Revision 4f988f152ee087831ea5c1c77cda4454cacc052c authored by Linus Torvalds on 04 May 2012, 22:13:54 UTC, committed by Linus Torvalds on 04 May 2012, 22:13:54 UTC
The normal read_seqcount_begin() function will wait for any current
writers to exit their critical region by looping until the sequence
count is even.

That "wait for sequence count to stabilize" is the right thing to do if
the read-locker will just retry the whole operation on contention: no
point in doing a potentially expensive reader sequence if we know at the
beginning that we'll just end up re-doing it all.

HOWEVER.  Some users don't actually retry the operation, but instead
will abort and do the operation with proper locking.  So the sequence
count case may be the optimistic quick case, but in the presense of
writers you may want to do full locking in order to guarantee forward
progress.  The prime example of this would be the RCU name lookup.

And in that case, you may well be better off without the "retry early",
and are in a rush to instead get to the failure handling.  Thus this
"raw" interface that just returns the sequence number without testing it
- it just forces the low bit to zero so that read_seqcount_retry() will
always fail such a "active concurrent writer" scenario.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 2f62427
Raw File
serpent_generic.c
/*
 * Cryptographic API.
 *
 * Serpent Cipher Algorithm.
 *
 * Copyright (C) 2002 Dag Arne Osvik <osvik@ii.uib.no>
 *               2003 Herbert Valerio Riedel <hvr@gnu.org>
 *
 * Added tnepres support:
 *		Ruben Jesus Garcia Hernandez <ruben@ugr.es>, 18.10.2004
 *              Based on code by hvr
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <asm/byteorder.h>
#include <linux/crypto.h>
#include <linux/types.h>
#include <crypto/serpent.h>

/* Key is padded to the maximum of 256 bits before round key generation.
 * Any key length <= 256 bits (32 bytes) is allowed by the algorithm.
 */

#define PHI 0x9e3779b9UL

#define keyiter(a, b, c, d, i, j) \
	({ b ^= d; b ^= c; b ^= a; b ^= PHI ^ i; b = rol32(b, 11); k[j] = b; })

#define loadkeys(x0, x1, x2, x3, i) \
	({ x0 = k[i]; x1 = k[i+1]; x2 = k[i+2]; x3 = k[i+3]; })

#define storekeys(x0, x1, x2, x3, i) \
	({ k[i] = x0; k[i+1] = x1; k[i+2] = x2; k[i+3] = x3; })

#define store_and_load_keys(x0, x1, x2, x3, s, l) \
	({ storekeys(x0, x1, x2, x3, s); loadkeys(x0, x1, x2, x3, l); })

#define K(x0, x1, x2, x3, i) ({				\
	x3 ^= k[4*(i)+3];        x2 ^= k[4*(i)+2];	\
	x1 ^= k[4*(i)+1];        x0 ^= k[4*(i)+0];	\
	})

#define LK(x0, x1, x2, x3, x4, i) ({					   \
							x0 = rol32(x0, 13);\
	x2 = rol32(x2, 3);	x1 ^= x0;		x4  = x0 << 3;	   \
	x3 ^= x2;		x1 ^= x2;				   \
	x1 = rol32(x1, 1);	x3 ^= x4;				   \
	x3 = rol32(x3, 7);	x4  = x1;				   \
	x0 ^= x1;		x4 <<= 7;		x2 ^= x3;	   \
	x0 ^= x3;		x2 ^= x4;		x3 ^= k[4*i+3];	   \
	x1 ^= k[4*i+1];		x0 = rol32(x0, 5);	x2 = rol32(x2, 22);\
	x0 ^= k[4*i+0];		x2 ^= k[4*i+2];				   \
	})

#define KL(x0, x1, x2, x3, x4, i) ({					   \
	x0 ^= k[4*i+0];		x1 ^= k[4*i+1];		x2 ^= k[4*i+2];	   \
	x3 ^= k[4*i+3];		x0 = ror32(x0, 5);	x2 = ror32(x2, 22);\
	x4 =  x1;		x2 ^= x3;		x0 ^= x3;	   \
	x4 <<= 7;		x0 ^= x1;		x1 = ror32(x1, 1); \
	x2 ^= x4;		x3 = ror32(x3, 7);	x4 = x0 << 3;	   \
	x1 ^= x0;		x3 ^= x4;		x0 = ror32(x0, 13);\
	x1 ^= x2;		x3 ^= x2;		x2 = ror32(x2, 3); \
	})

#define S0(x0, x1, x2, x3, x4) ({			\
					x4  = x3;	\
	x3 |= x0;	x0 ^= x4;	x4 ^= x2;	\
	x4 = ~x4;	x3 ^= x1;	x1 &= x0;	\
	x1 ^= x4;	x2 ^= x0;	x0 ^= x3;	\
	x4 |= x0;	x0 ^= x2;	x2 &= x1;	\
	x3 ^= x2;	x1 = ~x1;	x2 ^= x4;	\
	x1 ^= x2;					\
	})

