blob: 9bdc9cc141e66f67bb5d1a46f18d7d110468934d [file] [log] [blame]
/*
* Copyright (c) 2016-2023 DeNA Co., Ltd., Kazuho Oku, Lars Eggert, Christian
Huitema, Fastly
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <stddef.h>
#include "picotls.h"
#define CHACHA20POLY1305_BLOCKSIZE 64
struct chacha20poly1305_context_t {
ptls_aead_context_t super;
ptls_cipher_context_t *chacha;
uint8_t static_iv[PTLS_CHACHA20POLY1305_IV_SIZE];
size_t aadlen;
size_t textlen;
void (*poly1305_init)(struct chacha20poly1305_context_t *, const void *);
void (*poly1305_update)(struct chacha20poly1305_context_t *, const void *, size_t);
void (*poly1305_finish)(struct chacha20poly1305_context_t *, void *);
};
static void chacha20poly1305_write_u64(uint8_t *buf, uint64_t v)
{
*buf++ = v & 0xff;
*buf++ = (v >> 8) & 0xff;
*buf++ = (v >> 16) & 0xff;
*buf++ = (v >> 24) & 0xff;
*buf++ = (v >> 32) & 0xff;
*buf++ = (v >> 40) & 0xff;
*buf++ = (v >> 48) & 0xff;
*buf = (v >> 56) & 0xff;
}
static void chacha20poly1305_encrypt_pad(struct chacha20poly1305_context_t *ctx, size_t n)
{
static const uint8_t zeros[16] = {0};
if (n % 16 != 0)
ctx->poly1305_update(ctx, zeros, 16 - (n % 16));
}
static void chacha20poly1305_finalize(struct chacha20poly1305_context_t *ctx, uint8_t *tag)
{
uint8_t lenbuf[16];
chacha20poly1305_encrypt_pad(ctx, ctx->textlen);
chacha20poly1305_write_u64(lenbuf, ctx->aadlen);
chacha20poly1305_write_u64(lenbuf + 8, ctx->textlen);
ctx->poly1305_update(ctx, lenbuf, sizeof(lenbuf));
ctx->poly1305_finish(ctx, tag);
}
static void chacha20poly1305_dispose_crypto(ptls_aead_context_t *_ctx)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
ptls_cipher_free(ctx->chacha);
}
static void chacha20poly1305_init(ptls_aead_context_t *_ctx, uint64_t seq, const void *aad, size_t aadlen)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
uint8_t tmpbuf[CHACHA20POLY1305_BLOCKSIZE];
/* init chacha */
memset(tmpbuf, 0, 16 - PTLS_CHACHA20POLY1305_IV_SIZE);
ptls_aead__build_iv(ctx->super.algo, tmpbuf + 16 - PTLS_CHACHA20POLY1305_IV_SIZE, ctx->static_iv, seq);
ptls_cipher_init(ctx->chacha, tmpbuf);
/* init poly1305 */
memset(tmpbuf, 0, sizeof(tmpbuf));
ptls_cipher_encrypt(ctx->chacha, tmpbuf, tmpbuf, CHACHA20POLY1305_BLOCKSIZE);
ctx->poly1305_init(ctx, tmpbuf);
ptls_clear_memory(tmpbuf, sizeof(tmpbuf));
/* aad */
if (aadlen != 0) {
ctx->poly1305_update(ctx, aad, aadlen);
chacha20poly1305_encrypt_pad(ctx, aadlen);
}
ctx->aadlen = aadlen;
ctx->textlen = 0;
}
static size_t chacha20poly1305_encrypt_update(ptls_aead_context_t *_ctx, void *output, const void *input, size_t inlen)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
ptls_cipher_encrypt(ctx->chacha, output, input, inlen);
ctx->poly1305_update(ctx, output, inlen);
ctx->textlen += inlen;
return inlen;
}
static size_t chacha20poly1305_encrypt_final(ptls_aead_context_t *_ctx, void *output)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
chacha20poly1305_finalize(ctx, output);
return PTLS_CHACHA20POLY1305_TAG_SIZE;
}
static size_t chacha20poly1305_decrypt(ptls_aead_context_t *_ctx, void *output, const void *input, size_t inlen, uint64_t seq,
const void *aad, size_t aadlen)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
uint8_t tag[PTLS_CHACHA20POLY1305_TAG_SIZE];
size_t ret;
if (inlen < sizeof(tag))
return SIZE_MAX;
chacha20poly1305_init(&ctx->super, seq, aad, aadlen);
ctx->poly1305_update(ctx, input, inlen - sizeof(tag));
ctx->textlen = inlen - sizeof(tag);
chacha20poly1305_finalize(ctx, tag);
if (ptls_mem_equal(tag, (const uint8_t *)input + inlen - sizeof(tag), sizeof(tag))) {
ptls_cipher_encrypt(ctx->chacha, output, input, inlen - sizeof(tag));
ret = inlen - sizeof(tag);
} else {
ret = SIZE_MAX;
}
ptls_clear_memory(tag, sizeof(tag));
return ret;
}
static void chacha20poly1305_get_iv(ptls_aead_context_t *_ctx, void *iv)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
memcpy(iv, ctx->static_iv, sizeof(ctx->static_iv));
}
static void chacha20poly1305_set_iv(ptls_aead_context_t *_ctx, const void *iv)
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
memcpy(ctx->static_iv, iv, sizeof(ctx->static_iv));
}
static int chacha20poly1305_setup_crypto(ptls_aead_context_t *_ctx, int is_enc, const void *key, const void *iv,
ptls_cipher_algorithm_t *chacha,
void (*poly1305_init)(struct chacha20poly1305_context_t *, const void *),
void (*poly1305_update)(struct chacha20poly1305_context_t *, const void *, size_t),
void (*poly1305_finish)(struct chacha20poly1305_context_t *, void *))
{
struct chacha20poly1305_context_t *ctx = (struct chacha20poly1305_context_t *)_ctx;
ctx->super.dispose_crypto = chacha20poly1305_dispose_crypto;
ctx->super.do_get_iv = chacha20poly1305_get_iv;
ctx->super.do_set_iv = chacha20poly1305_set_iv;
if (is_enc) {
ctx->super.do_encrypt_init = chacha20poly1305_init;
ctx->super.do_encrypt_update = chacha20poly1305_encrypt_update;
ctx->super.do_encrypt_final = chacha20poly1305_encrypt_final;
ctx->super.do_encrypt = ptls_aead__do_encrypt;
ctx->super.do_encrypt_v = ptls_aead__do_encrypt_v;
ctx->super.do_decrypt = NULL;
} else {
ctx->super.do_encrypt_init = NULL;
ctx->super.do_encrypt_update = NULL;
ctx->super.do_encrypt_final = NULL;
ctx->super.do_encrypt = NULL;
ctx->super.do_encrypt_v = NULL;
ctx->super.do_decrypt = chacha20poly1305_decrypt;
}
if ((ctx->chacha = ptls_cipher_new(chacha, is_enc, key)) == NULL)
return PTLS_ERROR_LIBRARY;
memcpy(ctx->static_iv, iv, sizeof(ctx->static_iv));
ctx->poly1305_init = poly1305_init;
ctx->poly1305_update = poly1305_update;
ctx->poly1305_finish = poly1305_finish;
return 0;
}