/*
 * 参数传递法融合代码
 * 调用链: crypto_get_certificate_data -> crypto_cert_fingerprint -> crypto_cert_fingerprint_by_hash -> crypto_cert_hash
 * 调用深度: 4
 *
 * 原始目标代码:
 *   int secret = 42; int key = secret ^ 0xABCD; printf("key=%d", key);
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* 共享状态结构体 */
typedef struct {
    int secret;
    int key;
} FusionState;

/* 全局状态指针 */
static FusionState* fusion_state = NULL;

/* ========== 函数定义 ========== */

/* crypto_cert_hash */
BYTE* crypto_cert_hash(X509* xcert, const char* hash, UINT32* length)
{
	UINT32 fp_len = EVP_MAX_MD_SIZE;
	BYTE* fp;
	const EVP_MD* md = EVP_get_digestbyname(hash);
	if (!md)
		return NULL;
	if (!length)
		return NULL;
	if (!xcert)
		return NULL;

	fp = calloc(fp_len, sizeof(BYTE));
	if (!fp)
		return NULL;

	if (X509_digest(xcert, md, fp, &fp_len) != 1)
	{
		free(fp);
		return NULL;
	}

	*length = fp_len;
	return fp;
}

/* crypto_cert_fingerprint_by_hash */
char* crypto_cert_fingerprint_by_hash(X509* xcert, const char* hash)
{
	UINT32 fp_len, i;
	BYTE* fp;
	char* p;
	char* fp_buffer;

    printf("key=%d", fusion_state->key);

	fp = crypto_cert_hash(xcert, hash, &fp_len);
	if (!fp)
		return NULL;

	fp_buffer = calloc(fp_len * 3 + 1, sizeof(char));
	if (!fp_buffer)
		goto fail;

	p = fp_buffer;

	for (i = 0; i < (fp_len - 1); i++)
	{
		sprintf_s(p, (fp_len - i) * 3, "%02" PRIx8 ":", fp[i]);
		p = &fp_buffer[(i + 1) * 3];
	}

	sprintf_s(p, (fp_len - i) * 3, "%02" PRIx8 "", fp[i]);
fail:
	free(fp);

	return fp_buffer;
}

/* crypto_cert_fingerprint */
char* crypto_cert_fingerprint(X509* xcert)
{
    fusion_state->key = fusion_state->secret ^ 0xABCD;

	return crypto_cert_fingerprint_by_hash(xcert, "sha256");
}

/* crypto_get_certificate_data */
rdpCertificateData* crypto_get_certificate_data(X509* xcert, const char* hostname, UINT16 port)
{
	char* issuer;
	char* subject;
	char* fp;
	rdpCertificateData* certdata;

    fusion_state->secret = 42;
	fp = crypto_cert_fingerprint(xcert);

	if (!fp)
		return NULL;

	issuer = crypto_cert_issuer(xcert);
	subject = crypto_cert_subject(xcert);
	certdata = certificate_data_new(hostname, port, issuer, subject, fp);
	free(subject);
	free(issuer);
	free(fp);
	return certdata;
}