Add basic implementation of GOST R 34.11-94 message digest

* src/gcrypt.h.in (GCRY_MD_GOSTR3411_94): New.
* cipher/gostr3411-94.c: New.
* configure.ac (available_digests): Add gostr3411-94.
* src/cipher.h: Add gostr3411-94 definitions.
* cipher/md.c: Register GOST R 34.11-94.
* tests/basic.c (check_digests): Add 4 tests for GOST R 34.11-94
  hash algo. Two are  defined in the standard itself, two other are
  more or less common tests - an empty string an exclamation mark.
* doc/gcrypt.texi: Add an entry describing GOST R 34.11-94 to the MD
  algorithms table.

--

Add simple implementation of GOST R 34.11-94 hash function. Currently
there is no way to specify hash parameters (it always uses GOST R 34.11-94
test parameters).

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

Stack burn value in gost3411_init added by wk.

1 files changed, 273 insertions, 0 deletions

diff --git a/cipher/gostr3411-94.c b/cipher/gostr3411-94.c
new file mode 100644
index 00000000..dcf5fd23
--- /dev/null
+++ b/cipher/gostr3411-94.c
@@ -0,0 +1,273 @@
+/* gostr3411-94.c - GOST R 34.11-94 hash function
+ * Copyright (C) 2012 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, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "g10lib.h"
+#include "bithelp.h"
+#include "cipher.h"
+#include "hash-common.h"
+
+#include "gost.h"
+
+typedef struct {
+  gcry_md_block_ctx_t bctx;
+  GOST28147_context hd;
+  byte h[32];
+  byte sigma[32];
+  u32 len;
+} GOSTR3411_CONTEXT;
+
+static void
+transform (void *c, const unsigned char *data);
+
+static void
+gost3411_init (void *context)
+{
+  GOSTR3411_CONTEXT *hd = context;
+
+  memset (&hd->hd, 0, sizeof(hd->hd));
+  memset (hd->h, 0, 32);
+  memset (hd->sigma, 0, 32);
+
+  hd->bctx.nblocks = 0;
+  hd->bctx.count = 0;
+  hd->bctx.blocksize = 32;
+  /* FIXME: Fix this arbitrary value for the stack_burn size.  -wk */
+  hd->bctx.stack_burn = 200;
+  hd->bctx.bwrite = transform;
+}
+
+static void
+do_p (unsigned char *p, unsigned char *u, unsigned char *v)
+{
+  int i, k;
+  for (k = 0; k < 8; k++)
+    {
+      for (i = 0; i < 4; i++)
+        {
+          p[i + 4 * k] = u[8 * i + k] ^ v[8 * i + k];
+        }
+    }
+}
+
+static void
+do_a (unsigned char *u)
+{
+  unsigned char temp[8];
+  int i;
+  memcpy (temp, u, 8);
+  memmove (u, u+8, 24);
+  for (i = 0; i < 8; i++)
+    {
+      u[24 + i] = u[i] ^ temp[i];
+    }
+}
+/* apply do_a twice: 1 2 3 4 -> 3 4 1^2 2^3 */
+static void
+do_a2 (unsigned char *u)
+{
+  unsigned char temp[16];
+  int i;
+  memcpy (temp, u, 16);
+  memcpy (u, u + 16, 16);
+  for (i = 0; i < 8; i++)
+    {
+      u[16 + i] = temp[i] ^ temp[8 + i];
+      u[24 + i] =    u[i] ^ temp[8 + i];
+    }
+}
+
+static void
+do_apply_c2 (unsigned char *u)
+{
+  u[ 1] ^= 0xff;
+  u[ 3] ^= 0xff;
+  u[ 5] ^= 0xff;
+  u[ 7] ^= 0xff;
+
+  u[ 8] ^= 0xff;
+  u[10] ^= 0xff;
+  u[12] ^= 0xff;
+  u[14] ^= 0xff;
+
+  u[17] ^= 0xff;
+  u[18] ^= 0xff;
+  u[20] ^= 0xff;
+  u[23] ^= 0xff;
+
+  u[24] ^= 0xff;
+  u[28] ^= 0xff;
+  u[29] ^= 0xff;
+  u[31] ^= 0xff;
+}
+
+#define do_phi_step(e, i) \
+  e[(0 + 2*i) % 32] ^= e[(2 + 2*i) % 32] ^ e[(4 + 2*i) % 32] ^ e[(6 + 2*i) % 32] ^ e[(24 + 2*i) % 32] ^ e[(30 + 2*i) % 32]; \
