crypto_xor.c

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// SPDX-FileCopyrightText: 2009-2017 pancake <pancake@nopcode.org>
// SPDX-License-Identifier: LGPL-3.0-only
 
#include <rz_lib.h>
#include <rz_crypto.h>
#include <rz_util.h>
 
#define MAX_xor_KEY_SIZE 32768
 
struct xor_state {
    ut8 *key;
    int key_size;
};
 
static bool xor_init_state(struct xor_state *const state, const ut8 *key, int keylen) {
    if (!state || !key || keylen < 1) { // || keylen > MAX_xor_KEY_SIZE) {
        return false;
    }
    state->key_size = keylen;
    state->key = malloc(keylen);
    if (!state->key) {
        return false;
    }
    memcpy(state->key, key, keylen);
    return true;
}
 
// Encrypt/Decrypt xor state buffer using the supplied key
static void xor_crypt(struct xor_state *const state, const ut8 *inbuf, ut8 *outbuf, int buflen) {
    int i; // index for input
    for (i = 0; i < buflen; i++) {
        outbuf[i] = inbuf[i] ^ state->key[(i % state->key_size)];
    }
}
 
static bool xor_set_key(RzCrypto *cry, const ut8 *key, int keylen, int mode, int direction) {
    rz_return_val_if_fail(cry->user, 0);
    struct xor_state *st = (struct xor_state *)cry->user;
 
    return xor_init_state(st, key, keylen);
}
 
static int xor_get_key_size(RzCrypto *cry) {
    rz_return_val_if_fail(cry->user, 0);
    struct xor_state *st = (struct xor_state *)cry->user;
 
    return st->key_size;
}
 
static bool xor_use(const char *algo) {
    return !strcmp(algo, "xor");
}
 
static bool update(RzCrypto *cry, const ut8 *buf, int len) {
    rz_return_val_if_fail(cry->user, false);
    struct xor_state *st = (struct xor_state *)cry->user;
 
    ut8 *obuf = calloc(1, len);
    if (!obuf) {
        return false;
    }
    xor_crypt(st, buf, obuf, len);
    rz_crypto_append(cry, obuf, len);
    free(obuf);
    return true;
}
 
static bool final(RzCrypto *cry, const ut8 *buf, int len) {
    return update(cry, buf, len);
}
 
static bool xor_init(RzCrypto *cry) {
    rz_return_val_if_fail(cry, false);
 
    cry->user = RZ_NEW0(struct xor_state);
    return cry->user != NULL;
}
 
static bool xor_fini(RzCrypto *cry) {
    rz_return_val_if_fail(cry, false);
    struct xor_state *state = (struct xor_state *)cry->user;
 
    if (state) {
        free(state->key);
    }
    free(cry->user);
    return true;
}
 
RzCryptoPlugin rz_crypto_plugin_xor = {
    .name = "xor",
    .author = "pancake",
    .license = "LGPL-3",
    .set_key = xor_set_key,
    .get_key_size = xor_get_key_size,
    .use = xor_use,
    .update = update,
    .final = final,
    .init = xor_init,
    .fini = xor_fini,
};
 
#ifndef RZ_PLUGIN_INCORE
RZ_API RzLibStruct rizin_plugin = {
    .type = RZ_LIB_TYPE_CRYPTO,
    .data = &rz_crypto_plugin_xor,
    .version = RZ_VERSION
};
#endif