cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

binderfs_example.c (1987B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3#define _GNU_SOURCE
      4#include <errno.h>
      5#include <fcntl.h>
      6#include <sched.h>
      7#include <stdio.h>
      8#include <stdlib.h>
      9#include <string.h>
     10#include <sys/ioctl.h>
     11#include <sys/mount.h>
     12#include <sys/stat.h>
     13#include <sys/types.h>
     14#include <unistd.h>
     15#include <linux/android/binder.h>
     16#include <linux/android/binderfs.h>
     17
     18int main(int argc, char *argv[])
     19{
     20	int fd, ret, saved_errno;
     21	struct binderfs_device device = { 0 };
     22
     23	ret = unshare(CLONE_NEWNS);
     24	if (ret < 0) {
     25		fprintf(stderr, "%s - Failed to unshare mount namespace\n",
     26			strerror(errno));
     27		exit(EXIT_FAILURE);
     28	}
     29
     30	ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
     31	if (ret < 0) {
     32		fprintf(stderr, "%s - Failed to mount / as private\n",
     33			strerror(errno));
     34		exit(EXIT_FAILURE);
     35	}
     36
     37	ret = mkdir("/dev/binderfs", 0755);
     38	if (ret < 0 && errno != EEXIST) {
     39		fprintf(stderr, "%s - Failed to create binderfs mountpoint\n",
     40			strerror(errno));
     41		exit(EXIT_FAILURE);
     42	}
     43
     44	ret = mount(NULL, "/dev/binderfs", "binder", 0, 0);
     45	if (ret < 0) {
     46		fprintf(stderr, "%s - Failed to mount binderfs\n",
     47			strerror(errno));
     48		exit(EXIT_FAILURE);
     49	}
     50
     51	memcpy(device.name, "my-binder", strlen("my-binder"));
     52
     53	fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC);
     54	if (fd < 0) {
     55		fprintf(stderr, "%s - Failed to open binder-control device\n",
     56			strerror(errno));
     57		exit(EXIT_FAILURE);
     58	}
     59
     60	ret = ioctl(fd, BINDER_CTL_ADD, &device);
     61	saved_errno = errno;
     62	close(fd);
     63	errno = saved_errno;
     64	if (ret < 0) {
     65		fprintf(stderr, "%s - Failed to allocate new binder device\n",
     66			strerror(errno));
     67		exit(EXIT_FAILURE);
     68	}
     69
     70	printf("Allocated new binder device with major %d, minor %d, and name %s\n",
     71	       device.major, device.minor, device.name);
     72
     73	ret = unlink("/dev/binderfs/my-binder");
     74	if (ret < 0) {
     75		fprintf(stderr, "%s - Failed to delete binder device\n",
     76			strerror(errno));
     77		exit(EXIT_FAILURE);
     78	}
     79
     80	/* Cleanup happens when the mount namespace dies. */
     81	exit(EXIT_SUCCESS);
     82}