scrap-is-not-scrap/pic-linux.c

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <string.h>
#include <errno.h>
#include <sysexits.h>
#include <openssl/sha.h>

char *picProto(void *picAddr, size_t picSize, void *clonePtr) {
  char *(*cloneFunc)(void *, size_t) = clonePtr;
  return cloneFunc(picAddr, picSize);
}

char *clone(void *picAddr, size_t picSize) {
  auto retVal = EX_SOFTWARE;

  srand((unsigned int)time(NULL));

  unsigned int picOffset = (rand() % (picSize + 1));

  ((char *)picAddr)[picOffset] = ((char *)picAddr)[picOffset] & (rand() % 1);

  unsigned char *digest = NULL;
  SHA_CTX sha;

  SHA1_Init(&sha);
  SHA1_Update(&sha, picAddr, picSize);
  SHA1_Final(digest, &sha);

  char *fileOutPath = NULL;
  sprintf(fileOutPath, "./%s_%x.bin", digest, rand());

  FILE *fileOutHandle = fopen(fileOutPath, "wb");
  if (NULL == fileOutHandle) {
    retVal = EX_SOFTWARE;
    goto CLONE_CLEANUP;
  }

  retVal = fwrite(picAddr, 1, picSize, fileOutHandle);
  if (retVal != picSize) {
    retVal = EX_SOFTWARE;
    goto CLONE_CLEANUP;
  }

  retVal = EX_OK;
CLONE_CLEANUP:
  if (fileOutHandle) {
    fclose(fileOutHandle);
  }
  return fileOutPath;
}

int main(int argc, const char **argv) {
  auto retVal = EX_SOFTWARE;
  char *fileInPath = argv[1];

  FILE *fileInHandle = fopen(fileInPath, "rb");
  if (NULL == fileInHandle) {
    retVal = EX_SOFTWARE;
    goto MAIN_CLEANUP;
  }

  fseek(fileInHandle, 0L, SEEK_END);
  size_t picBuffer_len = ftell(fileInHandle);
  fseek(fileInHandle, 0L, SEEK_SET);
  if (0 >= picBuffer_len) {
    retVal = EX_SOFTWARE;
    goto MAIN_CLEANUP;
  }

  void *picBuffer = malloc(picBuffer_len);
  if (NULL == picBuffer) {
    retVal = EX_SOFTWARE;
    goto MAIN_CLEANUP;
  }

  memset_s(&picBuffer, picBuffer_len, 0, picBuffer_len);
  retVal = mprotect(picBuffer, picBuffer_len, PROT_EXEC);
  if (0 == retVal) {
    retVal = EX_SOFTWARE;
    goto MAIN_CLEANUP;
  }

  retVal = fread(picBuffer, 1, picBuffer_len, fileInHandle);
  if (retVal != picBuffer_len) {
    retVal = EX_SOFTWARE;
    goto MAIN_CLEANUP;
  }

  if (fileInHandle) {
    fclose(fileInHandle);
  }

  char *(*cloneFunc)(void *, size_t) = clone;
  void *(*picFunc)(void *, size_t, void *) = picBuffer;

  char *childPath = picFunc(picBuffer, picBuffer_len, cloneFunc);

  retVal = EX_OK;
MAIN_CLEANUP:
  if (fileInHandle) {
    fclose(fileInHandle);
  }
  if (picBuffer) {
    free(picBuffer);
  }
  return retVal;
}