From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- crypto/ecdh.c | 247 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 247 insertions(+) create mode 100644 crypto/ecdh.c (limited to 'crypto/ecdh.c') diff --git a/crypto/ecdh.c b/crypto/ecdh.c new file mode 100644 index 000000000..9f0b93b31 --- /dev/null +++ b/crypto/ecdh.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* ECDH key-agreement protocol + * + * Copyright (c) 2016, Intel Corporation + * Authors: Salvator Benedetto + */ + +#include +#include +#include +#include +#include +#include + +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 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; + int ret = 0; + + if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0 || + params.key_size > sizeof(u64) * ctx->ndigits) + return -EINVAL; + + memset(ctx->private_key, 0, sizeof(ctx->private_key)); + + if (!params.key || !params.key_size) + return ecc_gen_privkey(ctx->curve_id, ctx->ndigits, + ctx->private_key); + + ecc_digits_from_bytes(params.key, params.key_size, + ctx->private_key, ctx->ndigits); + + if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits, + ctx->private_key, params.key_size) < 0) { + memzero_explicit(ctx->private_key, params.key_size); + ret = -EINVAL; + } + + return ret; +} + +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: + kfree_sensitive(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 int ecdh_nist_p192_init_tfm(struct crypto_kpp *tfm) +{ + struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); + + ctx->curve_id = ECC_CURVE_NIST_P192; + ctx->ndigits = ECC_CURVE_NIST_P192_DIGITS; + + return 0; +} + +static struct kpp_alg ecdh_nist_p192 = { + .set_secret = ecdh_set_secret, + .generate_public_key = ecdh_compute_value, + .compute_shared_secret = ecdh_compute_value, + .max_size = ecdh_max_size, + .init = ecdh_nist_p192_init_tfm, + .base = { + .cra_name = "ecdh-nist-p192", + .cra_driver_name = "ecdh-nist-p192-generic", + .cra_priority = 100, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct ecdh_ctx), + }, +}; + +static int ecdh_nist_p256_init_tfm(struct crypto_kpp *tfm) +{ + struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); + + ctx->curve_id = ECC_CURVE_NIST_P256; + ctx->ndigits = ECC_CURVE_NIST_P256_DIGITS; + + return 0; +} + +static struct kpp_alg ecdh_nist_p256 = { + .set_secret = ecdh_set_secret, + .generate_public_key = ecdh_compute_value, + .compute_shared_secret = ecdh_compute_value, + .max_size = ecdh_max_size, + .init = ecdh_nist_p256_init_tfm, + .base = { + .cra_name = "ecdh-nist-p256", + .cra_driver_name = "ecdh-nist-p256-generic", + .cra_priority = 100, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct ecdh_ctx), + }, +}; + +static int ecdh_nist_p384_init_tfm(struct crypto_kpp *tfm) +{ + struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); + + ctx->curve_id = ECC_CURVE_NIST_P384; + ctx->ndigits = ECC_CURVE_NIST_P384_DIGITS; + + return 0; +} + +static struct kpp_alg ecdh_nist_p384 = { + .set_secret = ecdh_set_secret, + .generate_public_key = ecdh_compute_value, + .compute_shared_secret = ecdh_compute_value, + .max_size = ecdh_max_size, + .init = ecdh_nist_p384_init_tfm, + .base = { + .cra_name = "ecdh-nist-p384", + .cra_driver_name = "ecdh-nist-p384-generic", + .cra_priority = 100, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct ecdh_ctx), + }, +}; + +static bool ecdh_nist_p192_registered; + +static int __init ecdh_init(void) +{ + int ret; + + /* NIST p192 will fail to register in FIPS mode */ + ret = crypto_register_kpp(&ecdh_nist_p192); + ecdh_nist_p192_registered = ret == 0; + + ret = crypto_register_kpp(&ecdh_nist_p256); + if (ret) + goto nist_p256_error; + + ret = crypto_register_kpp(&ecdh_nist_p384); + if (ret) + goto nist_p384_error; + + return 0; + +nist_p384_error: + crypto_unregister_kpp(&ecdh_nist_p256); + +nist_p256_error: + if (ecdh_nist_p192_registered) + crypto_unregister_kpp(&ecdh_nist_p192); + return ret; +} + +static void __exit ecdh_exit(void) +{ + if (ecdh_nist_p192_registered) + crypto_unregister_kpp(&ecdh_nist_p192); + crypto_unregister_kpp(&ecdh_nist_p256); + crypto_unregister_kpp(&ecdh_nist_p384); +} + +module_init(ecdh_init); +module_exit(ecdh_exit); +MODULE_ALIAS_CRYPTO("ecdh"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("ECDH generic algorithm"); -- cgit v1.3.1