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Extract shared CCM and streaming media cryptography

stream-multiview
evgeny 1 week ago
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2 changed files with 198 additions and 0 deletions
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  1. 164
      src/media_async/media_crypto.c
  2. 34
      src/media_async/media_crypto.h

164
src/media_async/media_crypto.c
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/* Общая AES-256-CCM криптография сообщений и потоковых файлов; без БД и сети. */
#include "media_crypto.h"
#include "../../lib/debug_config.h"
#include <openssl/evp.h>
#include <openssl/sha.h>
#include <string.h>
#define MEDIA_CRYPTO_ID "media_crypto"
void media_cipher_nonce(uint64_t author, const uint8_t media_id[16], uint64_t part, uint8_t nonce[MEDIA_CIPHER_NONCE_SIZE]) {
SHA256_CTX ctx;
uint8_t hash[32];
SHA256_Init(&ctx);
SHA256_Update(&ctx, "utun_dm_media", 13);
SHA256_Update(&ctx, &author, sizeof(author));
SHA256_Update(&ctx, media_id, 16);
SHA256_Update(&ctx, &part, sizeof(part));
SHA256_Final(hash, &ctx);
memcpy(nonce, hash, MEDIA_CIPHER_NONCE_SIZE);
}
static int media_ccm_crypt(const uint8_t key[MEDIA_CIPHER_KEY_SIZE], const uint8_t nonce[MEDIA_CIPHER_NONCE_SIZE],
const uint8_t* in, size_t in_len, uint8_t* out, size_t* out_len,
int encrypt, const uint8_t* tag_in) {
if (!key || !nonce || (!in && in_len) || !out || !out_len ||
(encrypt ? in_len > MEDIA_CIPHER_PLAIN_MAX : in_len < MEDIA_CIPHER_TAG_SIZE || in_len - MEDIA_CIPHER_TAG_SIZE > MEDIA_CIPHER_PLAIN_MAX)) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: invalid CCM arguments encrypt=%d bytes=%zu", MEDIA_CRYPTO_ID, encrypt, in_len);
return -1;
}
*out_len = 0;
static const uint8_t empty = 0;
if (!in) in = &empty;
EVP_CIPHER_CTX* ectx = EVP_CIPHER_CTX_new();
if (!ectx) { DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: CCM context allocation failed", MEDIA_CRYPTO_ID); return -1; }
const EVP_CIPHER* cipher = EVP_aes_256_ccm();
int rc = -1;
if (encrypt) {
if (EVP_EncryptInit_ex(ectx, cipher, NULL, NULL, NULL) != 1
|| EVP_CIPHER_CTX_ctrl(ectx, EVP_CTRL_AEAD_SET_IVLEN, MEDIA_CIPHER_NONCE_SIZE, NULL) != 1
|| EVP_CIPHER_CTX_ctrl(ectx, EVP_CTRL_AEAD_SET_TAG, MEDIA_CIPHER_TAG_SIZE, NULL) != 1
|| EVP_EncryptInit_ex(ectx, NULL, NULL, key, nonce) != 1) goto done;
int outl;
if (EVP_EncryptUpdate(ectx, NULL, &outl, NULL, (int)in_len) != 1) goto done;
if (EVP_EncryptUpdate(ectx, out, &outl, in, (int)in_len) != 1 || outl != (int)in_len) goto done;
int tmpl;
if (EVP_EncryptFinal_ex(ectx, out + outl, &tmpl) != 1) goto done;
if (EVP_CIPHER_CTX_ctrl(ectx, EVP_CTRL_AEAD_GET_TAG, MEDIA_CIPHER_TAG_SIZE, out + in_len) != 1) goto done;
*out_len = in_len + MEDIA_CIPHER_TAG_SIZE;
} else {
if (in_len < MEDIA_CIPHER_TAG_SIZE) goto done;
size_t body = in_len - MEDIA_CIPHER_TAG_SIZE;
if (EVP_DecryptInit_ex(ectx, cipher, NULL, NULL, NULL) != 1
|| EVP_CIPHER_CTX_ctrl(ectx, EVP_CTRL_AEAD_SET_IVLEN, MEDIA_CIPHER_NONCE_SIZE, NULL) != 1
|| EVP_CIPHER_CTX_ctrl(ectx, EVP_CTRL_AEAD_SET_TAG, MEDIA_CIPHER_TAG_SIZE, (void*)(tag_in ? tag_in : in + body)) != 1
|| EVP_DecryptInit_ex(ectx, NULL, NULL, key, nonce) != 1) goto done;
int outl;
if (EVP_DecryptUpdate(ectx, NULL, &outl, NULL, (int)body) != 1) goto done;