#define S1(x0, x1, x2, x3, x4) ({			\
					x4  = x1;	\
	x1 ^= x0;	x0 ^= x3;	x3 = ~x3;	\
	x4 &= x1;	x0 |= x1;	x3 ^= x2;	\
	x0 ^= x3;	x1 ^= x3;	x3 ^= x4;	\
	x1 |= x4;	x4 ^= x2;	x2 &= x0;	\
	x2 ^= x1;	x1 |= x0;	x0 = ~x0;	\
	x0 ^= x2;	x4 ^= x1;			\
	})

#define S2(x0, x1, x2, x3, x4) ({			\
					x3 = ~x3;	\
	x1 ^= x0;	x4  = x0;	x0 &= x2;	\
	x0 ^= x3;	x3 |= x4;	x2 ^= x1;	\
	x3 ^= x1;	x1 &= x0;	x0 ^= x2;	\
	x2 &= x3;	x3 |= x1;	x0 = ~x0;	\
	x3 ^= x0;	x4 ^= x0;	x0 ^= x2;	\
	x1 |= x2;					\
	})

#define S3(x0, x1, x2, x3, x4) ({			\
					x4  = x1;	\
	x1 ^= x3;	x3 |= x0;	x4 &= x0;	\
	x0 ^= x2;	x2 ^= x1;	x1 &= x3;	\
	x2 ^= x3;	x0 |= x4;	x4 ^= x3;	\
	x1 ^= x0;	x0 &= x3;	x3 &= x4;	\
	x3 ^= x2;	x4 |= x1;	x2 &= x1;	\
	x4 ^= x3;	x0 ^= x3;	x3 ^= x2;	\
	})

#define S4(x0, x1, x2, x3, x4) ({			\
					x4  = x3;	\
	x3 &= x0;	x0 ^= x4;			\
	x3 ^= x2;	x2 |= x4;	x0 ^= x1;	\
	x4 ^= x3;	x2 |= x0;			\
	x2 ^= x1;	x1 &= x0;			\
	x1 ^= x4;	x4 &= x2;	x2 ^= x3;	\
	x4 ^= x0;	x3 |= x1;	x1 = ~x1;	\
	x3 ^= x0;					\
	})

#define S5(x0, x1, x2, x3, x4) ({			\
	x4  = x1;	x1 |= x0;			\
	x2 ^= x1;	x3 = ~x3;	x4 ^= x0;	\
	x0 ^= x2;	x1 &= x4;	x4 |= x3;	\
	x4 ^= x0;	x0 &= x3;	x1 ^= x3;	\
	x3 ^= x2;	x0 ^= x1;	x2 &= x4;	\
	x1 ^= x2;	x2 &= x0;			\
	x3 ^= x2;					\
	})

#define S6(x0, x1, x2, x3, x4) ({			\
					x4  = x1;	\
	x3 ^= x0;	x1 ^= x2;	x2 ^= x0;	\
	x0 &= x3;	x1 |= x3;	x4 = ~x4;	\
	x0 ^= x1;	x1 ^= x2;			\
	x3 ^= x4;	x4 ^= x0;	x2 &= x0;	\
	x4 ^= x1;	x2 ^= x3;	x3 &= x1;	\
	x3 ^= x0;	x1 ^= x2;			\
	})

#define S7(x0, x1, x2, x3, x4) ({			\
					x1 = ~x1;	\
	x4  = x1;	x0 = ~x0;	x1 &= x2;	\
	x1 ^= x3;	x3 |= x4;	x4 ^= x2;	\
	x2 ^= x3;	x3 ^= x0;	x0 |= x1;	\
	x2 &= x0;	x0 ^= x4;	x4 ^= x3;	\
	x3 &= x0;	x4 ^= x1;			\
	x2 ^= x4;	x3 ^= x1;	x4 |= x0;	\
	x4 ^= x1;					\
	})

#define SI0(x0, x1, x2, x3, x4) ({			\
			x4  = x3;	x1 ^= x0;	\
	x3 |= x1;	x4 ^= x1;	x0 = ~x0;	\
	x2 ^= x3;	x3 ^= x0;	x0 &= x1;	\
	x0 ^= x2;	x2 &= x3;	x3 ^= x4;	\
	x2 ^= x3;	x1 ^= x3;	x3 &= x0;	\
	x1 ^= x0;	x0 ^= x2;	x4 ^= x3;	\
	})

#define SI1(x0, x1, x2, x3, x4) ({			\
	x1 ^= x3;	x4  = x0;			\
	x0 ^= x2;	x2 = ~x2;	x4 |= x1;	\
	x4 ^= x3;	x3 &= x1;	x1 ^= x2;	\
	x2 &= x4;	x4 ^= x1;	x1 |= x3;	\
	x3 ^= x0;	x2 ^= x0;	x0 |= x4;	\
	x2 ^= x4;	x1 ^= x0;			\
	x4 ^= x1;					\
	})