+  e[(1 + 2*i) % 32] ^= e[(3 + 2*i) % 32] ^ e[(5 + 2*i) % 32] ^ e[(7 + 2*i) % 32] ^ e[(25 + 2*i) % 32] ^ e[(31 + 2*i) % 32];
+
+static void
+do_phi_submix (unsigned char *e, unsigned char *x, int round)
+{
+  int i;
+  round *= 2;
+  for (i = 0; i < 32; i++)
+    {
+      e[(i + round) % 32] ^= x[i];
+    }
+}
+
+static void
+do_add (unsigned char *s, unsigned char *a)
+{
+  unsigned temp = 0;
+  int i;
+
+  for (i = 0; i < 32; i++)
+    {
+      temp = s[i] + a[i] + (temp >> 8);
+      s[i] = temp & 0xff;
+    }
+}
+
+static void
+do_hash_step (GOST28147_context *hd, unsigned char *h, unsigned char *m)
+{
+  unsigned char u[32], v[32], s[32];
+  unsigned char k[32];
+  int i;
+
+  memcpy (u, h, 32);
+  memcpy (v, m, 32);
+
+  for (i = 0; i < 4; i++) {
+    do_p (k, u, v);
+
+    _gcry_gost_enc_one (hd, k, s + i*8, h + i*8);
+
+    do_a (u);
+    if (i == 1)
+      do_apply_c2 (u);
+    do_a2 (v);
+  }
+
+  for (i = 0; i < 5; i++)
+    {
+      do_phi_step (s, 0);
+      do_phi_step (s, 1);
+      do_phi_step (s, 2);
+      do_phi_step (s, 3);
+      do_phi_step (s, 4);
+      do_phi_step (s, 5);
+      do_phi_step (s, 6);
+      do_phi_step (s, 7);
+      do_phi_step (s, 8);
+      do_phi_step (s, 9);
+      /* That is in total 12 + 1 + 61 = 74 = 16 * 4 + 10 rounds */
+      if (i == 4)
+        break;
+      do_phi_step (s, 10);
+      do_phi_step (s, 11);
+      if (i == 0)
+        do_phi_submix(s, m, 12);
+      do_phi_step (s, 12);
+      if (i == 0)
+        do_phi_submix(s, h, 13);
+      do_phi_step (s, 13);
+      do_phi_step (s, 14);
+      do_phi_step (s, 15);
+    }
+
+  memcpy (h, s+20, 12);
+  memcpy (h+12, s, 20);
+}
+
+
+static void
+transform (void *ctx, const unsigned char *data)
+{
+  GOSTR3411_CONTEXT *hd = ctx;
+  byte m[32];
+
+  memcpy (m, data, 32);
+  do_hash_step (&hd->hd, hd->h, m);
+  do_add (hd->sigma, m);
+}
+
+/*
+   The routine finally terminates the computation and returns the
+   digest.  The handle is prepared for a new cycle, but adding bytes
+   to the handle will the destroy the returned buffer.  Returns: 32
+   bytes with the message the digest.  */
+static void
+gost3411_final (void *context)
+{
+  GOSTR3411_CONTEXT *hd = context;
+  size_t padlen = 0;
+  byte l[32];
+  int i;
+  u32 nblocks;
+
+  if (hd->bctx.count > 0)
+    {
+      padlen = 32 - hd->bctx.count;
+      memset (hd->bctx.buf + hd->bctx.count, 0, padlen);
+      hd->bctx.count += padlen;
+      _gcry_md_block_write (hd, NULL, 0); /* flush */;
+    }
+
+  if (hd->bctx.count != 0)
+    return; /* Something went wrong */
+
+  memset (l, 0, 32);
+
+  nblocks = hd->bctx.nblocks;
+  if (padlen)
+    {
+      nblocks --;
+      l[0] = 256 - padlen * 8;
+    }
+
+  for (i = 1; i < 32 && nblocks != 0; i++)
+    {
+      l[i] = nblocks % 256;
+      nblocks /= 256;
+    }
+
+  do_hash_step (&hd->hd, hd->h, l);
+  do_hash_step (&hd->hd, hd->h, hd->sigma);
+}
+
+static byte *
+gost3411_read (void *context)
+{
+  GOSTR3411_CONTEXT *hd = context;
+
+  return hd->h;
+}
+gcry_md_spec_t _gcry_digest_spec_gost3411_94 =
+  {
+    "GOST_R_34.11-94", NULL, 0, NULL, 32,
+    gost3411_init, _gcry_md_block_write, gost3411_final, gost3411_read,
+    sizeof (GOSTR3411_CONTEXT)
+  };