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authorJoachim Fritschi <jfritschi@freenet.de>2010-06-03 21:02:51 +1000
committerHerbert Xu <herbert@gondor.apana.org.au>2010-06-03 21:02:51 +1000
commit5b04fc170382195d7d33fd08e3ccc2ad8e50e782 (patch)
tree47530362afd11dd2637ad5c00e70472fe09e4284 /crypto/twofish_generic.c
parent0b767f96164b2b27488e3daa722ff16e89d49314 (diff)
downloadlinux-linaro-android-5b04fc170382195d7d33fd08e3ccc2ad8e50e782.tar.gz
crypto: twofish: Rename twofish to twofish_generic and add an alias
This fixes the broken autoloading of the corresponding twofish assembler ciphers on x86 and x86_64 if they are available. The module name of the generic implementation was in conflict with the alias in the assembler modules. The generic twofish c implementation is renamed to twofish_generic according to the other algorithms with assembler implementations and an module alias is added for 'twofish'. You can now load 'twofish' giving you the best implementation by priority, 'twofish-generic' to get the c implementation or 'twofish-asm' to get the assembler version of cipher. Signed-off-by: Joachim Fritschi <jfritschi@freenet.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/twofish_generic.c')
-rw-r--r--crypto/twofish_generic.c215
1 files changed, 215 insertions, 0 deletions
diff --git a/crypto/twofish_generic.c b/crypto/twofish_generic.c
new file mode 100644
index 00000000000..1f07b843e07
--- /dev/null
+++ b/crypto/twofish_generic.c
@@ -0,0 +1,215 @@
+/*
+ * Twofish for CryptoAPI
+ *
+ * Originally Twofish for GPG
+ * By Matthew Skala <mskala@ansuz.sooke.bc.ca>, July 26, 1998
+ * 256-bit key length added March 20, 1999
+ * Some modifications to reduce the text size by Werner Koch, April, 1998
+ * Ported to the kerneli patch by Marc Mutz <Marc@Mutz.com>
+ * Ported to CryptoAPI by Colin Slater <hoho@tacomeat.net>
+ *
+ * The original author has disclaimed all copyright interest in this
+ * code and thus put it in the public domain. The subsequent authors
+ * have put this under the GNU General Public License.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the 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 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 Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ *
+ * This code is a "clean room" implementation, written from the paper
+ * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
+ * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
+ * through http://www.counterpane.com/twofish.html
+ *
+ * For background information on multiplication in finite fields, used for
+ * the matrix operations in the key schedule, see the book _Contemporary
+ * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
+ * Third Edition.
+ */
+
+#include <asm/byteorder.h>
+#include <crypto/twofish.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/crypto.h>
+#include <linux/bitops.h>
+
+/* Macros to compute the g() function in the encryption and decryption
+ * rounds. G1 is the straight g() function; G2 includes the 8-bit
+ * rotation for the high 32-bit word. */
+
+#define G1(a) \
+ (ctx->s[0][(a) & 0xFF]) ^ (ctx->s[1][((a) >> 8) & 0xFF]) \
+ ^ (ctx->s[2][((a) >> 16) & 0xFF]) ^ (ctx->s[3][(a) >> 24])
+
+#define G2(b) \
+ (ctx->s[1][(b) & 0xFF]) ^ (ctx->s[2][((b) >> 8) & 0xFF]) \
+ ^ (ctx->s[3][((b) >> 16) & 0xFF]) ^ (ctx->s[0][(b) >> 24])
+
+/* Encryption and decryption Feistel rounds. Each one calls the two g()
+ * macros, does the PHT, and performs the XOR and the appropriate bit
+ * rotations. The parameters are the round number (used to select subkeys),
+ * and the four 32-bit chunks of the text. */
+
+#define ENCROUND(n, a, b, c, d) \
+ x = G1 (a); y = G2 (b); \
+ x += y; y += x + ctx->k[2 * (n) + 1]; \
+ (c) ^= x + ctx->k[2 * (n)]; \
+ (c) = ror32((c), 1); \
+ (d) = rol32((d), 1) ^ y
+
+#define DECROUND(n, a, b, c, d) \
+ x = G1 (a); y = G2 (b); \
+ x += y; y += x; \
+ (d) ^= y + ctx->k[2 * (n) + 1]; \
+ (d) = ror32((d), 1); \
+ (c) = rol32((c), 1); \
+ (c) ^= (x + ctx->k[2 * (n)])
+
+/* Encryption and decryption cycles; each one is simply two Feistel rounds
+ * with the 32-bit chunks re-ordered to simulate the "swap" */
+
+#define ENCCYCLE(n) \
+ ENCROUND (2 * (n), a, b, c, d); \
+ ENCROUND (2 * (n) + 1, c, d, a, b)
+
+#define DECCYCLE(n) \
+ DECROUND (2 * (n) + 1, c, d, a, b); \
+ DECROUND (2 * (n), a, b, c, d)
+
+/* Macros to convert the input and output bytes into 32-bit words,
+ * and simultaneously perform the whitening step. INPACK packs word
+ * number n into the variable named by x, using whitening subkey number m.
