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>

1 files changed, 102 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0045-crypto-curve25519-Fix-selftest-build-error.patch b/target/linux/generic/backport-5.4/080-wireguard-0045-crypto-curve25519-Fix-selftest-build-error.patch
new file mode 100644
index 0000000000..6247d99fea
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0045-crypto-curve25519-Fix-selftest-build-error.patch
@@ -0,0 +1,102 @@
+From a7e800af9c95490f8b42934eccc88d02d0af6d2a Mon Sep 17 00:00:00 2001
+From: Herbert Xu <herbert@gondor.apana.org.au>
+Date: Wed, 8 Jan 2020 12:37:35 +0800
+Subject: [PATCH 045/124] crypto: curve25519 - Fix selftest build error
+
+commit a8bdf2c42ee4d1ee42af1f3601f85de94e70a421 upstream.
+
+If CRYPTO_CURVE25519 is y, CRYPTO_LIB_CURVE25519_GENERIC will be
+y, but CRYPTO_LIB_CURVE25519 may be set to m, this causes build
+errors:
+
+lib/crypto/curve25519-selftest.o: In function `curve25519':
+curve25519-selftest.c:(.text.unlikely+0xc): undefined reference to `curve25519_arch'
+lib/crypto/curve25519-selftest.o: In function `curve25519_selftest':
+curve25519-selftest.c:(.init.text+0x17e): undefined reference to `curve25519_base_arch'
+
+This is because the curve25519 self-test code is being controlled
+by the GENERIC option rather than the overall CURVE25519 option,
+as is the case with blake2s.  To recap, the GENERIC and ARCH options
+for CURVE25519 are internal only and selected by users such as
+the Crypto API, or the externally visible CURVE25519 option which
+in turn is selected by wireguard.  The self-test is specific to the
+the external CURVE25519 option and should not be enabled by the
+Crypto API.
+
+This patch fixes this by splitting the GENERIC module from the
+CURVE25519 module with the latter now containing just the self-test.
+
+Reported-by: Hulk Robot <hulkci@huawei.com>
+Fixes: aa127963f1ca ("crypto: lib/curve25519 - re-add selftests")
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ lib/crypto/Makefile             |  9 ++++++---
+ lib/crypto/curve25519-generic.c | 24 ++++++++++++++++++++++++
+ lib/crypto/curve25519.c         |  7 -------
+ 3 files changed, 30 insertions(+), 10 deletions(-)
+ create mode 100644 lib/crypto/curve25519-generic.c
+
+--- a/lib/crypto/Makefile
++++ b/lib/crypto/Makefile
+@@ -19,9 +19,12 @@ libblake2s-y					+= blake2s.o
+ obj-$(CONFIG_CRYPTO_LIB_CHACHA20POLY1305)	+= libchacha20poly1305.o
+ libchacha20poly1305-y				+= chacha20poly1305.o
+ 
+-obj-$(CONFIG_CRYPTO_LIB_CURVE25519_GENERIC)	+= libcurve25519.o
+-libcurve25519-y					:= curve25519-fiat32.o
+-libcurve25519-$(CONFIG_ARCH_SUPPORTS_INT128)	:= curve25519-hacl64.o
++obj-$(CONFIG_CRYPTO_LIB_CURVE25519_GENERIC)	+= libcurve25519-generic.o
++libcurve25519-generic-y				:= curve25519-fiat32.o
++libcurve25519-generic-$(CONFIG_ARCH_SUPPORTS_INT128)	:= curve25519-hacl64.o
++libcurve25519-generic-y				+= curve25519-generic.o
++
++obj-$(CONFIG_CRYPTO_LIB_CURVE25519)		+= libcurve25519.o
+ libcurve25519-y					+= curve25519.o
+ 
+ obj-$(CONFIG_CRYPTO_LIB_DES)			+= libdes.o
+--- /dev/null
++++ b/lib/crypto/curve25519-generic.c
+@@ -0,0 +1,24 @@
++// SPDX-License-Identifier: GPL-2.0 OR MIT
++/*
++ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
++ *
++ * This is an implementation of the Curve25519 ECDH algorithm, using either
++ * a 32-bit implementation or a 64-bit implementation with 128-bit integers,
++ * depending on what is supported by the target compiler.
++ *
++ * Information: https://cr.yp.to/ecdh.html
++ */
++
++#include <crypto/curve25519.h>
++#include <linux/module.h>
++
++const u8 curve25519_null_point[CURVE25519_KEY_SIZE] __aligned(32) = { 0 };
++const u8 curve25519_base_point[CURVE25519_KEY_SIZE] __aligned(32) = { 9 };
++
++EXPORT_SYMBOL(curve25519_null_point);
++EXPORT_SYMBOL(curve25519_base_point);
++EXPORT_SYMBOL(curve25519_generic);
++
++MODULE_LICENSE("GPL v2");
++MODULE_DESCRIPTION("Curve25519 scalar multiplication");
++MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
+--- a/lib/crypto/curve25519.c
++++ b/lib/crypto/curve25519.c
+@@ -15,13 +15,6 @@
+ 
+ bool curve25519_selftest(void);
+ 
+-const u8 curve25519_null_point[CURVE25519_KEY_SIZE] __aligned(32) = { 0 };
+-const u8 curve25519_base_point[CURVE25519_KEY_SIZE] __aligned(32) = { 9 };
+-
+-EXPORT_SYMBOL(curve25519_null_point);
+-EXPORT_SYMBOL(curve25519_base_point);
+-EXPORT_SYMBOL(curve25519_generic);
+-
+ static int __init mod_init(void)
+ {
+ 	if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS) &&