1 files changed, 306 insertions, 0 deletions
diff --git a/crypto/pcbc.c b/crypto/pcbc.c
new file mode 100644
index 000000000..1b182dfed
--- /dev/null
+++ b/crypto/pcbc.c
@@ -0,0 +1,306 @@
+/*
+ * PCBC: Propagating Cipher Block Chaining mode
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * Derived from cbc.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 <crypto/internal/skcipher.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/compiler.h>
+
+struct crypto_pcbc_ctx {
+	struct crypto_cipher *child;
+};
+
+static int crypto_pcbc_setkey(struct crypto_skcipher *parent, const u8 *key,
+			      unsigned int keylen)
+{
+	struct crypto_pcbc_ctx *ctx = crypto_skcipher_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_skcipher_get_flags(parent) &
+				       CRYPTO_TFM_REQ_MASK);
+	err = crypto_cipher_setkey(child, key, keylen);
+	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
+					  CRYPTO_TFM_RES_MASK);
+	return err;
+}
+
+static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
+				       struct skcipher_walk *walk,
+				       struct crypto_cipher *tfm)
+{
+	int bsize = crypto_cipher_blocksize(tfm);
+	unsigned int nbytes = walk->nbytes;
+	u8 *src = walk->src.virt.addr;
+	u8 *dst = walk->dst.virt.addr;
+	u8 * const iv = walk->iv;
+
+	do {
+		crypto_xor(iv, src, bsize);
+		crypto_cipher_encrypt_one(tfm, dst, iv);
+		crypto_xor_cpy(iv, dst, src, bsize);
+
+		src += bsize;
+		dst += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	return nbytes;
+}
+
+static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
+				       struct skcipher_walk *walk,
+				       struct crypto_cipher *tfm)
+{
+	int bsize = crypto_cipher_blocksize(tfm);
+	unsigned int nbytes = walk->nbytes;
+	u8 *src = walk->src.virt.addr;
+	u8 * const iv = walk->iv;
+	u8 tmpbuf[MAX_CIPHER_BLOCKSIZE];
+
+	do {
+		memcpy(tmpbuf, src, bsize);
+		crypto_xor(iv, src, bsize);
+		crypto_cipher_encrypt_one(tfm, src, iv);
+		crypto_xor_cpy(iv, tmpbuf, src, bsize);
+
+		src += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	return nbytes;
+}
+
+static int crypto_pcbc_encrypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_cipher *child = ctx->child;
+	struct skcipher_walk walk;
+	unsigned int nbytes;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, false);
+
+	while ((nbytes = walk.nbytes)) {
+		if (walk.src.virt.addr == walk.dst.virt.addr)
+			nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
+							     child);
+		else
+			nbytes = crypto_pcbc_encrypt_segment(req, &walk,
+							     child);
+		err = skcipher_walk_done(&walk, nbytes);
+	}
+
+	return err;
+}
+
+static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
+				       struct skcipher_walk *walk,
+				       struct crypto_cipher *tfm)
+{
+	int bsize = crypto_cipher_blocksize(tfm);
+	unsigned int nbytes = walk->nbytes;
+	u8 *src = walk->src.virt.addr;
+	u8 *dst = walk->dst.virt.addr;
+	u8 * const iv = walk->iv;
+
+	do {
+		crypto_cipher_decrypt_one(tfm, dst, src);
+		crypto_xor(dst, iv, bsize);
+		crypto_xor_cpy(iv, dst, src, bsize);
+
+		src += bsize;
+		dst += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	return nbytes;
+}
+
+static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
+				       struct skcipher_walk *walk,
+				       struct crypto_cipher *tfm)
+{
+	int bsize = crypto_cipher_blocksize(tfm);
+	unsigned int nbytes = walk->nbytes;
+	u8 *src = walk->src.virt.addr;
+	u8 * const iv = walk->iv;
+	u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32));
+
+	do {
+		memcpy(tmpbuf, src, bsize);
+		crypto_cipher_decrypt_one(tfm, src, src);
+		crypto_xor(src, iv, bsize);
