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partial DSA support

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This commit is contained in:
Werner Koch 1998-03-09 21:44:06 +00:00
parent 1b1a6d7e77
commit a6a8f1e706
62 changed files with 2247 additions and 447 deletions
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15
cipher/ChangeLog
View file

@ -1,3 +1,18 @@
Mon Mar 9 12:59:08 1998 Werner Koch (wk@isil.d.shuttle.de)
* dsa.c, dsa.h: Removed some unused code.
Wed Mar 4 10:39:22 1998 Werner Koch (wk@isil.d.shuttle.de)
* md.c (md_open): Add call to fast_random_poll.
blowfish.c (blowfish_setkey): Ditto.
Tue Mar 3 13:32:54 1998 Werner Koch (wk@isil.d.shuttle.de)
* rmd160.c (rmd160_mixblock): New.
* random.c: Restructured to start with a new RNG implementation.
* random.h: New.
Mon Mar 2 19:21:46 1998 Werner Koch (wk@isil.d.shuttle.de)
* gost.c, gost.h: Removed because they did only conatin trash.

1
cipher/Makefile.am
View file

@ -13,6 +13,7 @@ libcipher_a_SOURCES = blowfish.c \
md5.c \
md5.h \
primegen.c \
random.h \
random.c \
rmd.h \
rmd160.c \

1
cipher/Makefile.in
View file

@ -104,6 +104,7 @@ libcipher_a_SOURCES = blowfish.c \
md5.c \
md5.h \
primegen.c \
random.h \
random.c \
rmd.h \
rmd160.c \

3
cipher/blowfish.c
View file

@ -37,6 +37,7 @@
#include "util.h"
#include "types.h"
#include "blowfish.h"
#include "random.h"
/* precomputed S boxes */
static const u32 ks0[256] = {
@ -421,6 +422,8 @@ blowfish_setkey( BLOWFISH_context *c, byte *key, unsigned keylen )
selftest();
}
fast_random_poll();
for(i=0; i < BLOWFISH_ROUNDS+2; i++ )
c->p[i] = ps[i];
for(i=0; i < 256; i++ ) {

