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-rw-r--r--comm/third_party/libgcrypt/cipher/cipher-cfb.c317
1 files changed, 317 insertions, 0 deletions
diff --git a/comm/third_party/libgcrypt/cipher/cipher-cfb.c b/comm/third_party/libgcrypt/cipher/cipher-cfb.c
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+++ b/comm/third_party/libgcrypt/cipher/cipher-cfb.c
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+/* cipher-cfb.c - Generic CFB 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 "bufhelp.h"
+#include "./cipher-internal.h"
+
+
+gcry_err_code_t
+_gcry_cipher_cfb_encrypt (gcry_cipher_hd_t c,
+ unsigned char *outbuf, size_t outbuflen,
+ const unsigned char *inbuf, size_t inbuflen)
+{
+ unsigned char *ivp;
+ gcry_cipher_encrypt_t enc_fn = c->spec->encrypt;
+ size_t blocksize_shift = _gcry_blocksize_shift(c);
+ size_t blocksize = 1 << blocksize_shift;
+ size_t blocksize_x_2 = blocksize + blocksize;
+ unsigned int burn, nburn;
+
+ if (outbuflen < inbuflen)
+ return GPG_ERR_BUFFER_TOO_SHORT;
+
+ if ( inbuflen <= c->unused )
+ {
+ /* Short enough to be encoded by the remaining XOR mask. */
+ /* XOR the input with the IV and store input into IV. */
+ ivp = c->u_iv.iv + blocksize - c->unused;
+ buf_xor_2dst(outbuf, ivp, inbuf, inbuflen);
+ c->unused -= inbuflen;
+ return 0;
+ }
+
+ burn = 0;
+
+ if ( c->unused )
+ {
+ /* XOR the input with the IV and store input into IV */
+ inbuflen -= c->unused;
+ ivp = c->u_iv.iv + blocksize - c->unused;
+ buf_xor_2dst(outbuf, ivp, inbuf, c->unused);
+ outbuf += c->unused;
+ inbuf += c->unused;
+ c->unused = 0;
+ }
+
+ /* Now we can process complete blocks. We use a loop as long as we
+ have at least 2 blocks and use conditions for the rest. This
+ also allows to use a bulk encryption function if available. */
+ if (inbuflen >= blocksize_x_2 && c->bulk.cfb_enc)
+ {
+ size_t nblocks = inbuflen >> blocksize_shift;
+ c->bulk.cfb_enc (&c->context.c, c->u_iv.iv, outbuf, inbuf, nblocks);
+ outbuf += nblocks << blocksize_shift;
+ inbuf += nblocks << blocksize_shift;
+ inbuflen -= nblocks << blocksize_shift;
+ }
+ else
+ {
+ while ( inbuflen >= blocksize_x_2 )
+ {
+ /* Encrypt the IV. */
+ nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+ /* XOR the input with the IV and store input into IV. */
+ cipher_block_xor_2dst(outbuf, c->u_iv.iv, inbuf, blocksize);
+ outbuf += blocksize;
+ inbuf += blocksize;
+ inbuflen -= blocksize;
+ }
+ }
+
+ if ( inbuflen >= blocksize )
+ {
+ /* Save the current IV and then encrypt the IV. */
+ cipher_block_cpy( c->lastiv, c->u_iv.iv, blocksize );
+ nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+ /* XOR the input with the IV and store input into IV */
+ cipher_block_xor_2dst(outbuf, c->u_iv.iv, inbuf, blocksize);
+ outbuf += blocksize;
+ inbuf += blocksize;
+ inbuflen -= blocksize;
+ }
+ if ( inbuflen )
+ {
+ /* Save the current IV and then encrypt the IV. */
+ cipher_block_cpy( c->lastiv, c->u_iv.iv, blocksize );
+ nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+ c->unused = blocksize;
+ /* Apply the XOR. */
+ c->unused -= inbuflen;
+ buf_xor_2dst(outbuf, c->u_iv.iv, inbuf, inbuflen);
+ outbuf += inbuflen;
+ inbuf += inbuflen;
+ inbuflen = 0;
+ }
+
+ if (burn > 0)
+ _gcry_burn_stack (burn + 4 * sizeof(void *));
+
+ return 0;
+}
+
+
+gcry_err_code_t
+_gcry_cipher_cfb_decrypt (gcry_cipher_hd_t c,
+ unsigned char *outbuf, size_t outbuflen,
+ const unsigned char *inbuf, size_t inbuflen)
+{
+ unsigned char *ivp;
+ gcry_cipher_encrypt_t enc_fn = c->spec->encrypt;
+ size_t blocksize_shift = _gcry_blocksize_shift(c);
+ size_t blocksize = 1 << blocksize_shift;
+ size_t blocksize_x_2 = blocksize + blocksize;
+ unsigned int burn, nburn;
+
+ if (outbuflen < inbuflen)
+ return GPG_ERR_BUFFER_TOO_SHORT;
+
+ if (inbuflen <= c->unused)
+ {
+ /* Short enough to be encoded by the remaining XOR mask. */
+ /* XOR the input with the IV and store input into IV. */
+ ivp = c->u_iv.iv + blocksize - c->unused;