+ * OUTUNPACK unpacks word number n from the variable named by x, using
+ * whitening subkey number m. */
+
+#define INPACK(n, x, m) \
+ x = le32_to_cpu(src[n]) ^ ctx->w[m]
+
+#define OUTUNPACK(n, x, m) \
+ x ^= ctx->w[m]; \
+ dst[n] = cpu_to_le32(x)
+
+
+
+/* Encrypt one block. in and out may be the same. */
+static void twofish_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
+ const __le32 *src = (const __le32 *)in;
+ __le32 *dst = (__le32 *)out;
+
+ /* The four 32-bit chunks of the text. */
+ u32 a, b, c, d;
+
+ /* Temporaries used by the round function. */
+ u32 x, y;
+
+ /* Input whitening and packing. */
+ INPACK (0, a, 0);
+ INPACK (1, b, 1);
+ INPACK (2, c, 2);
+ INPACK (3, d, 3);
+
+ /* Encryption Feistel cycles. */
+ ENCCYCLE (0);
+ ENCCYCLE (1);
+ ENCCYCLE (2);
+ ENCCYCLE (3);
+ ENCCYCLE (4);
+ ENCCYCLE (5);
+ ENCCYCLE (6);
+ ENCCYCLE (7);
+
+ /* Output whitening and unpacking. */
+ OUTUNPACK (0, c, 4);
+ OUTUNPACK (1, d, 5);
+ OUTUNPACK (2, a, 6);
+ OUTUNPACK (3, b, 7);
+
+}
+
+/* Decrypt one block. in and out may be the same. */
+static void twofish_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
+ const __le32 *src = (const __le32 *)in;
+ __le32 *dst = (__le32 *)out;
+
+ /* The four 32-bit chunks of the text. */
+ u32 a, b, c, d;
+
+ /* Temporaries used by the round function. */
+ u32 x, y;
+
+ /* Input whitening and packing. */
+ INPACK (0, c, 4);
+ INPACK (1, d, 5);
+ INPACK (2, a, 6);
+ INPACK (3, b, 7);
+
+ /* Encryption Feistel cycles. */
+ DECCYCLE (7);
+ DECCYCLE (6);
+ DECCYCLE (5);
+ DECCYCLE (4);
+ DECCYCLE (3);
+ DECCYCLE (2);
+ DECCYCLE (1);
+ DECCYCLE (0);
+
+ /* Output whitening and unpacking. */
+ OUTUNPACK (0, a, 0);
+ OUTUNPACK (1, b, 1);
+ OUTUNPACK (2, c, 2);
+ OUTUNPACK (3, d, 3);
+
+}
+
+static struct crypto_alg alg = {
+ .cra_name = "twofish",
+ .cra_driver_name = "twofish-generic",
+ .cra_priority = 100,
+ .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
+ .cra_blocksize = TF_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct twofish_ctx),
+ .cra_alignmask = 3,
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_u = { .cipher = {
+ .cia_min_keysize = TF_MIN_KEY_SIZE,
+ .cia_max_keysize = TF_MAX_KEY_SIZE,
+ .cia_setkey = twofish_setkey,
+ .cia_encrypt = twofish_encrypt,
+ .cia_decrypt = twofish_decrypt } }
+};
+
+static int __init twofish_mod_init(void)
+{
+ return crypto_register_alg(&alg);
+}
+
+static void __exit twofish_mod_fini(void)
+{
+ crypto_unregister_alg(&alg);
+}
+
+module_init(twofish_mod_init);
+module_exit(twofish_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION ("Twofish Cipher Algorithm");
+MODULE_ALIAS("twofish");