197
cipher/dsa.c
View file

@ -32,6 +32,7 @@ void
dsa_free_public_key( DSA_public_key *pk )
{
mpi_free( pk->p ); pk->p = NULL;
mpi_free( pk->q ); pk->q = NULL;
mpi_free( pk->g ); pk->g = NULL;
mpi_free( pk->y ); pk->y = NULL;
}
@ -40,121 +41,13 @@ void
dsa_free_secret_key( DSA_secret_key *sk )
{
mpi_free( sk->p ); sk->p = NULL;
mpi_free( sk->q ); sk->q = NULL;
mpi_free( sk->g ); sk->g = NULL;
mpi_free( sk->y ); sk->y = NULL;
mpi_free( sk->x ); sk->x = NULL;
}
static void
test_keys( DSA_public_key *pk, DSA_secret_key *sk, unsigned nbits )
{
MPI test = mpi_alloc( nbits / BITS_PER_MPI_LIMB );
MPI out1_a = mpi_alloc( nbits / BITS_PER_MPI_LIMB );
MPI out1_b = mpi_alloc( nbits / BITS_PER_MPI_LIMB );
MPI out2 = mpi_alloc( nbits / BITS_PER_MPI_LIMB );
mpi_set_bytes( test, nbits, get_random_byte, 0 );
dsa_sign( out1_a, out1_b, test, sk );
if( !dsa_verify( out1_a, out1_b, test, pk ) )
log_fatal("DSA operation: sign, verify failed\n");
mpi_free( test );
mpi_free( out1_a );
mpi_free( out1_b );
mpi_free( out2 );
}
/****************
* generate a random secret exponent k from prime p, so
* that k is relatively prime to p-1
*/
static MPI
gen_k( MPI p )
{
MPI k = mpi_alloc_secure( mpi_get_nlimbs(p) );
MPI temp = mpi_alloc( mpi_get_nlimbs(p) );
MPI p_1 = mpi_copy(p);
unsigned nbits = mpi_get_nbits(p);
if( DBG_CIPHER )
log_debug("choosing a random k ");
mpi_sub_ui( p_1, p, 1);
for(;;) {
if( DBG_CIPHER )
fputc('.', stderr);
mpi_set_bytes( k, nbits, get_random_byte, 1 );
mpi_set_highbit( k, nbits-1 ); /* make sure it's high (really needed?) */
if( mpi_cmp( k, p_1 ) >= 0 )
continue; /* is not smaller than (p-1) */
if( mpi_gcd( temp, k, p_1 ) )
break; /* okay, k is relatively prime to (p-1) */
}
if( DBG_CIPHER )
fputc('\n', stderr);
mpi_free(p_1);
mpi_free(temp);
return k;
}
/****************
* Generate a key pair with a key of size NBITS
* Returns: 2 structures filles with all needed values
*/
void
dsa_generate( DSA_public_key *pk, DSA_secret_key *sk, unsigned nbits )
{
MPI p; /* the prime */
MPI g;
MPI x; /* the secret exponent */
MPI y;
p = generate_public_prime( nbits );
/* FIXME: check wether we shall assert that (p-1)/2 is also prime
* Schneier votes against it
*/
g = mpi_alloc_set_ui(3);
/* select a random number */
x = mpi_alloc_secure( nbits/BITS_PER_MPI_LIMB );
if( DBG_CIPHER )
log_debug("choosing a random x ");
do {
if( DBG_CIPHER )
fputc('.', stderr);
mpi_set_bytes( x, nbits, get_random_byte, 1 ); /* fixme: should be 2 */
mpi_set_highbit( x, nbits-1 ); /* make sure it's high (needed?) */
} while( mpi_cmp( x, p ) >= 0 ); /* x must be smaller than p */
y = mpi_alloc(nbits/BITS_PER_MPI_LIMB);
mpi_powm( y, g, x, p );
if( DBG_CIPHER ) {
fputc('\n', stderr);
log_mpidump("dsa p= ", p );
log_mpidump("dsa g= ", g );
log_mpidump("dsa y= ", y );
log_mpidump("dsa x= ", x );
}
/* copy the stuff to the key structures */
pk->p = mpi_copy(p);
pk->g = mpi_copy(g);
pk->y = mpi_copy(y);
sk->p = p;
sk->g = g;
sk->y = y;
sk->x = x;
/* now we can test our keys (this should never fail!) */
test_keys( pk, sk, nbits - 64 );
}
/****************
* Test wether the secret key is valid.
* Returns: if this is a valid key.
@ -174,72 +67,58 @@ dsa_check_secret_key( DSA_secret_key *sk )
/****************
* Make an Elgamal signature out of INPUT
* Make a DSA signature out of INPUT
*/
void
dsa_sign(MPI a, MPI b, MPI input, DSA_secret_key *skey )
dsa_sign(MPI r, MPI s, MPI input, DSA_secret_key *skey )
{
MPI k;
MPI t = mpi_alloc( mpi_get_nlimbs(a) );
MPI inv = mpi_alloc( mpi_get_nlimbs(a) );
MPI p_1 = mpi_copy(skey->p);
/*
* b = (t * inv) mod (p-1)
* b = (t * inv(k,(p-1),(p-1)) mod (p-1)
* b = (((M-x*a) mod (p-1)) * inv(k,(p-1),(p-1))) mod (p-1)
*
*/
mpi_sub_ui(p_1, p_1, 1);
k = gen_k( skey->p );
mpi_powm( a, skey->g, k, skey->p );
mpi_mul(t, skey->x, a );
mpi_subm(t, input, t, p_1 );
while( mpi_is_neg(t) )
mpi_add(t, t, p_1);
mpi_invm(inv, k, p_1 );
mpi_mulm(b, t, inv, p_1 );
#if 0
if( DBG_CIPHER ) {
log_mpidump("dsa sign p= ", skey->p);
log_mpidump("dsa sign g= ", skey->g);
log_mpidump("dsa sign y= ", skey->y);
log_mpidump("dsa sign x= ", skey->x);
log_mpidump("dsa sign k= ", k);
log_mpidump("dsa sign M= ", input);
log_mpidump("dsa sign a= ", a);
log_mpidump("dsa sign b= ", b);
}
#endif
mpi_free(k);
mpi_free(t);
mpi_free(inv);
mpi_free(p_1);
}
/****************
* Returns true if the signature composed from A and B is valid.
* Returns true if the signature composed from R and S is valid.
*/
int
dsa_verify(MPI a, MPI b, MPI input, DSA_public_key *pkey )
dsa_verify(MPI r, MPI s, MPI input, DSA_public_key *pkey )
{
int rc;
MPI t1 = mpi_alloc( mpi_get_nlimbs(a) );
MPI t2 = mpi_alloc( mpi_get_nlimbs(a) );
MPI w, u1, u2, v;
MPI base[3];
MPI exp[3];
mpi_powm( t1, pkey->y, a, pkey->p );
mpi_powm( t2, a, b, pkey->p );
mpi_mulm( t1, t1, t2, pkey->p );
if( !(mpi_cmp_ui( r, 0 ) > 0 && mpi_cmp( r, pkey->q ) < 0) )
return 0; /* assertion 0 < r < q failed */
if( !(mpi_cmp_ui( s, 0 ) > 0 && mpi_cmp( s, pkey->q ) < 0) )
return 0; /* assertion 0 < s < q failed */
mpi_powm( t2, pkey->g, input, pkey->p );
w = mpi_alloc( mpi_get_nlimbs(pkey->q) );
u1 = mpi_alloc( mpi_get_nlimbs(pkey->q) );
u2 = mpi_alloc( mpi_get_nlimbs(pkey->q) );
v = mpi_alloc( mpi_get_nlimbs(pkey->p) );
rc = !mpi_cmp( t1, t2 );
/* w = s^(-1) mod q */
mpi_invm( w, s, pkey->q );
mpi_free(t1);
mpi_free(t2);
/* u1 = (input * w) mod q */
mpi_mulm( u1, input, w, pkey->q );
/* u2 = r * w mod q */
mpi_mulm( u2, r, w, pkey->q );
/* v = g^u1 * y^u2 mod p mod q */
base[0] = pkey->g; exp[0] = u1;
base[1] = pkey->y; exp[1] = u2;
base[2] = NULL; exp[2] = NULL;
mpi_mulpowm( v, base, exp, pkey->p );
mpi_fdiv_r( v, v, pkey->q );
rc = !mpi_cmp( v, r );
mpi_free(w);
mpi_free(u1);
mpi_free(u2);
mpi_free(v);
return rc;
}

