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/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include "chacha20poly1305.h"
#include "chacha20.h"
#include "poly1305.h"
#include <asm/unaligned.h>
#include <linux/kernel.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_KEYLEN],
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, simd_context);
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_finish(&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_KEYLEN])
{
simd_context_t simd_context;
simd_context = simd_get();
__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, nonce, key, simd_context);
simd_put(simd_context);
}
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_KEYLEN],
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, simd_context);
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);
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_finish(&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;
}
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_KEYLEN],
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, simd_context);
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_finish(&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_KEYLEN])
{
simd_context_t simd_context, ret;
simd_context = simd_get();
ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len, nonce, key, simd_context);
simd_put(simd_context);
return ret;
}
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_KEYLEN],
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, simd_context);
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);
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_finish(&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;
}
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_NONCELEN],
const u8 key[CHACHA20POLY1305_KEYLEN])
{
simd_context_t simd_context = simd_get();
u8 derived_key[CHACHA20POLY1305_KEYLEN] __aligned(16);
hchacha20(derived_key, nonce, key, simd_context);
__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, get_unaligned_le64(nonce + 16), derived_key, simd_context);
memzero_explicit(derived_key, CHACHA20POLY1305_KEYLEN);
simd_put(simd_context);
}
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_NONCELEN],
const u8 key[CHACHA20POLY1305_KEYLEN])
{
bool ret, simd_context = simd_get();
u8 derived_key[CHACHA20POLY1305_KEYLEN] __aligned(16);
hchacha20(derived_key, nonce, key, simd_context);
ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len, get_unaligned_le64(nonce + 16), derived_key, simd_context);
memzero_explicit(derived_key, CHACHA20POLY1305_KEYLEN);
simd_put(simd_context);
return ret;
}
#include "../selftest/chacha20poly1305.h"
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