linux-stable/lib/crypto/chacha20poly1305.c
Jason A. Donenfeld ac88c322d0 crypto: lib/chacha20poly1305 - define empty module exit function
With no mod_exit function, users are unable to unload the module after
use. I'm not aware of any reason why module unloading should be
prohibited for this one, so this commit simply adds an empty exit
function.

Reported-and-tested-by: John Donnelly <john.p.donnelly@oracle.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-01-22 14:58:03 +11:00

373 lines
9.9 KiB
C

// 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 <crypto/algapi.h>
#include <crypto/chacha20poly1305.h>
#include <crypto/chacha.h>
#include <crypto/poly1305.h>
#include <crypto/scatterwalk.h>
#include <asm/unaligned.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/module.h>
#define CHACHA_KEY_WORDS (CHACHA_KEY_SIZE / sizeof(u32))
static void chacha_load_key(u32 *k, const u8 *in)
{
k[0] = get_unaligned_le32(in);
k[1] = get_unaligned_le32(in + 4);
k[2] = get_unaligned_le32(in + 8);
k[3] = get_unaligned_le32(in + 12);
k[4] = get_unaligned_le32(in + 16);
k[5] = get_unaligned_le32(in + 20);
k[6] = get_unaligned_le32(in + 24);
k[7] = get_unaligned_le32(in + 28);
}
static void xchacha_init(u32 *chacha_state, const u8 *key, const u8 *nonce)
{
u32 k[CHACHA_KEY_WORDS];
u8 iv[CHACHA_IV_SIZE];
memset(iv, 0, 8);
memcpy(iv + 8, nonce + 16, 8);
chacha_load_key(k, key);
/* Compute the subkey given the original key and first 128 nonce bits */
chacha_init(chacha_state, k, nonce);
hchacha_block(chacha_state, k, 20);
chacha_init(chacha_state, k, iv);
memzero_explicit(k, sizeof(k));
memzero_explicit(iv, sizeof(iv));
}
static void
__chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len, u32 *chacha_state)
{
const u8 *pad0 = page_address(ZERO_PAGE(0));
struct poly1305_desc_ctx poly1305_state;
union {
u8 block0[POLY1305_KEY_SIZE];
__le64 lens[2];
} b;
chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
poly1305_init(&poly1305_state, b.block0);
poly1305_update(&poly1305_state, ad, ad_len);
if (ad_len & 0xf)
poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
chacha20_crypt(chacha_state, dst, src, src_len);
poly1305_update(&poly1305_state, dst, src_len);
if (src_len & 0xf)
poly1305_update(&poly1305_state, pad0, 0x10 - (src_len & 0xf));
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));
poly1305_final(&poly1305_state, dst + src_len);
memzero_explicit(chacha_state, CHACHA_STATE_WORDS * sizeof(u32));
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])
{
u32 chacha_state[CHACHA_STATE_WORDS];
u32 k[CHACHA_KEY_WORDS];
__le64 iv[2];
chacha_load_key(k, key);
iv[0] = 0;
iv[1] = cpu_to_le64(nonce);
chacha_init(chacha_state, k, (u8 *)iv);
__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, chacha_state);
memzero_explicit(iv, sizeof(iv));
memzero_explicit(k, sizeof(k));
}
EXPORT_SYMBOL(chacha20poly1305_encrypt);
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])
{
u32 chacha_state[CHACHA_STATE_WORDS];
xchacha_init(chacha_state, key, nonce);
__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, chacha_state);
}
EXPORT_SYMBOL(xchacha20poly1305_encrypt);
static bool
__chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
const u8 *ad, const size_t ad_len, u32 *chacha_state)
{
const u8 *pad0 = page_address(ZERO_PAGE(0));
struct poly1305_desc_ctx poly1305_state;
size_t dst_len;
int ret;
union {
u8 block0[POLY1305_KEY_SIZE];
u8 mac[POLY1305_DIGEST_SIZE];
__le64 lens[2];
} b;
if (unlikely(src_len < POLY1305_DIGEST_SIZE))
return false;
chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
poly1305_init(&poly1305_state, b.block0);
poly1305_update(&poly1305_state, ad, ad_len);
if (ad_len & 0xf)
poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
dst_len = src_len - POLY1305_DIGEST_SIZE;
poly1305_update(&poly1305_state, src, dst_len);
if (dst_len & 0xf)
poly1305_update(&poly1305_state, pad0, 0x10 - (dst_len & 0xf));
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));
poly1305_final(&poly1305_state, b.mac);
ret = crypto_memneq(b.mac, src + dst_len, POLY1305_DIGEST_SIZE);
if (likely(!ret))
chacha20_crypt(chacha_state, dst, src, dst_len);
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])
{
u32 chacha_state[CHACHA_STATE_WORDS];