4
cipher/dsa.h
View file

@ -43,7 +43,7 @@ void dsa_free_public_key( DSA_public_key *pk );
void dsa_free_secret_key( DSA_secret_key *sk );
void dsa_generate( DSA_public_key *pk, DSA_secret_key *sk, unsigned nbits );
int dsa_check_secret_key( DSA_secret_key *sk );
void dsa_sign(MPI a, MPI b, MPI input, DSA_secret_key *skey);
int dsa_verify(MPI a, MPI b, MPI input, DSA_public_key *pkey);
void dsa_sign(MPI r, MPI s, MPI input, DSA_secret_key *skey);
int dsa_verify(MPI r, MPI s, MPI input, DSA_public_key *pkey);
#endif /*G10_DSA_H*/

1
cipher/md.c
View file

@ -42,6 +42,7 @@ md_open( int algo, int secure )
hd->secure = secure;
if( algo )
md_enable( hd, algo );
fast_random_poll();
return hd;
}

1
cipher/misc.c
View file

@ -174,6 +174,7 @@ check_pubkey_algo( int algo )
{
switch( algo ) {
case PUBKEY_ALGO_ELGAMAL:
case PUBKEY_ALGO_DSA:
#ifdef HAVE_RSA_CIPHER
case PUBKEY_ALGO_RSA:
#endif

