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242 lines
5.7 KiB
242 lines
5.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* ECDH key-agreement protocol |
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* |
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* Copyright (c) 2016, Intel Corporation |
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* Authors: Salvator Benedetto <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <crypto/internal/ecc.h> |
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#include <crypto/internal/kpp.h> |
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#include <crypto/kpp.h> |
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#include <crypto/ecdh.h> |
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#include <linux/scatterlist.h> |
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struct ecdh_ctx { |
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unsigned int curve_id; |
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unsigned int ndigits; |
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u64 private_key[ECC_MAX_DIGITS]; |
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}; |
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static inline struct ecdh_ctx *ecdh_get_ctx(struct crypto_kpp *tfm) |
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{ |
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return kpp_tfm_ctx(tfm); |
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} |
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static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, |
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unsigned int len) |
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{ |
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struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); |
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struct ecdh params; |
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if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0 || |
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params.key_size > sizeof(u64) * ctx->ndigits) |
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return -EINVAL; |
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if (!params.key || !params.key_size) |
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return ecc_gen_privkey(ctx->curve_id, ctx->ndigits, |
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ctx->private_key); |
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memcpy(ctx->private_key, params.key, params.key_size); |
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if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits, |
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ctx->private_key, params.key_size) < 0) { |
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memzero_explicit(ctx->private_key, params.key_size); |
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return -EINVAL; |
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} |
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return 0; |
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} |
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static int ecdh_compute_value(struct kpp_request *req) |
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{ |
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struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); |
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struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); |
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u64 *public_key; |
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u64 *shared_secret = NULL; |
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void *buf; |
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size_t copied, nbytes, public_key_sz; |
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int ret = -ENOMEM; |
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nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT; |
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/* Public part is a point thus it has both coordinates */ |
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public_key_sz = 2 * nbytes; |
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public_key = kmalloc(public_key_sz, GFP_KERNEL); |
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if (!public_key) |
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return -ENOMEM; |
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if (req->src) { |
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shared_secret = kmalloc(nbytes, GFP_KERNEL); |
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if (!shared_secret) |
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goto free_pubkey; |
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/* from here on it's invalid parameters */ |
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ret = -EINVAL; |
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/* must have exactly two points to be on the curve */ |
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if (public_key_sz != req->src_len) |
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goto free_all; |
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copied = sg_copy_to_buffer(req->src, |
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sg_nents_for_len(req->src, |
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public_key_sz), |
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public_key, public_key_sz); |
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if (copied != public_key_sz) |
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goto free_all; |
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ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits, |
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ctx->private_key, public_key, |
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shared_secret); |
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buf = shared_secret; |
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} else { |
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ret = ecc_make_pub_key(ctx->curve_id, ctx->ndigits, |
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ctx->private_key, public_key); |
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buf = public_key; |
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nbytes = public_key_sz; |
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} |
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if (ret < 0) |
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goto free_all; |
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/* might want less than we've got */ |
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nbytes = min_t(size_t, nbytes, req->dst_len); |
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copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst, |
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nbytes), |
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buf, nbytes); |
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if (copied != nbytes) |
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ret = -EINVAL; |
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/* fall through */ |
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free_all: |
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kfree_sensitive(shared_secret); |
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free_pubkey: |
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kfree(public_key); |
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return ret; |
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} |
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static unsigned int ecdh_max_size(struct crypto_kpp *tfm) |
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{ |
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struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); |
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/* Public key is made of two coordinates, add one to the left shift */ |
