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// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Copyright (C) 2015-2018 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 <zinc/chacha20poly1305.h>
#include <zinc/chacha20.h>
#include <zinc/poly1305.h>
#include <asm/unaligned.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <crypto/scatterwalk.h>
static const u8 pad0[16] = { 0 };
static struct crypto_alg chacha20_alg = {
.cra_blocksize = 1,
.cra_alignmask = sizeof(u32) - 1
};
static struct crypto_blkcipher chacha20_cipher = {
.base = {
.__crt_alg = &chacha20_alg
}
};
static struct blkcipher_desc chacha20_desc = {
.tfm = &chacha20_cipher
};
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);
bool chacha20poly1305_encrypt_sg(struct scatterlist *dst,
struct scatterlist *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 = 0;
struct blkcipher_walk walk;
union {
u8 block0[POLY1305_KEY_SIZE];
u8 mac[POLY1305_MAC_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);
if (likely(src_len)) {
blkcipher_walk_init(&walk, dst, src, src_len);
ret = blkcipher_walk_virt_block(&chacha20_desc, &walk,
CHACHA20_BLOCK_SIZE);
while (walk.nbytes >= CHACHA20_BLOCK_SIZE) {
size_t chunk_len =
rounddown(walk.nbytes, CHACHA20_BLOCK_SIZE);
chacha20(&chacha20_state, walk.dst.virt.addr,
walk.src.virt.addr, chunk_len, simd_context);
poly1305_update(&poly1305_state, walk.dst.virt.addr,
chunk_len, simd_context);
simd_relax(simd_context);
ret = blkcipher_walk_done(&chacha20_desc, &walk,
walk.nbytes % CHACHA20_BLOCK_SIZE);
}
if (walk.nbytes) {
chacha20(&chacha20_state, walk.dst.virt.addr,
walk.src.virt.addr, walk.nbytes, simd_context);
poly1305_update(&poly1305_state, walk.dst.virt.addr,
walk.nbytes, simd_context);
ret = blkcipher_walk_done(&chacha20_desc, &walk, 0);
}
}
if (unlikely(ret))
goto err;
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, b.mac, simd_context);
scatterwalk_map_and_copy(b.mac, dst, src_len, sizeof(b.mac), 1);
err:
memzero_explicit(&chacha20_state, sizeof(chacha20_state));
memzero_explicit(&b, sizeof(b));
return !ret;
}
EXPORT_SYMBOL(chacha20poly1305_encrypt_sg);
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))
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);
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, 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);
bool chacha20poly1305_decrypt_sg(struct scatterlist *dst,
struct scatterlist *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;
struct blkcipher_walk walk;
int ret = 0;
size_t dst_len;
union {
u8 block0[POLY1305_KEY_SIZE];
struct {
u8 read_mac[POLY1305_MAC_SIZE];
u8 computed_mac[POLY1305_MAC_SIZE];
};
__le64 lens[2];
} b = { { 0 } };
if (unlikely(src_len < POLY1305_MAC_SIZE))
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;
if (likely(dst_len)) {
blkcipher_walk_init(&walk, dst, src, dst_len);
ret = blkcipher_walk_virt_block(&chacha20_desc, &walk,
CHACHA20_BLOCK_SIZE);
while (walk.nbytes >= CHACHA20_BLOCK_SIZE) {
size_t chunk_len =
rounddown(walk.nbytes, CHACHA20_BLOCK_SIZE);
poly1305_update(&poly1305_state, walk.src.virt.addr,
chunk_len, simd_context);
chacha20(&chacha20_state, walk.dst.virt.addr,
walk.src.virt.addr, chunk_len, simd_context);
simd_relax(simd_context);
ret = blkcipher_walk_done(&chacha20_desc, &walk,
walk.nbytes % CHACHA20_BLOCK_SIZE);
}
if (walk.nbytes) {
poly1305_update(&poly1305_state, walk.src.virt.addr,
walk.nbytes, simd_context);
chacha20(&chacha20_state, walk.dst.virt.addr,
walk.src.virt.addr, walk.nbytes, simd_context);
ret = blkcipher_walk_done(&chacha20_desc, &walk, 0);
}
}
if (unlikely(ret))
goto err;
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.computed_mac, simd_context);
scatterwalk_map_and_copy(b.read_mac, src, dst_len, POLY1305_MAC_SIZE, 0);
ret = crypto_memneq(b.read_mac, b.computed_mac, POLY1305_MAC_SIZE);
err:
memzero_explicit(&chacha20_state, sizeof(chacha20_state));
memzero_explicit(&b, sizeof(b));
return !ret;
}
EXPORT_SYMBOL(chacha20poly1305_decrypt_sg);
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.h"
#ifndef COMPAT_ZINC_IS_A_MODULE
int __init chacha20poly1305_mod_init(void)
#else
static int __init mod_init(void)
#endif
{
#ifdef CONFIG_ZINC_SELFTEST
if (!chacha20poly1305_selftest())
return -ENOTRECOVERABLE;
#endif
return 0;
}
#ifdef COMPAT_ZINC_IS_A_MODULE
static void __exit mod_exit(void)
{
}
module_init(mod_init);
module_exit(mod_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ChaCha20Poly1305 AEAD construction");
MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
#endif
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