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-rw-r--r--crypto/ctr.c360
1 files changed, 360 insertions, 0 deletions
diff --git a/crypto/ctr.c b/crypto/ctr.c
new file mode 100644
index 000000000..c39fcffba
--- /dev/null
+++ b/crypto/ctr.c
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * CTR: Counter mode
+ *
+ * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/ctr.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>
+
+struct crypto_rfc3686_ctx {
+ struct crypto_skcipher *child;
+ u8 nonce[CTR_RFC3686_NONCE_SIZE];
+};
+
+struct crypto_rfc3686_req_ctx {
+ u8 iv[CTR_RFC3686_BLOCK_SIZE];
+ struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
+};
+
+static void crypto_ctr_crypt_final(struct skcipher_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[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_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_cpy(dst, keystream, src, nbytes);
+
+ crypto_inc(ctrblk, bsize);
+}
+
+static int crypto_ctr_crypt_segment(struct skcipher_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 skcipher_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[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_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 skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
+ const unsigned int bsize = crypto_cipher_blocksize(cipher);
+ struct skcipher_walk walk;
+ unsigned int nbytes;
+ int err;
+
+ err = skcipher_walk_virt(&walk, req, false);
+
+ while (walk.nbytes >= bsize) {
+ if (walk.src.virt.addr == walk.dst.virt.addr)
+ nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
+ else
+ nbytes = crypto_ctr_crypt_segment(&walk, cipher);
+
+ err = skcipher_walk_done(&walk, nbytes);
+ }
+
+ if (walk.nbytes) {
+ crypto_ctr_crypt_final(&walk, cipher);
+ err = skcipher_walk_done(&walk, 0);
+ }
+
+ return err;
+}
+
+static int crypto_ctr_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+ struct skcipher_instance *inst;
+ struct crypto_alg *alg;
+ int err;
+
+ inst = skcipher_alloc_instance_simple(tmpl, tb);
+ if (IS_ERR(inst))
+ return PTR_ERR(inst);
+
+ alg = skcipher_ialg_simple(inst);
+
+ /* Block size must be >= 4 bytes. */
+ err = -EINVAL;
+ if (alg->cra_blocksize < 4)
+ goto out_free_inst;
+
+ /* If this is false we'd fail the alignment of crypto_inc. */
+ if (alg->cra_blocksize % 4)
+ goto out_free_inst;
+
+ /* CTR mode is a stream cipher. */
+ inst->alg.base.cra_blocksize = 1;
+
+ /*
+ * To simplify the implementation, configure the skcipher walk to only
+ * give a partial block at the very end, never earlier.
+ */
+ inst->alg.chunksize = alg->cra_blocksize;
+
+ inst->alg.encrypt = crypto_ctr_crypt;
+ inst->alg.decrypt = crypto_ctr_crypt;
+
+ err = skcipher_register_instance(tmpl, inst);
+ if (err) {
+out_free_inst:
+ inst->free(inst);
+ }
+
+ return err;
+}
+
+static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
+ const u8 *key, unsigned int keylen)
+{
+ struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
+ struct crypto_skcipher *child = ctx->child;
+
+ /* 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_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+ crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
+ CRYPTO_TFM_REQ_MASK);
+ return crypto_skcipher_setkey(child, key, keylen);
+}
+
+static int crypto_rfc3686_crypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct crypto_skcipher *child = ctx->child;
+ unsigned long align = crypto_skcipher_alignmask(tfm);
+ struct crypto_rfc3686_req_ctx *rctx =
+ (void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);
+ struct skcipher_request *subreq = &rctx->subreq;
+ u8 *iv = rctx->iv;
+
+ /* set up counter block */
+ memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
+ memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);
+
+ /* initialize counter portion of counter block */
+ *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
+ cpu_to_be32(1);
+
+ skcipher_request_set_tfm(subreq, child);
+ skcipher_request_set_callback(subreq, req->base.flags,