#define SI2(x0, x1, x2, x3, x4) ({			\
	x2 ^= x1;	x4  = x3;	x3 = ~x3;	\
	x3 |= x2;	x2 ^= x4;	x4 ^= x0;	\
	x3 ^= x1;	x1 |= x2;	x2 ^= x0;	\
	x1 ^= x4;	x4 |= x3;	x2 ^= x3;	\
	x4 ^= x2;	x2 &= x1;			\
	x2 ^= x3;	x3 ^= x4;	x4 ^= x0;	\
	})

#define SI3(x0, x1, x2, x3, x4) ({			\
					x2 ^= x1;	\
	x4  = x1;	x1 &= x2;			\
	x1 ^= x0;	x0 |= x4;	x4 ^= x3;	\
	x0 ^= x3;	x3 |= x1;	x1 ^= x2;	\
	x1 ^= x3;	x0 ^= x2;	x2 ^= x3;	\
	x3 &= x1;	x1 ^= x0;	x0 &= x2;	\
	x4 ^= x3;	x3 ^= x0;	x0 ^= x1;	\
	})

#define SI4(x0, x1, x2, x3, x4) ({			\
	x2 ^= x3;	x4  = x0;	x0 &= x1;	\
	x0 ^= x2;	x2 |= x3;	x4 = ~x4;	\
	x1 ^= x0;	x0 ^= x2;	x2 &= x4;	\
	x2 ^= x0;	x0 |= x4;			\
	x0 ^= x3;	x3 &= x2;			\
	x4 ^= x3;	x3 ^= x1;	x1 &= x0;	\
	x4 ^= x1;	x0 ^= x3;			\
	})

#define SI5(x0, x1, x2, x3, x4) ({			\
			x4  = x1;	x1 |= x2;	\
	x2 ^= x4;	x1 ^= x3;	x3 &= x4;	\
	x2 ^= x3;	x3 |= x0;	x0 = ~x0;	\
	x3 ^= x2;	x2 |= x0;	x4 ^= x1;	\
	x2 ^= x4;	x4 &= x0;	x0 ^= x1;	\
	x1 ^= x3;	x0 &= x2;	x2 ^= x3;	\
	x0 ^= x2;	x2 ^= x4;	x4 ^= x3;	\
	})

#define SI6(x0, x1, x2, x3, x4) ({			\
			x0 ^= x2;			\
	x4  = x0;	x0 &= x3;	x2 ^= x3;	\
	x0 ^= x2;	x3 ^= x1;	x2 |= x4;	\
	x2 ^= x3;	x3 &= x0;	x0 = ~x0;	\
	x3 ^= x1;	x1 &= x2;	x4 ^= x0;	\
	x3 ^= x4;	x4 ^= x2;	x0 ^= x1;	\
	x2 ^= x0;					\
	})

#define SI7(x0, x1, x2, x3, x4) ({			\
	x4  = x3;	x3 &= x0;	x0 ^= x2;	\
	x2 |= x4;	x4 ^= x1;	x0 = ~x0;	\
	x1 |= x3;	x4 ^= x0;	x0 &= x2;	\
	x0 ^= x1;	x1 &= x2;	x3 ^= x2;	\
	x4 ^= x3;	x2 &= x3;	x3 |= x0;	\
	x1 ^= x4;	x3 ^= x4;	x4 &= x0;	\
	x4 ^= x2;					\
	})

int __serpent_setkey(struct serpent_ctx *ctx, const u8 *key,
		     unsigned int keylen)
{
	u32 *k = ctx->expkey;
	u8  *k8 = (u8 *)k;
	u32 r0, r1, r2, r3, r4;
	int i;

	/* Copy key, add padding */

	for (i = 0; i < keylen; ++i)
		k8[i] = key[i];
	if (i < SERPENT_MAX_KEY_SIZE)
		k8[i++] = 1;
	while (i < SERPENT_MAX_KEY_SIZE)
		k8[i++] = 0;

	/* Expand key using polynomial */

	r0 = le32_to_cpu(k[3]);
	r1 = le32_to_cpu(k[4]);
	r2 = le32_to_cpu(k[5]);
	r3 = le32_to_cpu(k[6]);
	r4 = le32_to_cpu(k[7]);

	keyiter(le32_to_cpu(k[0]), r0, r4, r2, 0, 0);
	keyiter(le32_to_cpu(k[1]), r1, r0, r3, 1, 1);
	keyiter(le32_to_cpu(k[2]), r2, r1, r4, 2, 2);
	keyiter(le32_to_cpu(k[3]), r3, r2, r0, 3, 3);
	keyiter(le32_to_cpu(k[4]), r4, r3, r1, 4, 4);
	keyiter(le32_to_cpu(k[5]), r0, r4, r2, 5, 5);
	keyiter(le32_to_cpu(k[6]), r1, r0, r3, 6, 6);
	keyiter(le32_to_cpu(k[7]), r2, r1, r4, 7, 7);

