--- /dev/null
+/*
+ * 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 <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_pcbc_ctx {
+ struct crypto_cipher *child;
+};
+
+static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,
+ unsigned int keylen)
+{
+ struct crypto_pcbc_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_pcbc_encrypt_segment(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ struct crypto_cipher *tfm)
+{
+ void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
+ crypto_cipher_alg(tfm)->cia_encrypt;
+ int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int nbytes = walk->nbytes;
+ u8 *src = walk->src.virt.addr;
+ u8 *dst = walk->dst.virt.addr;
+ u8 *iv = walk->iv;
+
+ do {
+ crypto_xor(iv, src, bsize);
+ fn(crypto_cipher_tfm(tfm), dst, iv);
+ memcpy(iv, dst, bsize);
+ crypto_xor(iv, src, bsize);
+
+ src += bsize;
+ dst += bsize;
+ } while ((nbytes -= bsize) >= bsize);
+
+ return nbytes;
+}
+
+static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ struct crypto_cipher *tfm)
+{
+ void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
+ crypto_cipher_alg(tfm)->cia_encrypt;
+ int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int nbytes = walk->nbytes;
+ u8 *src = walk->src.virt.addr;
+ u8 *iv = walk->iv;
+ u8 tmpbuf[bsize];
+
+ do {
+ memcpy(tmpbuf, src, bsize);
+ crypto_xor(iv, src, bsize);
+ fn(crypto_cipher_tfm(tfm), src, iv);
+ memcpy(iv, tmpbuf, bsize);
+ crypto_xor(iv, src, bsize);
+
+ src += bsize;
+ } while ((nbytes -= bsize) >= bsize);
+
+ memcpy(walk->iv, iv, bsize);
+
+ return nbytes;
+}
+
+static int crypto_pcbc_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_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ struct crypto_cipher *child = ctx->child;
+ int err;
+
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+ err = blkcipher_walk_virt(desc, &walk);
+
+ while ((nbytes = walk.nbytes)) {
+ if (walk.src.virt.addr == walk.dst.virt.addr)
+ nbytes = crypto_pcbc_encrypt_inplace(desc, &walk,
+ child);
+ else
+ nbytes = crypto_pcbc_encrypt_segment(desc, &walk,
+ child);
+ err = blkcipher_walk_done(desc, &walk, nbytes);
+ }
+
+ return err;
+}
+
+static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ struct crypto_cipher *tfm)
+{
+ void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
+ crypto_cipher_alg(tfm)->cia_decrypt;
+ int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int nbytes = walk->nbytes;
+ u8 *src = walk->src.virt.addr;
+ u8 *dst = walk->dst.virt.addr;
+ u8 *iv = walk->iv;
+
+ do {
+ fn(crypto_cipher_tfm(tfm), dst, src);
+ crypto_xor(dst, iv, bsize);
+ memcpy(iv, src, bsize);
+ crypto_xor(iv, dst, bsize);
+
+ src += bsize;
+ dst += bsize;
+ } while ((nbytes -= bsize) >= bsize);
+
+ memcpy(walk->iv, iv, bsize);
+
+ return nbytes;
+}
+
+static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ struct crypto_cipher *tfm)
+{
+ void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
+ crypto_cipher_alg(tfm)->cia_decrypt;
+ int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int nbytes = walk->nbytes;
+ u8 *src = walk->src.virt.addr;
+ u8 *iv = walk->iv;
+ u8 tmpbuf[bsize];
+
+ do {
+ memcpy(tmpbuf, src, bsize);
+ fn(crypto_cipher_tfm(tfm), src, src);
+ crypto_xor(src, iv, bsize);
+ memcpy(iv, tmpbuf, bsize);
+ crypto_xor(iv, src, bsize);
+
+ src += bsize;
+ } while ((nbytes -= bsize) >= bsize);
+
+ memcpy(walk->iv, iv, bsize);
+
+ return nbytes;
+}
+
+static int crypto_pcbc_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_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ struct crypto_cipher *child = ctx->child;
+ int err;
+
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+ err = blkcipher_walk_virt(desc, &walk);
+
+ while ((nbytes = walk.nbytes)) {
+ if (walk.src.virt.addr == walk.dst.virt.addr)
+ nbytes = crypto_pcbc_decrypt_inplace(desc, &walk,
+ child);
+ else
+ nbytes = crypto_pcbc_decrypt_segment(desc, &walk,
+ child);
+ err = blkcipher_walk_done(desc, &walk, nbytes);
+ }
+
+ return err;
+}
+
+static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+ struct crypto_pcbc_ctx *ctx = crypto_tfm_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_tfm *tfm)
+{
+ struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
+ crypto_free_cipher(ctx->child);
+}
+
+static struct crypto_instance *crypto_pcbc_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_CAST(alg);
+
+ inst = crypto_alloc_instance("pcbc", 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;
+
+ /* We access the data as u32s when xoring. */
+ inst->alg.cra_alignmask |= __alignof__(u32) - 1;
+
+ inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
+ 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_pcbc_ctx);
+
+ inst->alg.cra_init = crypto_pcbc_init_tfm;
+ inst->alg.cra_exit = crypto_pcbc_exit_tfm;
+
+ inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;
+ inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;
+ inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;
+
+out_put_alg:
+ crypto_mod_put(alg);
+ return inst;
+}
+
+static void crypto_pcbc_free(struct crypto_instance *inst)
+{
+ crypto_drop_spawn(crypto_instance_ctx(inst));
+ kfree(inst);
+}
+
+static struct crypto_template crypto_pcbc_tmpl = {
+ .name = "pcbc",
+ .alloc = crypto_pcbc_alloc,
+ .free = crypto_pcbc_free,
+ .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");
Code Review / kvmfornfv.git / blobdiff