* cast6.c - Cast6 cipher algorithm [rfc2612].
*
* CAST-256 (*cast6*) is a DES like Substitution-Permutation Network (SPN)
* cryptosystem built upon the CAST-128 (*cast5*) [rfc2144] encryption
* algorithm.
*
* Copyright (C) 2003 Kartikey Mahendra Bhatt <kartik_me@hotmail.com>.
*/
#include <asm/unaligned.h>
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <crypto/cast6.h>
#define s1 cast_s1
#define s2 cast_s2
#define s3 cast_s3
#define s4 cast_s4
#define F1(D, r, m) ((I = ((m) + (D))), (I = rol32(I, (r))), \
(((s1[I >> 24] ^ s2[(I>>16)&0xff]) - s3[(I>>8)&0xff]) + s4[I&0xff]))
#define F2(D, r, m) ((I = ((m) ^ (D))), (I = rol32(I, (r))), \
(((s1[I >> 24] - s2[(I>>16)&0xff]) + s3[(I>>8)&0xff]) ^ s4[I&0xff]))
#define F3(D, r, m) ((I = ((m) - (D))), (I = rol32(I, (r))), \
(((s1[I >> 24] + s2[(I>>16)&0xff]) ^ s3[(I>>8)&0xff]) - s4[I&0xff]))
static const u32 Tm[24][8] = {
{ 0x5a827999, 0xc95c653a, 0x383650db, 0xa7103c7c, 0x15ea281d,
0x84c413be, 0xf39dff5f, 0x6277eb00 } ,
{ 0xd151d6a1, 0x402bc242, 0xaf05ade3, 0x1ddf9984, 0x8cb98525,
0xfb9370c6, 0x6a6d5c67, 0xd9474808 } ,
{ 0x482133a9, 0xb6fb1f4a, 0x25d50aeb, 0x94aef68c, 0x0388e22d,
0x7262cdce, 0xe13cb96f, 0x5016a510 } ,
{ 0xbef090b1, 0x2dca7c52, 0x9ca467f3, 0x0b7e5394, 0x7a583f35,
0xe9322ad6, 0x580c1677, 0xc6e60218 } ,
{ 0x35bfedb9, 0xa499d95a, 0x1373c4fb, 0x824db09c, 0xf1279c3d,
0x600187de, 0xcedb737f, 0x3db55f20 } ,
{ 0xac8f4ac1, 0x1b693662, 0x8a432203, 0xf91d0da4, 0x67f6f945,
0xd6d0e4e6, 0x45aad087, 0xb484bc28 } ,
{ 0x235ea7c9, 0x9238936a, 0x01127f0b, 0x6fec6aac, 0xdec6564d,
0x4da041ee, 0xbc7a2d8f, 0x2b541930 } ,
{ 0x9a2e04d1, 0x0907f072, 0x77e1dc13, 0xe6bbc7b4, 0x5595b355,
0xc46f9ef6, 0x33498a97, 0xa2237638 } ,
{ 0x10fd61d9, 0x7fd74d7a, 0xeeb1391b, 0x5d8b24bc, 0xcc65105d,
0x3b3efbfe, 0xaa18e79f, 0x18f2d340 } ,
{ 0x87ccbee1, 0xf6a6aa82, 0x65809623, 0xd45a81c4, 0x43346d65,
0xb20e5906, 0x20e844a7, 0x8fc23048 } ,
{ 0xfe9c1be9, 0x6d76078a, 0xdc4ff32b, 0x4b29decc, 0xba03ca6d,
0x28ddb60e, 0x97b7a1af, 0x06918d50 } ,
{ 0x756b78f1, 0xe4456492, 0x531f5033, 0xc1f93bd4, 0x30d32775,
0x9fad1316, 0x0e86feb7, 0x7d60ea58 } ,
{ 0xec3ad5f9, 0x5b14c19a, 0xc9eead3b, 0x38c898dc, 0xa7a2847d,
0x167c701e, 0x85565bbf, 0xf4304760 } ,
{ 0x630a3301, 0xd1e41ea2, 0x40be0a43, 0xaf97f5e4, 0x1e71e185,
0x8d4bcd26, 0xfc25b8c7, 0x6affa468 } ,
{ 0xd9d99009, 0x48b37baa, 0xb78d674b, 0x266752ec, 0x95413e8d,
0x041b2a2e, 0x72f515cf, 0xe1cf0170 } ,
{ 0x50a8ed11, 0xbf82d8b2, 0x2e5cc453, 0x9d36aff4, 0x0c109b95,
0x7aea8736, 0xe9c472d7, 0x589e5e78 } ,
{ 0xc7784a19, 0x365235ba, 0xa52c215b, 0x14060cfc, 0x82dff89d,
0xf1b9e43e, 0x6093cfdf, 0xcf6dbb80 } ,
{ 0x3e47a721, 0xad2192c2, 0x1bfb7e63, 0x8ad56a04, 0xf9af55a5,
0x68894146, 0xd7632ce7, 0x463d1888 } ,
{ 0xb5170429, 0x23f0efca, 0x92cadb6b, 0x01a4c70c, 0x707eb2ad,
0xdf589e4e, 0x4e3289ef, 0xbd0c7590 } ,
{ 0x2be66131, 0x9ac04cd2, 0x099a3873, 0x78742414, 0xe74e0fb5,
0x5627fb56, 0xc501e6f7, 0x33dbd298 } ,
{ 0xa2b5be39, 0x118fa9da, 0x8069957b, 0xef43811c, 0x5e1d6cbd,
