linux-stable/crypto/sha512_generic.c
Lukas Bulwahn 6ae51ffe5e crypto: sha512 - remove imaginary and mystifying clearing of variables
The function sha512_transform() assigns all local variables to 0 before
returning to its caller with the intent to erase sensitive data.

However, make clang-analyzer warns that all these assignments are dead
stores, and as commit 7a4295f6c9 ("crypto: lib/sha256 - Don't clear
temporary variables") already points out for sha256_transform():

  The assignments to clear a through h and t1/t2 are optimized out by the
  compiler because they are unused after the assignments.

  Clearing individual scalar variables is unlikely to be useful, as they
  may have been assigned to registers, and even if stack spilling was
  required, there may be compiler-generated temporaries that are
  impossible to clear in any case.

This applies here again as well. Drop meaningless clearing of local
variables and avoid this way that the code suggests that data is erased,
which simply does not happen.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-08-27 16:30:19 +08:00

227 lines
7.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* SHA-512 code by Jean-Luc Cooke <jlcooke@certainkey.com>
*
* Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
* Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
* Copyright (c) 2003 Kyle McMartin <kyle@debian.org>
*/
#include <crypto/internal/hash.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/types.h>
#include <crypto/sha2.h>
#include <crypto/sha512_base.h>
#include <linux/percpu.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
const u8 sha384_zero_message_hash[SHA384_DIGEST_SIZE] = {
0x38, 0xb0, 0x60, 0xa7, 0x51, 0xac, 0x96, 0x38,
0x4c, 0xd9, 0x32, 0x7e, 0xb1, 0xb1, 0xe3, 0x6a,
0x21, 0xfd, 0xb7, 0x11, 0x14, 0xbe, 0x07, 0x43,
0x4c, 0x0c, 0xc7, 0xbf, 0x63, 0xf6, 0xe1, 0xda,
0x27, 0x4e, 0xde, 0xbf, 0xe7, 0x6f, 0x65, 0xfb,
0xd5, 0x1a, 0xd2, 0xf1, 0x48, 0x98, 0xb9, 0x5b
};
EXPORT_SYMBOL_GPL(sha384_zero_message_hash);
const u8 sha512_zero_message_hash[SHA512_DIGEST_SIZE] = {
0xcf, 0x83, 0xe1, 0x35, 0x7e, 0xef, 0xb8, 0xbd,
0xf1, 0x54, 0x28, 0x50, 0xd6, 0x6d, 0x80, 0x07,
0xd6, 0x20, 0xe4, 0x05, 0x0b, 0x57, 0x15, 0xdc,
0x83, 0xf4, 0xa9, 0x21, 0xd3, 0x6c, 0xe9, 0xce,
0x47, 0xd0, 0xd1, 0x3c, 0x5d, 0x85, 0xf2, 0xb0,
0xff, 0x83, 0x18, 0xd2, 0x87, 0x7e, 0xec, 0x2f,
0x63, 0xb9, 0x31, 0xbd, 0x47, 0x41, 0x7a, 0x81,
0xa5, 0x38, 0x32, 0x7a, 0xf9, 0x27, 0xda, 0x3e
};
EXPORT_SYMBOL_GPL(sha512_zero_message_hash);
static inline u64 Ch(u64 x, u64 y, u64 z)
{
return z ^ (x & (y ^ z));
}
static inline u64 Maj(u64 x, u64 y, u64 z)
{
return (x & y) | (z & (x | y));
}
static const u64 sha512_K[80] = {
0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL,
0xe9b5dba58189dbbcULL, 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL, 0xd807aa98a3030242ULL,
0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL,
0xc19bf174cf692694ULL, 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL, 0x2de92c6f592b0275ULL,
0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL,
0xbf597fc7beef0ee4ULL, 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
0x06ca6351e003826fULL, 0x142929670a0e6e70ULL, 0x27b70a8546d22ffcULL,
0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL,
0x92722c851482353bULL, 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL, 0xd192e819d6ef5218ULL,
0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL,
0x34b0bcb5e19b48a8ULL, 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL, 0x748f82ee5defb2fcULL,
0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL,
0xc67178f2e372532bULL, 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL, 0x06f067aa72176fbaULL,
0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL,
0x431d67c49c100d4cULL, 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL,
};
#define e0(x) (ror64(x,28) ^ ror64(x,34) ^ ror64(x,39))
