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-rw-r--r--crypto/pcbc.c195
1 files changed, 195 insertions, 0 deletions
diff --git a/crypto/pcbc.c b/crypto/pcbc.c
new file mode 100644
index 000000000..7030f59e4
--- /dev/null
+++ b/crypto/pcbc.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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>
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/internal/cipher.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+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_cipher *cipher = skcipher_cipher_simple(tfm);
+ 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,
+ cipher);
+ else
+ nbytes = crypto_pcbc_encrypt_segment(req, &walk,
+ cipher);
+ 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_cipher *cipher = skcipher_cipher_simple(tfm);
+ 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,
+ cipher);
+ else
+ nbytes = crypto_pcbc_decrypt_segment(req, &walk,
+ cipher);
+ err = skcipher_walk_done(&walk, nbytes);
+ }
+
+ return err;
+}
+
+static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+ struct skcipher_instance *inst;
+ int err;
+
+ inst = skcipher_alloc_instance_simple(tmpl, tb);
+ if (IS_ERR(inst))
+ return PTR_ERR(inst);
+
+ inst->alg.encrypt = crypto_pcbc_encrypt;
+ inst->alg.decrypt = crypto_pcbc_decrypt;
+
+ err = skcipher_register_instance(tmpl, inst);
+ if (err)
+ inst->free(inst);
+
+ return err;
+}
+
+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);
+}
+
+subsys_initcall(crypto_pcbc_module_init);
+module_exit(crypto_pcbc_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("PCBC block cipher mode of operation");
+MODULE_ALIAS_CRYPTO("pcbc");
+MODULE_IMPORT_NS(CRYPTO_INTERNAL);