	keyiter(k[0], r3, r2, r0, 8, 8);
	keyiter(k[1], r4, r3, r1, 9, 9);
	keyiter(k[2], r0, r4, r2, 10, 10);
	keyiter(k[3], r1, r0, r3, 11, 11);
	keyiter(k[4], r2, r1, r4, 12, 12);
	keyiter(k[5], r3, r2, r0, 13, 13);
	keyiter(k[6], r4, r3, r1, 14, 14);
	keyiter(k[7], r0, r4, r2, 15, 15);
	keyiter(k[8], r1, r0, r3, 16, 16);
	keyiter(k[9], r2, r1, r4, 17, 17);
	keyiter(k[10], r3, r2, r0, 18, 18);
	keyiter(k[11], r4, r3, r1, 19, 19);
	keyiter(k[12], r0, r4, r2, 20, 20);
	keyiter(k[13], r1, r0, r3, 21, 21);
	keyiter(k[14], r2, r1, r4, 22, 22);
	keyiter(k[15], r3, r2, r0, 23, 23);
	keyiter(k[16], r4, r3, r1, 24, 24);
	keyiter(k[17], r0, r4, r2, 25, 25);
	keyiter(k[18], r1, r0, r3, 26, 26);
	keyiter(k[19], r2, r1, r4, 27, 27);
	keyiter(k[20], r3, r2, r0, 28, 28);
	keyiter(k[21], r4, r3, r1, 29, 29);
	keyiter(k[22], r0, r4, r2, 30, 30);
	keyiter(k[23], r1, r0, r3, 31, 31);

	k += 50;

	keyiter(k[-26], r2, r1, r4, 32, -18);
	keyiter(k[-25], r3, r2, r0, 33, -17);
	keyiter(k[-24], r4, r3, r1, 34, -16);
	keyiter(k[-23], r0, r4, r2, 35, -15);
	keyiter(k[-22], r1, r0, r3, 36, -14);
	keyiter(k[-21], r2, r1, r4, 37, -13);
	keyiter(k[-20], r3, r2, r0, 38, -12);
	keyiter(k[-19], r4, r3, r1, 39, -11);
	keyiter(k[-18], r0, r4, r2, 40, -10);
	keyiter(k[-17], r1, r0, r3, 41, -9);
	keyiter(k[-16], r2, r1, r4, 42, -8);
	keyiter(k[-15], r3, r2, r0, 43, -7);
	keyiter(k[-14], r4, r3, r1, 44, -6);
	keyiter(k[-13], r0, r4, r2, 45, -5);
	keyiter(k[-12], r1, r0, r3, 46, -4);
	keyiter(k[-11], r2, r1, r4, 47, -3);
	keyiter(k[-10], r3, r2, r0, 48, -2);
	keyiter(k[-9], r4, r3, r1, 49, -1);
	keyiter(k[-8], r0, r4, r2, 50, 0);
	keyiter(k[-7], r1, r0, r3, 51, 1);
	keyiter(k[-6], r2, r1, r4, 52, 2);
	keyiter(k[-5], r3, r2, r0, 53, 3);
	keyiter(k[-4], r4, r3, r1, 54, 4);
	keyiter(k[-3], r0, r4, r2, 55, 5);
	keyiter(k[-2], r1, r0, r3, 56, 6);
	keyiter(k[-1], r2, r1, r4, 57, 7);
	keyiter(k[0], r3, r2, r0, 58, 8);
	keyiter(k[1], r4, r3, r1, 59, 9);
	keyiter(k[2], r0, r4, r2, 60, 10);
	keyiter(k[3], r1, r0, r3, 61, 11);
	keyiter(k[4], r2, r1, r4, 62, 12);
	keyiter(k[5], r3, r2, r0, 63, 13);
	keyiter(k[6], r4, r3, r1, 64, 14);
	keyiter(k[7], r0, r4, r2, 65, 15);
	keyiter(k[8], r1, r0, r3, 66, 16);
	keyiter(k[9], r2, r1, r4, 67, 17);
	keyiter(k[10], r3, r2, r0, 68, 18);
	keyiter(k[11], r4, r3, r1, 69, 19);
	keyiter(k[12], r0, r4, r2, 70, 20);
	keyiter(k[13], r1, r0, r3, 71, 21);
	keyiter(k[14], r2, r1, r4, 72, 22);
	keyiter(k[15], r3, r2, r0, 73, 23);
	keyiter(k[16], r4, r3, r1, 74, 24);
	keyiter(k[17], r0, r4, r2, 75, 25);
	keyiter(k[18], r1, r0, r3, 76, 26);
	keyiter(k[19], r2, r1, r4, 77, 27);
	keyiter(k[20], r3, r2, r0, 78, 28);
	keyiter(k[21], r4, r3, r1, 79, 29);
	keyiter(k[22], r0, r4, r2, 80, 30);
	keyiter(k[23], r1, r0, r3, 81, 31);

	k += 50;

