2.6.24-rc8

 crypto

diff --git a/crypto/xts.c b/crypto/xts.c
new file mode 100644
index 0000000..8eb08bf
--- /dev/null
+++ b/crypto/xts.c
@@ -0,0 +1,292 @@
+/* XTS: as defined in IEEE1619/D16
+ *   http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
+ *   (sector sizes which are not a multiple of 16 bytes are,
+ *   however currently unsupported)
+ *
+ * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
+ *
+ * Based om ecb.c
+ * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * 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.
+ */
+#include <crypto/algapi.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+#include <crypto/b128ops.h>
+#include <crypto/gf128mul.h>
+
+struct priv {
+   struct crypto_cipher *child;
+   struct crypto_cipher *tweak;
+};
+
+static int setkey(struct crypto_tfm *parent, const u8 *key,
+        unsigned int keylen)
+{
+   struct priv *ctx = crypto_tfm_ctx(parent);
+   struct crypto_cipher *child = ctx->tweak;
+   u32 *flags = &parent->crt_flags;
+   int err;
+
+   /* key consists of keys of equal size concatenated, therefore
+    * the length must be even */
+   if (keylen % 2) {
+      /* tell the user why there was an error */
+      *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+      return -EINVAL;
+   }
+
+   /* we need two cipher instances: one to compute the inital 'tweak'
+    * by encrypting the IV (usually the 'plain' iv) and the other
+    * one to encrypt and decrypt the data */
+
+   /* tweak cipher, uses Key2 i.e. the second half of *key */
+   crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+   crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
+                   CRYPTO_TFM_REQ_MASK);
+   err = crypto_cipher_setkey(child, key + keylen/2, keylen/2);
+   if (err)
+      return err;
+
+   crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
+                 CRYPTO_TFM_RES_MASK);
+
+   child = ctx->child;
+
+   /* data cipher, uses Key1 i.e. the first half of *key */
+   crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+   crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
+                   CRYPTO_TFM_REQ_MASK);
+   err = crypto_cipher_setkey(child, key, keylen/2);
+   if (err)
+      return err;
+
+   crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
+                 CRYPTO_TFM_RES_MASK);
+
+   return 0;
+}
+
+struct sinfo {
+   be128 t;
+   struct crypto_tfm *tfm;
+   void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
+};
+
+static inline void xts_round(struct sinfo *s, void *dst, const void *src)
+{
+   be128_xor(dst, &s->t, src);      /* PP <- T xor P */
+   s->fn(s->tfm, dst, dst);      /* CC <- E(Key1,PP) */
+   be128_xor(dst, dst, &s->t);      /* C <- T xor CC */
+}
+
+static int crypt(struct blkcipher_desc *d,
+       struct blkcipher_walk *w, struct priv *ctx,
+       void (*tw)(struct crypto_tfm *, u8 *, const u8 *),
+       void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
+{
+   int err;
+   unsigned int avail;
+   const int bs = crypto_cipher_blocksize(ctx->child);
+   struct sinfo s = {
+      .tfm = crypto_cipher_tfm(ctx->child),
+      .fn = fn
+   };
+   be128 *iv;
+   u8 *wsrc;
+   u8 *wdst;
+
+   err = blkcipher_walk_virt(d, w);
+   if (!w->nbytes)
+      return err;
+
+   avail = w->nbytes;
+
+   wsrc = w->src.virt.addr;
+   wdst = w->dst.virt.addr;
+
+   /* calculate first value of T */
+   iv = (be128 *)w->iv;
+   tw(crypto_cipher_tfm(ctx->tweak), (void *)&s.t, w->iv);
+
+   goto first;
+
+   for (;;) {
+      do {
+         gf128mul_x_ble(&s.t, &s.t);
+
+first:
+         xts_round(&s, wdst, wsrc);
+
+         wsrc += bs;
+         wdst += bs;
+      } while ((avail -= bs) >= bs);
+
+      err = blkcipher_walk_done(d, w, avail);
+      if (!w->nbytes)
+         break;
+
+      avail = w->nbytes;
+
+      wsrc = w->src.virt.addr;
+      wdst = w->dst.virt.addr;
+   }
+
+   return err;
+}
+
