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/*****************************************************************************
* Copyright (c) 2015-2021 IBM Corporation
* All rights reserved.
* This program and the accompanying materials
* are made available under the terms of the BSD License
* which accompanies this distribution, and is available at
* http://www.opensource.org/licenses/bsd-license.php
*
* Contributors:
* IBM Corporation - initial implementation
*****************************************************************************/
/*
* See: NIST standard for SHA-1 in FIPS PUB 180-4
*/
#include "byteorder.h"
#include "sha.h"
#include "string.h"
typedef struct _sha1_ctx {
uint32_t h[5];
} sha1_ctx;
#define rol(VAL, N) \
({ \
uint32_t res; \
__asm__ ( \
"rotlwi %0, %1, %2\n\t" \
: "=r" (res) \
: "r" (VAL), "i" (N) \
); \
res; \
})
static void sha1_block(uint32_t *w, sha1_ctx *ctx)
{
uint32_t i;
uint32_t a,b,c,d,e,f;
uint32_t tmp;
uint32_t idx;
/*
* FIPS 180-4 4.2.1: SHA1 Constants
*/
static const uint32_t sha_ko[4] = {
0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6
};
/*
* FIPS 180-4 6.1.2: step 1
*
* 0 <= i <= 15:
* W(t) = M(t)
* 16 <= i <= 79:
* W(t) = ROTL(W(t-3) XOR W(t-8) XOR W(t-14) XOR W(t-16), 1)
*/
/* w(0)..w(15) are in big endian format */
for (i = 0; i <= 15; i++)
w[i] = be32_to_cpu(w[i]);
for (i = 16; i <= 79; i++) {
tmp = w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16];
w[i] = rol(tmp, 1);
}
/*
* step 2: a = H0, b = H1, c = H2, d = H3, e = H4.
*/
a = ctx->h[0];
b = ctx->h[1];
c = ctx->h[2];
d = ctx->h[3];
e = ctx->h[4];
/*
* step 3: For i = 0 to 79:
* T = ROTL(a, 5) + f(i; b,c,d) + e + W(t) + K(t);
*/
for (i = 0; i <= 79; i++) {
/*
* FIPS 180-4: 4.1.1 : definition of f(i; b,c,d)
*/
if (i <= 19) {
/*
* 0 <= i <= 19:
* f(i; b,c,d) = (b AND c) OR ((NOT b) AND d)
*/
f = (b & c) | ((b ^ 0xffffffff) & d);
idx = 0;
} else if (i <= 39) {
/*
* 20 <= i <= 39:
* f(i; b,c,d) = b XOR c XOR d
*/
f = b ^ c ^ d;
idx = 1;
} else if (i <= 59) {
/*
* 40 <= i <= 59:
* f(i; b,c,d) = (b AND c) OR (b AND d) OR (c AND d)
*/
f = (b & c) | (b & d) | (c & d);
idx = 2;
} else {
/*
* 60 <= i <= 79:
* f(i; b,c,d) = b XOR c XOR d
*/
f = b ^ c ^ d;
idx = 3;
}
/*
* step 3:
* t = ROTL(a, 5) + f(t;b,c,d) + e + K(t) + W(t);
* e = d; d = c; c = ROTL(b, 30); b = a; a = t;
*/
tmp = rol(a, 5) +
f +
e +
sha_ko[idx] +
w[i];
e = d;
d = c;
c = rol(b, 30);
b = a;
a = tmp;
}
/*
* step 4:
* H0 = a + H0, H1 = b + H1, H2 = c + H2, H3 = d + H3, H4 = e + H4
*/
ctx->h[0] += a;
ctx->h[1] += b;
ctx->h[2] += c;
ctx->h[3] += d;
ctx->h[4] += e;
}
static void sha1_do(sha1_ctx *ctx, const uint8_t *data32, uint32_t length)
{
uint32_t offset = 0;
uint16_t num;
uint64_t bits = 0;
uint32_t w[80];
uint64_t tmp;
/* treat data in 64-byte chunks */
for (offset = 0; length - offset >= 64; offset += 64) {
memcpy(w, data32 + offset, 64);
sha1_block((uint32_t *)w, ctx);
bits += (64 * 8);
}
/* last block with less than 64 bytes */
num = length - offset;
bits += (num << 3);
memcpy(w, data32 + offset, num);
/*
* FIPS 180-4 5.1: Padding the Message
*/
((uint8_t *)w)[num] = 0x80;
if (64 - (num + 1) > 0)
memset( &((uint8_t *)w)[num + 1], 0, 64 - (num + 1));
if (num >= 56) {
/* cannot append number of bits here */
sha1_block((uint32_t *)w, ctx);
memset(w, 0, 60);
}
/* write number of bits to end of block */
tmp = cpu_to_be64(bits);
memcpy(&w[14], &tmp, 8);
sha1_block(w, ctx);
/* need to switch result's endianness */
for (num = 0; num < 5; num++)
ctx->h[num] = cpu_to_be32(ctx->h[num]);
}
void sha1(const uint8_t *data, uint32_t length, uint8_t *hash)
{
sha1_ctx ctx = {
.h = {
/*
* FIPS 180-4: 6.1.1
* -> 5.3.1: initial hash value
*/
0x67452301,
0xefcdab89,
0x98badcfe,
0x10325476,
0xc3d2e1f0,
}
};
sha1_do(&ctx, data, length);
memcpy(hash, &ctx.h[0], 20);
}
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