mirror of
https://github.com/brain-hackers/linux-brain.git
synced 2024-06-09 15:26:21 +09:00
c32e053a11
commitecaaab5649upstream. When asked to encrypt or decrypt 0 bytes, both the generic and x86 implementations of Salsa20 crash in blkcipher_walk_done(), either when doing 'kfree(walk->buffer)' or 'free_page((unsigned long)walk->page)', because walk->buffer and walk->page have not been initialized. The bug is that Salsa20 is calling blkcipher_walk_done() even when nothing is in 'walk.nbytes'. But blkcipher_walk_done() is only meant to be called when a nonzero number of bytes have been provided. The broken code is part of an optimization that tries to make only one call to salsa20_encrypt_bytes() to process inputs that are not evenly divisible by 64 bytes. To fix the bug, just remove this "optimization" and use the blkcipher_walk API the same way all the other users do. Reproducer: #include <linux/if_alg.h> #include <sys/socket.h> #include <unistd.h> int main() { int algfd, reqfd; struct sockaddr_alg addr = { .salg_type = "skcipher", .salg_name = "salsa20", }; char key[16] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (void *)&addr, sizeof(addr)); reqfd = accept(algfd, 0, 0); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)); read(reqfd, key, sizeof(key)); } Reported-by: syzbot <syzkaller@googlegroups.com> Fixes:eb6f13eb9f("[CRYPTO] salsa20_generic: Fix multi-page processing") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
246 lines
6.5 KiB
C
246 lines
6.5 KiB
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);
|
|
|
|
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_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_CRYPTO("salsa20");
|
|
MODULE_ALIAS_CRYPTO("salsa20-generic");
|