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return ctx->ndigits << (ECC_DIGITS_TO_BYTES_SHIFT + 1); |
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} |
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static int ecdh_nist_p192_init_tfm(struct crypto_kpp *tfm) |
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{ |
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struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); |
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ctx->curve_id = ECC_CURVE_NIST_P192; |
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ctx->ndigits = ECC_CURVE_NIST_P192_DIGITS; |
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return 0; |
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} |
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static struct kpp_alg ecdh_nist_p192 = { |
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.set_secret = ecdh_set_secret, |
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.generate_public_key = ecdh_compute_value, |
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.compute_shared_secret = ecdh_compute_value, |
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.max_size = ecdh_max_size, |
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.init = ecdh_nist_p192_init_tfm, |
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.base = { |
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.cra_name = "ecdh-nist-p192", |
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.cra_driver_name = "ecdh-nist-p192-generic", |
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.cra_priority = 100, |
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.cra_module = THIS_MODULE, |
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.cra_ctxsize = sizeof(struct ecdh_ctx), |
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}, |
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}; |
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static int ecdh_nist_p256_init_tfm(struct crypto_kpp *tfm) |
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{ |
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struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); |
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ctx->curve_id = ECC_CURVE_NIST_P256; |
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ctx->ndigits = ECC_CURVE_NIST_P256_DIGITS; |
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return 0; |
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} |
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static struct kpp_alg ecdh_nist_p256 = { |
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.set_secret = ecdh_set_secret, |
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.generate_public_key = ecdh_compute_value, |
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.compute_shared_secret = ecdh_compute_value, |
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.max_size = ecdh_max_size, |
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.init = ecdh_nist_p256_init_tfm, |
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.base = { |
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.cra_name = "ecdh-nist-p256", |
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.cra_driver_name = "ecdh-nist-p256-generic", |
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.cra_priority = 100, |
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.cra_module = THIS_MODULE, |
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.cra_ctxsize = sizeof(struct ecdh_ctx), |
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}, |
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}; |
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static int ecdh_nist_p384_init_tfm(struct crypto_kpp *tfm) |
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{ |
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struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); |
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ctx->curve_id = ECC_CURVE_NIST_P384; |
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ctx->ndigits = ECC_CURVE_NIST_P384_DIGITS; |
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return 0; |
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} |
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static struct kpp_alg ecdh_nist_p384 = { |
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.set_secret = ecdh_set_secret, |
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.generate_public_key = ecdh_compute_value, |
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.compute_shared_secret = ecdh_compute_value, |
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.max_size = ecdh_max_size, |
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.init = ecdh_nist_p384_init_tfm, |
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.base = { |
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.cra_name = "ecdh-nist-p384", |
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.cra_driver_name = "ecdh-nist-p384-generic", |
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.cra_priority = 100, |
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.cra_module = THIS_MODULE, |
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.cra_ctxsize = sizeof(struct ecdh_ctx), |
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}, |
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}; |
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static bool ecdh_nist_p192_registered; |
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static int __init ecdh_init(void) |
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{ |
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int ret; |
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/* NIST p192 will fail to register in FIPS mode */ |
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ret = crypto_register_kpp(&ecdh_nist_p192); |
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ecdh_nist_p192_registered = ret == 0; |
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ret = crypto_register_kpp(&ecdh_nist_p256); |
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if (ret) |
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goto nist_p256_error; |
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ret = crypto_register_kpp(&ecdh_nist_p384); |
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if (ret) |
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goto nist_p384_error; |
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return 0; |
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nist_p384_error: |
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crypto_unregister_kpp(&ecdh_nist_p256); |
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nist_p256_error: |
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if (ecdh_nist_p192_registered) |
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crypto_unregister_kpp(&ecdh_nist_p192); |
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return ret; |
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} |
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static void __exit ecdh_exit(void) |
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{ |
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if (ecdh_nist_p192_registered) |
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crypto_unregister_kpp(&ecdh_nist_p192); |
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crypto_unregister_kpp(&ecdh_nist_p256); |
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crypto_unregister_kpp(&ecdh_nist_p384); |
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} |
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subsys_initcall(ecdh_init); |
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module_exit(ecdh_exit); |
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MODULE_ALIAS_CRYPTO("ecdh"); |
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MODULE_LICENSE("GPL"); |
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MODULE_DESCRIPTION("ECDH generic algorithm");
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