openwrt/target/linux/generic/backport-5.4/080-wireguard-0027-crypto-curve25519-implement-generic-KPP-driver.patch
Jason A. Donenfeld 3888fa7880 kernel: 5.4: import wireguard backport
Rather than using the clunky, old, slower wireguard-linux-compat out of
tree module, this commit does a patch-by-patch backport of upstream's
wireguard to 5.4. This specific backport is in widespread use, being
part of SUSE's enterprise kernel, Oracle's enterprise kernel, Google's
Android kernel, Gentoo's distro kernel, and probably more I've forgotten
about. It's definately the "more proper" way of adding wireguard to a
kernel than the ugly compat.h hell of the wireguard-linux-compat repo.
And most importantly for OpenWRT, it allows using the same module
configuration code for 5.10 as for 5.4, with no need for bifurcation.

These patches are from the backport tree which is maintained in the
open here: https://git.zx2c4.com/wireguard-linux/log/?h=backport-5.4.y
I'll be sending PRs to update this as needed.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-02-26 20:41:01 +01:00

137 lines
3.8 KiB
Diff

From 54bdc995d525de6ae20f74af36d079f8b79e52fa Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Fri, 8 Nov 2019 13:22:34 +0100
Subject: [PATCH 027/124] crypto: curve25519 - implement generic KPP driver
commit ee772cb641135739c1530647391d5a04c39db192 upstream.
Expose the generic Curve25519 library via the crypto API KPP interface.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
crypto/Kconfig | 5 +++
crypto/Makefile | 1 +
crypto/curve25519-generic.c | 90 +++++++++++++++++++++++++++++++++++++
3 files changed, 96 insertions(+)
create mode 100644 crypto/curve25519-generic.c
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -264,6 +264,11 @@ config CRYPTO_ECRDSA
standard algorithms (called GOST algorithms). Only signature verification
is implemented.
+config CRYPTO_CURVE25519
+ tristate "Curve25519 algorithm"
+ select CRYPTO_KPP
+ select CRYPTO_LIB_CURVE25519_GENERIC
+
comment "Authenticated Encryption with Associated Data"
config CRYPTO_CCM
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -167,6 +167,7 @@ obj-$(CONFIG_CRYPTO_ZSTD) += zstd.o
obj-$(CONFIG_CRYPTO_OFB) += ofb.o
obj-$(CONFIG_CRYPTO_ECC) += ecc.o
obj-$(CONFIG_CRYPTO_ESSIV) += essiv.o
+obj-$(CONFIG_CRYPTO_CURVE25519) += curve25519-generic.o
ecdh_generic-y += ecdh.o
ecdh_generic-y += ecdh_helper.o
--- /dev/null
+++ b/crypto/curve25519-generic.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <crypto/curve25519.h>
+#include <crypto/internal/kpp.h>
+#include <crypto/kpp.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+
+static int curve25519_set_secret(struct crypto_kpp *tfm, const void *buf,
+ unsigned int len)
+{
+ u8 *secret = kpp_tfm_ctx(tfm);
+
+ if (!len)
+ curve25519_generate_secret(secret);
+ else if (len == CURVE25519_KEY_SIZE &&
+ crypto_memneq(buf, curve25519_null_point, CURVE25519_KEY_SIZE))
+ memcpy(secret, buf, CURVE25519_KEY_SIZE);
+ else
+ return -EINVAL;
+ return 0;
+}
+
+static int curve25519_compute_value(struct kpp_request *req)
+{
+ struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
+ const u8 *secret = kpp_tfm_ctx(tfm);
+ u8 public_key[CURVE25519_KEY_SIZE];
+ u8 buf[CURVE25519_KEY_SIZE];
+ int copied, nbytes;
+ u8 const *bp;
+
+ if (req->src) {
+ copied = sg_copy_to_buffer(req->src,
+ sg_nents_for_len(req->src,
+ CURVE25519_KEY_SIZE),
+ public_key, CURVE25519_KEY_SIZE);
+ if (copied != CURVE25519_KEY_SIZE)
+ return -EINVAL;
+ bp = public_key;
+ } else {
+ bp = curve25519_base_point;
+ }
+
+ curve25519_generic(buf, secret, bp);
+
+ /* might want less than we've got */
+ nbytes = min_t(size_t, CURVE25519_KEY_SIZE, req->dst_len);
+ copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst,
+ nbytes),
+ buf, nbytes);
+ if (copied != nbytes)
+ return -EINVAL;
+ return 0;
+}
+
+static unsigned int curve25519_max_size(struct crypto_kpp *tfm)
+{
+ return CURVE25519_KEY_SIZE;
+}
+
+static struct kpp_alg curve25519_alg = {
+ .base.cra_name = "curve25519",
+ .base.cra_driver_name = "curve25519-generic",
+ .base.cra_priority = 100,
+ .base.cra_module = THIS_MODULE,
+ .base.cra_ctxsize = CURVE25519_KEY_SIZE,
+
+ .set_secret = curve25519_set_secret,
+ .generate_public_key = curve25519_compute_value,
+ .compute_shared_secret = curve25519_compute_value,
+ .max_size = curve25519_max_size,
+};
+
+static int curve25519_init(void)
+{
+ return crypto_register_kpp(&curve25519_alg);
+}
+
+static void curve25519_exit(void)
+{
+ crypto_unregister_kpp(&curve25519_alg);
+}
+
+subsys_initcall(curve25519_init);
+module_exit(curve25519_exit);
+
+MODULE_ALIAS_CRYPTO("curve25519");
+MODULE_ALIAS_CRYPTO("curve25519-generic");
+MODULE_LICENSE("GPL");