Initial revision

1 files changed, 486 insertions, 0 deletions

diff --git a/pwmanager/libcrypt/cipher/dsa.c b/pwmanager/libcrypt/cipher/dsa.c
new file mode 100644
index 0000000..c3b4c82
--- a/dev/null
+++ b/pwmanager/libcrypt/cipher/dsa.c
@@ -0,0 +1,486 @@
+/* dsa.c  -  DSA signature scheme
+ * Copyright (C) 1998, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser general Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * Libgcrypt 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser 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
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "g10lib.h"
+#include "mpi.h"
+#include "cipher.h"
+
+typedef struct
+{
+  gcry_mpi_t p;	    /* prime */
+  gcry_mpi_t q;	    /* group order */
+  gcry_mpi_t g;	    /* group generator */
+  gcry_mpi_t y;	    /* g^x mod p */
+} DSA_public_key;
+
+
+typedef struct
+{
+  gcry_mpi_t p;	    /* prime */
+  gcry_mpi_t q;	    /* group order */
+  gcry_mpi_t g;	    /* group generator */
+  gcry_mpi_t y;	    /* g^x mod p */
+  gcry_mpi_t x;	    /* secret exponent */
+} DSA_secret_key;
+
+
+static gcry_mpi_t gen_k (gcry_mpi_t q);
+static void test_keys (DSA_secret_key *sk, unsigned qbits);
+static int check_secret_key (DSA_secret_key *sk);
+static void generate (DSA_secret_key *sk, unsigned nbits,
+                      gcry_mpi_t **ret_factors);
+static void sign (gcry_mpi_t r, gcry_mpi_t s, gcry_mpi_t input,
+                  DSA_secret_key *skey);
+static int verify (gcry_mpi_t r, gcry_mpi_t s, gcry_mpi_t input,
+                   DSA_public_key *pkey);
+
+static void (*progress_cb) (void *,const char *, int, int, int );
+static void *progress_cb_data;
+
+
+void
+_gcry_register_pk_dsa_progress (void (*cb) (void *, const char *,
+                                            int, int, int),
+				void *cb_data)
+{
+  progress_cb = cb;
+  progress_cb_data = cb_data;
+}
+
+
+static void
+progress (int c)
+{
+  if (progress_cb)
+    progress_cb (progress_cb_data, "pk_dsa", c, 0, 0);
+}
+
+
+/*
+ * Generate a random secret exponent k less than q.
+ */
+static gcry_mpi_t
+gen_k( gcry_mpi_t q )
+{
+  gcry_mpi_t k = mpi_alloc_secure( mpi_get_nlimbs(q) );
+  unsigned int nbits = mpi_get_nbits(q);
+  unsigned int nbytes = (nbits+7)/8;
+  char *rndbuf = NULL;
+
+  if ( DBG_CIPHER )
+    log_debug("choosing a random k ");
+  for (;;) 
+    {
+      if( DBG_CIPHER )
+        progress('.');
+
+      if ( !rndbuf || nbits < 32 ) 
+        {
+          gcry_free(rndbuf);
+          rndbuf = gcry_random_bytes_secure( (nbits+7)/8, GCRY_STRONG_RANDOM );
+	}
+      else
+        { /* Change only some of the higher bits.  We could improve
+	     this by directly requesting more memory at the first call
