1 files changed, 422 insertions, 0 deletions
diff --git a/crypto/ctr.c b/crypto/ctr.c
new file mode 100644
index 00000000000..2d7425f0e7b
--- /dev/null
+++ b/crypto/ctr.c
@@ -0,0 +1,422 @@
+/*
+ * CTR: Counter mode
+ *
+ * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
+ *
+ * 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/ctr.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+struct crypto_ctr_ctx {
+	struct crypto_cipher *child;
+};
+
+struct crypto_rfc3686_ctx {
+	struct crypto_blkcipher *child;
+	u8 nonce[CTR_RFC3686_NONCE_SIZE];
+};
+
+static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
+			     unsigned int keylen)
+{
+	struct crypto_ctr_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 void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
+				   struct crypto_cipher *tfm)
+{
+	unsigned int bsize = crypto_cipher_blocksize(tfm);
+	unsigned long alignmask = crypto_cipher_alignmask(tfm);
+	u8 *ctrblk = walk->iv;
+	u8 tmp[bsize + alignmask];
+	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
+	u8 *src = walk->src.virt.addr;
+	u8 *dst = walk->dst.virt.addr;
+	unsigned int nbytes = walk->nbytes;
+
+	crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
+	crypto_xor(keystream, src, nbytes);
+	memcpy(dst, keystream, nbytes);
+
+	crypto_inc(ctrblk, bsize);
+}
+
+static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
+				    struct crypto_cipher *tfm)
+{
+	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
+		   crypto_cipher_alg(tfm)->cia_encrypt;
+	unsigned int bsize = crypto_cipher_blocksize(tfm);
+	u8 *ctrblk = walk->iv;
+	u8 *src = walk->src.virt.addr;
+	u8 *dst = walk->dst.virt.addr;
+	unsigned int nbytes = walk->nbytes;
+
+	do {
+		/* create keystream */
+		fn(crypto_cipher_tfm(tfm), dst, ctrblk);
+		crypto_xor(dst, src, bsize);
+
+		/* increment counter in counterblock */
+		crypto_inc(ctrblk, bsize);
+
+		src += bsize;
+		dst += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	return nbytes;
+}
+
+static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
+				    struct crypto_cipher *tfm)
+{
+	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
+		   crypto_cipher_alg(tfm)->cia_encrypt;
+	unsigned int bsize = crypto_cipher_blocksize(tfm);
+	unsigned long alignmask = crypto_cipher_alignmask(tfm);
+	unsigned int nbytes = walk->nbytes;
+	u8 *ctrblk = walk->iv;
+	u8 *src = walk->src.virt.addr;
+	u8 tmp[bsize + alignmask];
+	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
+
+	do {
+		/* create keystream */
+		fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
+		crypto_xor(src, keystream, bsize);
+
+		/* increment counter in counterblock */
+		crypto_inc(ctrblk, bsize);
+
+		src += bsize;
+	} while ((nbytes -= bsize) >= bsize);
+
+	return nbytes;
+}
+
+static int crypto_ctr_crypt(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_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
+	struct crypto_cipher *child = ctx->child;
+	unsigned int bsize = crypto_cipher_blocksize(child);
+	int err;
+
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt_block(desc, &walk, bsize);
+
+	while (walk.nbytes >= bsize) {
+		if (walk.src.virt.addr == walk.dst.virt.addr)
+			nbytes = crypto_ctr_crypt_inplace(&walk, child);
+		else
+			nbytes = crypto_ctr_crypt_segment(&walk, child);
+
+		err = blkcipher_walk_done(desc, &walk, nbytes);
+	}
+
+	if (walk.nbytes) {
+		crypto_ctr_crypt_final(&walk, child);
+		err = blkcipher_walk_done(desc, &walk, 0);
+	}
+
+	return err;
+}
+
+static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = (void *)tfm->__crt_alg;
+	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+	struct crypto_ctr_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_ctr_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	crypto_free_cipher(ctx->child);
+}
+
+static struct crypto_instance *crypto_ctr_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_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
+				  CRYPTO_ALG_TYPE_MASK);
+	if (IS_ERR(alg))
+		return ERR_PTR(PTR_ERR(alg));
+
+	/* Block size must be >= 4 bytes. */
+	err = -EINVAL;
+	if (alg->cra_blocksize < 4)
+		goto out_put_alg;
+
+	/* If this is false we'd fail the alignment of crypto_inc. */
+	if (alg->cra_blocksize % 4)
+		goto out_put_alg;
+
+	inst = crypto_alloc_instance("ctr", alg);
+	if (IS_ERR(inst))
+		goto out;
+
+	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
+	inst->alg.cra_priority = alg->cra_priority;
+	inst->alg.cra_blocksize = 1;
+	inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
+	inst->alg.cra_type = &crypto_blkcipher_type;
+
+	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_ctr_ctx);
+
+	inst->alg.cra_init = crypto_ctr_init_tfm;
+	inst->alg.cra_exit = crypto_ctr_exit_tfm;
+
+	inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
+	inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
+	inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
+
+out:
+	crypto_mod_put(alg);
+	return inst;
+
+out_put_alg:
+	inst = ERR_PTR(err);
+	goto out;
+}
+
+static void crypto_ctr_free(struct crypto_instance *inst)
+{
+	crypto_drop_spawn(crypto_instance_ctx(inst));
+	kfree(inst);
+}
+
+static struct crypto_template crypto_ctr_tmpl = {
+	.name = "ctr",
+	.alloc = crypto_ctr_alloc,
+	.free = crypto_ctr_free,
+	.module = THIS_MODULE,
+};
+
+static int crypto_rfc3686_setkey(struct crypto_tfm *parent, const u8 *key,
+				 unsigned int keylen)
+{
+	struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(parent);
+	struct crypto_blkcipher *child = ctx->child;
+	int err;
+
+	/* the nonce is stored in bytes at end of key */
+	if (keylen < CTR_RFC3686_NONCE_SIZE)
+		return -EINVAL;
+
+	memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
+	       CTR_RFC3686_NONCE_SIZE);
+
+	keylen -= CTR_RFC3686_NONCE_SIZE;
+
+	crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+	crypto_blkcipher_set_flags(child, crypto_tfm_get_flags(parent) &
+					  CRYPTO_TFM_REQ_MASK);
+	err = crypto_blkcipher_setkey(child, key, keylen);
+	crypto_tfm_set_flags(parent, crypto_blkcipher_get_flags(child) &
+				     CRYPTO_TFM_RES_MASK);
+
+	return err;
+}
+
+static int crypto_rfc3686_crypt(struct blkcipher_desc *desc,
+				struct scatterlist *dst,
+				struct scatterlist *src, unsigned int nbytes)
+{
+	struct crypto_blkcipher *tfm = desc->tfm;
+	struct crypto_rfc3686_ctx *ctx = crypto_blkcipher_ctx(tfm);
+	struct crypto_blkcipher *child = ctx->child;
+	unsigned long alignmask = crypto_blkcipher_alignmask(tfm);
+	u8 ivblk[CTR_RFC3686_BLOCK_SIZE + alignmask];
+	u8 *iv = PTR_ALIGN(ivblk + 0, alignmask + 1);
+	u8 *info = desc->info;
+	int err;
+
+	/* set up counter block */
+	memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
+	memcpy(iv + CTR_RFC3686_NONCE_SIZE, info, CTR_RFC3686_IV_SIZE);
+
+	/* initialize counter portion of counter block */
+	*(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
+		cpu_to_be32(1);
+
+	desc->tfm = child;
+	desc->info = iv;
+	err = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
+	desc->tfm = tfm;
+	desc->info = info;
+
+	return err;
+}
+
+static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = (void *)tfm->__crt_alg;
+	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+	struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct crypto_blkcipher *cipher;
+
+	cipher = crypto_spawn_blkcipher(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+
+	return 0;
+}
+
+static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	crypto_free_blkcipher(ctx->child);
+}
+
+static struct crypto_instance *crypto_rfc3686_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_attr_alg(tb[1], CRYPTO_ALG_TYPE_BLKCIPHER,
+				  CRYPTO_ALG_TYPE_MASK);
+	err = PTR_ERR(alg);
+	if (IS_ERR(alg))
+		return ERR_PTR(err);
+
+	/* We only support 16-byte blocks. */
+	err = -EINVAL;
+	if (alg->cra_blkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE)
+		goto out_put_alg;
+
+	/* Not a stream cipher? */
+	if (alg->cra_blocksize != 1)
+		goto out_put_alg;
+
+	inst = crypto_alloc_instance("rfc3686", alg);
+	if (IS_ERR(inst))
+		goto out;
+
+	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
+	inst->alg.cra_priority = alg->cra_priority;
+	inst->alg.cra_blocksize = 1;
+	inst->alg.cra_alignmask = alg->cra_alignmask;
+	inst->alg.cra_type = &crypto_blkcipher_type;
+
+	inst->alg.cra_blkcipher.ivsize = CTR_RFC3686_IV_SIZE;
+	inst->alg.cra_blkcipher.min_keysize = alg->cra_blkcipher.min_keysize
+					      + CTR_RFC3686_NONCE_SIZE;
+	inst->alg.cra_blkcipher.max_keysize = alg->cra_blkcipher.max_keysize
+					      + CTR_RFC3686_NONCE_SIZE;
+
+	inst->alg.cra_blkcipher.geniv = "seqiv";
+
+	inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
+
+	inst->alg.cra_init = crypto_rfc3686_init_tfm;
+	inst->alg.cra_exit = crypto_rfc3686_exit_tfm;
+
+	inst->alg.cra_blkcipher.setkey = crypto_rfc3686_setkey;
+	inst->alg.cra_blkcipher.encrypt = crypto_rfc3686_crypt;
+	inst->alg.cra_blkcipher.decrypt = crypto_rfc3686_crypt;
+
+out:
+	crypto_mod_put(alg);
+	return inst;
+
+out_put_alg:
+	inst = ERR_PTR(err);
+	goto out;
+}
+
+static struct crypto_template crypto_rfc3686_tmpl = {
+	.name = "rfc3686",
+	.alloc = crypto_rfc3686_alloc,
+	.free = crypto_ctr_free,
+	.module = THIS_MODULE,
+};
+
+static int __init crypto_ctr_module_init(void)
+{
+	int err;
+
+	err = crypto_register_template(&crypto_ctr_tmpl);
+	if (err)
+		goto out;
+
+	err = crypto_register_template(&crypto_rfc3686_tmpl);
+	if (err)
+		goto out_drop_ctr;
+
+out:
+	return err;
+
+out_drop_ctr:
+	crypto_unregister_template(&crypto_ctr_tmpl);
+	goto out;
+}
+
+static void __exit crypto_ctr_module_exit(void)
+{
+	crypto_unregister_template(&crypto_rfc3686_tmpl);
+	crypto_unregister_template(&crypto_ctr_tmpl);
+}
+
+module_init(crypto_ctr_module_init);
+module_exit(crypto_ctr_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("CTR Counter block mode");
+MODULE_ALIAS("rfc3686");