#define e1(x) (ror64(x,14) ^ ror64(x,18) ^ ror64(x,41))
#define s0(x) (ror64(x, 1) ^ ror64(x, 8) ^ (x >> 7))
#define s1(x) (ror64(x,19) ^ ror64(x,61) ^ (x >> 6))
static inline void LOAD_OP(int I, u64 *W, const u8 *input)
{
W[I] = get_unaligned_be64((__u64 *)input + I);
}
static inline void BLEND_OP(int I, u64 *W)
{
W[I & 15] += s1(W[(I-2) & 15]) + W[(I-7) & 15] + s0(W[(I-15) & 15]);
}
static void
sha512_transform(u64 *state, const u8 *input)
{
u64 a, b, c, d, e, f, g, h, t1, t2;
int i;
u64 W[16];
/* load the state into our registers */
a=state[0]; b=state[1]; c=state[2]; d=state[3];
e=state[4]; f=state[5]; g=state[6]; h=state[7];
/* now iterate */
for (i=0; i<80; i+=8) {
if (!(i & 8)) {
int j;
if (i < 16) {
/* load the input */
for (j = 0; j < 16; j++)
LOAD_OP(i + j, W, input);
} else {
for (j = 0; j < 16; j++) {
BLEND_OP(i + j, W);
}
}
}
t1 = h + e1(e) + Ch(e,f,g) + sha512_K[i ] + W[(i & 15)];
t2 = e0(a) + Maj(a,b,c); d+=t1; h=t1+t2;
t1 = g + e1(d) + Ch(d,e,f) + sha512_K[i+1] + W[(i & 15) + 1];
t2 = e0(h) + Maj(h,a,b); c+=t1; g=t1+t2;
t1 = f + e1(c) + Ch(c,d,e) + sha512_K[i+2] + W[(i & 15) + 2];
t2 = e0(g) + Maj(g,h,a); b+=t1; f=t1+t2;
t1 = e + e1(b) + Ch(b,c,d) + sha512_K[i+3] + W[(i & 15) + 3];
t2 = e0(f) + Maj(f,g,h); a+=t1; e=t1+t2;
t1 = d + e1(a) + Ch(a,b,c) + sha512_K[i+4] + W[(i & 15) + 4];
t2 = e0(e) + Maj(e,f,g); h+=t1; d=t1+t2;
t1 = c + e1(h) + Ch(h,a,b) + sha512_K[i+5] + W[(i & 15) + 5];
t2 = e0(d) + Maj(d,e,f); g+=t1; c=t1+t2;
t1 = b + e1(g) + Ch(g,h,a) + sha512_K[i+6] + W[(i & 15) + 6];
t2 = e0(c) + Maj(c,d,e); f+=t1; b=t1+t2;
t1 = a + e1(f) + Ch(f,g,h) + sha512_K[i+7] + W[(i & 15) + 7];
t2 = e0(b) + Maj(b,c,d); e+=t1; a=t1+t2;
}
state[0] += a; state[1] += b; state[2] += c; state[3] += d;
state[4] += e; state[5] += f; state[6] += g; state[7] += h;
}
static void sha512_generic_block_fn(struct sha512_state *sst, u8 const *src,
int blocks)
{
while (blocks--) {
sha512_transform(sst->state, src);
src += SHA512_BLOCK_SIZE;
}
}
int crypto_sha512_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
return sha512_base_do_update(desc, data, len, sha512_generic_block_fn);
}
EXPORT_SYMBOL(crypto_sha512_update);
static int sha512_final(struct shash_desc *desc, u8 *hash)
{
sha512_base_do_finalize(desc, sha512_generic_block_fn);
return sha512_base_finish(desc, hash);
}
int crypto_sha512_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *hash)
{
sha512_base_do_update(desc, data, len, sha512_generic_block_fn);
return sha512_final(desc, hash);
}
EXPORT_SYMBOL(crypto_sha512_finup);
static struct shash_alg sha512_algs[2] = { {
.digestsize = SHA512_DIGEST_SIZE,
.init = sha512_base_init,
.update = crypto_sha512_update,
.final = sha512_final,
.finup = crypto_sha512_finup,
.descsize = sizeof(struct sha512_state),
.base = {
.cra_name = "sha512",
.cra_driver_name = "sha512-generic",
.cra_priority = 100,
.cra_blocksize = SHA512_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
}, {
.digestsize = SHA384_DIGEST_SIZE,
.init = sha384_base_init,
.update = crypto_sha512_update,
.final = sha512_final,
.finup = crypto_sha512_finup,
.descsize = sizeof(struct sha512_state),
.base = {
.cra_name = "sha384",
.cra_driver_name = "sha384-generic",
.cra_priority = 100,
.cra_blocksize = SHA384_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
} };
static int __init sha512_generic_mod_init(void)
{
return crypto_register_shashes(sha512_algs, ARRAY_SIZE(sha512_algs));
}
static void __exit sha512_generic_mod_fini(void)
{
crypto_unregister_shashes(sha512_algs, ARRAY_SIZE(sha512_algs));
}
subsys_initcall(sha512_generic_mod_init);
module_exit(sha512_generic_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA-512 and SHA-384 Secure Hash Algorithms");
MODULE_ALIAS_CRYPTO("sha384");
MODULE_ALIAS_CRYPTO("sha384-generic");
MODULE_ALIAS_CRYPTO("sha512");
MODULE_ALIAS_CRYPTO("sha512-generic");