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/*
* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
/** @file
*
* SHA-1 algorithm
*
*/
#include <stdint.h>
#include <string.h>
#include <byteswap.h>
#include <assert.h>
#include <ipxe/rotate.h>
#include <ipxe/crypto.h>
#include <ipxe/asn1.h>
#include <ipxe/sha1.h>
/** SHA-1 variables */
struct sha1_variables {
/* This layout matches that of struct sha1_digest_data,
* allowing for efficient endianness-conversion,
*/
uint32_t a;
uint32_t b;
uint32_t c;
uint32_t d;
uint32_t e;
uint32_t w[80];
} __attribute__ (( packed ));
/**
* f(a,b,c,d) for steps 0 to 19
*
* @v v SHA-1 variables
* @ret f f(a,b,c,d)
*/
static uint32_t sha1_f_0_19 ( struct sha1_variables *v ) {
return ( ( v->b & v->c ) | ( (~v->b) & v->d ) );
}
/**
* f(a,b,c,d) for steps 20 to 39 and 60 to 79
*
* @v v SHA-1 variables
* @ret f f(a,b,c,d)
*/
static uint32_t sha1_f_20_39_60_79 ( struct sha1_variables *v ) {
return ( v->b ^ v->c ^ v->d );
}
/**
* f(a,b,c,d) for steps 40 to 59
*
* @v v SHA-1 variables
* @ret f f(a,b,c,d)
*/
static uint32_t sha1_f_40_59 ( struct sha1_variables *v ) {
return ( ( v->b & v->c ) | ( v->b & v->d ) | ( v->c & v->d ) );
}
/** An SHA-1 step function */
struct sha1_step {
/**
* Calculate f(a,b,c,d)
*
* @v v SHA-1 variables
* @ret f f(a,b,c,d)
*/
uint32_t ( * f ) ( struct sha1_variables *v );
/** Constant k */
uint32_t k;
};
/** SHA-1 steps */
static struct sha1_step sha1_steps[4] = {
/** 0 to 19 */
{ .f = sha1_f_0_19, .k = 0x5a827999 },
/** 20 to 39 */
{ .f = sha1_f_20_39_60_79, .k = 0x6ed9eba1 },
/** 40 to 59 */
{ .f = sha1_f_40_59, .k = 0x8f1bbcdc },
/** 60 to 79 */
{ .f = sha1_f_20_39_60_79, .k = 0xca62c1d6 },
};
/**
* Initialise SHA-1 algorithm
*
* @v ctx SHA-1 context
*/
static void sha1_init ( void *ctx ) {
struct sha1_context *context = ctx;
context->ddd.dd.digest.h[0] = cpu_to_be32 ( 0x67452301 );
context->ddd.dd.digest.h[1] = cpu_to_be32 ( 0xefcdab89 );
context->ddd.dd.digest.h[2] = cpu_to_be32 ( 0x98badcfe );
context->ddd.dd.digest.h[3] = cpu_to_be32 ( 0x10325476 );
context->ddd.dd.digest.h[4] = cpu_to_be32 ( 0xc3d2e1f0 );
context->len = 0;
}
/**
* Calculate SHA-1 digest of accumulated data
*
* @v context SHA-1 context
*/
static void sha1_digest ( struct sha1_context *context ) {
union {
union sha1_digest_data_dwords ddd;
struct sha1_variables v;
} u;
uint32_t *a = &u.v.a;
uint32_t *b = &u.v.b;
uint32_t *c = &u.v.c;
uint32_t *d = &u.v.d;
uint32_t *e = &u.v.e;
uint32_t *w = u.v.w;
uint32_t f;
uint32_t k;
uint32_t temp;
struct sha1_step *step;
unsigned int i;
/* Sanity checks */
assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 );
linker_assert ( &u.ddd.dd.digest.h[0] == a, sha1_bad_layout );
linker_assert ( &u.ddd.dd.digest.h[1] == b, sha1_bad_layout );
linker_assert ( &u.ddd.dd.digest.h[2] == c, sha1_bad_layout );
linker_assert ( &u.ddd.dd.digest.h[3] == d, sha1_bad_layout );
linker_assert ( &u.ddd.dd.digest.h[4] == e, sha1_bad_layout );
linker_assert ( &u.ddd.dd.data.dword[0] == w, sha1_bad_layout );
DBGC ( context, "SHA1 digesting:\n" );
DBGC_HDA ( context, 0, &context->ddd.dd.digest,
