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3BSD-licensed implementation of the chacha20 stream cipher, intended for

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use by the upcoming arc4random replacement.
This commit is contained in:
Dag-Erling Smørgrav 2017-04-15 20:51:53 +00:00
parent 1af6dc18b9
commit d196586a6c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=316982
5 changed files with 273 additions and 0 deletions
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1
sys/conf/files
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@ -591,6 +591,7 @@ crypto/blowfish/bf_ecb.c optional ipsec | ipsec_support
crypto/blowfish/bf_skey.c optional crypto | ipsec | ipsec_support
crypto/camellia/camellia.c optional crypto | ipsec | ipsec_support
crypto/camellia/camellia-api.c optional crypto | ipsec | ipsec_support
crypto/chacha20/chacha20.c optional chacha20
crypto/des/des_ecb.c optional crypto | ipsec | ipsec_support | netsmb
crypto/des/des_setkey.c optional crypto | ipsec | ipsec_support | netsmb
crypto/rc4/rc4.c optional netgraph_mppc_encryption | kgssapi

210
sys/crypto/chacha20/chacha20.c Normal file
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@ -0,0 +1,210 @@
/*-
* Copyright (c) 2017 Dag-Erling Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifdef _KERNEL
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/module.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#else
#include <stdint.h>
#include <string.h>
#endif
#include <sys/endian.h>
#include <crypto/chacha20/chacha20.h>
#define rol32(x, n) \
((x) << ((n) & 0x1f) | (x) >> (-(n) & 0x1f))
#define CHACHA_QR(x, a, b, c, d) \
do { \
x[a] = x[a] + x[b]; x[d] = rol32(x[d] ^ x[a], 16); \
x[c] = x[c] + x[d]; x[b] = rol32(x[b] ^ x[c], 12); \
x[a] = x[a] + x[b]; x[d] = rol32(x[d] ^ x[a], 8); \
x[c] = x[c] + x[d]; x[b] = rol32(x[b] ^ x[c], 7); \
} while (0)
static const char magic128[] = "expand 16-byte k";
static const char magic256[] = "expand 32-byte k";
/*
* Fill the state array with 16 bytes of magic and 32 bytes of key,
* repeating the key if necessary. The 8-byte stream position and the
* 8-byte nonce are initialized to all-zeroes.
*/
void
chacha20_init(chacha20_ctx *ctx, const uint8_t *key, size_t keylen)
{
memset(ctx, 0, sizeof *ctx);
if (keylen == 32) {
/* magic */
ctx->state[ 0] = le32dec(magic256 + 0);
ctx->state[ 1] = le32dec(magic256 + 4);
ctx->state[ 2] = le32dec(magic256 + 8);
ctx->state[ 3] = le32dec(magic256 + 12);
/* first half of key */
ctx->state[ 4] = le32dec(key + 0);
ctx->state[ 5] = le32dec(key + 4);
ctx->state[ 6] = le32dec(key + 8);
ctx->state[ 7] = le32dec(key + 12);
/* second half of key */
ctx->state[ 8] = le32dec(key + 16);
ctx->state[ 9] = le32dec(key + 20);
ctx->state[10] = le32dec(key + 24);
ctx->state[11] = le32dec(key + 28);
} else {
/* magic */
ctx->state[ 0] = le32dec(magic128 + 0);
ctx->state[ 1] = le32dec(magic128 + 4);
ctx->state[ 2] = le32dec(magic128 + 8);
ctx->state[ 3] = le32dec(magic128 + 12);
/* first half of key */
ctx->state[ 4] = le32dec(key + 0);
ctx->state[ 5] = le32dec(key + 4);
ctx->state[ 6] = le32dec(key + 8);
ctx->state[ 7] = le32dec(key + 12);
/* repeat first half of key */
ctx->state[ 8] = le32dec(key + 0);
ctx->state[ 9] = le32dec(key + 4);
ctx->state[10] = le32dec(key + 8);
ctx->state[11] = le32dec(key + 12);
}
}
/*
* Reset the stream position and load a new nonce.
*/
void
chacha20_reset(chacha20_ctx *ctx, const uint8_t *nonce)
{
/* reset stream counter */
ctx->state[12] = 0;
ctx->state[13] = 0;
/* copy nonce */
ctx->state[14] = le32dec(nonce + 0);
ctx->state[15] = le32dec(nonce + 4);
}
/*
* Encryption: generate a block of keystream, xor it with the plaintext to
* produce the ciphertext, and increment the stream position. If vpt is
* NULL, simply copy the requested keystream to the output buffer.
*/
size_t
chacha20_encrypt(chacha20_ctx *ctx, const void *vpt, uint8_t *ct, size_t len)
{
const uint8_t *pt = vpt;
uint64_t ctr;
uint32_t mix[16];
uint8_t ks[64];
unsigned int b, i;
len -= len % sizeof ks;
for (b = 0; b < len; b += sizeof ks) {
memcpy(mix, ctx->state, sizeof mix);
for (i = 0; i < 20; i += 2) {
CHACHA_QR(mix, 0, 4, 8, 12);
CHACHA_QR(mix, 1, 5, 9, 13);
CHACHA_QR(mix, 2, 6, 10, 14);
CHACHA_QR(mix, 3, 7, 11, 15);
CHACHA_QR(mix, 0, 5, 10, 15);
CHACHA_QR(mix, 1, 6, 11, 12);
CHACHA_QR(mix, 2, 7, 8, 13);
CHACHA_QR(mix, 3, 4, 9, 14);
}
for (i = 0; i < 16; ++i)
le32enc(ks + i * 4, ctx->state[i] + mix[i]);
if (pt == NULL) {
memcpy(ct, ks, sizeof ks);
ct += sizeof ks;
} else {
for (i = 0; i < 64 && i < len; ++i)
*ct++ = *pt++ ^ ks[i];
}
ctr = le64dec(ctx->state + 12);
le64enc(ctx->state + 12, ++ctr);
}
return (len);
}
/*
* Decryption: identical to encryption.
*/
size_t
chacha20_decrypt(chacha20_ctx *ctx, const uint8_t *ct, void *vpt, size_t len)
{
return (chacha20_encrypt(ctx, ct, vpt, len));
}
/*
* Wipe our state.
*/
void
chacha20_finish(chacha20_ctx *ctx)
{
memset(ctx, 0, sizeof *ctx);
}
#ifdef _KERNEL
static int
chacha20_modevent(module_t mod, int evtype, void *unused)
{
switch (evtype) {
case MOD_LOAD:
return (0);
case MOD_UNLOAD:
return (0);
default:
return (EOPNOTSUPP);
}
}
static moduledata_t chacha20_mod = {
"chacha20",
chacha20_modevent,
0
};
DECLARE_MODULE(chacha20, chacha20_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
MODULE_VERSION(chacha20, 1);
#endif

