1 files changed, 109 insertions, 131 deletions

diff --git a/crypto/cbc.c b/crypto/cbc.c
index b761b1f9c6ca..ed3df6246765 100644
--- a/crypto/cbc.c
+++ b/crypto/cbc.c
@@ -1,188 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * CBC: Cipher Block Chaining mode
  *
  * Copyright (c) 2006-2016 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/cbc.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/log2.h>
 #include <linux/module.h>
-#include <linux/slab.h>
 
-struct crypto_cbc_ctx {
-	struct crypto_cipher *child;
-};
-
-static int crypto_cbc_setkey(struct crypto_skcipher *parent, const u8 *key,
-			     unsigned int keylen)
+static int crypto_cbc_encrypt_segment(struct crypto_lskcipher *tfm,
+				      const u8 *src, u8 *dst, unsigned nbytes,
+				      u8 *iv)
 {
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(parent);
-	struct crypto_cipher *child = ctx->child;
-	int err;
+	unsigned int bsize = crypto_lskcipher_blocksize(tfm);
 
-	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;
+	for (; nbytes >= bsize; src += bsize, dst += bsize, nbytes -= bsize) {
+		crypto_xor(iv, src, bsize);
+		crypto_lskcipher_encrypt(tfm, iv, dst, bsize, NULL);
+		memcpy(iv, dst, bsize);
+	}
+
+	return nbytes;
 }
 
-static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
-					  const u8 *src, u8 *dst)
+static int crypto_cbc_encrypt_inplace(struct crypto_lskcipher *tfm,
+				      u8 *src, unsigned nbytes, u8 *oiv)
 {
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	unsigned int bsize = crypto_lskcipher_blocksize(tfm);
+	u8 *iv = oiv;
 
-	crypto_cipher_encrypt_one(ctx->child, dst, src);
-}
+	if (nbytes < bsize)
+		goto out;
 
-static int crypto_cbc_encrypt(struct skcipher_request *req)
-{
-	return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
+	do {
+		crypto_xor(src, iv, bsize);
+		crypto_lskcipher_encrypt(tfm, src, src, bsize, NULL);
+		iv = src;
+
+		src += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	memcpy(oiv, iv, bsize);
+
+out:
+	return nbytes;
 }
 
-static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
-					  const u8 *src, u8 *dst)
+static int crypto_cbc_encrypt(struct crypto_lskcipher *tfm, const u8 *src,
+			      u8 *dst, unsigned len, u8 *iv, u32 flags)
 {
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_lskcipher **ctx = crypto_lskcipher_ctx(tfm);
+	bool final = flags & CRYPTO_LSKCIPHER_FLAG_FINAL;
+	struct crypto_lskcipher *cipher = *ctx;
+	int rem;
+
+	if (src == dst)
+		rem = crypto_cbc_encrypt_inplace(cipher, dst, len, iv);
+	else
+		rem = crypto_cbc_encrypt_segment(cipher, src, dst, len, iv);
 
-	crypto_cipher_decrypt_one(ctx->child, dst, src);
+	return rem && final ? -EINVAL : rem;
 }
 
-static int crypto_cbc_decrypt(struct skcipher_request *req)
+static int crypto_cbc_decrypt_segment(struct crypto_lskcipher *tfm,
+				      const u8 *src, u8 *dst, unsigned nbytes,
+				      u8 *oiv)
 {
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct skcipher_walk walk;
-	int err;
+	unsigned int bsize = crypto_lskcipher_blocksize(tfm);
+	const u8 *iv = oiv;
 
-	err = skcipher_walk_virt(&walk, req, false);
+	if (nbytes < bsize)
+		goto out;
 
-	while (walk.nbytes) {
-		err = crypto_cbc_decrypt_blocks(&walk, tfm,
-						crypto_cbc_decrypt_one);
-		err = skcipher_walk_done(&walk, err);
-	}
+	do {
+		crypto_lskcipher_decrypt(tfm, src, dst, bsize, NULL);
+		crypto_xor(dst, iv, bsize);
+		iv = src;
 
-	return err;
+		src += bsize;
+		dst += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	memcpy(oiv, iv, bsize);
+
+out:
+	return nbytes;
 }
 