+	     to get_random_bytes() and use this the here maybe it is
+	     easier to do this directly in random.c. */
+          char *pp = gcry_random_bytes_secure( 4, GCRY_STRONG_RANDOM );
+          memcpy( rndbuf,pp, 4 );
+          gcry_free(pp);
+	}
+      _gcry_mpi_set_buffer( k, rndbuf, nbytes, 0 );
+      if ( mpi_test_bit( k, nbits-1 ) )
+        mpi_set_highbit( k, nbits-1 );
+      else
+        {
+          mpi_set_highbit( k, nbits-1 );
+          mpi_clear_bit( k, nbits-1 );
+	}
+
+      if( !(mpi_cmp( k, q ) < 0) ) /* check: k < q */
+        {	
+          if( DBG_CIPHER )
+            progress('+');
+          continue; /* no  */
+        }
+      if( !(mpi_cmp_ui( k, 0 ) > 0) )  /* check: k > 0 */
+        {
+          if( DBG_CIPHER )
+            progress('-');
+          continue; /* no */
+        }
+      break;	/* okay */
+    }
+  gcry_free(rndbuf);
+  if( DBG_CIPHER )
+    progress('\n');
+  
+  return k;
+}
+
+
+static void
+test_keys( DSA_secret_key *sk, unsigned qbits )
+{
+  DSA_public_key pk;
+  gcry_mpi_t test = gcry_mpi_new ( qbits  );
+  gcry_mpi_t out1_a = gcry_mpi_new ( qbits );
+  gcry_mpi_t out1_b = gcry_mpi_new ( qbits );
+
+  pk.p = sk->p;
+  pk.q = sk->q;
+  pk.g = sk->g;
+  pk.y = sk->y;
+  gcry_mpi_randomize( test, qbits, GCRY_WEAK_RANDOM );
+
+  sign( out1_a, out1_b, test, sk );
+  if( !verify( out1_a, out1_b, test, &pk ) )
+    log_fatal("DSA:: sign, verify failed\n");
+
+  gcry_mpi_release ( test );
+  gcry_mpi_release ( out1_a );
+  gcry_mpi_release ( out1_b );
+}
+
+
+
+/*
+   Generate a DSA key pair with a key of size NBITS.
+   Returns: 2 structures filled with all needed values
+ 	    and an array with the n-1 factors of (p-1)
+ */
+static void
+generate( DSA_secret_key *sk, unsigned nbits, gcry_mpi_t **ret_factors )
+{
+  gcry_mpi_t p;    /* the prime */
+  gcry_mpi_t q;    /* the 160 bit prime factor */
+  gcry_mpi_t g;    /* the generator */
+  gcry_mpi_t y;    /* g^x mod p */
+  gcry_mpi_t x;    /* the secret exponent */
+  gcry_mpi_t h, e;  /* helper */
+  unsigned qbits;
+  byte *rndbuf;
+
+  assert( nbits >= 512 && nbits <= 1024 );
+
+  qbits = 160;
+  p = _gcry_generate_elg_prime( 1, nbits, qbits, NULL, ret_factors );
+  /* get q out of factors */
+  q = mpi_copy((*ret_factors)[0]);
+  if( mpi_get_nbits(q) != qbits )
+    BUG();
+
+  /* Find a generator g (h and e are helpers).
+     e = (p-1)/q */
+  e = mpi_alloc( mpi_get_nlimbs(p) );
+  mpi_sub_ui( e, p, 1 );
+  mpi_fdiv_q( e, e, q );
+  g = mpi_alloc( mpi_get_nlimbs(p) );
+  h = mpi_alloc_set_ui( 1 ); /* we start with 2 */
+  do
+    {
+      mpi_add_ui( h, h, 1 );
+      /* g = h^e mod p */
+      gcry_mpi_powm( g, h, e, p );
+    } 
+  while( !mpi_cmp_ui( g, 1 ) );  /* continue until g != 1 */