53
sys/crypto/chacha20/chacha20.h Normal file
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@ -0,0 +1,53 @@
/*-
* Copyright (c) 2017 Dag-Erling Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef SYS_CRYPTO_CHACHA20_H_INCLUDED
#define SYS_CRYPTO_CHACHA20_H_INCLUDED
#ifdef __cplusplus
extern "C" {
#endif
typedef struct {
uint32_t state[16];
} chacha20_ctx;
void chacha20_init(chacha20_ctx *, const uint8_t *, size_t);
void chacha20_reset(chacha20_ctx *, const uint8_t *);
size_t chacha20_encrypt(chacha20_ctx *, const void *, uint8_t *, size_t);
size_t chacha20_decrypt(chacha20_ctx *, const uint8_t *, void *, size_t);
void chacha20_finish(chacha20_ctx *);
#ifdef __cplusplus
}
#endif
#endif

1
sys/modules/Makefile
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@ -73,6 +73,7 @@ SUBDIR= \
cd9660_iconv \
${_ce} \
${_cfi} \
chacha20 \
${_chromebook_platform} \
${_ciss} \
cloudabi \

8
sys/modules/chacha20/Makefile Normal file
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@ -0,0 +1,8 @@
# $FreeBSD$
.PATH: ${SRCTOP}/sys/crypto/chacha20
KMOD= chacha20
SRCS= chacha20.c
.include <bsd.kmod.mk>