#include <crypto/chacha.h>
#include <crypto/chacha20poly1305.h>
#include <crypto/poly1305.h>
#include <crypto/utils.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/unaligned.h>
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(struct chacha_state *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);
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,
struct chacha_state *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);
chacha_zeroize_state(chacha_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[at_least CHACHA20POLY1305_KEY_SIZE])
{
struct chacha_state chacha_state;
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[at_least XCHACHA20POLY1305_NONCE_SIZE],
const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
{
struct chacha_state chacha_state;
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,
struct chacha_state *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[at_least CHACHA20POLY1305_KEY_SIZE])
{
struct chacha_state chacha_state;
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);
chacha_zeroize_state(&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[at_least XCHACHA20POLY1305_NONCE_SIZE],
const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
{
struct chacha_state chacha_state;
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[at_least CHACHA20POLY1305_KEY_SIZE],
int encrypt)
{
const u8 *pad0 = page_address(ZERO_PAGE(0));
struct poly1305_desc_ctx poly1305_state;
struct chacha_state chacha_state;
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]);
sg_copy_buffer(src, sg_nents(src), b.mac[encrypt],
sizeof(b.mac[1]), src_len, !encrypt);
ret = encrypt ||
!crypto_memneq(b.mac[0], b.mac[1], POLY1305_DIGEST_SIZE);
}
chacha_zeroize_state(&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[at_least 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[at_least 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 chacha20poly1305_init(void)
{
if (IS_ENABLED(CONFIG_CRYPTO_SELFTESTS) &&
WARN_ON(!chacha20poly1305_selftest()))
return -ENODEV;
return 0;
}
static void __exit chacha20poly1305_exit(void)
{
}
module_init(chacha20poly1305_init);
module_exit(chacha20poly1305_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ChaCha20Poly1305 AEAD construction");
MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
