Revision 7ab02af428c2d312c0cf8fb0b01cc1eb21131a3d authored by Linus Torvalds on 02 February 2010, 20:37:44 UTC, committed by Linus Torvalds on 02 February 2010, 20:37:44 UTC
Commit 221af7f87b9 ("Split 'flush_old_exec' into two functions") split the function at the point of no return - ie right where there were no more error cases to check. That made sense from a technical standpoint, but when we then also combined it with the actual personality setting going in between flush_old_exec() and setup_new_exec(), it needs to be a bit more careful. In particular, we need to make sure that we really flush the old personality bits in the 'flush' stage, rather than later in the 'setup' stage, since otherwise we might be flushing the _new_ personality state that we're just setting up. So this moves the flags and personality flushing (and 'flush_thread()', which is the arch-specific function that generally resets lazy FP state etc) of the old process into flush_old_exec(), so that it doesn't affect any state that execve() is setting up for the new process environment. This was reported by Michal Simek as breaking his Microblaze qemu environment. Reported-and-tested-by: Michal Simek <michal.simek@petalogix.com> Cc: Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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salsa20_generic.c
/*
* Salsa20: Salsa20 stream cipher algorithm
*
* Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com>
*
* Derived from:
* - salsa20.c: Public domain C code by Daniel J. Bernstein <djb@cr.yp.to>
*
* Salsa20 is a stream cipher candidate in eSTREAM, the ECRYPT Stream
* Cipher Project. It is designed by Daniel J. Bernstein <djb@cr.yp.to>.
* More information about eSTREAM and Salsa20 can be found here:
* http://www.ecrypt.eu.org/stream/
* http://cr.yp.to/snuffle.html
*
* 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 <linux/crypto.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <crypto/algapi.h>
#include <asm/byteorder.h>
#define SALSA20_IV_SIZE 8U
#define SALSA20_MIN_KEY_SIZE 16U
#define SALSA20_MAX_KEY_SIZE 32U
/*
* Start of code taken from D. J. Bernstein's reference implementation.
* With some modifications and optimizations made to suit our needs.
*/
/*
salsa20-ref.c version 20051118
D. J. Bernstein
Public domain.
*/
#define U32TO8_LITTLE(p, v) \
{ (p)[0] = (v >> 0) & 0xff; (p)[1] = (v >> 8) & 0xff; \
(p)[2] = (v >> 16) & 0xff; (p)[3] = (v >> 24) & 0xff; }
#define U8TO32_LITTLE(p) \
(((u32)((p)[0]) ) | ((u32)((p)[1]) << 8) | \
((u32)((p)[2]) << 16) | ((u32)((p)[3]) << 24) )
struct salsa20_ctx
{
u32 input[16];
};
static void salsa20_wordtobyte(u8 output[64], const u32 input[16])
{
u32 x[16];
int i;
memcpy(x, input, sizeof(x));
for (i = 20; i > 0; i -= 2) {
x[ 4] ^= rol32((x[ 0] + x[12]), 7);
x[ 8] ^= rol32((x[ 4] + x[ 0]), 9);
x[12] ^= rol32((x[ 8] + x[ 4]), 13);
x[ 0] ^= rol32((x[12] + x[ 8]), 18);
x[ 9] ^= rol32((x[ 5] + x[ 1]), 7);
x[13] ^= rol32((x[ 9] + x[ 5]), 9);
x[ 1] ^= rol32((x[13] + x[ 9]), 13);
x[ 5] ^= rol32((x[ 1] + x[13]), 18);
x[14] ^= rol32((x[10] + x[ 6]), 7);
x[ 2] ^= rol32((x[14] + x[10]), 9);
x[ 6] ^= rol32((x[ 2] + x[14]), 13);
x[10] ^= rol32((x[ 6] + x[ 2]), 18);
x[ 3] ^= rol32((x[15] + x[11]), 7);
x[ 7] ^= rol32((x[ 3] + x[15]), 9);
x[11] ^= rol32((x[ 7] + x[ 3]), 13);
x[15] ^= rol32((x[11] + x[ 7]), 18);
x[ 1] ^= rol32((x[ 0] + x[ 3]), 7);
x[ 2] ^= rol32((x[ 1] + x[ 0]), 9);
x[ 3] ^= rol32((x[ 2] + x[ 1]), 13);
x[ 0] ^= rol32((x[ 3] + x[ 2]), 18);
x[ 6] ^= rol32((x[ 5] + x[ 4]), 7);
x[ 7] ^= rol32((x[ 6] + x[ 5]), 9);
x[ 4] ^= rol32((x[ 7] + x[ 6]), 13);
x[ 5] ^= rol32((x[ 4] + x[ 7]), 18);
x[11] ^= rol32((x[10] + x[ 9]), 7);
