1 files changed, 116 insertions, 0 deletions
diff --git a/source/tools/decrypter.c b/source/tools/decrypter.c
new file mode 100644
index 0000000..fcdbb72
--- /dev/null
+++ b/source/tools/decrypter.c
@@ -0,0 +1,116 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#ifdef __MINGW32__
+#include <windows.h>
+#else
+#define __cdecl
+#include <string.h>
+#endif
+
+#ifndef i386
+#error "decrypter does work with 32 bit compilation mode only at the moment"
+#endif
+
+#include "crypt.h"
+#include "helper.h"
+
+
+/* see source/decrypter_x86.asm */
+__cdecl int decrypt_data(uint32_t* buf, uint32_t siz, uint32_t* iv, uint32_t* key, uint32_t ivkeysiz) __asm__("__decrypt_x86");
+
+
+int main(int argc, char** argv)
+{
+  bool verbose = false;
+
+  if (argc != 2) {
+    fprintf(stderr, "usage: %s [TESTFILE]\n", argv[0]);
+    return -1;
+  }
+
+  if (getenv("VERBOSE") != NULL) {
+    if (strcmp(getenv("VERBOSE"), "1") == 0) {
+      verbose = true;
+    } else {
+      fprintf(stderr, "%s: quiet mode, activate verbose mode with `export VERBOSE=1`\n", argv[0]);
+    }
+  }
+
+  /* decrypter test */
+  printf("Decrypter........: 0x%p\n", decrypt_data);
+
+  size_t bufsiz = 0;
+  char* buf = mapfile(argv[1], &bufsiz);
+  if (!buf) {
+    return 1;
+  }
+  printf("buffer size......: 0x%p (%lu)\n", (void*)bufsiz, (long unsigned int)bufsiz);
+
+  uint32_t iv[]  = { xor32_randomkey(), xor32_randomkey(), xor32_randomkey(), xor32_randomkey(), xor32_randomkey() };
+  uint32_t key[] = { xor32_randomkey(), xor32_randomkey(), xor32_randomkey(), xor32_randomkey(), xor32_randomkey() };
+  size_t ivkeysiz = sizeof(iv)/sizeof(uint32_t);
+
+  printf("\n---------- Crypter ----------\n");
+  printf("plain buffer adr.: 0x%p\n", buf);
+  printf("iv adr...........: 0x%p\n", &iv[0]);
+  printf("key adr..........: 0x%p\n", &key[0]);
+  if (verbose) {
+    char* bufdata = bintostr(buf, bufsiz, 1, NULL);
+    printf("buffer...........: %s\n", bufdata);
+    free(bufdata);
+  }
+  char* ivdata  = bintostr((char*)&iv[0] , sizeof(iv),  1, NULL);
+  char* keydata = bintostr((char*)&key[0], sizeof(key), 1, NULL);
+  printf("iv...............: %s\n", ivdata);
+  printf("key..............: %s\n", keydata);
+
+  uint32_t* xorbuf = calloc( (bufsiz/sizeof(uint32_t)) + ivkeysiz, sizeof(uint32_t));
+  memcpy((void*)xorbuf, buf, bufsiz);
+  uint32_t xorsiz = xor32n_pcbc_crypt_buf(xorbuf, bufsiz, &iv[0], &key[0], ivkeysiz);
+  printf("encryoted buf adr: 0x%p\n", xorbuf);
+  printf("encrypted size...: 0x%p (%lu)\n", (void*)xorsiz, (long unsigned int)xorsiz);
+
+  char* plainbuf = calloc(xorsiz, sizeof(char));
+  memcpy((void*)plainbuf, (void*)xorbuf, xorsiz);
+  xor32n_pcbc_crypt_buf((uint32_t*)plainbuf, xorsiz, &iv[0], &key[0], ivkeysiz);
+
+  if (verbose) {
+    printf("xor32n_pcbc......: ");
+    char* xordata = bintostr((char*)xorbuf, xorsiz, 1, NULL);
+    printf("%s\n", xordata);
+    free(xordata);
+
+    printf("plaintext........: ");
+    char* plaindata = bintostr((char*)plainbuf, bufsiz, 1, NULL);
+    printf("%s\n", plaindata);
+    free(plaindata);
+  }
+
+  int retval = decrypt_data(xorbuf, xorsiz, &iv[0], &key[0], ivkeysiz);
+  printf("\n--------- Decrypter ---------\n");
+  printf("retval...........: 0x%p (%d)\n", (void*)retval, retval);
+  if (verbose) {
+    printf("decrypted........: ");
+    char* decpdata = bintostr((char*)xorbuf, bufsiz, 1, NULL);
+    printf("%s\n", decpdata);
+    free(decpdata);
+  }
+
+  if (memcmp(plainbuf, buf, bufsiz) != 0) {
+    fprintf(stderr, "%s: c decrypter failed to decrypt data correctly\n", argv[0]);
+    return 1;
+  }
+  if (memcmp(xorbuf, plainbuf, xorsiz) != 0) {
+    fprintf(stderr, "%s: asm decrypter failed to decrypt data correctly\n", argv[0]);
+    return 1;
+  }
+  fprintf(stderr, "\n%s: success\n", argv[0]);
+
+  free(plainbuf);
+  free(xorbuf);
+  free(keydata);
+  free(ivdata);
+
+  return 0;
+}