lilcrypto/aead_chacha20_poly1305.c

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/*
* Copyright (c) 2024 Lucas Gabriel Vuotto <lucas@lgv5.net>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <limits.h>
#include <string.h>
#include "internal.h"
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#include "util.h"
/*
* Implements ChaCha20-Poly1305 according to RFC 8439, XChaCha20-Poly1305
* according to draft-irtf-cfrg-xchacha-03.
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*/
enum aead_mode {
AEAD_SEAL,
AEAD_OPEN,
};
static int
chacha20_poly1305_anycrypt_init(void *arg, void *initparams, enum aead_mode m)
{
struct lc_chacha20_poly1305_params *params = initparams;
struct chacha20_poly1305_state *state = arg;
struct lc_chacha20_params cparams;
struct lc_poly1305_params aparams;
size_t olen;
if (params->cipher->impl != lc_cipher_impl_chacha20() ||
params->auth->impl != lc_auth_impl_poly1305())
return 0;
state->auth = params->auth;
state->cipher = params->cipher;
state->aadlen = state->ctlen = 0;
state->aaddone = 0;
memcpy(cparams.key, params->key, sizeof(params->key));
memcpy(cparams.nonce, params->nonce, sizeof(params->nonce));
cparams.counter = 0;
if (!lc_cipher_encrypt(state->cipher->impl, aparams.key, &olen,
&cparams, zerobuf, LC_POLY1305_KEYLEN))
return 0;
if (!lc_auth_init(state->auth, &aparams))
return 0;
cparams.counter = 1;
switch (m) {
case AEAD_SEAL:
if (!lc_cipher_encrypt_init(state->cipher, &cparams))
return 0;
break;
case AEAD_OPEN:
if (!lc_cipher_decrypt_init(state->cipher, &cparams))
return 0;
break;
default:
return 0;
}
return 1;
}
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static int
xchacha20_poly1305_anycrypt_init(void *arg, void *initparams, enum aead_mode m)
{
struct lc_xchacha20_poly1305_params *params = initparams;
struct chacha20_poly1305_state *state = arg;
struct lc_xchacha20_params cparams;
struct lc_poly1305_params aparams;
size_t olen;
if (params->cipher->impl != lc_cipher_impl_xchacha20() ||
params->auth->impl != lc_auth_impl_poly1305())
return 0;
state->auth = params->auth;
state->cipher = params->cipher;
state->aadlen = state->ctlen = 0;
state->aaddone = 0;
memcpy(cparams.key, params->key, sizeof(params->key));
memcpy(cparams.nonce, params->nonce, sizeof(params->nonce));
cparams.counter = 0;
if (!lc_cipher_encrypt(state->cipher->impl, aparams.key, &olen,
&cparams, zerobuf, LC_POLY1305_KEYLEN))
return 0;
if (!lc_auth_init(state->auth, &aparams))
return 0;
cparams.counter = 1;
switch (m) {
case AEAD_SEAL:
if (!lc_cipher_encrypt_init(state->cipher, &cparams))
return 0;
break;
case AEAD_OPEN:
if (!lc_cipher_decrypt_init(state->cipher, &cparams))
return 0;
break;
default:
return 0;
}
return 1;
}
static int
c20_xc20_poly1305_anycrypt_update(void *arg, uint8_t *out, size_t *outlen,
const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen,
enum aead_mode m)
{
struct chacha20_poly1305_state *state = arg;
size_t ctlen;
*outlen = 0;
switch (m) {
case AEAD_SEAL:
if (!lc_cipher_encrypt_update(state->cipher, NULL, &ctlen, in,
inlen))
return 0;
break;
case AEAD_OPEN:
if (!lc_cipher_decrypt_update(state->cipher, NULL, &ctlen, in,
inlen))
return 0;
break;
default:
if (!lc_cipher_decrypt_update(state->cipher, NULL, &ctlen, in,