if (EVP_DecryptUpdate(ectx, out, &outl, in, (int)body) != 1 || outl != (int)body) goto done;
*out_len = body;
}
rc = 0;
done:
EVP_CIPHER_CTX_free(ectx);
if (rc) DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: CCM %s failed bytes=%zu", MEDIA_CRYPTO_ID, encrypt ? "encrypt" : "decrypt", in_len);
return rc;
}
int media_ccm_encrypt(const uint8_t key[MEDIA_CIPHER_KEY_SIZE], const uint8_t nonce[MEDIA_CIPHER_NONCE_SIZE],
const uint8_t* plain, size_t plain_len, uint8_t* out, size_t* out_len) {
return media_ccm_crypt(key, nonce, plain, plain_len, out, out_len, 1, NULL);
}
int media_ccm_decrypt(const uint8_t key[MEDIA_CIPHER_KEY_SIZE], const uint8_t nonce[MEDIA_CIPHER_NONCE_SIZE],
const uint8_t* ct, size_t ct_len, uint8_t* out, size_t* out_len) {
return media_ccm_crypt(key, nonce, ct, ct_len, out, out_len, 0, NULL);
}
/* Каждая порция имеет собственный nonce, ciphertext неизменен для всех сетевых повторов. */
int media_encrypt_stream(const uint8_t key[MEDIA_CIPHER_KEY_SIZE], uint64_t author, const uint8_t media_id[16],
FILE* src, FILE* dst, uint64_t* plain_size, uint8_t ciphertext_hash[32]) {
if (!key || !author || !media_id || !src || !dst || src == dst || !plain_size || !ciphertext_hash) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: invalid media encryption arguments", MEDIA_CRYPTO_ID);
return -1;
}
*plain_size = 0;
memset(ciphertext_hash, 0, 32);
uint8_t plain[MEDIA_CIPHER_CHUNK_SIZE], cipher[MEDIA_CIPHER_CHUNK_SIZE + MEDIA_CIPHER_TAG_SIZE], nonce[MEDIA_CIPHER_NONCE_SIZE];
uint64_t part = 0, total = 0;
SHA256_CTX hash;
SHA256_Init(&hash);
for (;;) {
size_t n = fread(plain, 1, sizeof(plain), src);
if (ferror(src)) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media source read failed part=%llu", MEDIA_CRYPTO_ID, (unsigned long long)part);
return -1;
}
if (!n && part) break;
size_t clen = 0;
media_cipher_nonce(author, media_id, part, nonce);
if (media_ccm_encrypt(key, nonce, plain, n, cipher, &clen) != 0) return -1;
if (fwrite(cipher, 1, clen, dst) != clen) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media ciphertext write failed part=%llu", MEDIA_CRYPTO_ID, (unsigned long long)part);
return -1;
}
SHA256_Update(&hash, cipher, clen);
total += n;
part++;
if (n < sizeof(plain)) break;
}
if (fflush(dst) != 0) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media ciphertext flush failed", MEDIA_CRYPTO_ID);
return -1;
}
SHA256_Final(ciphertext_hash, &hash);
*plain_size = total;
DEBUG_DEBUG(DEBUG_CATEGORY_MEDIA, "%s: media encrypted author=%llu plain=%llu records=%llu", MEDIA_CRYPTO_ID,
(unsigned long long)author, (unsigned long long)total, (unsigned long long)part);
return 0;
}
/* Размер и хеш берутся из подписанного manifest; никакого size-only принятия файла. */
int media_decrypt_stream(const uint8_t key[MEDIA_CIPHER_KEY_SIZE], uint64_t author, const uint8_t media_id[16],
uint64_t plain_size, const uint8_t ciphertext_hash[32], FILE* src, FILE* dst) {
if (!key || !author || !media_id || !ciphertext_hash || !src || !dst || src == dst) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: invalid media decryption arguments", MEDIA_CRYPTO_ID);
return -1;
}
uint8_t plain[MEDIA_CIPHER_CHUNK_SIZE], cipher[MEDIA_CIPHER_CHUNK_SIZE + MEDIA_CIPHER_TAG_SIZE], nonce[MEDIA_CIPHER_NONCE_SIZE];
uint64_t remaining = plain_size, part = 0;
SHA256_CTX hash;
SHA256_Init(&hash);
do {