-static int crypto_cbc_init_tfm(struct crypto_skcipher *tfm)
+static int crypto_cbc_decrypt_inplace(struct crypto_lskcipher *tfm,
+				      u8 *src, unsigned nbytes, u8 *iv)
 {
-	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
-	struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct crypto_cipher *cipher;
+	unsigned int bsize = crypto_lskcipher_blocksize(tfm);
+	u8 last_iv[MAX_CIPHER_BLOCKSIZE];
+
+	if (nbytes < bsize)
+		goto out;
+
+	/* Start of the last block. */
+	src += nbytes - (nbytes & (bsize - 1)) - bsize;
+	memcpy(last_iv, src, bsize);
+
+	for (;;) {
+		crypto_lskcipher_decrypt(tfm, src, src, bsize, NULL);
+		if ((nbytes -= bsize) < bsize)
+			break;
+		crypto_xor(src, src - bsize, bsize);
+		src -= bsize;
+	}
 
-	cipher = crypto_spawn_cipher(spawn);
-	if (IS_ERR(cipher))
-		return PTR_ERR(cipher);
+	crypto_xor(src, iv, bsize);
+	memcpy(iv, last_iv, bsize);
 
-	ctx->child = cipher;
-	return 0;
+out:
+	return nbytes;
 }
 
-static void crypto_cbc_exit_tfm(struct crypto_skcipher *tfm)
+static int crypto_cbc_decrypt(struct crypto_lskcipher *tfm, const u8 *src,
+			      u8 *dst, unsigned len, u8 *iv, u32 flags)
 {
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_lskcipher **ctx = crypto_lskcipher_ctx(tfm);
+	bool final = flags & CRYPTO_LSKCIPHER_FLAG_FINAL;
+	struct crypto_lskcipher *cipher = *ctx;
+	int rem;
 
-	crypto_free_cipher(ctx->child);
-}
+	if (src == dst)
+		rem = crypto_cbc_decrypt_inplace(cipher, dst, len, iv);
+	else
+		rem = crypto_cbc_decrypt_segment(cipher, src, dst, len, iv);
 
-static void crypto_cbc_free(struct skcipher_instance *inst)
-{
-	crypto_drop_skcipher(skcipher_instance_ctx(inst));
-	kfree(inst);
+	return rem && final ? -EINVAL : rem;
 }
 
 static int crypto_cbc_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;
-	u32 mask;
+	struct lskcipher_instance *inst;
 	int err;
 
-	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
-	if (err)
-		return err;
-
-	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
-	if (!inst)
-		return -ENOMEM;
-
-	algt = crypto_get_attr_type(tb);
-	err = PTR_ERR(algt);
-	if (IS_ERR(algt))
-		goto err_free_inst;
-
-	mask = CRYPTO_ALG_TYPE_MASK |
-		crypto_requires_off(algt->type, algt->mask,
-				    CRYPTO_ALG_NEED_FALLBACK);
-
-	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
-	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);
-	crypto_mod_put(alg);
-	if (err)
-		goto err_free_inst;
-
-	err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
-	if (err)
-		goto err_drop_spawn;
+	inst = lskcipher_alloc_instance_simple(tmpl, tb);
+	if (IS_ERR(inst))
+		return PTR_ERR(inst);
 
 	err = -EINVAL;
-	if (!is_power_of_2(alg->cra_blocksize))
-		goto err_drop_spawn;
-
-	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_cbc_ctx);
+	if (!is_power_of_2(inst->alg.co.base.cra_blocksize))
+		goto out_free_inst;
 
-	inst->alg.init = crypto_cbc_init_tfm;
-	inst->alg.exit = crypto_cbc_exit_tfm;
+	if (inst->alg.co.statesize)
+		goto out_free_inst;
 
-	inst->alg.setkey = crypto_cbc_setkey;
 	inst->alg.encrypt = crypto_cbc_encrypt;
 	inst->alg.decrypt = crypto_cbc_decrypt;
 
-	inst->free = crypto_cbc_free;
-
-	err = skcipher_register_instance(tmpl, inst);
-	if (err)
-		goto err_drop_spawn;
+	err = lskcipher_register_instance(tmpl, inst);
+	if (err) {
+out_free_inst:
+		inst->free(inst);
+	}
 
-out:
 	return err;
-
-err_drop_spawn:
-	crypto_drop_spawn(spawn);
-err_free_inst:
-	kfree(inst);
-	goto out;
 }
 
 static struct crypto_template crypto_cbc_tmpl = {
@@ -205,5 +183,5 @@ module_init(crypto_cbc_module_init);
 module_exit(crypto_cbc_module_exit);
 
 MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("CBC block cipher algorithm");
+MODULE_DESCRIPTION("CBC block cipher mode of operation");
 MODULE_ALIAS_CRYPTO("cbc");