0xccf7585e, 0x3bd143ff, 0xaaab2fa0 } ,
{ 0x19851b41, 0x885f06e2, 0xf738f283, 0x6612de24, 0xd4ecc9c5,
0x43c6b566, 0xb2a0a107, 0x217a8ca8 } ,
{ 0x90547849, 0xff2e63ea, 0x6e084f8b, 0xdce23b2c, 0x4bbc26cd,
0xba96126e, 0x296ffe0f, 0x9849e9b0 } ,
{ 0x0723d551, 0x75fdc0f2, 0xe4d7ac93, 0x53b19834, 0xc28b83d5,
0x31656f76, 0xa03f5b17, 0x0f1946b8 }
};
static const u8 Tr[4][8] = {
{ 0x13, 0x04, 0x15, 0x06, 0x17, 0x08, 0x19, 0x0a } ,
{ 0x1b, 0x0c, 0x1d, 0x0e, 0x1f, 0x10, 0x01, 0x12 } ,
{ 0x03, 0x14, 0x05, 0x16, 0x07, 0x18, 0x09, 0x1a } ,
{ 0x0b, 0x1c, 0x0d, 0x1e, 0x0f, 0x00, 0x11, 0x02 }
};
/* forward octave */
static inline void W(u32 *key, unsigned int i)
{
u32 I;
key[6] ^= F1(key[7], Tr[i % 4][0], Tm[i][0]);
key[5] ^= F2(key[6], Tr[i % 4][1], Tm[i][1]);
key[4] ^= F3(key[5], Tr[i % 4][2], Tm[i][2]);
key[3] ^= F1(key[4], Tr[i % 4][3], Tm[i][3]);
key[2] ^= F2(key[3], Tr[i % 4][4], Tm[i][4]);
key[1] ^= F3(key[2], Tr[i % 4][5], Tm[i][5]);
key[0] ^= F1(key[1], Tr[i % 4][6], Tm[i][6]);
key[7] ^= F2(key[0], Tr[i % 4][7], Tm[i][7]);
}
int __cast6_setkey(struct cast6_ctx *c, const u8 *in_key, unsigned int key_len)
{
int i;
u32 key[8];
__be32 p_key[8]; /* padded key */
if (key_len % 4 != 0)
return -EINVAL;
memset(p_key, 0, 32);
memcpy(p_key, in_key, key_len);
key[0] = be32_to_cpu(p_key[0]); /* A */
key[1] = be32_to_cpu(p_key[1]); /* B */
key[2] = be32_to_cpu(p_key[2]); /* C */
key[3] = be32_to_cpu(p_key[3]); /* D */
key[4] = be32_to_cpu(p_key[4]); /* E */
key[5] = be32_to_cpu(p_key[5]); /* F */
key[6] = be32_to_cpu(p_key[6]); /* G */
key[7] = be32_to_cpu(p_key[7]); /* H */
for (i = 0; i < 12; i++) {
W(key, 2 * i);
W(key, 2 * i + 1);
c->Kr[i][0] = key[0] & 0x1f;
c->Kr[i][1] = key[2] & 0x1f;
c->Kr[i][2] = key[4] & 0x1f;
c->Kr[i][3] = key[6] & 0x1f;
c->Km[i][0] = key[7];
c->Km[i][1] = key[5];
c->Km[i][2] = key[3];
c->Km[i][3] = key[1];
}
return 0;
}
EXPORT_SYMBOL_GPL(__cast6_setkey);
int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
return __cast6_setkey(crypto_tfm_ctx(tfm), key, keylen);
}
EXPORT_SYMBOL_GPL(cast6_setkey);
/*forward quad round*/
static inline void Q(u32 *block, const u8 *Kr, const u32 *Km)
{
u32 I;
block[2] ^= F1(block[3], Kr[0], Km[0]);
block[1] ^= F2(block[2], Kr[1], Km[1]);
block[0] ^= F3(block[1], Kr[2], Km[2]);
block[3] ^= F1(block[0], Kr[3], Km[3]);
}
/*reverse quad round*/
static inline void QBAR(u32 *block, const u8 *Kr, const u32 *Km)
{
u32 I;
block[3] ^= F1(block[0], Kr[3], Km[3]);
block[0] ^= F3(block[1], Kr[2], Km[2]);
block[1] ^= F2(block[2], Kr[1], Km[1]);
block[2] ^= F1(block[3], Kr[0], Km[0]);
}
void __cast6_encrypt(const void *ctx, u8 *outbuf, const u8 *inbuf)
{
const struct cast6_ctx *c = ctx;
u32 block[4];
const u32 *Km;
const u8 *Kr;
block[0] = get_unaligned_be32(inbuf);
block[1] = get_unaligned_be32(inbuf + 4);
block[2] = get_unaligned_be32(inbuf + 8);
block[3] = get_unaligned_be32(inbuf + 12);
Km = c->Km[0]; Kr = c->Kr[0]; Q(block, Kr, Km);
