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Commit 996fba14 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
Browse files

lib/crypto: sha1: re-roll loops to reduce code size 



commit 9a1536b093bb5bf60689021275fd24d513bb8db0 upstream.

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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c4f48374

lib/sha1.c

+14 −81
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/export.h>

#include <linux/bitops.h>

#include <linux/cryptohash.h>

#include <linux/string.h>

#include <asm/unaligned.h>



/*
@@ -55,7 +56,8 @@ 
#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); } while (0)

	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 )
@@ -82,6 +84,7 @@ 
void sha_transform(__u32 *digest, const char *data, __u32 *array)

{

	__u32 A, B, C, D, E;

	unsigned int i = 0;



	A = digest[0];

	B = digest[1];
@@ -90,94 +93,24 @@ void sha_transform(__u32 *digest, const char *data, __u32 *array) 
	E = digest[4];



	/* Round 1 - iterations 0-16 take their input from 'data' */

	T_0_15( 0, A, B, C, D, E);

	T_0_15( 1, E, A, B, C, D);

	T_0_15( 2, D, E, A, B, C);

	T_0_15( 3, C, D, E, A, B);

	T_0_15( 4, B, C, D, E, A);

	T_0_15( 5, A, B, C, D, E);

	T_0_15( 6, E, A, B, C, D);

	T_0_15( 7, D, E, A, B, C);

	T_0_15( 8, C, D, E, A, B);

	T_0_15( 9, B, C, D, E, A);

	T_0_15(10, A, B, C, D, E);

	T_0_15(11, E, A, B, C, D);

	T_0_15(12, D, E, A, B, C);

	T_0_15(13, C, D, E, A, B);

	T_0_15(14, B, C, D, E, A);

	T_0_15(15, A, B, C, D, E);

	for (; i < 16; ++i)

		T_0_15(i, A, B, C, D, E);



	/* Round 1 - tail. Input from 512-bit mixing array */

	T_16_19(16, E, A, B, C, D);

	T_16_19(17, D, E, A, B, C);

	T_16_19(18, C, D, E, A, B);

	T_16_19(19, B, C, D, E, A);

	for (; i < 20; ++i)

		T_16_19(i, A, B, C, D, E);



	/* Round 2 */

	T_20_39(20, A, B, C, D, E);

	T_20_39(21, E, A, B, C, D);

	T_20_39(22, D, E, A, B, C);

	T_20_39(23, C, D, E, A, B);

	T_20_39(24, B, C, D, E, A);

	T_20_39(25, A, B, C, D, E);

	T_20_39(26, E, A, B, C, D);

	T_20_39(27, D, E, A, B, C);

	T_20_39(28, C, D, E, A, B);

	T_20_39(29, B, C, D, E, A);

	T_20_39(30, A, B, C, D, E);

	T_20_39(31, E, A, B, C, D);

	T_20_39(32, D, E, A, B, C);

	T_20_39(33, C, D, E, A, B);

	T_20_39(34, B, C, D, E, A);

	T_20_39(35, A, B, C, D, E);

	T_20_39(36, E, A, B, C, D);

	T_20_39(37, D, E, A, B, C);

	T_20_39(38, C, D, E, A, B);

	T_20_39(39, B, C, D, E, A);

	for (; i < 40; ++i)

		T_20_39(i, A, B, C, D, E);



	/* Round 3 */

	T_40_59(40, A, B, C, D, E);

	T_40_59(41, E, A, B, C, D);

	T_40_59(42, D, E, A, B, C);

	T_40_59(43, C, D, E, A, B);

	T_40_59(44, B, C, D, E, A);

	T_40_59(45, A, B, C, D, E);

	T_40_59(46, E, A, B, C, D);

	T_40_59(47, D, E, A, B, C);

	T_40_59(48, C, D, E, A, B);

	T_40_59(49, B, C, D, E, A);

	T_40_59(50, A, B, C, D, E);

	T_40_59(51, E, A, B, C, D);

	T_40_59(52, D, E, A, B, C);

	T_40_59(53, C, D, E, A, B);

	T_40_59(54, B, C, D, E, A);

	T_40_59(55, A, B, C, D, E);

	T_40_59(56, E, A, B, C, D);

	T_40_59(57, D, E, A, B, C);

	T_40_59(58, C, D, E, A, B);

	T_40_59(59, B, C, D, E, A);

	for (; i < 60; ++i)

		T_40_59(i, A, B, C, D, E);



	/* Round 4 */

	T_60_79(60, A, B, C, D, E);

	T_60_79(61, E, A, B, C, D);

	T_60_79(62, D, E, A, B, C);

	T_60_79(63, C, D, E, A, B);

	T_60_79(64, B, C, D, E, A);

	T_60_79(65, A, B, C, D, E);

	T_60_79(66, E, A, B, C, D);

	T_60_79(67, D, E, A, B, C);

	T_60_79(68, C, D, E, A, B);

	T_60_79(69, B, C, D, E, A);

	T_60_79(70, A, B, C, D, E);

	T_60_79(71, E, A, B, C, D);

	T_60_79(72, D, E, A, B, C);

	T_60_79(73, C, D, E, A, B);

	T_60_79(74, B, C, D, E, A);

	T_60_79(75, A, B, C, D, E);

	T_60_79(76, E, A, B, C, D);

	T_60_79(77, D, E, A, B, C);

	T_60_79(78, C, D, E, A, B);

	T_60_79(79, B, C, D, E, A);

	for (; i < 80; ++i)

		T_60_79(i, A, B, C, D, E);



	digest[0] += A;

	digest[1] += B;