v4.19.13 snapshot.
diff --git a/crypto/ecdh.c b/crypto/ecdh.c
new file mode 100644
index 0000000..bf63001
--- /dev/null
+++ b/crypto/ecdh.c
@@ -0,0 +1,173 @@
+/* ECDH key-agreement protocol
+ *
+ * Copyright (c) 2016, Intel Corporation
+ * Authors: Salvator Benedetto <salvatore.benedetto@intel.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 <linux/module.h>
+#include <crypto/internal/kpp.h>
+#include <crypto/kpp.h>
+#include <crypto/ecdh.h>
+#include <linux/scatterlist.h>
+#include "ecc.h"
+
+struct ecdh_ctx {
+ unsigned int curve_id;
+ unsigned int ndigits;
+ u64 private_key[ECC_MAX_DIGITS];
+};
+
+static inline struct ecdh_ctx *ecdh_get_ctx(struct crypto_kpp *tfm)
+{
+ return kpp_tfm_ctx(tfm);
+}
+
+static unsigned int ecdh_supported_curve(unsigned int curve_id)
+{
+ switch (curve_id) {
+ case ECC_CURVE_NIST_P192: return ECC_CURVE_NIST_P192_DIGITS;
+ case ECC_CURVE_NIST_P256: return ECC_CURVE_NIST_P256_DIGITS;
+ default: return 0;
+ }
+}
+
+static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
+ unsigned int len)
+{
+ struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+ struct ecdh params;
+ unsigned int ndigits;
+
+ if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0)
+ return -EINVAL;
+
+ ndigits = ecdh_supported_curve(params.curve_id);
+ if (!ndigits)
+ return -EINVAL;
+
+ ctx->curve_id = params.curve_id;
+ ctx->ndigits = ndigits;
+
+ if (!params.key || !params.key_size)
+ return ecc_gen_privkey(ctx->curve_id, ctx->ndigits,
+ ctx->private_key);
+
+ if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
+ (const u64 *)params.key, params.key_size) < 0)
+ return -EINVAL;
+
+ memcpy(ctx->private_key, params.key, params.key_size);
+
+ return 0;
+}
+
+static int ecdh_compute_value(struct kpp_request *req)
+{
+ struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
+ struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+ u64 *public_key;
+ u64 *shared_secret = NULL;
+ void *buf;
+ size_t copied, nbytes, public_key_sz;
+ int ret = -ENOMEM;
+
+ nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+ /* Public part is a point thus it has both coordinates */
+ public_key_sz = 2 * nbytes;
+
+ public_key = kmalloc(public_key_sz, GFP_KERNEL);
+ if (!public_key)
+ return -ENOMEM;
+
+ if (req->src) {
+ shared_secret = kmalloc(nbytes, GFP_KERNEL);
+ if (!shared_secret)
+ goto free_pubkey;
+
+ /* from here on it's invalid parameters */
+ ret = -EINVAL;
+
+ /* must have exactly two points to be on the curve */
+ if (public_key_sz != req->src_len)
+ goto free_all;
+
+ copied = sg_copy_to_buffer(req->src,
+ sg_nents_for_len(req->src,
+ public_key_sz),
+ public_key, public_key_sz);
+ if (copied != public_key_sz)
+ goto free_all;
+
+ ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
+ ctx->private_key, public_key,
+ shared_secret);
+
+ buf = shared_secret;
+ } else {
+ ret = ecc_make_pub_key(ctx->curve_id, ctx->ndigits,
+ ctx->private_key, public_key);
+ buf = public_key;
+ nbytes = public_key_sz;
+ }
+
+ if (ret < 0)
+ goto free_all;
+
+ /* might want less than we've got */
+ nbytes = min_t(size_t, nbytes, req->dst_len);
+ copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst,
+ nbytes),
+ buf, nbytes);
+ if (copied != nbytes)
+ ret = -EINVAL;
+
+ /* fall through */
+free_all:
+ kzfree(shared_secret);
+free_pubkey:
+ kfree(public_key);
+ return ret;
+}
+
+static unsigned int ecdh_max_size(struct crypto_kpp *tfm)
+{
+ struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+
+ /* Public key is made of two coordinates, add one to the left shift */
+ return ctx->ndigits << (ECC_DIGITS_TO_BYTES_SHIFT + 1);
+}
+
+static struct kpp_alg ecdh = {
+ .set_secret = ecdh_set_secret,
+ .generate_public_key = ecdh_compute_value,
+ .compute_shared_secret = ecdh_compute_value,
+ .max_size = ecdh_max_size,
+ .base = {
+ .cra_name = "ecdh",
+ .cra_driver_name = "ecdh-generic",
+ .cra_priority = 100,
+ .cra_module = THIS_MODULE,
+ .cra_ctxsize = sizeof(struct ecdh_ctx),
+ },
+};
+
+static int ecdh_init(void)
+{
+ return crypto_register_kpp(&ecdh);
+}
+
+static void ecdh_exit(void)
+{
+ crypto_unregister_kpp(&ecdh);
+}
+
+module_init(ecdh_init);
+module_exit(ecdh_exit);
+MODULE_ALIAS_CRYPTO("ecdh");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ECDH generic algorithm");