	keyiter(k[-26], r2, r1, r4, 82, -18);
	keyiter(k[-25], r3, r2, r0, 83, -17);
	keyiter(k[-24], r4, r3, r1, 84, -16);
	keyiter(k[-23], r0, r4, r2, 85, -15);
	keyiter(k[-22], r1, r0, r3, 86, -14);
	keyiter(k[-21], r2, r1, r4, 87, -13);
	keyiter(k[-20], r3, r2, r0, 88, -12);
	keyiter(k[-19], r4, r3, r1, 89, -11);
	keyiter(k[-18], r0, r4, r2, 90, -10);
	keyiter(k[-17], r1, r0, r3, 91, -9);
	keyiter(k[-16], r2, r1, r4, 92, -8);
	keyiter(k[-15], r3, r2, r0, 93, -7);
	keyiter(k[-14], r4, r3, r1, 94, -6);
	keyiter(k[-13], r0, r4, r2, 95, -5);
	keyiter(k[-12], r1, r0, r3, 96, -4);
	keyiter(k[-11], r2, r1, r4, 97, -3);
	keyiter(k[-10], r3, r2, r0, 98, -2);
	keyiter(k[-9], r4, r3, r1, 99, -1);
	keyiter(k[-8], r0, r4, r2, 100, 0);
	keyiter(k[-7], r1, r0, r3, 101, 1);
	keyiter(k[-6], r2, r1, r4, 102, 2);
	keyiter(k[-5], r3, r2, r0, 103, 3);
	keyiter(k[-4], r4, r3, r1, 104, 4);
	keyiter(k[-3], r0, r4, r2, 105, 5);
	keyiter(k[-2], r1, r0, r3, 106, 6);
	keyiter(k[-1], r2, r1, r4, 107, 7);
	keyiter(k[0], r3, r2, r0, 108, 8);
	keyiter(k[1], r4, r3, r1, 109, 9);
	keyiter(k[2], r0, r4, r2, 110, 10);
	keyiter(k[3], r1, r0, r3, 111, 11);
	keyiter(k[4], r2, r1, r4, 112, 12);
	keyiter(k[5], r3, r2, r0, 113, 13);
	keyiter(k[6], r4, r3, r1, 114, 14);
	keyiter(k[7], r0, r4, r2, 115, 15);
	keyiter(k[8], r1, r0, r3, 116, 16);
	keyiter(k[9], r2, r1, r4, 117, 17);
	keyiter(k[10], r3, r2, r0, 118, 18);
	keyiter(k[11], r4, r3, r1, 119, 19);
	keyiter(k[12], r0, r4, r2, 120, 20);
	keyiter(k[13], r1, r0, r3, 121, 21);
	keyiter(k[14], r2, r1, r4, 122, 22);
	keyiter(k[15], r3, r2, r0, 123, 23);
	keyiter(k[16], r4, r3, r1, 124, 24);
	keyiter(k[17], r0, r4, r2, 125, 25);
	keyiter(k[18], r1, r0, r3, 126, 26);
	keyiter(k[19], r2, r1, r4, 127, 27);
	keyiter(k[20], r3, r2, r0, 128, 28);
	keyiter(k[21], r4, r3, r1, 129, 29);
	keyiter(k[22], r0, r4, r2, 130, 30);
	keyiter(k[23], r1, r0, r3, 131, 31);

