[CRYPTO] cipher: Added block ciphers for CBC/ECB
This patch adds two block cipher algorithms, CBC and ECB. These
are implemented as templates on top of existing single-block cipher
algorithms. They invoke the single-block cipher through the new
encrypt_one/decrypt_one interface.
This also optimises the in-place encryption and decryption to remove
the cost of an IV copy each round.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/ecb.c b/crypto/ecb.c
new file mode 100644
index 0000000..f239aa9
--- /dev/null
+++ b/crypto/ecb.c
@@ -0,0 +1,181 @@
+/*
+ * ECB: Electronic CodeBook mode
+ *
+ * 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>
+
+struct crypto_ecb_ctx {
+ struct crypto_cipher *child;
+};
+
+static int crypto_ecb_setkey(struct crypto_tfm *parent, const u8 *key,
+ unsigned int keylen)
+{
+ struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(parent);
+ struct crypto_cipher *child = ctx->child;
+ int err;
+
+ 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);
+ crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
+ CRYPTO_TFM_RES_MASK);
+ return err;
+}
+
+static int crypto_ecb_crypt(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ struct crypto_cipher *tfm,
+ void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
+{
+ int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int nbytes;
+ int err;
+
+ err = blkcipher_walk_virt(desc, walk);
+
+ while ((nbytes = walk->nbytes)) {
+ u8 *wsrc = walk->src.virt.addr;
+ u8 *wdst = walk->dst.virt.addr;
+
+ do {
+ fn(crypto_cipher_tfm(tfm), wdst, wsrc);
+
+ wsrc += bsize;
+ wdst += bsize;
+ } while ((nbytes -= bsize) >= bsize);
+
+ err = blkcipher_walk_done(desc, walk, nbytes);
+ }
+
+ return err;
+}
+
+static int crypto_ecb_encrypt(struct blkcipher_desc *desc,
+ struct scatterlist *dst, struct scatterlist *src,
+ unsigned int nbytes)
+{
+ struct blkcipher_walk walk;
+ struct crypto_blkcipher *tfm = desc->tfm;
+ struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ struct crypto_cipher *child = ctx->child;
+
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+ return crypto_ecb_crypt(desc, &walk, child,
+ crypto_cipher_alg(child)->cia_encrypt);
+}
+
+static int crypto_ecb_decrypt(struct blkcipher_desc *desc,
+ struct scatterlist *dst, struct scatterlist *src,
+ unsigned int nbytes)
+{
+ struct blkcipher_walk walk;
+ struct crypto_blkcipher *tfm = desc->tfm;
+ struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ struct crypto_cipher *child = ctx->child;
+
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+ return crypto_ecb_crypt(desc, &walk, child,
+ crypto_cipher_alg(child)->cia_decrypt);
+}
+
+static int crypto_ecb_init_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+ struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ tfm = crypto_spawn_tfm(spawn);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ ctx->child = crypto_cipher_cast(tfm);
+ return 0;
+}
+
+static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
+ crypto_free_cipher(ctx->child);
+}
+
+static struct crypto_instance *crypto_ecb_alloc(void *param, unsigned int len)
+{
+ struct crypto_instance *inst;
+ struct crypto_alg *alg;
+
+ alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
+ CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
+ if (IS_ERR(alg))
+ return ERR_PTR(PTR_ERR(alg));
+
+ inst = crypto_alloc_instance("ecb", 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;
+ inst->alg.cra_alignmask = alg->cra_alignmask;
+ inst->alg.cra_type = &crypto_blkcipher_type;
+
+ inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
+ inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
+
+ inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);
+
+ inst->alg.cra_init = crypto_ecb_init_tfm;
+ inst->alg.cra_exit = crypto_ecb_exit_tfm;
+
+ inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;
+ inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;
+ inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;
+
+out_put_alg:
+ crypto_mod_put(alg);
+ return inst;
+}
+
+static void crypto_ecb_free(struct crypto_instance *inst)
+{
+ crypto_drop_spawn(crypto_instance_ctx(inst));
+ kfree(inst);
+}
+
+static struct crypto_template crypto_ecb_tmpl = {
+ .name = "ecb",
+ .alloc = crypto_ecb_alloc,
+ .free = crypto_ecb_free,
+ .module = THIS_MODULE,
+};
+
+static int __init crypto_ecb_module_init(void)
+{
+ return crypto_register_template(&crypto_ecb_tmpl);
+}
+
+static void __exit crypto_ecb_module_exit(void)
+{
+ crypto_unregister_template(&crypto_ecb_tmpl);
+}
+
+module_init(crypto_ecb_module_init);
+module_exit(crypto_ecb_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ECB block cipher algorithm");