1 files changed, 95 insertions, 0 deletions
diff --git a/grub-core/disk/AFSplitter.c b/grub-core/disk/AFSplitter.c
new file mode 100644
index 0000000..249163f
--- /dev/null
+++ b/grub-core/disk/AFSplitter.c
@@ -0,0 +1,95 @@
+/*
+ * AFsplitter - Anti forensic information splitter
+ * Copyright 2004, Clemens Fruhwirth <clemens@endorphin.org>
+ *
+ * AFsplitter diffuses information over a large stripe of data,
+ * therefor supporting secure data destruction.
+ *
+ *  This program is grub_free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the grub_free Software Foundation; either version 2 of the License, or
+ *  (at your option) 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 Library 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 grub_free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <grub/crypto.h>
+#include <grub/dl.h>
+#include <grub/mm.h>
+#include <grub/misc.h>
+
+GRUB_MOD_LICENSE ("GPLv2+");
+
+gcry_err_code_t AF_merge (const gcry_md_spec_t * hash, grub_uint8_t * src,
+			  grub_uint8_t * dst, grub_size_t blocksize,
+			  grub_size_t blocknumbers);
+
+static void
+diffuse (const gcry_md_spec_t * hash, grub_uint8_t * src,
+	 grub_uint8_t * dst, grub_size_t size)
+{
+  grub_size_t i;
+  grub_uint32_t IV;		/* host byte order independend hash IV */
+
+  grub_size_t fullblocks = size / hash->mdlen;
+  int padding = size % hash->mdlen;
+  grub_uint8_t final[GRUB_CRYPTO_MAX_MDLEN];
+  grub_uint8_t temp[sizeof (IV) + GRUB_CRYPTO_MAX_MDLEN];
+
+  /* hash block the whole data set with different IVs to produce
+   * more than just a single data block
+   */
+  for (i = 0; i < fullblocks; i++)
+    {
+      IV = grub_cpu_to_be32 (i);
+      grub_memcpy (temp, &IV, sizeof (IV));
+      grub_memcpy (temp + sizeof (IV), src + hash->mdlen * i, hash->mdlen);
+      grub_crypto_hash (hash, dst + hash->mdlen * i, temp,
+			sizeof (IV) + hash->mdlen);
+    }
+
+  if (padding)
+    {
+      IV = grub_cpu_to_be32 (i);
+      grub_memcpy (temp, &IV, sizeof (IV));
+      grub_memcpy (temp + sizeof (IV), src + hash->mdlen * i, padding);
+      grub_crypto_hash (hash, final, temp, sizeof (IV) + padding);
+      grub_memcpy (dst + hash->mdlen * i, final, padding);
+    }
+}
+
+/**
+ * Merges the splitted master key stored on disk into the original key
+ */
+gcry_err_code_t
+AF_merge (const gcry_md_spec_t * hash, grub_uint8_t * src, grub_uint8_t * dst,
+	  grub_size_t blocksize, grub_size_t blocknumbers)
+{
+  grub_size_t i;
+  grub_uint8_t *bufblock;
+
+  if (hash->mdlen > GRUB_CRYPTO_MAX_MDLEN || hash->mdlen == 0)
+    return GPG_ERR_INV_ARG;
+
+  bufblock = grub_zalloc (blocksize);
+  if (bufblock == NULL)
+    return GPG_ERR_OUT_OF_MEMORY;
+
+  grub_memset (bufblock, 0, blocksize);
+  for (i = 0; i < blocknumbers - 1; i++)
+    {
+      grub_crypto_xor (bufblock, src + (blocksize * i), bufblock, blocksize);
+      diffuse (hash, bufblock, bufblock, blocksize);
+    }
+  grub_crypto_xor (dst, src + (i * blocksize), bufblock, blocksize);
+
+  grub_free (bufblock);
+  return GPG_ERR_NO_ERROR;
+}