1 files changed, 187 insertions, 0 deletions
diff --git a/cipher/cipher-cbc.c b/cipher/cipher-cbc.c
new file mode 100644
index 00000000..b8525898
--- /dev/null
+++ b/cipher/cipher-cbc.c
@@ -0,0 +1,187 @@
+/* cipher-cbc.c  - Generic CBC mode implementation
+ * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
+ *               2005, 2007, 2008, 2009, 2011 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 <errno.h>
+
+#include "g10lib.h"
+#include "cipher.h"
+#include "ath.h"
+#include "./cipher-internal.h"
+
+
+
+gcry_err_code_t
+_gcry_cipher_cbc_encrypt (gcry_cipher_hd_t c,
+                          unsigned char *outbuf, unsigned int outbuflen,
+                          const unsigned char *inbuf, unsigned int inbuflen)
+{
+  unsigned int n;
+  unsigned char *ivp;
+  int i;
+  size_t blocksize = c->cipher->blocksize;
+  unsigned nblocks = inbuflen / blocksize;
+
+  if (outbuflen < ((c->flags & GCRY_CIPHER_CBC_MAC)? blocksize : inbuflen))
+    return GPG_ERR_BUFFER_TOO_SHORT;
+
+  if ((inbuflen % c->cipher->blocksize)
+      && !(inbuflen > c->cipher->blocksize
+           && (c->flags & GCRY_CIPHER_CBC_CTS)))
+    return GPG_ERR_INV_LENGTH;
+
+  if ((c->flags & GCRY_CIPHER_CBC_CTS) && inbuflen > blocksize)
+    {
+      if ((inbuflen % blocksize) == 0)
+	nblocks--;
+    }
+
+  if (c->bulk.cbc_enc)
+    {
+      c->bulk.cbc_enc (&c->context.c, c->u_iv.iv, outbuf, inbuf, nblocks,
+                       (c->flags & GCRY_CIPHER_CBC_MAC));
+      inbuf  += nblocks * blocksize;
+      if (!(c->flags & GCRY_CIPHER_CBC_MAC))
+        outbuf += nblocks * blocksize;
+    }
+  else
+    {
+      for (n=0; n < nblocks; n++ )
+        {
+          for (ivp=c->u_iv.iv,i=0; i < blocksize; i++ )
+            outbuf[i] = inbuf[i] ^ *ivp++;
+          c->cipher->encrypt ( &c->context.c, outbuf, outbuf );
+          memcpy (c->u_iv.iv, outbuf, blocksize );
+          inbuf  += blocksize;
+          if (!(c->flags & GCRY_CIPHER_CBC_MAC))
+            outbuf += blocksize;
+        }
+    }
+
+  if ((c->flags & GCRY_CIPHER_CBC_CTS) && inbuflen > blocksize)
+    {
+      /* We have to be careful here, since outbuf might be equal to
+         inbuf.  */
+      int restbytes;
+      unsigned char b;
+
+      if ((inbuflen % blocksize) == 0)
+        restbytes = blocksize;
+      else
+        restbytes = inbuflen % blocksize;
+
+      outbuf -= blocksize;
+      for (ivp = c->u_iv.iv, i = 0; i < restbytes; i++)
+        {
+          b = inbuf[i];
+          outbuf[blocksize + i] = outbuf[i];
+          outbuf[i] = b ^ *ivp++;
+        }
+      for (; i < blocksize; i++)
+        outbuf[i] = 0 ^ *ivp++;
+
+      c->cipher->encrypt (&c->context.c, outbuf, outbuf);
+      memcpy (c->u_iv.iv, outbuf, blocksize);
+    }
+
+  return 0;
+}
+
+
+gcry_err_code_t
+_gcry_cipher_cbc_decrypt (gcry_cipher_hd_t c,
+                          unsigned char *outbuf, unsigned int outbuflen,
+                          const unsigned char *inbuf, unsigned int inbuflen)
+{
+  unsigned int n;
+  unsigned char *ivp;
+  int i;
+  size_t blocksize = c->cipher->blocksize;
+  unsigned int nblocks = inbuflen / blocksize;
+
+  if (outbuflen < inbuflen)
+    return GPG_ERR_BUFFER_TOO_SHORT;
+
+  if ((inbuflen % c->cipher->blocksize)
+      && !(inbuflen > c->cipher->blocksize
+           && (c->flags & GCRY_CIPHER_CBC_CTS)))
+    return GPG_ERR_INV_LENGTH;
+
+  if ((c->flags & GCRY_CIPHER_CBC_CTS) && inbuflen > blocksize)
+    {
+      nblocks--;
+      if ((inbuflen % blocksize) == 0)
+	nblocks--;
+      memcpy (c->lastiv, c->u_iv.iv, blocksize);
+    }
+
+  if (c->bulk.cbc_dec)
+    {
+      c->bulk.cbc_dec (&c->context.c, c->u_iv.iv, outbuf, inbuf, nblocks);
+      inbuf  += nblocks * blocksize;
+      outbuf += nblocks * blocksize;
+    }
+  else
+    {
+      for (n=0; n < nblocks; n++ )
+        {
+          /* Because outbuf and inbuf might be the same, we have to
+           * save the original ciphertext block.  We use LASTIV for
+           * this here because it is not used otherwise. */
+          memcpy (c->lastiv, inbuf, blocksize);
+          c->cipher->decrypt ( &c->context.c, outbuf, inbuf );
+          for (ivp=c->u_iv.iv,i=0; i < blocksize; i++ )
+	    outbuf[i] ^= *ivp++;
+          memcpy(c->u_iv.iv, c->lastiv, blocksize );
+          inbuf  += c->cipher->blocksize;
+          outbuf += c->cipher->blocksize;
+        }
+    }
+
+  if ((c->flags & GCRY_CIPHER_CBC_CTS) && inbuflen > blocksize)
+    {
+      int restbytes;
+
+      if ((inbuflen % blocksize) == 0)
+        restbytes = blocksize;
+      else
+        restbytes = inbuflen % blocksize;
+
+      memcpy (c->lastiv, c->u_iv.iv, blocksize );         /* Save Cn-2. */
+      memcpy (c->u_iv.iv, inbuf + blocksize, restbytes ); /* Save Cn. */
+
+      c->cipher->decrypt ( &c->context.c, outbuf, inbuf );
+      for (ivp=c->u_iv.iv,i=0; i < restbytes; i++ )
+        outbuf[i] ^= *ivp++;
+
+      memcpy(outbuf + blocksize, outbuf, restbytes);
+      for(i=restbytes; i < blocksize; i++)
+        c->u_iv.iv[i] = outbuf[i];
+      c->cipher->decrypt (&c->context.c, outbuf, c->u_iv.iv);
+      for(ivp=c->lastiv,i=0; i < blocksize; i++ )
+        outbuf[i] ^= *ivp++;
+      /* c->lastiv is now really lastlastiv, does this matter? */
+    }
+
+  return 0;
+}