Km = c->Km[1]; Kr = c->Kr[1]; Q(block, Kr, Km);
Km = c->Km[2]; Kr = c->Kr[2]; Q(block, Kr, Km);
Km = c->Km[3]; Kr = c->Kr[3]; Q(block, Kr, Km);
Km = c->Km[4]; Kr = c->Kr[4]; Q(block, Kr, Km);
Km = c->Km[5]; Kr = c->Kr[5]; Q(block, Kr, Km);
Km = c->Km[6]; Kr = c->Kr[6]; QBAR(block, Kr, Km);
Km = c->Km[7]; Kr = c->Kr[7]; QBAR(block, Kr, Km);
Km = c->Km[8]; Kr = c->Kr[8]; QBAR(block, Kr, Km);
Km = c->Km[9]; Kr = c->Kr[9]; QBAR(block, Kr, Km);
Km = c->Km[10]; Kr = c->Kr[10]; QBAR(block, Kr, Km);
Km = c->Km[11]; Kr = c->Kr[11]; QBAR(block, Kr, Km);
put_unaligned_be32(block[0], outbuf);
put_unaligned_be32(block[1], outbuf + 4);
put_unaligned_be32(block[2], outbuf + 8);
put_unaligned_be32(block[3], outbuf + 12);
}
EXPORT_SYMBOL_GPL(__cast6_encrypt);
static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
{
__cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
}
void __cast6_decrypt(const void *ctx, u8 *outbuf, const u8 *inbuf)
{
const struct cast6_ctx *c = ctx;
u32 block[4];
const u32 *Km;
const u8 *Kr;
block[0] = get_unaligned_be32(inbuf);
block[1] = get_unaligned_be32(inbuf + 4);
block[2] = get_unaligned_be32(inbuf + 8);
block[3] = get_unaligned_be32(inbuf + 12);
Km = c->Km[11]; Kr = c->Kr[11]; Q(block, Kr, Km);
Km = c->Km[10]; Kr = c->Kr[10]; Q(block, Kr, Km);
Km = c->Km[9]; Kr = c->Kr[9]; Q(block, Kr, Km);
Km = c->Km[8]; Kr = c->Kr[8]; Q(block, Kr, Km);
Km = c->Km[7]; Kr = c->Kr[7]; Q(block, Kr, Km);
Km = c->Km[6]; Kr = c->Kr[6]; Q(block, Kr, Km);
Km = c->Km[5]; Kr = c->Kr[5]; QBAR(block, Kr, Km);
Km = c->Km[4]; Kr = c->Kr[4]; QBAR(block, Kr, Km);
Km = c->Km[3]; Kr = c->Kr[3]; QBAR(block, Kr, Km);
Km = c->Km[2]; Kr = c->Kr[2]; QBAR(block, Kr, Km);
Km = c->Km[1]; Kr = c->Kr[1]; QBAR(block, Kr, Km);
Km = c->Km[0]; Kr = c->Kr[0]; QBAR(block, Kr, Km);
put_unaligned_be32(block[0], outbuf);
put_unaligned_be32(block[1], outbuf + 4);
put_unaligned_be32(block[2], outbuf + 8);
put_unaligned_be32(block[3], outbuf + 12);
}
EXPORT_SYMBOL_GPL(__cast6_decrypt);
static void cast6_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
{
__cast6_decrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
}
static struct crypto_alg alg = {
.cra_name = "cast6",
.cra_driver_name = "cast6-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = CAST6_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct cast6_ctx),
.cra_module = THIS_MODULE,
.cra_u = {
.cipher = {
.cia_min_keysize = CAST6_MIN_KEY_SIZE,
.cia_max_keysize = CAST6_MAX_KEY_SIZE,
.cia_setkey = cast6_setkey,
.cia_encrypt = cast6_encrypt,
.cia_decrypt = cast6_decrypt}
}
};
static int __init cast6_mod_init(void)
{
return crypto_register_alg(&alg);
}
static void __exit cast6_mod_fini(void)
{
crypto_unregister_alg(&alg);
}
subsys_initcall(cast6_mod_init);
module_exit(cast6_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Cast6 Cipher Algorithm");
MODULE_ALIAS_CRYPTO("cast6");
MODULE_ALIAS_CRYPTO("cast6-generic");
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