+
+  /* Select a random number which has these properties:
+   *	 0 < x < q-1
+   * This must be a very good random number because this
+   * is the secret part. */
+  if( DBG_CIPHER )
+    log_debug("choosing a random x ");
+  assert( qbits >= 160 );
+  x = mpi_alloc_secure( mpi_get_nlimbs(q) );
+  mpi_sub_ui( h, q, 1 );  /* put q-1 into h */
+  rndbuf = NULL;
+  do 
+    {
+      if( DBG_CIPHER )
+        progress('.');
+      if( !rndbuf )
+        rndbuf = gcry_random_bytes_secure( (qbits+7)/8,
+                                           GCRY_VERY_STRONG_RANDOM );
+      else 
+        { /* Change only some of the higher bits (= 2 bytes)*/
+          char *r = gcry_random_bytes_secure (2, GCRY_VERY_STRONG_RANDOM);
+          memcpy(rndbuf, r, 2 );
+          gcry_free(r);
+        }
+
+      _gcry_mpi_set_buffer( x, rndbuf, (qbits+7)/8, 0 );
+      mpi_clear_highbit( x, qbits+1 );
+    } 
+  while ( !( mpi_cmp_ui( x, 0 )>0 && mpi_cmp( x, h )<0 ) );
+  gcry_free(rndbuf);
+  mpi_free( e );
+  mpi_free( h );
+
+  /* y = g^x mod p */
+  y = mpi_alloc( mpi_get_nlimbs(p) );
+  gcry_mpi_powm( y, g, x, p );
+
+  if( DBG_CIPHER ) 
+    {
+      progress('\n');
+      log_mpidump("dsa  p= ", p );
+      log_mpidump("dsa  q= ", q );
+      log_mpidump("dsa  g= ", g );
+      log_mpidump("dsa  y= ", y );
+      log_mpidump("dsa  x= ", x );
+    }
+
+  /* Copy the stuff to the key structures. */
+  sk->p = p;
+  sk->q = q;
+  sk->g = g;
+  sk->y = y;
+  sk->x = x;
+
+  /* Now we can test our keys (this should never fail!). */
+  test_keys( sk, qbits );
+}
+
+
+
+/*
+   Test whether the secret key is valid.
+   Returns: if this is a valid key.
+ */
+static int
+check_secret_key( DSA_secret_key *sk )
+{
+  int rc;
+  gcry_mpi_t y = mpi_alloc( mpi_get_nlimbs(sk->y) );
+
+  gcry_mpi_powm( y, sk->g, sk->x, sk->p );
+  rc = !mpi_cmp( y, sk->y );
+  mpi_free( y );
+  return rc;
+}
+
+
+
+/*
+   Make a DSA signature from HASH and put it into r and s.
+ */
+static void
+sign(gcry_mpi_t r, gcry_mpi_t s, gcry_mpi_t hash, DSA_secret_key *skey )
+{
+  gcry_mpi_t k;
+  gcry_mpi_t kinv;
+  gcry_mpi_t tmp;
+
+  /* Select a random k with 0 < k < q */
+  k = gen_k( skey->q );
+
+  /* r = (a^k mod p) mod q */
+  gcry_mpi_powm( r, skey->g, k, skey->p );
+  mpi_fdiv_r( r, r, skey->q );
+
+  /* kinv = k^(-1) mod q */
+  kinv = mpi_alloc( mpi_get_nlimbs(k) );
+  mpi_invm(kinv, k, skey->q );
+
+  /* s = (kinv * ( hash + x * r)) mod q */
+  tmp = mpi_alloc( mpi_get_nlimbs(skey->p) );
+  mpi_mul( tmp, skey->x, r );
+  mpi_add( tmp, tmp, hash );
+  mpi_mulm( s , kinv, tmp, skey->q );
+
+  mpi_free(k);
+  mpi_free(kinv);
+  mpi_free(tmp);
+}
+
+
+/*
+   Returns true if the signature composed from R and S is valid.
