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// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* This is an implementation of the ChaCha20Poly1305 AEAD construction.
*
* Information: https://tools.ietf.org/html/rfc8439
*/
#include <sys/support.h>
#include <zinc/chacha20poly1305.h>
#include <zinc/chacha20.h>
#include <zinc/poly1305.h>
#include "selftest/run.h"
static const u8 pad0[CHACHA20_BLOCK_SIZE] = { 0 };
static inline void
__chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len, const u64 nonce,
const u8 key[CHACHA20POLY1305_KEY_SIZE],
simd_context_t *simd_context)
{
struct poly1305_ctx poly1305_state;
struct chacha20_ctx chacha20_state;
union {
u8 block0[POLY1305_KEY_SIZE];
__le64 lens[2];
} b = { { 0 } };
chacha20_init(&chacha20_state, key, nonce);
chacha20(&chacha20_state, b.block0, b.block0, sizeof(b.block0),
simd_context);
poly1305_init(&poly1305_state, b.block0);
poly1305_update(&poly1305_state, ad, ad_len, simd_context);
poly1305_update(&poly1305_state, pad0, (0x10 - ad_len) & 0xf,
simd_context);
chacha20(&chacha20_state, dst, src, src_len, simd_context);
poly1305_update(&poly1305_state, dst, src_len, simd_context);
poly1305_update(&poly1305_state, pad0, (0x10 - src_len) & 0xf,
simd_context);
b.lens[0] = cpu_to_le64(ad_len);
b.lens[1] = cpu_to_le64(src_len);
poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens),
simd_context);
poly1305_final(&poly1305_state, dst + src_len, simd_context);
memzero_explicit(&chacha20_state, sizeof(chacha20_state));
memzero_explicit(&b, sizeof(b));
}
void chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len,
const u64 nonce,
const u8 key[CHACHA20POLY1305_KEY_SIZE])
{
simd_context_t simd_context;
simd_get(&simd_context);
__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, nonce, key,
&simd_context);
simd_put(&simd_context);
}
EXPORT_SYMBOL(chacha20poly1305_encrypt);
static inline bool
__chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len, const u64 nonce,
const u8 key[CHACHA20POLY1305_KEY_SIZE],
simd_context_t *simd_context)
{
struct poly1305_ctx poly1305_state;
struct chacha20_ctx chacha20_state;
int ret;
size_t dst_len;
union {
u8 block0[POLY1305_KEY_SIZE];
u8 mac[POLY1305_MAC_SIZE];
__le64 lens[2];
} b = { { 0 } };
if (unlikely(src_len < POLY1305_MAC_SIZE)) {
printf("src_len too short\n");
return false;
}
chacha20_init(&chacha20_state, key, nonce);
chacha20(&chacha20_state, b.block0, b.block0, sizeof(b.block0),
simd_context);
poly1305_init(&poly1305_state, b.block0);
poly1305_update(&poly1305_state, ad, ad_len, simd_context);
poly1305_update(&poly1305_state, pad0, (0x10 - ad_len) & 0xf,
simd_context);
dst_len = src_len - POLY1305_MAC_SIZE;
poly1305_update(&poly1305_state, src, dst_len, simd_context);
poly1305_update(&poly1305_state, pad0, (0x10 - dst_len) & 0xf,
simd_context);
b.lens[0] = cpu_to_le64(ad_len);
b.lens[1] = cpu_to_le64(dst_len);
poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens),
simd_context);
poly1305_final(&poly1305_state, b.mac, simd_context);
ret = crypto_memneq(b.mac, src + dst_len, POLY1305_MAC_SIZE);
if (likely(!ret))
chacha20(&chacha20_state, dst, src, dst_len, simd_context);
else {
printf("calculated: %16D\n", b.mac, "");
printf("sent : %16D\n", src + dst_len, "");
}
memzero_explicit(&chacha20_state, sizeof(chacha20_state));
memzero_explicit(&b, sizeof(b));
return !ret;
}
bool chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len,
const u64 nonce,
const u8 key[CHACHA20POLY1305_KEY_SIZE])
{
simd_context_t simd_context;
bool ret;
simd_get(&simd_context);
ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len, nonce,
key, &simd_context);
simd_put(&simd_context);
return ret;
}
EXPORT_SYMBOL(chacha20poly1305_decrypt);
void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len,
const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
const u8 key[CHACHA20POLY1305_KEY_SIZE])
{
simd_context_t simd_context;
u32 derived_key[CHACHA20_KEY_WORDS] __aligned(16);
simd_get(&simd_context);
hchacha20(derived_key, nonce, key, &simd_context);
cpu_to_le32_array(derived_key, ARRAY_SIZE(derived_key));
__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len,
get_unaligned_le64(nonce + 16),
(u8 *)derived_key, &simd_context);
memzero_explicit(derived_key, CHACHA20POLY1305_KEY_SIZE);
simd_put(&simd_context);
}
EXPORT_SYMBOL(xchacha20poly1305_encrypt);
bool xchacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len,
const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
const u8 key[CHACHA20POLY1305_KEY_SIZE])
{
bool ret;
simd_context_t simd_context;
u32 derived_key[CHACHA20_KEY_WORDS] __aligned(16);
simd_get(&simd_context);
hchacha20(derived_key, nonce, key, &simd_context);
cpu_to_le32_array(derived_key, ARRAY_SIZE(derived_key));
ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
get_unaligned_le64(nonce + 16),
(u8 *)derived_key, &simd_context);
memzero_explicit(derived_key, CHACHA20POLY1305_KEY_SIZE);
simd_put(&simd_context);
return ret;
}
EXPORT_SYMBOL(xchacha20poly1305_decrypt);
#include "selftest/chacha20poly1305.c"
static int __init mod_init(void)
{
if (!selftest_run("chacha20poly1305", chacha20poly1305_selftest,
NULL, 0))
return -ENOTRECOVERABLE;
return 0;
}
static void __exit mod_exit(void)
{
}
module_init(mod_init);
module_exit(mod_exit);
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