crypto_aes.c

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// SPDX-FileCopyrightText: 2015-2017 pancake <pancake@nopcode.org>
// SPDX-License-Identifier: LGPL-3.0-only
 
#include <rz_lib.h>
#include <rz_crypto.h>
#include <rz_util.h>
#include <aes.h>
 
static void encryptaes(struct aes_ctx *ctx, ut8 *in, ut8 *out) {
    switch (ctx->key_size) {
    case AES128_KEY_SIZE:
        aes128_encrypt(&ctx->u.ctx128, AES_BLOCK_SIZE, out, in);
        break;
    case AES192_KEY_SIZE:
        aes192_encrypt(&ctx->u.ctx192, AES_BLOCK_SIZE, out, in);
        break;
    case AES256_KEY_SIZE:
        aes256_encrypt(&ctx->u.ctx256, AES_BLOCK_SIZE, out, in);
        break;
    default:
        rz_warn_if_reached();
        break;
    }
}
 
static void decryptaes(struct aes_ctx *ctx, ut8 *in, ut8 *out) {
    switch (ctx->key_size) {
    case AES128_KEY_SIZE:
        aes128_decrypt(&ctx->u.ctx128, AES_BLOCK_SIZE, out, in);
        break;
    case AES192_KEY_SIZE:
        aes192_decrypt(&ctx->u.ctx192, AES_BLOCK_SIZE, out, in);
        break;
    case AES256_KEY_SIZE:
        aes256_decrypt(&ctx->u.ctx256, AES_BLOCK_SIZE, out, in);
        break;
    default:
        rz_warn_if_reached();
        break;
    }
}
 
static bool aes_set_key(RzCrypto *cry, const ut8 *key, int keylen, int mode, int direction) {
    rz_return_val_if_fail(cry->user && key, false);
    struct aes_ctx *st = (struct aes_ctx *)cry->user;
 
    if (!(keylen == AES128_KEY_SIZE || keylen == AES192_KEY_SIZE || keylen == AES256_KEY_SIZE)) {
        return false;
    }
    st->key_size = keylen;
    switch (keylen) {
    case AES128_KEY_SIZE:
        if (direction == RZ_CRYPTO_DIR_ENCRYPT) {
            aes128_set_encrypt_key(&st->u.ctx128, key);
        } else {
            aes128_set_decrypt_key(&st->u.ctx128, key);
        }
        break;
    case AES192_KEY_SIZE:
        if (direction == RZ_CRYPTO_DIR_ENCRYPT) {
            aes192_set_encrypt_key(&st->u.ctx192, key);
        } else {
            aes192_set_decrypt_key(&st->u.ctx192, key);
        }
        break;
    case AES256_KEY_SIZE:
        if (direction == RZ_CRYPTO_DIR_ENCRYPT) {
            aes256_set_encrypt_key(&st->u.ctx256, key);
        } else {
            aes256_set_decrypt_key(&st->u.ctx256, key);
        }
        break;
    default:
        rz_warn_if_reached();
        break;
    }
    cry->dir = direction;
    return true;
}
 
static int aes_get_key_size(RzCrypto *cry) {
    rz_return_val_if_fail(cry->user, 0);
    struct aes_ctx *st = (struct aes_ctx *)cry->user;
 
    return st->key_size;
}
 
static bool aes_use(const char *algo) {
    return !strcmp(algo, "aes-ecb");
}
 
static bool update(RzCrypto *cry, const ut8 *buf, int len) {
    rz_return_val_if_fail(cry->user, 0);
    struct aes_ctx *st = (struct aes_ctx *)cry->user;
 
    if (len < 1) {
        return false;
    }
 
    // Pad to the block size, do not append dummy block
    const int diff = (AES_BLOCK_SIZE - (len % AES_BLOCK_SIZE)) % AES_BLOCK_SIZE;
    const int size = len + diff;
    const int blocks = size / AES_BLOCK_SIZE;
    int i;
 
    ut8 *const obuf = calloc(1, size);
    if (!obuf) {
        return false;
    }
    ut8 *const ibuf = calloc(1, size);
    if (!ibuf) {
        free(obuf);
        return false;
    }
 
    memset(ibuf, 0, size);
    memcpy(ibuf, buf, len);
    // Padding should start like 100000...
    if (diff) {
        ibuf[len] = 8; // 0b1000;
    }
 
    if (cry->dir == RZ_CRYPTO_DIR_ENCRYPT) {
        for (i = 0; i < blocks; i++) {
            const int delta = AES_BLOCK_SIZE * i;
            encryptaes(st, ibuf + delta, obuf + delta);
        }
    } else {
        for (i = 0; i < blocks; i++) {
            const int delta = AES_BLOCK_SIZE * i;
            decryptaes(st, ibuf + delta, obuf + delta);
        }
    }
 
    // printf("%128s\n", obuf);
 
    rz_crypto_append(cry, obuf, size);
    free(obuf);
    free(ibuf);
    return true;
}
 
static bool final(RzCrypto *cry, const ut8 *buf, int len) {
    return update(cry, buf, len);
}
 
static bool aes_ecb_init(RzCrypto *cry) {
    rz_return_val_if_fail(cry, false);
 
    cry->user = RZ_NEW0(struct aes_ctx);
    return cry->user != NULL;
}
 
static bool aes_ecb_fini(RzCrypto *cry) {
    rz_return_val_if_fail(cry, false);
 
    free(cry->user);
    return true;
}
 
RzCryptoPlugin rz_crypto_plugin_aes = {
    .name = "aes-ecb",
    .author = "Nettle project (algorithm implementation), pancake (plugin)",
    .license = "LGPL3",
    .set_key = aes_set_key,
    .get_key_size = aes_get_key_size,
    .use = aes_use,
    .update = update,
    .final = final,
    .init = aes_ecb_init,
    .fini = aes_ecb_fini,
};
 
#ifndef RZ_PLUGIN_INCORE
RZ_API RzLibStruct rizin_plugin = {
    .type = RZ_LIB_TYPE_CRYPTO,
    .data = &rz_crypto_plugin_aes,
    .version = RZ_VERSION
};
#endif