mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 21:02:19 +00:00
9a1536b093
With SHA-1 no longer being used for anything performance oriented, and also soon to be phased out entirely, we can make up for the space added by unrolled BLAKE2s by simply re-rolling SHA-1. Since SHA-1 is so much more complex, re-rolling it more or less takes care of the code size added by BLAKE2s. And eventually, hopefully we'll see SHA-1 removed entirely from most small kernel builds. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ard Biesheuvel <ardb@kernel.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
138 lines
4.4 KiB
C
138 lines
4.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* SHA1 routine optimized to do word accesses rather than byte accesses,
|
|
* and to avoid unnecessary copies into the context array.
|
|
*
|
|
* This was based on the git SHA1 implementation.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/string.h>
|
|
#include <crypto/sha1.h>
|
|
#include <asm/unaligned.h>
|
|
|
|
/*
|
|
* If you have 32 registers or more, the compiler can (and should)
|
|
* try to change the array[] accesses into registers. However, on
|
|
* machines with less than ~25 registers, that won't really work,
|
|
* and at least gcc will make an unholy mess of it.
|
|
*
|
|
* So to avoid that mess which just slows things down, we force
|
|
* the stores to memory to actually happen (we might be better off
|
|
* with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
|
|
* suggested by Artur Skawina - that will also make gcc unable to
|
|
* try to do the silly "optimize away loads" part because it won't
|
|
* see what the value will be).
|
|
*
|
|
* Ben Herrenschmidt reports that on PPC, the C version comes close
|
|
* to the optimized asm with this (ie on PPC you don't want that
|
|
* 'volatile', since there are lots of registers).
|
|
*
|
|
* On ARM we get the best code generation by forcing a full memory barrier
|
|
* between each SHA_ROUND, otherwise gcc happily get wild with spilling and
|
|
* the stack frame size simply explode and performance goes down the drain.
|
|
*/
|
|
|
|
#ifdef CONFIG_X86
|
|
#define setW(x, val) (*(volatile __u32 *)&W(x) = (val))
|
|
#elif defined(CONFIG_ARM)
|
|
#define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
|
|
#else
|
|
#define setW(x, val) (W(x) = (val))
|
|
#endif
|
|
|
|
/* This "rolls" over the 512-bit array */
|
|
#define W(x) (array[(x)&15])
|
|
|
|
/*
|
|
* Where do we get the source from? The first 16 iterations get it from
|
|
* the input data, the next mix it from the 512-bit array.
|
|
*/
|
|
#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t)
|
|
#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
|
|
|
|
#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
|
|
__u32 TEMP = input(t); setW(t, TEMP); \
|
|
E += TEMP + rol32(A,5) + (fn) + (constant); \
|
|
B = ror32(B, 2); \
|
|
TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0)
|
|
|
|
#define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
|
|
#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
|
|
#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
|
|
#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
|
|
#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E )
|
|
|
|
/**
|
|
* sha1_transform - single block SHA1 transform (deprecated)
|
|
*
|
|
* @digest: 160 bit digest to update
|
|
* @data: 512 bits of data to hash
|
|
* @array: 16 words of workspace (see note)
|
|
*
|
|
* This function executes SHA-1's internal compression function. It updates the
|
|
* 160-bit internal state (@digest) with a single 512-bit data block (@data).
|
|
*
|
|
* Don't use this function. SHA-1 is no longer considered secure. And even if
|
|
* you do have to use SHA-1, this isn't the correct way to hash something with
|
|
* SHA-1 as this doesn't handle padding and finalization.
|
|
*
|
|
* Note: If the hash is security sensitive, the caller should be sure
|
|
* to clear the workspace. This is left to the caller to avoid
|
|
* unnecessary clears between chained hashing operations.
|
|
*/
|
|
void sha1_transform(__u32 *digest, const char *data, __u32 *array)
|
|
{
|
|
__u32 A, B, C, D, E;
|
|
unsigned int i = 0;
|
|
|
|
A = digest[0];
|
|
B = digest[1];
|
|
C = digest[2];
|
|
D = digest[3];
|
|
E = digest[4];
|
|
|
|
/* Round 1 - iterations 0-16 take their input from 'data' */
|
|
for (; i < 16; ++i)
|
|
T_0_15(i, A, B, C, D, E);
|
|
|
|
/* Round 1 - tail. Input from 512-bit mixing array */
|
|
for (; i < 20; ++i)
|
|
T_16_19(i, A, B, C, D, E);
|
|
|
|
/* Round 2 */
|
|
for (; i < 40; ++i)
|
|
T_20_39(i, A, B, C, D, E);
|
|
|
|
/* Round 3 */
|
|
for (; i < 60; ++i)
|
|
T_40_59(i, A, B, C, D, E);
|
|
|
|
/* Round 4 */
|
|
for (; i < 80; ++i)
|
|
T_60_79(i, A, B, C, D, E);
|
|
|
|
digest[0] += A;
|
|
digest[1] += B;
|
|
digest[2] += C;
|
|
digest[3] += D;
|
|
digest[4] += E;
|
|
}
|
|
EXPORT_SYMBOL(sha1_transform);
|
|
|
|
/**
|
|
* sha1_init - initialize the vectors for a SHA1 digest
|
|
* @buf: vector to initialize
|
|
*/
|
|
void sha1_init(__u32 *buf)
|
|
{
|
|
buf[0] = 0x67452301;
|
|
buf[1] = 0xefcdab89;
|
|
buf[2] = 0x98badcfe;
|
|
buf[3] = 0x10325476;
|
|
buf[4] = 0xc3d2e1f0;
|
|
}
|
|
EXPORT_SYMBOL(sha1_init);
|