	/* Apply S-boxes */

	S3(r3, r4, r0, r1, r2); store_and_load_keys(r1, r2, r4, r3, 28, 24);
	S4(r1, r2, r4, r3, r0); store_and_load_keys(r2, r4, r3, r0, 24, 20);
	S5(r2, r4, r3, r0, r1); store_and_load_keys(r1, r2, r4, r0, 20, 16);
	S6(r1, r2, r4, r0, r3); store_and_load_keys(r4, r3, r2, r0, 16, 12);
	S7(r4, r3, r2, r0, r1); store_and_load_keys(r1, r2, r0, r4, 12, 8);
	S0(r1, r2, r0, r4, r3); store_and_load_keys(r0, r2, r4, r1, 8, 4);
	S1(r0, r2, r4, r1, r3); store_and_load_keys(r3, r4, r1, r0, 4, 0);
	S2(r3, r4, r1, r0, r2); store_and_load_keys(r2, r4, r3, r0, 0, -4);
	S3(r2, r4, r3, r0, r1); store_and_load_keys(r0, r1, r4, r2, -4, -8);
	S4(r0, r1, r4, r2, r3); store_and_load_keys(r1, r4, r2, r3, -8, -12);
	S5(r1, r4, r2, r3, r0); store_and_load_keys(r0, r1, r4, r3, -12, -16);
	S6(r0, r1, r4, r3, r2); store_and_load_keys(r4, r2, r1, r3, -16, -20);
	S7(r4, r2, r1, r3, r0); store_and_load_keys(r0, r1, r3, r4, -20, -24);
	S0(r0, r1, r3, r4, r2); store_and_load_keys(r3, r1, r4, r0, -24, -28);
	k -= 50;
	S1(r3, r1, r4, r0, r2); store_and_load_keys(r2, r4, r0, r3, 22, 18);
	S2(r2, r4, r0, r3, r1); store_and_load_keys(r1, r4, r2, r3, 18, 14);
	S3(r1, r4, r2, r3, r0); store_and_load_keys(r3, r0, r4, r1, 14, 10);
	S4(r3, r0, r4, r1, r2); store_and_load_keys(r0, r4, r1, r2, 10, 6);
	S5(r0, r4, r1, r2, r3); store_and_load_keys(r3, r0, r4, r2, 6, 2);
	S6(r3, r0, r4, r2, r1); store_and_load_keys(r4, r1, r0, r2, 2, -2);
	S7(r4, r1, r0, r2, r3); store_and_load_keys(r3, r0, r2, r4, -2, -6);
	S0(r3, r0, r2, r4, r1); store_and_load_keys(r2, r0, r4, r3, -6, -10);
	S1(r2, r0, r4, r3, r1); store_and_load_keys(r1, r4, r3, r2, -10, -14);
	S2(r1, r4, r3, r2, r0); store_and_load_keys(r0, r4, r1, r2, -14, -18);
	S3(r0, r4, r1, r2, r3); store_and_load_keys(r2, r3, r4, r0, -18, -22);
	k -= 50;
	S4(r2, r3, r4, r0, r1); store_and_load_keys(r3, r4, r0, r1, 28, 24);
	S5(r3, r4, r0, r1, r2); store_and_load_keys(r2, r3, r4, r1, 24, 20);
	S6(r2, r3, r4, r1, r0); store_and_load_keys(r4, r0, r3, r1, 20, 16);
	S7(r4, r0, r3, r1, r2); store_and_load_keys(r2, r3, r1, r4, 16, 12);
	S0(r2, r3, r1, r4, r0); store_and_load_keys(r1, r3, r4, r2, 12, 8);
	S1(r1, r3, r4, r2, r0); store_and_load_keys(r0, r4, r2, r1, 8, 4);
	S2(r0, r4, r2, r1, r3); store_and_load_keys(r3, r4, r0, r1, 4, 0);
	S3(r3, r4, r0, r1, r2); storekeys(r1, r2, r4, r3, 0);

	return 0;
}
EXPORT_SYMBOL_GPL(__serpent_setkey);

int serpent_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
	return __serpent_setkey(crypto_tfm_ctx(tfm), key, keylen);
}
EXPORT_SYMBOL_GPL(serpent_setkey);

void __serpent_encrypt(struct serpent_ctx *ctx, u8 *dst, const u8 *src)
{
	const u32 *k = ctx->expkey;
	const __le32 *s = (const __le32 *)src;
	__le32	*d = (__le32 *)dst;
	u32	r0, r1, r2, r3, r4;

/*
 * Note: The conversions between u8* and u32* might cause trouble
 * on architectures with stricter alignment rules than x86
 */

	r0 = le32_to_cpu(s[0]);
	r1 = le32_to_cpu(s[1]);
	r2 = le32_to_cpu(s[2]);
	r3 = le32_to_cpu(s[3]);

					K(r0, r1, r2, r3, 0);
	S0(r0, r1, r2, r3, r4);		LK(r2, r1, r3, r0, r4, 1);
	S1(r2, r1, r3, r0, r4);		LK(r4, r3, r0, r2, r1, 2);
	S2(r4, r3, r0, r2, r1);		LK(r1, r3, r4, r2, r0, 3);
	S3(r1, r3, r4, r2, r0);		LK(r2, r0, r3, r1, r4, 4);
	S4(r2, r0, r3, r1, r4);		LK(r0, r3, r1, r4, r2, 5);
	S5(r0, r3, r1, r4, r2);		LK(r2, r0, r3, r4, r1, 6);
	S6(r2, r0, r3, r4, r1);		LK(r3, r1, r0, r4, r2, 7);
	S7(r3, r1, r0, r4, r2);		LK(r2, r0, r4, r3, r1, 8);
	S0(r2, r0, r4, r3, r1);		LK(r4, r0, r3, r2, r1, 9);
	S1(r4, r0, r3, r2, r1);		LK(r1, r3, r2, r4, r0, 10);
	S2(r1, r3, r2, r4, r0);		LK(r0, r3, r1, r4, r2, 11);
	S3(r0, r3, r1, r4, r2);		LK(r4, r2, r3, r0, r1, 12);
	S4(r4, r2, r3, r0, r1);		LK(r2, r3, r0, r1, r4, 13);
	S5(r2, r3, r0, r1, r4);		LK(r4, r2, r3, r1, r0, 14);
	S6(r4, r2, r3, r1, r0);		LK(r3, r0, r2, r1, r4, 15);
	S7(r3, r0, r2, r1, r4);		LK(r4, r2, r1, r3, r0, 16);
	S0(r4, r2, r1, r3, r0);		LK(r1, r2, r3, r4, r0, 17);
	S1(r1, r2, r3, r4, r0);		LK(r0, r3, r4, r1, r2, 18);
	S2(r0, r3, r4, r1, r2);		LK(r2, r3, r0, r1, r4, 19);
	S3(r2, r3, r0, r1, r4);		LK(r1, r4, r3, r2, r0, 20);
	S4(r1, r4, r3, r2, r0);		LK(r4, r3, r2, r0, r1, 21);
	S5(r4, r3, r2, r0, r1);		LK(r1, r4, r3, r0, r2, 22);
	S6(r1, r4, r3, r0, r2);		LK(r3, r2, r4, r0, r1, 23);
	S7(r3, r2, r4, r0, r1);		LK(r1, r4, r0, r3, r2, 24);
	S0(r1, r4, r0, r3, r2);		LK(r0, r4, r3, r1, r2, 25);
	S1(r0, r4, r3, r1, r2);		LK(r2, r3, r1, r0, r4, 26);
	S2(r2, r3, r1, r0, r4);		LK(r4, r3, r2, r0, r1, 27);
	S3(r4, r3, r2, r0, r1);		LK(r0, r1, r3, r4, r2, 28);
	S4(r0, r1, r3, r4, r2);		LK(r1, r3, r4, r2, r0, 29);
	S5(r1, r3, r4, r2, r0);		LK(r0, r1, r3, r2, r4, 30);
	S6(r0, r1, r3, r2, r4);		LK(r3, r4, r1, r2, r0, 31);
	S7(r3, r4, r1, r2, r0);		K(r0, r1, r2, r3, 32);