253
cipher/random.c
View file

@ -18,6 +18,17 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
/****************
* How it works:
*
* See Peter Gutmann's Paper: "Software Generation of Practically
* Strong Random Numbers"
*
* fixme!
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
@ -26,27 +37,88 @@
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifndef HAVE_GETTIMEOFTIME
#include <sys/times.h>
#endif
#ifdef HAVE_GETRUSAGE
#include <sys/resource.h>
#endif
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "util.h"
#include "cipher.h"
#include "random.h"
#include "rmd.h"
#include "ttyio.h"
#include "i18n.h"
#define BLOCKLEN 64 /* hash this amount of bytes */
#define DIGESTLEN 20 /* into a digest of this length (rmd160) */
/* poolblocks is the number of digests which make up the pool
* and poolsize must be a multiple of the digest length
* to make the AND operations faster, the size should also be
* a multiple of ulong
*/
#define POOLBLOCKS 30
#define POOLSIZE (POOLBLOCKS*DIGESTLEN)
#if (POOLSIZE % SIZEOF_UNSIGNED_LONG)
#error Please make sure that poolsize is a multiple of ulong
#endif
#define POOLWORDS (POOLSIZE / SIZEOF_UNSIGNED_LONG)
#if SIZEOF_UNSIGNED_LONG == 8
#define ADD_VALUE 0xa5a5a5a5a5a5a5a5
#elif SIZEOF_UNSIGNED_LONG == 4
#define ADD_VALUE 0xa5a5a5a5
#else
#error weird size for an unsigned long
#endif
struct cache {
int len;
byte buffer[100]; /* fixme: should be allocated with m_alloc_secure()*/
int size;
byte *buffer;
};
static int is_initialized;
static struct cache cache[3];
#define MASK_LEVEL(a) do {if( a > 2 ) a = 2; else if( a < 0 ) a = 0; } while(0)
static char *rndpool; /* allocated size is POOLSIZE+BLOCKLEN */
static char *keypool; /* allocated size is POOLSIZE+BLOCKLEN */
static size_t pool_readpos;
static size_t pool_writepos;
static int pool_filled;
static int just_mixed;
static void fill_buffer( byte *buffer, size_t length, int level );
static int secure_alloc;
static int quick_test;
static void read_pool( byte *buffer, size_t length, int level );
static void read_dev_random( byte *buffer, size_t length, int level );
static void
initialize()
{
/* The data buffer is allocated somewhat larger, so that
* we can use this extra space (which is allocated in secure memory)
* as a temporary hash buffer */
rndpool = secure_alloc ? m_alloc_secure_clear(POOLSIZE+BLOCKLEN)
: m_alloc_clear(POOLSIZE+BLOCKLEN);
keypool = secure_alloc ? m_alloc_secure_clear(POOLSIZE+BLOCKLEN)
: m_alloc_clear(POOLSIZE+BLOCKLEN);
is_initialized = 1;
}
void
secure_random_alloc()
{
secure_alloc = 1;
}
int
quick_random_gen( int onoff )
{
@ -78,14 +150,174 @@ get_random_byte( int level )
{
MASK_LEVEL(level);
if( !cache[level].len ) {
fill_buffer(cache[level].buffer, DIM(cache[level].buffer), level );
cache[level].len = DIM(cache[level].buffer);
if( !is_initialized )
initialize();
if( !cache[level].buffer ) {
cache[level].size = 100;
cache[level].buffer = level && secure_alloc?
m_alloc_secure( cache[level].size )
: m_alloc( cache[level].size );
}
read_pool(cache[level].buffer, cache[level].size, level );
cache[level].len = cache[level].size;
}
return cache[level].buffer[--cache[level].len];
}
/****************
* Mix the pool
*/
static void
mix_pool(byte *pool)
{
char *hashbuf = pool + POOLSIZE;
char *p, *pend;
int i, n;
RMD160_CONTEXT md;
rmd160_init( &md );
#if DIGESTLEN != 20
#error must have a digest length of 20 for ripe-md-160
#endif
/* loop over the pool */
pend = pool + POOLSIZE;
memcpy(hashbuf, pend - DIGESTLEN, DIGESTLEN );
memcpy(hashbuf+DIGESTLEN, pool, BLOCKLEN-DIGESTLEN);
rmd160_mixblock( &md, hashbuf);
memcpy(pool, hashbuf, 20 );
p = pool;
for( n=1; n < POOLBLOCKS; n++ ) {
memcpy(hashbuf, p, DIGESTLEN );
p += DIGESTLEN;
if( p+DIGESTLEN+BLOCKLEN < pend )
memcpy(hashbuf+DIGESTLEN, p+DIGESTLEN, BLOCKLEN-DIGESTLEN);
else {
char *pp = p+DIGESTLEN;
for(i=DIGESTLEN; i < BLOCKLEN; i++ ) {
if( pp >= pend )
pp = pool;
hashbuf[i] = *pp++;
}
}
rmd160_mixblock( &md, hashbuf);
memcpy(p, hashbuf, 20 );
}
}
static void
read_pool( byte *buffer, size_t length, int level )
{
int i;
ulong *sp, *dp;
if( length >= POOLSIZE )
BUG(); /* not allowed */
if( !level ) { /* read simple random bytes */
read_dev_random( buffer, length, level );
return;
}
/* always do a random poll if we need strong numbers */
if( pool_filled && level == 2 )
random_poll();
/* make sure the pool is filled */
while( !pool_filled )
random_poll();
/* do always a fast random poll */
fast_random_poll();
/* mix the pool (if add_randomness() didn't it) */
if( !just_mixed )
mix_pool(rndpool);
/* create a new pool */
for(i=0,dp=(ulong*)keypool, sp=(ulong*)rndpool;
i < POOLWORDS; i++, dp++, sp++ )
*dp = *sp + ADD_VALUE;
/* and mix both pools */
mix_pool(rndpool);
mix_pool(keypool);
/* read the required data
* we use a readpoiter to read from a different postion each
* time */
while( length-- ) {
*buffer++ = keypool[pool_readpos++];
if( pool_readpos >= POOLSIZE )
pool_readpos = 0;
}
/* and clear the keypool */
memset( keypool, 0, POOLSIZE );
}
/****************
* Add LENGTH bytes of randomness from buffer to the pool.
* source may be used to specify the randomeness source.
*/
void
add_randomness( const void *buffer, size_t length, int source )
{
if( !is_initialized )
initialize();
while( length-- ) {
rndpool[pool_writepos++] = *((byte*)buffer)++;
if( pool_writepos >= POOLSIZE ) {
pool_filled = 1;
pool_writepos = 0;
mix_pool(rndpool);
just_mixed = !length;
}
}
}
/********************
* FIXME: move these functions to rand_unix.c
*/
void
random_poll()
{
char buf[POOLSIZE/5];
read_dev_random( buf, POOLSIZE/5, 1 ); /* read /dev/urandom */
add_randomness( buf, POOLSIZE/5, 2);
memset( buf, 0, POOLSIZE/5);
}
void
fast_random_poll()
{
#ifdef HAVE_GETTIMEOFTIME
{ struct timeval tv;
if( gettimeofday( &tv, NULL ) )
BUG();
add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
add_randomness( &tv.tv_usec, sizeof(tv.tv_usec), 1 );
}
#else /* use times */
{ struct tms buf;
times( &buf );
add_randomness( &buf, sizeof buf, 1 );
}
#endif
#ifdef HAVE_GETRUSAGE
{ struct rusage buf;
if( getrusage( RUSAGE_SELF, &buf ) )
BUG();
add_randomness( &buf, sizeof buf, 1 );
memset( &buf, 0, sizeof buf );
}
#endif
}
#ifdef HAVE_DEV_RANDOM
@ -111,7 +343,7 @@ open_device( const char *name, int minor )
static void
fill_buffer( byte *buffer, size_t length, int level )
read_dev_random( byte *buffer, size_t length, int level )
{
static int fd_urandom = -1;
static int fd_random = -1;
@ -125,6 +357,9 @@ fill_buffer( byte *buffer, size_t length, int level )
fd = fd_random;
}
else {
/* fixme: we should use a simpler one for level 0,
* because reading from /dev/urandom removes entropy
* and the next read on /dev/random may have to wait */
if( fd_urandom == -1 )
fd_urandom = open_device( "/dev/urandom", 9 );
fd = fd_urandom;
@ -154,7 +389,7 @@ fill_buffer( byte *buffer, size_t length, int level )
continue;
}
assert( length < 200 );
assert( length < 500 );
do {
n = read(fd, buffer, length );
if( n >= 0 && n > length ) {
@ -178,7 +413,7 @@ fill_buffer( byte *buffer, size_t length, int level )
#endif
static void
fill_buffer( byte *buffer, size_t length, int level )
read_dev_random( byte *buffer, size_t length, int level )
{
static int initialized=0;