sizeof ( context->ddd.dd.digest ) );
DBGC_HDA ( context, context->len, &context->ddd.dd.data,
sizeof ( context->ddd.dd.data ) );
/* Convert h[0..4] to host-endian, and initialise a, b, c, d,
* e, and w[0..15]
*/
for ( i = 0 ; i < ( sizeof ( u.ddd.dword ) /
sizeof ( u.ddd.dword[0] ) ) ; i++ ) {
be32_to_cpus ( &context->ddd.dword[i] );
u.ddd.dword[i] = context->ddd.dword[i];
}
/* Initialise w[16..79] */
for ( i = 16 ; i < 80 ; i++ )
w[i] = rol32 ( ( w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16] ), 1 );
/* Main loop */
for ( i = 0 ; i < 80 ; i++ ) {
step = &sha1_steps[ i / 20 ];
f = step->f ( &u.v );
k = step->k;
temp = ( rol32 ( *a, 5 ) + f + *e + k + w[i] );
*e = *d;
*d = *c;
*c = rol32 ( *b, 30 );
*b = *a;
*a = temp;
DBGC2 ( context, "%2d : %08x %08x %08x %08x %08x\n",
i, *a, *b, *c, *d, *e );
}
/* Add chunk to hash and convert back to big-endian */
for ( i = 0 ; i < 5 ; i++ ) {
context->ddd.dd.digest.h[i] =
cpu_to_be32 ( context->ddd.dd.digest.h[i] +
u.ddd.dd.digest.h[i] );
}
DBGC ( context, "SHA1 digested:\n" );
DBGC_HDA ( context, 0, &context->ddd.dd.digest,
sizeof ( context->ddd.dd.digest ) );
}
/**
* Accumulate data with SHA-1 algorithm
*
* @v ctx SHA-1 context
* @v data Data
* @v len Length of data
*/
static void sha1_update ( void *ctx, const void *data, size_t len ) {
struct sha1_context *context = ctx;
const uint8_t *byte = data;
size_t offset;
/* Accumulate data a byte at a time, performing the digest
* whenever we fill the data buffer
*/
while ( len-- ) {
offset = ( context->len % sizeof ( context->ddd.dd.data ) );
context->ddd.dd.data.byte[offset] = *(byte++);
context->len++;
if ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 )
sha1_digest ( context );
}
}
/**
* Generate SHA-1 digest
*
* @v ctx SHA-1 context
* @v out Output buffer
*/
static void sha1_final ( void *ctx, void *out ) {
struct sha1_context *context = ctx;
uint64_t len_bits;
uint8_t pad;
/* Record length before pre-processing */
len_bits = cpu_to_be64 ( ( ( uint64_t ) context->len ) * 8 );
/* Pad with a single "1" bit followed by as many "0" bits as required */
pad = 0x80;
do {
sha1_update ( ctx, &pad, sizeof ( pad ) );
pad = 0x00;
} while ( ( context->len % sizeof ( context->ddd.dd.data ) ) !=
offsetof ( typeof ( context->ddd.dd.data ), final.len ) );
/* Append length (in bits) */
sha1_update ( ctx, &len_bits, sizeof ( len_bits ) );
assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 );
/* Copy out final digest */
memcpy ( out, &context->ddd.dd.digest,
sizeof ( context->ddd.dd.digest ) );
}
/** SHA-1 algorithm */
struct digest_algorithm sha1_algorithm = {
.name = "sha1",
.ctxsize = sizeof ( struct sha1_context ),
.blocksize = sizeof ( union sha1_block ),
.digestsize = sizeof ( struct sha1_digest ),
.init = sha1_init,
.update = sha1_update,
.final = sha1_final,
};
/** "sha1" object identifier */
static uint8_t oid_sha1[] = { ASN1_OID_SHA1 };
/** "sha1" OID-identified algorithm */
struct asn1_algorithm oid_sha1_algorithm __asn1_algorithm = {
.name = "sha1",
.digest = &sha1_algorithm,
.oid = ASN1_OID_CURSOR ( oid_sha1 ),
};
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