+ */
+static int
+verify (gcry_mpi_t r, gcry_mpi_t s, gcry_mpi_t hash, DSA_public_key *pkey )
+{
+  int rc;
+  gcry_mpi_t w, u1, u2, v;
+  gcry_mpi_t base[3];
+  gcry_mpi_t ex[3];
+
+  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 */
+
+  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) );
+
+  /* w = s^(-1) mod q */
+  mpi_invm( w, s, pkey->q );
+
+  /* u1 = (hash * w) mod q */
+  mpi_mulm( u1, hash, 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; ex[0] = u1;
+  base[1] = pkey->y; ex[1] = u2;
+  base[2] = NULL;    ex[2] = NULL;
+  mpi_mulpowm( v, base, ex, 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;
+}
+
+
+/*********************************************
+ **************  interface  ******************
+ *********************************************/
+
+gcry_err_code_t
+_gcry_dsa_generate (int algo, unsigned nbits, unsigned long dummy,
+                    gcry_mpi_t *skey, gcry_mpi_t **retfactors)
+{
+  DSA_secret_key sk;
+
+  generate (&sk, nbits, retfactors);
+  skey[0] = sk.p;
+  skey[1] = sk.q;
+  skey[2] = sk.g;
+  skey[3] = sk.y;
+  skey[4] = sk.x;
+
+  return GPG_ERR_NO_ERROR;
+}
+
+
+gcry_err_code_t
+_gcry_dsa_check_secret_key (int algo, gcry_mpi_t *skey)
+{
+  gcry_err_code_t err = GPG_ERR_NO_ERROR;
+  DSA_secret_key sk;
+
+  if ((! skey[0]) || (! skey[1]) || (! skey[2]) || (! skey[3]) || (! skey[4]))
+    err = GPG_ERR_BAD_MPI;
+  else
+    {
+      sk.p = skey[0];
+      sk.q = skey[1];
+      sk.g = skey[2];
+      sk.y = skey[3];
+      sk.x = skey[4];
+      if (! check_secret_key (&sk))
+	err = GPG_ERR_BAD_SECKEY;
+    }
+
+  return err;
+}
+
+
+gcry_err_code_t
+_gcry_dsa_sign (int algo, gcry_mpi_t *resarr, gcry_mpi_t data, gcry_mpi_t *skey)
+{
+  gcry_err_code_t err = GPG_ERR_NO_ERROR;
+  DSA_secret_key sk;
+
+  if ((! data)
+      || (! skey[0]) || (! skey[1]) || (! skey[2])
+      || (! skey[3]) || (! skey[4]))
+    err = GPG_ERR_BAD_MPI;
+  else
+    {
+      sk.p = skey[0];
+      sk.q = skey[1];
+      sk.g = skey[2];
+      sk.y = skey[3];
+      sk.x = skey[4];
+      resarr[0] = mpi_alloc (mpi_get_nlimbs (sk.p));
+      resarr[1] = mpi_alloc (mpi_get_nlimbs (sk.p));
+      sign (resarr[0], resarr[1], data, &sk);
+    }
+  return err;
+}
+
+gcry_err_code_t
+_gcry_dsa_verify (int algo, gcry_mpi_t hash, gcry_mpi_t *data, gcry_mpi_t *pkey,
+		  int (*cmp) (void *, gcry_mpi_t), void *opaquev)
+{
+  gcry_err_code_t err = GPG_ERR_NO_ERROR;
+  DSA_public_key pk;
+
+  if ((! data[0]) || (! data[1]) || (! hash)
+      || (! pkey[0]) || (! pkey[1]) || (! pkey[2]) || (! pkey[3]))
+    err = GPG_ERR_BAD_MPI;
+  else
+    {
+      pk.p = pkey[0];
+      pk.q = pkey[1];
+      pk.g = pkey[2];
+      pk.y = pkey[3];
+      if (! verify (data[0], data[1], hash, &pk))
+	err = GPG_ERR_BAD_SIGNATURE;
+    }
+  return err;
+}
+
+
+unsigned int
+_gcry_dsa_get_nbits (int algo, gcry_mpi_t *pkey)
+{
+  return mpi_get_nbits (pkey[0]);
+}
+
+static char *dsa_names[] =
+  {
+    "dsa",
+    "openpgp-dsa",
+    NULL,
+  };
+
+gcry_pk_spec_t _gcry_pubkey_spec_dsa =
+  {
+    "DSA", dsa_names, 
+    "pqgy", "pqgyx", "", "rs", "pqgy",
+    GCRY_PK_USAGE_SIGN,
+    _gcry_dsa_generate,
+    _gcry_dsa_check_secret_key,
+    NULL,
+    NULL,
+    _gcry_dsa_sign,
+    _gcry_dsa_verify,
+    _gcry_dsa_get_nbits,
+  };
+