/* * 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 *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 *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); memcpy(walk->iv, iv, 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 *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); memcpy(walk->iv, iv, 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 *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); memcpy(walk->iv, iv, 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");