Added function gnutls_random_art() to convert fingerprints to images (currently ascii-art).

3 files changed, 187 insertions, 0 deletions

diff --git a/lib/extras/Makefile.am b/lib/extras/Makefile.am
new file mode 100644
index 0000000000..b973b88d45
--- /dev/null
+++ b/lib/extras/Makefile.am
@@ -0,0 +1,37 @@
+## Process this file with automake to produce Makefile.in
+# Copyright (C) 2002-2011 Free Software Foundation, Inc.
+#
+# Author: Nikos Mavrogiannopoulos
+#
+# This file is part of GnuTLS.
+#
+# The GnuTLS 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 3 of
+# the License, or (at your option) any later version.
+#
+# The GnuTLS 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/>
+
+AM_CFLAGS = $(WERROR_CFLAGS) $(WSTACK_CFLAGS) $(WARN_CFLAGS)
+AM_CPPFLAGS = \
+	-I$(srcdir)/../../gl		\
+	-I$(builddir)/../../gl		\
+	-I$(srcdir)/../includes		\
+	-I$(builddir)/../includes	\
+	-I$(builddir)/../../gl          \
+	-I$(srcdir)/..			\
+	-I$(srcdir)/../opencdk
+
+if ENABLE_MINITASN1
+AM_CPPFLAGS += -I$(srcdir)/../minitasn1
+endif
+
+noinst_LTLIBRARIES = libgnutls_extras.la
+
+libgnutls_extras_la_SOURCES = randomart.c
diff --git a/lib/extras/randomart.c b/lib/extras/randomart.c
new file mode 100644
index 0000000000..c2ce08f4b0
--- /dev/null
+++ b/lib/extras/randomart.c
@@ -0,0 +1,147 @@
+/* $OpenBSD: key.c,v 1.98 2011/10/18 04:58:26 djm Exp $ */
+/*
+ * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <gnutls_int.h>
+#include <gnutls_errors.h>
+#include <randomart.h>
+
+/*
+ * Draw an ASCII-Art representing the fingerprint so human brain can
+ * profit from its built-in pattern recognition ability.
+ * This technique is called "random art" and can be found in some
+ * scientific publications like this original paper:
+ *
+ * "Hash Visualization: a New Technique to improve Real-World Security",
+ * Perrig A. and Song D., 1999, International Workshop on Cryptographic
+ * Techniques and E-Commerce (CrypTEC '99)
+ * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
+ *
+ * The subject came up in a talk by Dan Kaminsky, too.
+ *
+ * If you see the picture is different, the key is different.
+ * If the picture looks the same, you still know nothing.
+ *
+ * The algorithm used here is a worm crawling over a discrete plane,
+ * leaving a trace (augmenting the field) everywhere it goes.
+ * Movement is taken from dgst_raw 2bit-wise.  Bumping into walls
+ * makes the respective movement vector be ignored for this turn.
+ * Graphs are not unambiguous, because circles in graphs can be
+ * walked in either direction.
+ */
+
+/*
+ * Field sizes for the random art.  Have to be odd, so the starting point
+ * can be in the exact middle of the picture, and FLDBASE should be >=8 .
+ * Else pictures would be too dense, and drawing the frame would
+ * fail, too, because the key type would not fit in anymore.
+ */
+#define	FLDBASE		8
+#define	FLDSIZE_Y	(FLDBASE + 1)
+#define	FLDSIZE_X	(FLDBASE * 2 + 1)
+char *
+key_fingerprint_randomart (uint8_t * dgst_raw, u_int dgst_raw_len,
+                           const char *key_type, unsigned int key_size)
+{
+  /*
+   * Chars to be used after each other every time the worm
+   * intersects with itself.  Matter of taste.
+   */
+  const char augmentation_string[] = " .o+=*BOX@%&#/^SE";
+  char *retval, *p;
+  uint8_t field[FLDSIZE_X][FLDSIZE_Y];
+  u_int i, b;
+  int x, y;
+  const size_t len = sizeof(augmentation_string) - 1;
+
+  retval = gnutls_calloc (1, (FLDSIZE_X + 3) * (FLDSIZE_Y + 2));
+  if (retval == NULL)
+    {
+      gnutls_assert();
+      return NULL;
+    }
+
+  /* initialize field */
+  memset (field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof (char));
+  x = FLDSIZE_X / 2;
+  y = FLDSIZE_Y / 2;
+
+  /* process raw key */
+  for (i = 0; i < dgst_raw_len; i++)
+    {
+      int input;
+      /* each byte conveys four 2-bit move commands */
+      input = dgst_raw[i];
+      for (b = 0; b < 4; b++)
+        {
+          /* evaluate 2 bit, rest is shifted later */
+          x += (input & 0x1) ? 1 : -1;
+          y += (input & 0x2) ? 1 : -1;
+
+          /* assure we are still in bounds */
+          x = MAX (x, 0);
+          y = MAX (y, 0);
+          x = MIN (x, FLDSIZE_X - 1);
+          y = MIN (y, FLDSIZE_Y - 1);
+
+          /* augment the field */
+          if (field[x][y] < len - 2)
+            field[x][y]++;
+          input = input >> 2;
+        }
+    }
+
+  /* mark starting point and end point */
+  field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
+  field[x][y] = len;
+
+  /* fill in retval */
+  snprintf (retval, FLDSIZE_X, "+--[%4s %4u]", key_type, key_size);
+  p = strchr (retval, '\0');
+
+  /* output upper border */
+  for (i = p - retval - 1; i < FLDSIZE_X; i++)
+    *p++ = '-';
+  *p++ = '+';
+  *p++ = '\n';
+
+  /* output content */
+  for (y = 0; y < FLDSIZE_Y; y++)
+    {
+      *p++ = '|';
+      for (x = 0; x < FLDSIZE_X; x++)
+        *p++ = augmentation_string[MIN (field[x][y], len)];
+      *p++ = '|';
+      *p++ = '\n';
+    }
+
+  /* output lower border */
+  *p++ = '+';
+  for (i = 0; i < FLDSIZE_X; i++)
+    *p++ = '-';
+  *p++ = '+';
+
+  return retval;
+}
diff --git a/lib/extras/randomart.h b/lib/extras/randomart.h
new file mode 100644
index 0000000000..77d912b492
--- /dev/null
+++ b/lib/extras/randomart.h
@@ -0,0 +1,3 @@
+char *
+key_fingerprint_randomart (uint8_t * dgst_raw, u_int dgst_raw_len,
+                           const char *key_type, unsigned int key_size);