x[ 8] ^= rol32((x[11] + x[10]), 9);
x[ 9] ^= rol32((x[ 8] + x[11]), 13);
x[10] ^= rol32((x[ 9] + x[ 8]), 18);
x[12] ^= rol32((x[15] + x[14]), 7);
x[13] ^= rol32((x[12] + x[15]), 9);
x[14] ^= rol32((x[13] + x[12]), 13);
x[15] ^= rol32((x[14] + x[13]), 18);
}
for (i = 0; i < 16; ++i)
x[i] += input[i];
for (i = 0; i < 16; ++i)
U32TO8_LITTLE(output + 4 * i,x[i]);
}
static const char sigma[16] = "expand 32-byte k";
static const char tau[16] = "expand 16-byte k";
static void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k, u32 kbytes)
{
const char *constants;
ctx->input[1] = U8TO32_LITTLE(k + 0);
ctx->input[2] = U8TO32_LITTLE(k + 4);
ctx->input[3] = U8TO32_LITTLE(k + 8);
ctx->input[4] = U8TO32_LITTLE(k + 12);
if (kbytes == 32) { /* recommended */
k += 16;
constants = sigma;
} else { /* kbytes == 16 */
constants = tau;
}
ctx->input[11] = U8TO32_LITTLE(k + 0);
ctx->input[12] = U8TO32_LITTLE(k + 4);
ctx->input[13] = U8TO32_LITTLE(k + 8);
ctx->input[14] = U8TO32_LITTLE(k + 12);
ctx->input[0] = U8TO32_LITTLE(constants + 0);
ctx->input[5] = U8TO32_LITTLE(constants + 4);
ctx->input[10] = U8TO32_LITTLE(constants + 8);
ctx->input[15] = U8TO32_LITTLE(constants + 12);
}
static void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv)
{
ctx->input[6] = U8TO32_LITTLE(iv + 0);
ctx->input[7] = U8TO32_LITTLE(iv + 4);
ctx->input[8] = 0;
ctx->input[9] = 0;
}
static void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, u8 *dst,
const u8 *src, unsigned int bytes)
{
u8 buf[64];
if (dst != src)
memcpy(dst, src, bytes);
while (bytes) {
salsa20_wordtobyte(buf, ctx->input);
ctx->input[8]++;
if (!ctx->input[8])
ctx->input[9]++;
if (bytes <= 64) {
crypto_xor(dst, buf, bytes);
return;
}
crypto_xor(dst, buf, 64);
bytes -= 64;
dst += 64;
}
}
/*
* End of code taken from D. J. Bernstein's reference implementation.
*/
static int setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keysize)
{
struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm);
salsa20_keysetup(ctx, key, keysize);
return 0;
}
static int encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm);
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt_block(desc, &walk, 64);
salsa20_ivsetup(ctx, walk.iv);
if (likely(walk.nbytes == nbytes))
{
salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
walk.src.virt.addr, nbytes);
return blkcipher_walk_done(desc, &walk, 0);
}
while (walk.nbytes >= 64) {
salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
walk.src.virt.addr,
walk.nbytes - (walk.nbytes % 64));
err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64);
}
if (walk.nbytes) {
salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
walk.src.virt.addr, walk.nbytes);
err = blkcipher_walk_done(desc, &walk, 0);
}
return err;
}
static struct crypto_alg alg = {
.cra_name = "salsa20",
.cra_driver_name = "salsa20-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
.cra_type = &crypto_blkcipher_type,
.cra_blocksize = 1,
.cra_ctxsize = sizeof(struct salsa20_ctx),
.cra_alignmask = 3,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(alg.cra_list),
.cra_u = {
.blkcipher = {
.setkey = setkey,
.encrypt = encrypt,
.decrypt = encrypt,
.min_keysize = SALSA20_MIN_KEY_SIZE,
.max_keysize = SALSA20_MAX_KEY_SIZE,
.ivsize = SALSA20_IV_SIZE,
}
}
};
static int __init salsa20_generic_mod_init(void)
{
return crypto_register_alg(&alg);
}
static void __exit salsa20_generic_mod_fini(void)
{
crypto_unregister_alg(&alg);
}
module_init(salsa20_generic_mod_init);
module_exit(salsa20_generic_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm");
MODULE_ALIAS("salsa20");
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