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Diffstat (limited to 'arch/arm/crypto/curve25519-glue.c')
| -rw-r--r-- | arch/arm/crypto/curve25519-glue.c | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/arch/arm/crypto/curve25519-glue.c b/arch/arm/crypto/curve25519-glue.c new file mode 100644 index 0000000000..9bdafd5788 --- /dev/null +++ b/arch/arm/crypto/curve25519-glue.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * + * Based on public domain code from Daniel J. Bernstein and Peter Schwabe. This + * began from SUPERCOP's curve25519/neon2/scalarmult.s, but has subsequently been + * manually reworked for use in kernel space. + */ + +#include <asm/hwcap.h> +#include <asm/neon.h> +#include <asm/simd.h> +#include <crypto/internal/kpp.h> +#include <crypto/internal/simd.h> +#include <linux/types.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/jump_label.h> +#include <linux/scatterlist.h> +#include <crypto/curve25519.h> + +asmlinkage void curve25519_neon(u8 mypublic[CURVE25519_KEY_SIZE], + const u8 secret[CURVE25519_KEY_SIZE], + const u8 basepoint[CURVE25519_KEY_SIZE]); + +static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon); + +void curve25519_arch(u8 out[CURVE25519_KEY_SIZE], + const u8 scalar[CURVE25519_KEY_SIZE], + const u8 point[CURVE25519_KEY_SIZE]) +{ + if (static_branch_likely(&have_neon) && crypto_simd_usable()) { + kernel_neon_begin(); + curve25519_neon(out, scalar, point); + kernel_neon_end(); + } else { + curve25519_generic(out, scalar, point); + } +} +EXPORT_SYMBOL(curve25519_arch); + +void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE], + const u8 secret[CURVE25519_KEY_SIZE]) +{ + return curve25519_arch(pub, secret, curve25519_base_point); +} +EXPORT_SYMBOL(curve25519_base_arch); + +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_arch(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-neon", + .base.cra_priority = 200, + .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 __init arm_curve25519_init(void) +{ + if (elf_hwcap & HWCAP_NEON) { + static_branch_enable(&have_neon); + return IS_REACHABLE(CONFIG_CRYPTO_KPP) ? + crypto_register_kpp(&curve25519_alg) : 0; + } + return 0; +} + +static void __exit arm_curve25519_exit(void) +{ + if (IS_REACHABLE(CONFIG_CRYPTO_KPP) && elf_hwcap & HWCAP_NEON) + crypto_unregister_kpp(&curve25519_alg); +} + +module_init(arm_curve25519_init); +module_exit(arm_curve25519_exit); + +MODULE_ALIAS_CRYPTO("curve25519"); +MODULE_ALIAS_CRYPTO("curve25519-neon"); +MODULE_LICENSE("GPL v2"); |