inlen))
return 0;
return 0;
}
if (aadlen > UINT64_MAX - state->aadlen ||
ctlen > UINT64_MAX - state->ctlen)
return 0;
if (aadlen > 0 && state->aaddone)
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return 0;
if (out == NULL) {
*outlen = ctlen;
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return 1;
}
if (aadlen > 0) {
if (!lc_auth_update(state->auth, aad, aadlen))
return 0;
state->aadlen += aadlen;
}
if (inlen > 0) {
if (!state->aaddone) {
if (state->aadlen % 16 != 0 &&
!lc_auth_update(state->auth, zerobuf,
16 - (state->aadlen % 16)))
return 0;
state->aaddone = 1;
}
switch (m) {
case AEAD_SEAL:
if (!lc_cipher_encrypt_update(state->cipher, out,
outlen, in, inlen))
return 0;
if (!lc_auth_update(state->auth, out, *outlen))
return 0;
state->ctlen += *outlen;
break;
case AEAD_OPEN:
if (!lc_auth_update(state->auth, in, inlen))
return 0;
if (!lc_cipher_decrypt_update(state->cipher, out,
outlen, in, inlen))
return 0;
state->ctlen += inlen;
break;
default:
return 0;
}
}
return 1;
}
static int
chacha20_poly1305_seal_init(void *arg, void *initparams)
{
return chacha20_poly1305_anycrypt_init(arg, initparams, AEAD_SEAL);
}
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static int
xchacha20_poly1305_seal_init(void *arg, void *initparams)
{
return xchacha20_poly1305_anycrypt_init(arg, initparams, AEAD_SEAL);
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}
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static int
c20_xc20_poly1305_seal_update(void *arg, uint8_t *out, size_t *outlen,
const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen)
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{
return c20_xc20_poly1305_anycrypt_update(arg, out, outlen, aad, aadlen,
in, inlen, AEAD_SEAL);
}
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static int
c20_xc20_poly1305_seal_final(void *arg, uint8_t *out, size_t *outlen,
uint8_t *tag, size_t *taglen)
{
struct chacha20_poly1305_state *state = arg;
uint8_t buf[sizeof(uint64_t) * 2];
size_t ctlen;
*outlen = *taglen = 0;
if (!lc_cipher_encrypt_final(state->cipher, NULL, &ctlen))
return 0;
if (ctlen > UINT64_MAX - state->ctlen)
return 0;
if (out == NULL || tag == NULL) {
*outlen = ctlen;
*taglen = LC_POLY1305_TAGLEN;
return 1;
}
if (!state->aaddone) {
if (state->aadlen % 16 != 0 &&
!lc_auth_update(state->auth, zerobuf,
16 - (state->aadlen % 16)))
return 0;
state->aaddone = 1;
}
if (!lc_cipher_encrypt_final(state->cipher, out, outlen))
return 0;
if (!lc_auth_update(state->auth, out, *outlen))
return 0;
state->ctlen += *outlen;
if (state->ctlen % 16 != 0 &&
!lc_auth_update(state->auth, zerobuf, 16 - (state->ctlen % 16)))
return 0;
store64le(&buf[0], state->aadlen);
store64le(&buf[sizeof(uint64_t)], state->ctlen);
if (!lc_auth_update(state->auth, buf, sizeof(buf)) ||
!lc_auth_final(state->auth, tag, taglen))
return 0;
return 1;
}
static int
chacha20_poly1305_seal(uint8_t *out, size_t *outlen, uint8_t *tag,
size_t *taglen, void *initparams, const uint8_t *aad, size_t aadlen,
const uint8_t *in, size_t inlen)
{
struct chacha20_poly1305_state state;
size_t olen;
*outlen = *taglen = 0;
/* inlen and aadlen are capped by design. */
if (inlen > UINT64_MAX || aadlen > UINT64_MAX)
