[PATCH 15/22] /dev/random: kill unrolled SHA code

From: Matt Mackall
Date: Thu Mar 25 2004 - 19:09:01 EST


/dev/random kill unrolled SHA code

Kill the unrolled SHA variants. In the future, we can use cryptoapi
for faster hash functions.

tiny-mpm/drivers/char/random.c | 146 -----------------------------------------
1 files changed, 146 deletions(-)

diff -puN drivers/char/random.c~kill-sha-variants drivers/char/random.c
--- tiny/drivers/char/random.c~kill-sha-variants 2004-03-20 13:38:34.000000000 -0600
+++ tiny-mpm/drivers/char/random.c 2004-03-20 13:38:34.000000000 -0600
@@ -885,9 +885,6 @@ EXPORT_SYMBOL(add_disk_randomness);
#define HASH_BUFFER_SIZE 5
#define HASH_EXTRA_SIZE 80

-/* Various size/speed tradeoffs are available. Choose 0..3. */
-#define SHA_CODE_SIZE 0
-
/*
* SHA transform algorithm, taken from code written by Peter Gutmann,
* and placed in the public domain.
@@ -909,10 +906,6 @@ EXPORT_SYMBOL(add_disk_randomness);

#define ROTL(n,X) ( ( ( X ) << n ) | ( ( X ) >> ( 32 - n ) ) )

-#define subRound(a, b, c, d, e, f, k, data) \
- ( e += ROTL( 5, a ) + f( b, c, d ) + k + data, b = ROTL( 30, b ) )
-
-
static void sha_transform(__u32 digest[85], __u32 const data[16])
{
__u32 A, B, C, D, E; /* Local vars */
@@ -940,11 +933,6 @@ static void sha_transform(__u32 digest[8
E = digest[ 4 ];

