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freebsd-skq/sys/opencrypto/cast.c
John Baldwin 821fe3d3a4 Use 'const' for keys and IVs passed to software encryption algorithms. 
Specifically, use 'const' for the key passed to the 'setkey' method
and 'const' for the 'iv' passed to the 'reinit' method.

Reviewed by:	cem
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D21347
2019-08-22 00:02:08 +00:00

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7.8 KiB
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/* $OpenBSD: cast.c,v 1.2 2000/06/06 06:49:47 deraadt Exp $ */
/*-
* CAST-128 in C
* Written by Steve Reid <sreid@sea-to-sky.net>
* 100% Public Domain - no warranty
* Released 1997.10.11
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <opencrypto/cast.h>
#include <opencrypto/castsb.h>
/* Macros to access 8-bit bytes out of a 32-bit word */
#define U_INT8_Ta(x) ( (u_int8_t) (x>>24) )
#define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) )
#define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) )
#define U_INT8_Td(x) ( (u_int8_t) ((x)&255) )
/* Circular left shift */
#define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
/* CAST-128 uses three different round functions */
#define F1(l, r, i) \
t = ROL(key->xkey[i] + r, key->xkey[i+16]); \
l ^= ((cast_sbox1[U_INT8_Ta(t)] ^ cast_sbox2[U_INT8_Tb(t)]) - \
cast_sbox3[U_INT8_Tc(t)]) + cast_sbox4[U_INT8_Td(t)];
#define F2(l, r, i) \
t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \
l ^= ((cast_sbox1[U_INT8_Ta(t)] - cast_sbox2[U_INT8_Tb(t)]) + \
cast_sbox3[U_INT8_Tc(t)]) ^ cast_sbox4[U_INT8_Td(t)];
#define F3(l, r, i) \
t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \
cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)];
/***** Encryption Function *****/
void cast_encrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
{
u_int32_t t, l, r;
/* Get inblock into l,r */
l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
/* Do the work */
F1(l, r, 0);
F2(r, l, 1);
F3(l, r, 2);
F1(r, l, 3);
F2(l, r, 4);
F3(r, l, 5);
F1(l, r, 6);
F2(r, l, 7);
F3(l, r, 8);
F1(r, l, 9);
F2(l, r, 10);
F3(r, l, 11);
/* Only do full 16 rounds if key length > 80 bits */
if (key->rounds > 12) {
F1(l, r, 12);
F2(r, l, 13);
F3(l, r, 14);
F1(r, l, 15);
}
/* Put l,r into outblock */
outblock[0] = U_INT8_Ta(r);
outblock[1] = U_INT8_Tb(r);
outblock[2] = U_INT8_Tc(r);
outblock[3] = U_INT8_Td(r);
outblock[4] = U_INT8_Ta(l);
outblock[5] = U_INT8_Tb(l);
outblock[6] = U_INT8_Tc(l);
outblock[7] = U_INT8_Td(l);
/* Wipe clean */
t = l = r = 0;
}
/***** Decryption Function *****/
void cast_decrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
{
u_int32_t t, l, r;
/* Get inblock into l,r */
r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
/* Do the work */
/* Only do full 16 rounds if key length > 80 bits */
if (key->rounds > 12) {
F1(r, l, 15);
F3(l, r, 14);
F2(r, l, 13);
F1(l, r, 12);
}
F3(r, l, 11);
F2(l, r, 10);
F1(r, l, 9);
F3(l, r, 8);
F2(r, l, 7);
F1(l, r, 6);
F3(r, l, 5);
F2(l, r, 4);
F1(r, l, 3);
F3(l, r, 2);
F2(r, l, 1);
F1(l, r, 0);
/* Put l,r into outblock */
outblock[0] = U_INT8_Ta(l);
outblock[1] = U_INT8_Tb(l);
outblock[2] = U_INT8_Tc(l);
outblock[3] = U_INT8_Td(l);
outblock[4] = U_INT8_Ta(r);
outblock[5] = U_INT8_Tb(r);
outblock[6] = U_INT8_Tc(r);
outblock[7] = U_INT8_Td(r);
/* Wipe clean */
t = l = r = 0;
}
/***** Key Schedule *****/
void cast_setkey(cast_key* key, const u_int8_t* rawkey, int keybytes)
{
u_int32_t t[4] = {0, 0, 0, 0}, z[4] = {0, 0, 0, 0}, x[4];
int i;
/* Set number of rounds to 12 or 16, depending on key length */
key->rounds = (keybytes <= 10 ? 12 : 16);
/* Copy key to workspace x */
for (i = 0; i < 4; i++) {
x[i] = 0;
if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24;
if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16;
if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8;
if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3];
}
/* Generate 32 subkeys, four at a time */
for (i = 0; i < 32; i+=4) {
switch (i & 4) {
case 0:
t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^
cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^
cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])];
t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^
cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^
cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])];
t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^
cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^
cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])];
t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^
cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^
cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])];
break;
case 4:
t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^
cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^
cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])];
t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^
cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^
cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])];
t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^
cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^
cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])];
t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^
cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^
cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])];
break;
}
switch (i & 12) {
case 0:
case 12:
key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^
cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])];
key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^
cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])];
key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^
cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])];
key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^
cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])];
break;
case 4:
case 8:
key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^
cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])];
key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^
cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])];
key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^
cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])];
key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^
cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])];
break;
}
switch (i & 12) {
case 0:
key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])];
key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])];
key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])];
key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])];
break;
case 4:
key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])];
key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])];
key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])];
key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])];
break;
case 8:
key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])];
key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])];
key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])];
key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])];
break;
case 12:
key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])];
key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])];
key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])];
key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])];
break;
}
if (i >= 16) {
key->xkey[i+0] &= 31;
key->xkey[i+1] &= 31;
key->xkey[i+2] &= 31;
key->xkey[i+3] &= 31;
}
}
/* Wipe clean */
for (i = 0; i < 4; i++) {
t[i] = x[i] = z[i] = 0;
}
}
/* Made in Canada */
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