return 0;
/* Counter 0 is used for deriving Poly1305 key. */
if (inlen > SIZE_MAX - (LC_CHACHA20_BLOCKLEN - 1) ||
(inlen + LC_CHACHA20_BLOCKLEN - 1) / LC_CHACHA20_BLOCKLEN >
CHACHA20_CTRMAX - 1)
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return 0;
if (out == NULL || tag == NULL) {
*outlen = inlen;
*taglen = LC_POLY1305_TAGLEN;
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return 1;
}
if (!chacha20_poly1305_anycrypt_init(&state, initparams, AEAD_SEAL))
return 0;
if (!c20_xc20_poly1305_anycrypt_update(&state, out, &olen, aad, aadlen,
in, inlen, AEAD_SEAL))
return 0;
*outlen = olen;
if (!c20_xc20_poly1305_seal_final(&state, out + olen, &olen, tag,
taglen))
return 0;
*outlen += olen;
return 1;
}
static int
xchacha20_poly1305_seal(uint8_t *out, size_t *outlen, uint8_t *tag,
size_t *taglen, void *initparams, const uint8_t *aad, size_t aadlen,
const uint8_t *in, size_t inlen)
{
struct chacha20_poly1305_state state;
size_t olen;
*outlen = *taglen = 0;
/* inlen and aadlen are capped by design. */
if (inlen > UINT64_MAX || aadlen > UINT64_MAX)
return 0;
/* Counter 0 is used for deriving Poly1305 key. */
if (inlen > SIZE_MAX - (LC_CHACHA20_BLOCKLEN - 1) ||
(inlen + LC_CHACHA20_BLOCKLEN - 1) / LC_CHACHA20_BLOCKLEN >
CHACHA20_CTRMAX - 1)
return 0;
if (out == NULL || tag == NULL) {
*outlen = inlen;
*taglen = LC_POLY1305_TAGLEN;
return 1;
}
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if (!xchacha20_poly1305_anycrypt_init(&state, initparams, AEAD_SEAL))
return 0;
if (!c20_xc20_poly1305_anycrypt_update(&state, out, &olen, aad, aadlen,
in, inlen, AEAD_SEAL))
return 0;
*outlen = olen;
if (!c20_xc20_poly1305_seal_final(&state, out + olen, &olen, tag,
taglen))
return 0;
*outlen += olen;
return 1;
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}
static int
chacha20_poly1305_open_init(void *arg, void *initparams)
{
return chacha20_poly1305_anycrypt_init(arg, initparams, AEAD_OPEN);
}
static int
xchacha20_poly1305_open_init(void *arg, void *initparams)
{
return xchacha20_poly1305_anycrypt_init(arg, initparams, AEAD_OPEN);
}
static int
c20_xc20_poly1305_open_update(void *arg, uint8_t *out, size_t *outlen,
const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen)
{
return c20_xc20_poly1305_anycrypt_update(arg, out, outlen, aad, aadlen,
in, inlen, AEAD_OPEN);
}
static int
c20_xc20_poly1305_open_final(void *arg, uint8_t *out, size_t *outlen,
const uint8_t *tag, size_t taglen)
{
struct chacha20_poly1305_state *state = arg;
uint8_t buf[sizeof(uint64_t) * 2],
ctag[LC_POLY1305_TAGLEN];
size_t ctlen, ctaglen;
*outlen = 0;
if (!lc_cipher_decrypt_final(state->cipher, NULL, &ctlen))
return 0;
if (ctlen > UINT64_MAX - state->ctlen ||
taglen != LC_POLY1305_TAGLEN)
return 0;
if (out == NULL) {
*outlen = ctlen;
return 1;
}
if (!state->aaddone) {
if (state->aadlen % 16 != 0 &&
!lc_auth_update(state->auth, zerobuf,
16 - (state->aadlen % 16)))
return 0;
state->aaddone = 1;
}
if (state->ctlen % 16 != 0 &&
!lc_auth_update(state->auth, zerobuf, 16 - (state->ctlen % 16)))
return 0;
store64le(&buf[0], state->aadlen);
store64le(&buf[sizeof(uint64_t)], state->ctlen);
if (!lc_auth_update(state->auth, buf, sizeof(buf)) ||
!lc_auth_final(state->auth, ctag, &ctaglen))