	d[0] = cpu_to_le32(r0);
	d[1] = cpu_to_le32(r1);
	d[2] = cpu_to_le32(r2);
	d[3] = cpu_to_le32(r3);
}
EXPORT_SYMBOL_GPL(__serpent_encrypt);

static void serpent_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
	struct serpent_ctx *ctx = crypto_tfm_ctx(tfm);

	__serpent_encrypt(ctx, dst, src);
}

void __serpent_decrypt(struct serpent_ctx *ctx, u8 *dst, const u8 *src)
{
	const u32 *k = ctx->expkey;
	const __le32 *s = (const __le32 *)src;
	__le32	*d = (__le32 *)dst;
	u32	r0, r1, r2, r3, r4;

	r0 = le32_to_cpu(s[0]);
	r1 = le32_to_cpu(s[1]);
	r2 = le32_to_cpu(s[2]);
	r3 = le32_to_cpu(s[3]);

					K(r0, r1, r2, r3, 32);
	SI7(r0, r1, r2, r3, r4);	KL(r1, r3, r0, r4, r2, 31);
	SI6(r1, r3, r0, r4, r2);	KL(r0, r2, r4, r1, r3, 30);
	SI5(r0, r2, r4, r1, r3);	KL(r2, r3, r0, r4, r1, 29);
	SI4(r2, r3, r0, r4, r1);	KL(r2, r0, r1, r4, r3, 28);
	SI3(r2, r0, r1, r4, r3);	KL(r1, r2, r3, r4, r0, 27);
	SI2(r1, r2, r3, r4, r0);	KL(r2, r0, r4, r3, r1, 26);
	SI1(r2, r0, r4, r3, r1);	KL(r1, r0, r4, r3, r2, 25);
	SI0(r1, r0, r4, r3, r2);	KL(r4, r2, r0, r1, r3, 24);
	SI7(r4, r2, r0, r1, r3);	KL(r2, r1, r4, r3, r0, 23);
	SI6(r2, r1, r4, r3, r0);	KL(r4, r0, r3, r2, r1, 22);
	SI5(r4, r0, r3, r2, r1);	KL(r0, r1, r4, r3, r2, 21);
	SI4(r0, r1, r4, r3, r2);	KL(r0, r4, r2, r3, r1, 20);
	SI3(r0, r4, r2, r3, r1);	KL(r2, r0, r1, r3, r4, 19);
	SI2(r2, r0, r1, r3, r4);	KL(r0, r4, r3, r1, r2, 18);
	SI1(r0, r4, r3, r1, r2);	KL(r2, r4, r3, r1, r0, 17);
	SI0(r2, r4, r3, r1, r0);	KL(r3, r0, r4, r2, r1, 16);
	SI7(r3, r0, r4, r2, r1);	KL(r0, r2, r3, r1, r4, 15);
	SI6(r0, r2, r3, r1, r4);	KL(r3, r4, r1, r0, r2, 14);
	SI5(r3, r4, r1, r0, r2);	KL(r4, r2, r3, r1, r0, 13);
	SI4(r4, r2, r3, r1, r0);	KL(r4, r3, r0, r1, r2, 12);
	SI3(r4, r3, r0, r1, r2);	KL(r0, r4, r2, r1, r3, 11);
	SI2(r0, r4, r2, r1, r3);	KL(r4, r3, r1, r2, r0, 10);
	SI1(r4, r3, r1, r2, r0);	KL(r0, r3, r1, r2, r4, 9);
	SI0(r0, r3, r1, r2, r4);	KL(r1, r4, r3, r0, r2, 8);
	SI7(r1, r4, r3, r0, r2);	KL(r4, r0, r1, r2, r3, 7);
	SI6(r4, r0, r1, r2, r3);	KL(r1, r3, r2, r4, r0, 6);
	SI5(r1, r3, r2, r4, r0);	KL(r3, r0, r1, r2, r4, 5);
	SI4(r3, r0, r1, r2, r4);	KL(r3, r1, r4, r2, r0, 4);
	SI3(r3, r1, r4, r2, r0);	KL(r4, r3, r0, r2, r1, 3);
	SI2(r4, r3, r0, r2, r1);	KL(r3, r1, r2, r0, r4, 2);
	SI1(r3, r1, r2, r0, r4);	KL(r4, r1, r2, r0, r3, 1);
	SI0(r4, r1, r2, r0, r3);	K(r2, r3, r1, r4, 0);