+ req->base.complete, req->base.data);
+ skcipher_request_set_crypt(subreq, req->src, req->dst,
+ req->cryptlen, iv);
+
+ return crypto_skcipher_encrypt(subreq);
+}
+
+static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
+{
+ struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+ struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
+ struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct crypto_skcipher *cipher;
+ unsigned long align;
+ unsigned int reqsize;
+
+ cipher = crypto_spawn_skcipher(spawn);
+ if (IS_ERR(cipher))
+ return PTR_ERR(cipher);
+
+ ctx->child = cipher;
+
+ align = crypto_skcipher_alignmask(tfm);
+ align &= ~(crypto_tfm_ctx_alignment() - 1);
+ reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
+ crypto_skcipher_reqsize(cipher);
+ crypto_skcipher_set_reqsize(tfm, reqsize);
+
+ return 0;
+}
+
+static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
+{
+ struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ crypto_free_skcipher(ctx->child);
+}
+
+static void crypto_rfc3686_free(struct skcipher_instance *inst)
+{
+ struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
+
+ crypto_drop_skcipher(spawn);
+ kfree(inst);
+}
+
+static int crypto_rfc3686_create(struct crypto_template *tmpl,
+ struct rtattr **tb)
+{
+ struct skcipher_instance *inst;
+ struct skcipher_alg *alg;
+ struct crypto_skcipher_spawn *spawn;
+ u32 mask;
+ int err;
+
+ err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
+ if (err)
+ return err;
+
+ inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+ if (!inst)
+ return -ENOMEM;
+
+ spawn = skcipher_instance_ctx(inst);
+
+ err = crypto_grab_skcipher(spawn, skcipher_crypto_instance(inst),
+ crypto_attr_alg_name(tb[1]), 0, mask);
+ if (err)
+ goto err_free_inst;
+
+ alg = crypto_spawn_skcipher_alg(spawn);
+
+ /* We only support 16-byte blocks. */
+ err = -EINVAL;
+ if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
+ goto err_free_inst;
+
+ /* Not a stream cipher? */
+ if (alg->base.cra_blocksize != 1)
+ goto err_free_inst;
+
+ err = -ENAMETOOLONG;
+ if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
+ "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
+ goto err_free_inst;
+ if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+ "rfc3686(%s)", alg->base.cra_driver_name) >=
+ CRYPTO_MAX_ALG_NAME)
+ goto err_free_inst;
+
+ inst->alg.base.cra_priority = alg->base.cra_priority;
+ inst->alg.base.cra_blocksize = 1;
+ inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
+
+ inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
+ inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
+ inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
+ CTR_RFC3686_NONCE_SIZE;
+ inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
+ CTR_RFC3686_NONCE_SIZE;
+
+ inst->alg.setkey = crypto_rfc3686_setkey;
+ inst->alg.encrypt = crypto_rfc3686_crypt;
+ inst->alg.decrypt = crypto_rfc3686_crypt;
+
+ inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
+
+ inst->alg.init = crypto_rfc3686_init_tfm;
+ inst->alg.exit = crypto_rfc3686_exit_tfm;
+
+ inst->free = crypto_rfc3686_free;
+
+ err = skcipher_register_instance(tmpl, inst);
+ if (err) {
+err_free_inst:
+ crypto_rfc3686_free(inst);
+ }
+ return err;
+}
+
+static struct crypto_template crypto_ctr_tmpls[] = {
+ {
+ .name = "ctr",
+ .create = crypto_ctr_create,
+ .module = THIS_MODULE,
+ }, {
+ .name = "rfc3686",
+ .create = crypto_rfc3686_create,
+ .module = THIS_MODULE,
+ },
+};
+
+static int __init crypto_ctr_module_init(void)
+{
+ return crypto_register_templates(crypto_ctr_tmpls,
+ ARRAY_SIZE(crypto_ctr_tmpls));
+}
+
+static void __exit crypto_ctr_module_exit(void)
+{
+ crypto_unregister_templates(crypto_ctr_tmpls,
+ ARRAY_SIZE(crypto_ctr_tmpls));
+}
+
+subsys_initcall(crypto_ctr_module_init);
+module_exit(crypto_ctr_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("CTR block cipher mode of operation");
+MODULE_ALIAS_CRYPTO("rfc3686");
+MODULE_ALIAS_CRYPTO("ctr");