return 0;
if (!lc_ct_cmp(ctag, tag, LC_POLY1305_TAGLEN))
return 0;
return lc_cipher_decrypt_final(state->cipher, out, outlen);
}
static int
chacha20_poly1305_open(uint8_t *out, size_t *outlen, void *initparams,
const uint8_t *tag, size_t taglen, const uint8_t *aad, size_t aadlen,
const uint8_t *in, size_t inlen)
{
struct chacha20_poly1305_state state;
size_t olen;
*outlen = 0;
/* inlen and aadlen are capped by design. */
if (inlen > UINT64_MAX || aadlen > UINT64_MAX)
return 0;
/* Counter 0 is used for deriving Poly1305 key. */
if (inlen > SIZE_MAX - (LC_CHACHA20_BLOCKLEN - 1) ||
(inlen + LC_CHACHA20_BLOCKLEN - 1) / LC_CHACHA20_BLOCKLEN >
CHACHA20_CTRMAX - 1)
return 0;
if (out == NULL) {
*outlen = inlen;
return 1;
}
if (!chacha20_poly1305_anycrypt_init(&state, initparams, AEAD_OPEN))
return 0;
if (!c20_xc20_poly1305_anycrypt_update(&state, out, &olen, aad, aadlen,
in, inlen, AEAD_OPEN))
return 0;
*outlen = olen;
if (!c20_xc20_poly1305_open_final(&state, out + olen, &olen, tag,
taglen))
return 0;
*outlen += olen;
return 1;
}
static int
xchacha20_poly1305_open(uint8_t *out, size_t *outlen, void *initparams,
const uint8_t *tag, size_t taglen, const uint8_t *aad, size_t aadlen,
const uint8_t *in, size_t inlen)
{
struct chacha20_poly1305_state state;
size_t olen;
*outlen = 0;
/* inlen and aadlen are capped by design. */
if (inlen > UINT64_MAX || aadlen > UINT64_MAX)
return 0;
/* Counter 0 is used for deriving Poly1305 key. */
if (inlen > SIZE_MAX - (LC_CHACHA20_BLOCKLEN - 1) ||
(inlen + LC_CHACHA20_BLOCKLEN - 1) / LC_CHACHA20_BLOCKLEN >
CHACHA20_CTRMAX - 1)
return 0;
if (out == NULL) {
*outlen = inlen;
return 1;
}
if (!xchacha20_poly1305_anycrypt_init(&state, initparams, AEAD_OPEN))
return 0;
if (!c20_xc20_poly1305_anycrypt_update(&state, out, &olen, aad, aadlen,
in, inlen, AEAD_OPEN))
return 0;
*outlen = olen;
if (!c20_xc20_poly1305_open_final(&state, out + olen, &olen, tag,
taglen))
return 0;
*outlen += olen;
return 1;
}
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const struct lc_aead_impl *
lc_aead_impl_chacha20_poly1305(void)
{
static struct lc_aead_impl chacha20_poly1305_impl = {
.seal_init = &chacha20_poly1305_seal_init,
.seal_update = &c20_xc20_poly1305_seal_update,
.seal_final = &c20_xc20_poly1305_seal_final,
.seal = &chacha20_poly1305_seal,
.open_init = &chacha20_poly1305_open_init,
.open_update = &c20_xc20_poly1305_open_update,
.open_final = &c20_xc20_poly1305_open_final,
.open = &chacha20_poly1305_open,
.argsz = sizeof(struct chacha20_poly1305_state),
.blocklen = LC_CHACHA20_BLOCKLEN,
};
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return &chacha20_poly1305_impl;
}
const struct lc_aead_impl *
lc_aead_impl_xchacha20_poly1305(void)
{
static struct lc_aead_impl xchacha20_poly1305_impl = {
.seal_init = &xchacha20_poly1305_seal_init,
.seal_update = &c20_xc20_poly1305_seal_update,
.seal_final = &c20_xc20_poly1305_seal_final,
.seal = &xchacha20_poly1305_seal,
.open_init = &xchacha20_poly1305_open_init,
.open_update = &c20_xc20_poly1305_open_update,
.open_final = &c20_xc20_poly1305_open_final,
.open = &xchacha20_poly1305_open,
.argsz = sizeof(struct chacha20_poly1305_state),
.blocklen = LC_CHACHA20_BLOCKLEN,
};
return &xchacha20_poly1305_impl;
}