size_t n = remaining > MEDIA_CIPHER_CHUNK_SIZE ? MEDIA_CIPHER_CHUNK_SIZE : (size_t)remaining;
size_t clen = n + MEDIA_CIPHER_TAG_SIZE, plen = 0;
if (fread(cipher, 1, clen, src) != clen) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media ciphertext short/read failure part=%llu expected=%zu", MEDIA_CRYPTO_ID,
(unsigned long long)part, clen);
return -1;
}
SHA256_Update(&hash, cipher, clen);
media_cipher_nonce(author, media_id, part, nonce);
if (media_ccm_decrypt(key, nonce, cipher, clen, plain, &plen) != 0) return -1;
if (plen != n || fwrite(plain, 1, plen, dst) != plen) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media plaintext write/length failure part=%llu", MEDIA_CRYPTO_ID, (unsigned long long)part);
return -1;
}
remaining -= n;
part++;
} while (remaining);
uint8_t actual_hash[32];
SHA256_Final(actual_hash, &hash);
if (fgetc(src) != EOF || ferror(src) || memcmp(actual_hash, ciphertext_hash, 32)) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media ciphertext size/hash mismatch plain=%llu", MEDIA_CRYPTO_ID, (unsigned long long)plain_size);
return -1;
}
if (fflush(dst) != 0) {
DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: media plaintext flush failed", MEDIA_CRYPTO_ID);
return -1;
}
DEBUG_DEBUG(DEBUG_CATEGORY_MEDIA, "%s: media verified author=%llu plain=%llu records=%llu", MEDIA_CRYPTO_ID,
(unsigned long long)author, (unsigned long long)plain_size, (unsigned long long)part);
return 0;
}

34
src/media_async/media_crypto.h
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/* Общие AES-256-CCM примитивы. Файлы обрабатываются порциями с независимыми tags.
* nonce определяется author/UUID/part; UUID новый для каждой подготовки. Домен nonce
* utun_dm_media сохранён для существующего формата DM. Повторы используют готовый ciphertext.
* Файловые функции вызываются в worker; caller открывает файлы и публикует результат
* только после успешной проверки и durable сохранения. 0 = успех, -1 = ошибка. */
#ifndef MEDIA_CRYPTO_H
#define MEDIA_CRYPTO_H
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#ifdef __cplusplus
extern "C" {
#endif
#define MEDIA_CIPHER_KEY_SIZE 32
#define MEDIA_CIPHER_NONCE_SIZE 13
#define MEDIA_CIPHER_TAG_SIZE 16
#define MEDIA_CIPHER_PLAIN_MAX 65535u
#define MEDIA_CIPHER_CHUNK_SIZE 32768u
void media_cipher_nonce(uint64_t author, const uint8_t id[16], uint64_t part, uint8_t nonce[MEDIA_CIPHER_NONCE_SIZE]);
/* out вмещает plain_len+16; расшифровка проверяет tag до возврата plaintext. */
int media_ccm_encrypt(const uint8_t key[32], const uint8_t nonce[13], const uint8_t* plain,
size_t plain_len, uint8_t* out, size_t* out_len);
int media_ccm_decrypt(const uint8_t key[32], const uint8_t nonce[13], const uint8_t* cipher,
size_t cipher_len, uint8_t* out, size_t* out_len);
/* Поток plaintext → ciphertext; возвращает размер оригинала и SHA256 ciphertext. */
int media_encrypt_stream(const uint8_t key[32], uint64_t author, const uint8_t id[16],
FILE* src, FILE* dst, uint64_t* plain_size, uint8_t hash[32]);
/* Проверяет каждый tag, точный размер и полный hash; dst должен быть временным. */
int media_decrypt_stream(const uint8_t key[32], uint64_t author, const uint8_t id[16],
uint64_t plain_size, const uint8_t hash[32], FILE* src, FILE* dst);
#ifdef __cplusplus
}
#endif
#endif
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