+ buf_xor_n_copy(outbuf, ivp, inbuf, inbuflen);
+ c->unused -= inbuflen;
+ return 0;
+ }
+
+ burn = 0;
+
+ if (c->unused)
+ {
+ /* XOR the input with the IV and store input into IV. */
+ inbuflen -= c->unused;
+ ivp = c->u_iv.iv + blocksize - c->unused;
+ buf_xor_n_copy(outbuf, ivp, inbuf, c->unused);
+ outbuf += c->unused;
+ inbuf += c->unused;
+ c->unused = 0;
+ }
+
+ /* Now we can process complete blocks. We use a loop as long as we
+ have at least 2 blocks and use conditions for the rest. This
+ also allows to use a bulk encryption function if available. */
+ if (inbuflen >= blocksize_x_2 && c->bulk.cfb_dec)
+ {
+ size_t nblocks = inbuflen >> blocksize_shift;
+ c->bulk.cfb_dec (&c->context.c, c->u_iv.iv, outbuf, inbuf, nblocks);
+ outbuf += nblocks << blocksize_shift;
+ inbuf += nblocks << blocksize_shift;
+ inbuflen -= nblocks << blocksize_shift;
+ }
+ else
+ {
+ while (inbuflen >= blocksize_x_2 )
+ {
+ /* Encrypt the IV. */
+ nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+ /* XOR the input with the IV and store input into IV. */
+ cipher_block_xor_n_copy(outbuf, c->u_iv.iv, inbuf, blocksize);
+ outbuf += blocksize;
+ inbuf += blocksize;
+ inbuflen -= blocksize;
+ }
+ }
+
+ if (inbuflen >= blocksize )
+ {
+ /* Save the current IV and then encrypt the IV. */
+ cipher_block_cpy ( c->lastiv, c->u_iv.iv, blocksize);
+ nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+ /* XOR the input with the IV and store input into IV */
+ cipher_block_xor_n_copy(outbuf, c->u_iv.iv, inbuf, blocksize);
+ outbuf += blocksize;
+ inbuf += blocksize;
+ inbuflen -= blocksize;
+ }
+
+ if (inbuflen)
+ {
+ /* Save the current IV and then encrypt the IV. */
+ cipher_block_cpy ( c->lastiv, c->u_iv.iv, blocksize );
+ nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+ c->unused = blocksize;
+ /* Apply the XOR. */
+ c->unused -= inbuflen;
+ buf_xor_n_copy(outbuf, c->u_iv.iv, inbuf, inbuflen);
+ outbuf += inbuflen;
+ inbuf += inbuflen;
+ inbuflen = 0;
+ }
+
+ if (burn > 0)
+ _gcry_burn_stack (burn + 4 * sizeof(void *));
+
+ return 0;
+}
+
+
+gcry_err_code_t
+_gcry_cipher_cfb8_encrypt (gcry_cipher_hd_t c,
+ unsigned char *outbuf, size_t outbuflen,
+ const unsigned char *inbuf, size_t inbuflen)
+{
+ gcry_cipher_encrypt_t enc_fn = c->spec->encrypt;
+ size_t blocksize = c->spec->blocksize;
+ unsigned int burn, nburn;
+
+ if (outbuflen < inbuflen)
+ return GPG_ERR_BUFFER_TOO_SHORT;
+
+ burn = 0;
+
+ while ( inbuflen > 0)
+ {
+ int i;
+
+ /* Encrypt the IV. */
+ nburn = enc_fn ( &c->context.c, c->lastiv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+
+ outbuf[0] = c->lastiv[0] ^ inbuf[0];
+
+ /* Bitshift iv by 8 bit to the left */
+ for (i = 0; i < blocksize-1; i++)
+ c->u_iv.iv[i] = c->u_iv.iv[i+1];
+
+ /* append cipher text to iv */
+ c->u_iv.iv[blocksize-1] = outbuf[0];
+
+ outbuf += 1;
+ inbuf += 1;
+ inbuflen -= 1;
+ }
+
+ if (burn > 0)
+ _gcry_burn_stack (burn + 4 * sizeof(void *));
+
+ return 0;
+}
+
+
+gcry_err_code_t
+_gcry_cipher_cfb8_decrypt (gcry_cipher_hd_t c,
+ unsigned char *outbuf, size_t outbuflen,
+ const unsigned char *inbuf, size_t inbuflen)
+{
+ gcry_cipher_encrypt_t enc_fn = c->spec->encrypt;
+ size_t blocksize = c->spec->blocksize;
+ unsigned int burn, nburn;
+ unsigned char appendee;
+
+ if (outbuflen < inbuflen)
+ return GPG_ERR_BUFFER_TOO_SHORT;
+
+ burn = 0;
+
+ while (inbuflen > 0)
+ {
+ int i;
+
+ /* Encrypt the IV. */
+ nburn = enc_fn ( &c->context.c, c->lastiv, c->u_iv.iv );
+ burn = nburn > burn ? nburn : burn;
+
+ /* inbuf might == outbuf, make sure we keep the value
+ so we can append it later */
+ appendee = inbuf[0];
+
+ outbuf[0] = inbuf[0] ^ c->lastiv[0];
+
+ /* Bitshift iv by 8 bit to the left */
+ for (i = 0; i < blocksize-1; i++)
+ c->u_iv.iv[i] = c->u_iv.iv[i+1];
+
+ c->u_iv.iv[blocksize-1] = appendee;
+
+ outbuf += 1;
+ inbuf += 1;
+ inbuflen -= 1;
+ }
+
+ if (burn > 0)
+ _gcry_burn_stack (burn + 4 * sizeof(void *));
+
+ return 0;
+}
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