74 lines
2.0 KiB
C
74 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 OR MIT */
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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#ifndef CURVE25519_H
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#define CURVE25519_H
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#include <crypto/algapi.h> // For crypto_memneq.
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#include <linux/types.h>
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#include <linux/random.h>
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enum curve25519_lengths {
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CURVE25519_KEY_SIZE = 32
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};
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extern const u8 curve25519_null_point[];
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extern const u8 curve25519_base_point[];
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void curve25519_generic(u8 out[CURVE25519_KEY_SIZE],
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const u8 scalar[CURVE25519_KEY_SIZE],
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const u8 point[CURVE25519_KEY_SIZE]);
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void curve25519_arch(u8 out[CURVE25519_KEY_SIZE],
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const u8 scalar[CURVE25519_KEY_SIZE],
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const u8 point[CURVE25519_KEY_SIZE]);
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void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],
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const u8 secret[CURVE25519_KEY_SIZE]);
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bool curve25519_selftest(void);
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static inline
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bool __must_check curve25519(u8 mypublic[CURVE25519_KEY_SIZE],
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const u8 secret[CURVE25519_KEY_SIZE],
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const u8 basepoint[CURVE25519_KEY_SIZE])
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{
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if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519))
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curve25519_arch(mypublic, secret, basepoint);
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else
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curve25519_generic(mypublic, secret, basepoint);
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return crypto_memneq(mypublic, curve25519_null_point,
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CURVE25519_KEY_SIZE);
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}
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static inline bool
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__must_check curve25519_generate_public(u8 pub[CURVE25519_KEY_SIZE],
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const u8 secret[CURVE25519_KEY_SIZE])
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{
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if (unlikely(!crypto_memneq(secret, curve25519_null_point,
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CURVE25519_KEY_SIZE)))
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return false;
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if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519))
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curve25519_base_arch(pub, secret);
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else
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curve25519_generic(pub, secret, curve25519_base_point);
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return crypto_memneq(pub, curve25519_null_point, CURVE25519_KEY_SIZE);
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}
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static inline void curve25519_clamp_secret(u8 secret[CURVE25519_KEY_SIZE])
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{
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secret[0] &= 248;
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secret[31] = (secret[31] & 127) | 64;
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}
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static inline void curve25519_generate_secret(u8 secret[CURVE25519_KEY_SIZE])
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{
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get_random_bytes_wait(secret, CURVE25519_KEY_SIZE);
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curve25519_clamp_secret(secret);
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}
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#endif /* CURVE25519_H */
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