+		crypto_xor_cpy(iv, src, tmpbuf, bsize);
+
+		src += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	return nbytes;
+}
+
+static int crypto_pcbc_decrypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_cipher *child = ctx->child;
+	struct skcipher_walk walk;
+	unsigned int nbytes;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, false);
+
+	while ((nbytes = walk.nbytes)) {
+		if (walk.src.virt.addr == walk.dst.virt.addr)
+			nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
+							     child);
+		else
+			nbytes = crypto_pcbc_decrypt_segment(req, &walk,
+							     child);
+		err = skcipher_walk_done(&walk, nbytes);
+	}
+
+	return err;
+}
+
+static int crypto_pcbc_init_tfm(struct crypto_skcipher *tfm)
+{
+	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+	struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
+	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_cipher *cipher;
+
+	cipher = crypto_spawn_cipher(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+	return 0;
+}
+
+static void crypto_pcbc_exit_tfm(struct crypto_skcipher *tfm)
+{
+	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	crypto_free_cipher(ctx->child);
+}
+
+static void crypto_pcbc_free(struct skcipher_instance *inst)
+{
+	crypto_drop_skcipher(skcipher_instance_ctx(inst));
+	kfree(inst);
+}
+
+static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct skcipher_instance *inst;
+	struct crypto_attr_type *algt;
+	struct crypto_spawn *spawn;
+	struct crypto_alg *alg;
+	int err;
+
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return PTR_ERR(algt);
+
+	if (((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) &
+	    ~CRYPTO_ALG_INTERNAL)
+		return -EINVAL;
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER |
+				      (algt->type & CRYPTO_ALG_INTERNAL),
+				  CRYPTO_ALG_TYPE_MASK |
+				  (algt->mask & CRYPTO_ALG_INTERNAL));
+	err = PTR_ERR(alg);
+	if (IS_ERR(alg))
+		goto err_free_inst;
+
+	spawn = skcipher_instance_ctx(inst);
+	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
+				CRYPTO_ALG_TYPE_MASK);
+	if (err)
+		goto err_put_alg;
+
+	err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
+	if (err)
+		goto err_drop_spawn;
+
+	inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;
+	inst->alg.base.cra_priority = alg->cra_priority;
+	inst->alg.base.cra_blocksize = alg->cra_blocksize;
+	inst->alg.base.cra_alignmask = alg->cra_alignmask;
+
+	inst->alg.ivsize = alg->cra_blocksize;
+	inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
+	inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
+
+	inst->alg.init = crypto_pcbc_init_tfm;
+	inst->alg.exit = crypto_pcbc_exit_tfm;
+
+	inst->alg.setkey = crypto_pcbc_setkey;
+	inst->alg.encrypt = crypto_pcbc_encrypt;
+	inst->alg.decrypt = crypto_pcbc_decrypt;
+
+	inst->free = crypto_pcbc_free;
+
+	err = skcipher_register_instance(tmpl, inst);
+	if (err)
+		goto err_drop_spawn;
+	crypto_mod_put(alg);
+
+out:
+	return err;
+
+err_drop_spawn:
+	crypto_drop_spawn(spawn);
+err_put_alg:
+	crypto_mod_put(alg);
+err_free_inst:
+	kfree(inst);
+	goto out;
+}
+
+static struct crypto_template crypto_pcbc_tmpl = {
+	.name = "pcbc",
+	.create = crypto_pcbc_create,
+	.module = THIS_MODULE,
+};
+
+static int __init crypto_pcbc_module_init(void)
+{
+	return crypto_register_template(&crypto_pcbc_tmpl);
+}
+
+static void __exit crypto_pcbc_module_exit(void)
+{
+	crypto_unregister_template(&crypto_pcbc_tmpl);
+}
+
+module_init(crypto_pcbc_module_init);
+module_exit(crypto_pcbc_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("PCBC block cipher algorithm");
+MODULE_ALIAS_CRYPTO("pcbc");