+static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+         struct scatterlist *src, unsigned int nbytes)
+{
+   struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
+   struct blkcipher_walk w;
+
+   blkcipher_walk_init(&w, dst, src, nbytes);
+   return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt,
+           crypto_cipher_alg(ctx->child)->cia_encrypt);
+}
+
+static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+         struct scatterlist *src, unsigned int nbytes)
+{
+   struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
+   struct blkcipher_walk w;
+
+   blkcipher_walk_init(&w, dst, src, nbytes);
+   return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt,
+           crypto_cipher_alg(ctx->child)->cia_decrypt);
+}
+
+static int init_tfm(struct crypto_tfm *tfm)
+{
+   struct crypto_cipher *cipher;
+   struct crypto_instance *inst = (void *)tfm->__crt_alg;
+   struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+   struct priv *ctx = crypto_tfm_ctx(tfm);
+   u32 *flags = &tfm->crt_flags;
+
+   cipher = crypto_spawn_cipher(spawn);
+   if (IS_ERR(cipher))
+      return PTR_ERR(cipher);
+
+   if (crypto_cipher_blocksize(cipher) != 16) {
+      *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
+      crypto_free_cipher(cipher);
+      return -EINVAL;
+   }
+
+   ctx->child = cipher;
+
+   cipher = crypto_spawn_cipher(spawn);
+   if (IS_ERR(cipher)) {
+      crypto_free_cipher(ctx->child);
+      return PTR_ERR(cipher);
+   }
+
+   /* this check isn't really needed, leave it here just in case */
+   if (crypto_cipher_blocksize(cipher) != 16) {
+      crypto_free_cipher(cipher);
+      crypto_free_cipher(ctx->child);
+      *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
+      return -EINVAL;
+   }
+
+   ctx->tweak = cipher;
+
+   return 0;
+}
+
+static void exit_tfm(struct crypto_tfm *tfm)
+{
+   struct priv *ctx = crypto_tfm_ctx(tfm);
+   crypto_free_cipher(ctx->child);
+   crypto_free_cipher(ctx->tweak);
+}
+
+static struct crypto_instance *alloc(struct rtattr **tb)
+{
+   struct crypto_instance *inst;
+   struct crypto_alg *alg;
+   int err;
+
+   err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
+   if (err)
+      return ERR_PTR(err);
+
+   alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
+              CRYPTO_ALG_TYPE_MASK);
+   if (IS_ERR(alg))
+      return ERR_PTR(PTR_ERR(alg));
+
+   inst = crypto_alloc_instance("xts", alg);
+   if (IS_ERR(inst))
+      goto out_put_alg;
+
+   inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
+   inst->alg.cra_priority = alg->cra_priority;
+   inst->alg.cra_blocksize = alg->cra_blocksize;
+
+   if (alg->cra_alignmask < 7)
+      inst->alg.cra_alignmask = 7;
+   else
+      inst->alg.cra_alignmask = alg->cra_alignmask;
+
+   inst->alg.cra_type = &crypto_blkcipher_type;
+
+   inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
+   inst->alg.cra_blkcipher.min_keysize =
+      2 * alg->cra_cipher.cia_min_keysize;
+   inst->alg.cra_blkcipher.max_keysize =
+      2 * alg->cra_cipher.cia_max_keysize;
+
+   inst->alg.cra_ctxsize = sizeof(struct priv);
+
+   inst->alg.cra_init = init_tfm;
+   inst->alg.cra_exit = exit_tfm;
+
+   inst->alg.cra_blkcipher.setkey = setkey;
+   inst->alg.cra_blkcipher.encrypt = encrypt;
+   inst->alg.cra_blkcipher.decrypt = decrypt;
+
+out_put_alg:
+   crypto_mod_put(alg);
+   return inst;
+}
+
+static void free(struct crypto_instance *inst)
+{
+   crypto_drop_spawn(crypto_instance_ctx(inst));
+   kfree(inst);
+}
+
+static struct crypto_template crypto_tmpl = {
+   .name = "xts",
+   .alloc = alloc,
+   .free = free,
+   .module = THIS_MODULE,
+};
+
+static int __init crypto_module_init(void)
+{
+   return crypto_register_template(&crypto_tmpl);
+}
+
+static void __exit crypto_module_exit(void)
+{
+   crypto_unregister_template(&crypto_tmpl);
+}
+
+module_init(crypto_module_init);
+module_exit(crypto_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("XTS block cipher mode");