	d[0] = cpu_to_le32(r2);
	d[1] = cpu_to_le32(r3);
	d[2] = cpu_to_le32(r1);
	d[3] = cpu_to_le32(r4);
}
EXPORT_SYMBOL_GPL(__serpent_decrypt);

static void serpent_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
	struct serpent_ctx *ctx = crypto_tfm_ctx(tfm);

	__serpent_decrypt(ctx, dst, src);
}

static struct crypto_alg serpent_alg = {
	.cra_name		=	"serpent",
	.cra_driver_name	=	"serpent-generic",
	.cra_priority		=	100,
	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize		=	SERPENT_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct serpent_ctx),
	.cra_alignmask		=	3,
	.cra_module		=	THIS_MODULE,
	.cra_list		=	LIST_HEAD_INIT(serpent_alg.cra_list),
	.cra_u			=	{ .cipher = {
	.cia_min_keysize	=	SERPENT_MIN_KEY_SIZE,
	.cia_max_keysize	=	SERPENT_MAX_KEY_SIZE,
	.cia_setkey		=	serpent_setkey,
	.cia_encrypt		=	serpent_encrypt,
	.cia_decrypt		=	serpent_decrypt } }
};

static int tnepres_setkey(struct crypto_tfm *tfm, const u8 *key,
			  unsigned int keylen)
{
	u8 rev_key[SERPENT_MAX_KEY_SIZE];
	int i;

	for (i = 0; i < keylen; ++i)
		rev_key[keylen - i - 1] = key[i];

	return serpent_setkey(tfm, rev_key, keylen);
}

static void tnepres_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
	const u32 * const s = (const u32 * const)src;
	u32 * const d = (u32 * const)dst;

	u32 rs[4], rd[4];

	rs[0] = swab32(s[3]);
	rs[1] = swab32(s[2]);
	rs[2] = swab32(s[1]);
	rs[3] = swab32(s[0]);

	serpent_encrypt(tfm, (u8 *)rd, (u8 *)rs);

	d[0] = swab32(rd[3]);
	d[1] = swab32(rd[2]);
	d[2] = swab32(rd[1]);
	d[3] = swab32(rd[0]);
}

static void tnepres_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
	const u32 * const s = (const u32 * const)src;
	u32 * const d = (u32 * const)dst;

	u32 rs[4], rd[4];

	rs[0] = swab32(s[3]);
	rs[1] = swab32(s[2]);
	rs[2] = swab32(s[1]);
	rs[3] = swab32(s[0]);

	serpent_decrypt(tfm, (u8 *)rd, (u8 *)rs);

	d[0] = swab32(rd[3]);
	d[1] = swab32(rd[2]);
	d[2] = swab32(rd[1]);
	d[3] = swab32(rd[0]);
}

static struct crypto_alg tnepres_alg = {
	.cra_name		=	"tnepres",
	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize		=	SERPENT_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct serpent_ctx),
	.cra_alignmask		=	3,
	.cra_module		=	THIS_MODULE,
	.cra_list		=	LIST_HEAD_INIT(serpent_alg.cra_list),
	.cra_u			=	{ .cipher = {
	.cia_min_keysize	=	SERPENT_MIN_KEY_SIZE,
	.cia_max_keysize	=	SERPENT_MAX_KEY_SIZE,
	.cia_setkey		=	tnepres_setkey,
	.cia_encrypt		=	tnepres_encrypt,
	.cia_decrypt		=	tnepres_decrypt } }
};

static int __init serpent_mod_init(void)
{
	int ret = crypto_register_alg(&serpent_alg);

	if (ret)
		return ret;

	ret = crypto_register_alg(&tnepres_alg);

	if (ret)
		crypto_unregister_alg(&serpent_alg);

	return ret;
}

static void __exit serpent_mod_fini(void)
{
	crypto_unregister_alg(&tnepres_alg);
	crypto_unregister_alg(&serpent_alg);
}

module_init(serpent_mod_init);
module_exit(serpent_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Serpent and tnepres (kerneli compatible serpent reversed) Cipher Algorithm");
MODULE_AUTHOR("Dag Arne Osvik <osvik@ii.uib.no>");
MODULE_ALIAS("tnepres");
MODULE_ALIAS("serpent");
back to top