/* Heavy mangling, in 4 sub-rounds of 20 iterations each. */
-#if SHA_CODE_SIZE == 0
- /*
- * Approximately 50% of the speed of the largest version, but
- * takes up 1/16 the space. Saves about 6k on an i386 kernel.
- */
for (i = 0; i < 80; i++) {
if (i < 40) {
if (i < 20)
@@ -960,139 +948,6 @@ static void sha_transform(__u32 digest[8
TEMP += ROTL(5, A) + E + W[i];
E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
}
-#elif SHA_CODE_SIZE == 1
- for (i = 0; i < 20; i++) {
- TEMP = f1(B, C, D) + K1 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
- for (; i < 40; i++) {
- TEMP = f2(B, C, D) + K2 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
- for (; i < 60; i++) {
- TEMP = f3(B, C, D) + K3 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
- for (; i < 80; i++) {
- TEMP = f4(B, C, D) + K4 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
-#elif SHA_CODE_SIZE == 2
- for (i = 0; i < 20; i += 5) {
- subRound( A, B, C, D, E, f1, K1, W[ i ] );
- subRound( E, A, B, C, D, f1, K1, W[ i+1 ] );
- subRound( D, E, A, B, C, f1, K1, W[ i+2 ] );
- subRound( C, D, E, A, B, f1, K1, W[ i+3 ] );
- subRound( B, C, D, E, A, f1, K1, W[ i+4 ] );
- }
- for (; i < 40; i += 5) {
- subRound( A, B, C, D, E, f2, K2, W[ i ] );
- subRound( E, A, B, C, D, f2, K2, W[ i+1 ] );
- subRound( D, E, A, B, C, f2, K2, W[ i+2 ] );
- subRound( C, D, E, A, B, f2, K2, W[ i+3 ] );
- subRound( B, C, D, E, A, f2, K2, W[ i+4 ] );
- }
- for (; i < 60; i += 5) {
- subRound( A, B, C, D, E, f3, K3, W[ i ] );
- subRound( E, A, B, C, D, f3, K3, W[ i+1 ] );
- subRound( D, E, A, B, C, f3, K3, W[ i+2 ] );
- subRound( C, D, E, A, B, f3, K3, W[ i+3 ] );
- subRound( B, C, D, E, A, f3, K3, W[ i+4 ] );
- }
- for (; i < 80; i += 5) {
- subRound( A, B, C, D, E, f4, K4, W[ i ] );
- subRound( E, A, B, C, D, f4, K4, W[ i+1 ] );
- subRound( D, E, A, B, C, f4, K4, W[ i+2 ] );
- subRound( C, D, E, A, B, f4, K4, W[ i+3 ] );
- subRound( B, C, D, E, A, f4, K4, W[ i+4 ] );
- }
-#elif SHA_CODE_SIZE == 3 /* Really large version */
- subRound( A, B, C, D, E, f1, K1, W[ 0 ] );
- subRound( E, A, B, C, D, f1, K1, W[ 1 ] );
- subRound( D, E, A, B, C, f1, K1, W[ 2 ] );
- subRound( C, D, E, A, B, f1, K1, W[ 3 ] );
- subRound( B, C, D, E, A, f1, K1, W[ 4 ] );
- subRound( A, B, C, D, E, f1, K1, W[ 5 ] );
- subRound( E, A, B, C, D, f1, K1, W[ 6 ] );
- subRound( D, E, A, B, C, f1, K1, W[ 7 ] );
- subRound( C, D, E, A, B, f1, K1, W[ 8 ] );
- subRound( B, C, D, E, A, f1, K1, W[ 9 ] );
- subRound( A, B, C, D, E, f1, K1, W[ 10 ] );
- subRound( E, A, B, C, D, f1, K1, W[ 11 ] );
- subRound( D, E, A, B, C, f1, K1, W[ 12 ] );
- subRound( C, D, E, A, B, f1, K1, W[ 13 ] );
- subRound( B, C, D, E, A, f1, K1, W[ 14 ] );
- subRound( A, B, C, D, E, f1, K1, W[ 15 ] );
- subRound( E, A, B, C, D, f1, K1, W[ 16 ] );
- subRound( D, E, A, B, C, f1, K1, W[ 17 ] );
- subRound( C, D, E, A, B, f1, K1, W[ 18 ] );
- subRound( B, C, D, E, A, f1, K1, W[ 19 ] );
-
- subRound( A, B, C, D, E, f2, K2, W[ 20 ] );
- subRound( E, A, B, C, D, f2, K2, W[ 21 ] );
- subRound( D, E, A, B, C, f2, K2, W[ 22 ] );
- subRound( C, D, E, A, B, f2, K2, W[ 23 ] );
- subRound( B, C, D, E, A, f2, K2, W[ 24 ] );
- subRound( A, B, C, D, E, f2, K2, W[ 25 ] );
- subRound( E, A, B, C, D, f2, K2, W[ 26 ] );
- subRound( D, E, A, B, C, f2, K2, W[ 27 ] );
- subRound( C, D, E, A, B, f2, K2, W[ 28 ] );
- subRound( B, C, D, E, A, f2, K2, W[ 29 ] );
- subRound( A, B, C, D, E, f2, K2, W[ 30 ] );
- subRound( E, A, B, C, D, f2, K2, W[ 31 ] );
- subRound( D, E, A, B, C, f2, K2, W[ 32 ] );
- subRound( C, D, E, A, B, f2, K2, W[ 33 ] );
- subRound( B, C, D, E, A, f2, K2, W[ 34 ] );
- subRound( A, B, C, D, E, f2, K2, W[ 35 ] );
- subRound( E, A, B, C, D, f2, K2, W[ 36 ] );
- subRound( D, E, A, B, C, f2, K2, W[ 37 ] );
- subRound( C, D, E, A, B, f2, K2, W[ 38 ] );
- subRound( B, C, D, E, A, f2, K2, W[ 39 ] );
-
- subRound( A, B, C, D, E, f3, K3, W[ 40 ] );
- subRound( E, A, B, C, D, f3, K3, W[ 41 ] );
- subRound( D, E, A, B, C, f3, K3, W[ 42 ] );
- subRound( C, D, E, A, B, f3, K3, W[ 43 ] );
- subRound( B, C, D, E, A, f3, K3, W[ 44 ] );
- subRound( A, B, C, D, E, f3, K3, W[ 45 ] );
- subRound( E, A, B, C, D, f3, K3, W[ 46 ] );
- subRound( D, E, A, B, C, f3, K3, W[ 47 ] );
- subRound( C, D, E, A, B, f3, K3, W[ 48 ] );
- subRound( B, C, D, E, A, f3, K3, W[ 49 ] );
- subRound( A, B, C, D, E, f3, K3, W[ 50 ] );
- subRound( E, A, B, C, D, f3, K3, W[ 51 ] );
- subRound( D, E, A, B, C, f3, K3, W[ 52 ] );
- subRound( C, D, E, A, B, f3, K3, W[ 53 ] );
- subRound( B, C, D, E, A, f3, K3, W[ 54 ] );
- subRound( A, B, C, D, E, f3, K3, W[ 55 ] );
- subRound( E, A, B, C, D, f3, K3, W[ 56 ] );
- subRound( D, E, A, B, C, f3, K3, W[ 57 ] );
- subRound( C, D, E, A, B, f3, K3, W[ 58 ] );
- subRound( B, C, D, E, A, f3, K3, W[ 59 ] );
-
- subRound( A, B, C, D, E, f4, K4, W[ 60 ] );
- subRound( E, A, B, C, D, f4, K4, W[ 61 ] );
- subRound( D, E, A, B, C, f4, K4, W[ 62 ] );
- subRound( C, D, E, A, B, f4, K4, W[ 63 ] );
- subRound( B, C, D, E, A, f4, K4, W[ 64 ] );
- subRound( A, B, C, D, E, f4, K4, W[ 65 ] );
- subRound( E, A, B, C, D, f4, K4, W[ 66 ] );
- subRound( D, E, A, B, C, f4, K4, W[ 67 ] );
- subRound( C, D, E, A, B, f4, K4, W[ 68 ] );
- subRound( B, C, D, E, A, f4, K4, W[ 69 ] );
- subRound( A, B, C, D, E, f4, K4, W[ 70 ] );
- subRound( E, A, B, C, D, f4, K4, W[ 71 ] );
- subRound( D, E, A, B, C, f4, K4, W[ 72 ] );
- subRound( C, D, E, A, B, f4, K4, W[ 73 ] );
- subRound( B, C, D, E, A, f4, K4, W[ 74 ] );
- subRound( A, B, C, D, E, f4, K4, W[ 75 ] );
- subRound( E, A, B, C, D, f4, K4, W[ 76 ] );
- subRound( D, E, A, B, C, f4, K4, W[ 77 ] );
- subRound( C, D, E, A, B, f4, K4, W[ 78 ] );
- subRound( B, C, D, E, A, f4, K4, W[ 79 ] );
-#else
-#error Illegal SHA_CODE_SIZE
-#endif

/* Build message digest */
digest[ 0 ] += A;
@@ -1114,7 +969,6 @@ static void sha_transform(__u32 digest[8
#undef K2
#undef K3
#undef K4
-#undef subRound

/*********************************************************************
*

_
-
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