u32 k[CHACHA_KEY_WORDS];
__le64 iv[2];
bool ret;
chacha_load_key(k, key);
iv[0] = 0;
iv[1] = cpu_to_le64(nonce);
chacha_init(chacha_state, k, (u8 *)iv);
ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
chacha_state);
memzero_explicit(chacha_state, sizeof(chacha_state));
memzero_explicit(iv, sizeof(iv));
memzero_explicit(k, sizeof(k));
return ret;
}
EXPORT_SYMBOL(chacha20poly1305_decrypt);
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])
{
u32 chacha_state[CHACHA_STATE_WORDS];
xchacha_init(chacha_state, key, nonce);
return __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
chacha_state);
}
EXPORT_SYMBOL(xchacha20poly1305_decrypt);
static
bool chacha20poly1305_crypt_sg_inplace(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],
int encrypt)
{
const u8 *pad0 = page_address(ZERO_PAGE(0));
struct poly1305_desc_ctx poly1305_state;
u32 chacha_state[CHACHA_STATE_WORDS];
struct sg_mapping_iter miter;
size_t partial = 0;
unsigned int flags;
bool ret = true;
int sl;
union {
struct {
u32 k[CHACHA_KEY_WORDS];
__le64 iv[2];
};
u8 block0[POLY1305_KEY_SIZE];
u8 chacha_stream[CHACHA_BLOCK_SIZE];
struct {
u8 mac[2][POLY1305_DIGEST_SIZE];
};
__le64 lens[2];
} b __aligned(16);
if (WARN_ON(src_len > INT_MAX))
return false;
chacha_load_key(b.k, key);
b.iv[0] = 0;
b.iv[1] = cpu_to_le64(nonce);
chacha_init(chacha_state, b.k, (u8 *)b.iv);
chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
poly1305_init(&poly1305_state, b.block0);
if (unlikely(ad_len)) {
poly1305_update(&poly1305_state, ad, ad_len);
if (ad_len & 0xf)
poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
}
flags = SG_MITER_TO_SG | SG_MITER_ATOMIC;
sg_miter_start(&miter, src, sg_nents(src), flags);
for (sl = src_len; sl > 0 && sg_miter_next(&miter); sl -= miter.length) {
u8 *addr = miter.addr;
size_t length = min_t(size_t, sl, miter.length);
if (!encrypt)
poly1305_update(&poly1305_state, addr, length);
if (unlikely(partial)) {
size_t l = min(length, CHACHA_BLOCK_SIZE - partial);
crypto_xor(addr, b.chacha_stream + partial, l);
partial = (partial + l) & (CHACHA_BLOCK_SIZE - 1);
addr += l;
length -= l;
}
if (likely(length >= CHACHA_BLOCK_SIZE || length == sl)) {
size_t l = length;
if (unlikely(length < sl))
l &= ~(CHACHA_BLOCK_SIZE - 1);
chacha20_crypt(chacha_state, addr, addr, l);
addr += l;
length -= l;
}
if (unlikely(length > 0)) {
chacha20_crypt(chacha_state, b.chacha_stream, pad0,
CHACHA_BLOCK_SIZE);
crypto_xor(addr, b.chacha_stream, length);
partial = length;
}
if (encrypt)
poly1305_update(&poly1305_state, miter.addr,
min_t(size_t, sl, miter.length));
}
if (src_len & 0xf)
poly1305_update(&poly1305_state, pad0, 0x10 - (src_len & 0xf));
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));
if (likely(sl <= -POLY1305_DIGEST_SIZE)) {
if (encrypt) {
poly1305_final(&poly1305_state,
miter.addr + miter.length + sl);
ret = true;
} else {
poly1305_final(&poly1305_state, b.mac[0]);
ret = !crypto_memneq(b.mac[0],
miter.addr + miter.length + sl,
POLY1305_DIGEST_SIZE);
}
}
sg_miter_stop(&miter);
if (unlikely(sl > -POLY1305_DIGEST_SIZE)) {
poly1305_final(&poly1305_state, b.mac[1]);
scatterwalk_map_and_copy(b.mac[encrypt], src, src_len,
sizeof(b.mac[1]), encrypt);
ret = encrypt ||
!crypto_memneq(b.mac[0], b.mac[1], POLY1305_DIGEST_SIZE);
}
memzero_explicit(chacha_state, sizeof(chacha_state));
memzero_explicit(&b, sizeof(b));
return ret;
}
bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
const u8 *ad, const size_t ad_len,
const u64 nonce,
const u8 key[CHACHA20POLY1305_KEY_SIZE])
{
return chacha20poly1305_crypt_sg_inplace(src, src_len, ad, ad_len,
nonce, key, 1);
}
EXPORT_SYMBOL(chacha20poly1305_encrypt_sg_inplace);
bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
const u8 *ad, const size_t ad_len,
const u64 nonce,
const u8 key[CHACHA20POLY1305_KEY_SIZE])
{
if (unlikely(src_len < POLY1305_DIGEST_SIZE))
return false;
return chacha20poly1305_crypt_sg_inplace(src,
src_len - POLY1305_DIGEST_SIZE,
ad, ad_len, nonce, key, 0);
}
EXPORT_SYMBOL(chacha20poly1305_decrypt_sg_inplace);
static int __init mod_init(void)
{
if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS) &&
WARN_ON(!chacha20poly1305_selftest()))
return -ENODEV;
return 0;
}
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>");