39
cipher/random.h Normal file
View file

@ -0,0 +1,39 @@
/* random.h - random functions
* Copyright (C) 1998 Free Software Foundation, Inc.
*
* This file is part of GNUPG.
*
* GNUPG 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
* (at your option) any later version.
*
* GNUPG 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifndef G10_RANDOM_H
#define G10_RANDOM_H
#include "types.h"
/*-- random.c --*/
void secure_random_alloc(void);
int quick_random_gen( int onoff );
void randomize_buffer( byte *buffer, size_t length, int level );
byte get_random_byte( int level );
void add_randomness( const void *buffer, size_t length, int source );
/*-- the next two functions are implemented by all the system
specific source files rand_xxxx.s --*/
void random_poll(void);
void fast_random_poll(void);
#endif /*G10_RANDOM_H*/

1
cipher/rmd.h
View file

@ -33,6 +33,7 @@ typedef struct {
void rmd160_init( RMD160_CONTEXT *c );
void rmd160_write( RMD160_CONTEXT *hd, byte *inbuf, size_t inlen);
void rmd160_final(RMD160_CONTEXT *hd);
void rmd160_mixblock( RMD160_CONTEXT *hd, char *buffer );
#define rmd160_read(h) ( (h)->buf )
#endif /*G10_RMD_H*/

21
cipher/rmd160.c
View file

@ -300,6 +300,27 @@ rmd160_write( RMD160_CONTEXT *hd, byte *inbuf, size_t inlen)
}
/****************
* Apply the rmd160 transform function on the buffer which must have
* a length 64 bytes. Do not use this function together with the
* other functions, use rmd160_init to initialize intzernal variables.
* Returns: 16 bytes in buffer with the mixed contentes of buffer.
*/
void
rmd160_mixblock( RMD160_CONTEXT *hd, char *buffer )
{
char *p = buffer;
transform( hd, buffer );
#define X(a) do { *(u32*)p = hd->h##a ; p += 4; } while(0)
X(0);
X(1);
X(2);
X(3);
X(4);
#undef X
}
/* The routine terminates the computation
*/