CVE-2025-68360 in Linux
Sumário
de VulDB • 15/06/2026
This crash occurs in the MediaTek WED (Wireless Ethernet Dispatch) offload subsystem, specifically within `mt76_wed_offload_disable`. The call trace indicates that the kernel is trying to disable WED offload for a flow, but it is using an incorrect or stale WED device reference (`wed` pointer).
### Root Cause Analysis
1. **Race Condition / Stale Reference**: The `mtk_wed_flow_remove` function is called from the flow offload workqueue (`nf_flow_offload_ipv6_hook`). At this point, the network interface or the WED device itself might have already been detached, reset, or is in the process of being torn down. 2. **Incorrect WED Pointer**: The `mt76_wed_offload_disable` function expects a valid `struct mt76_wed *wed` pointer. However, the code is likely deriving this pointer from a flow entry or a netdev that no longer holds a valid reference to the active WED instance. 3. **Missing Validation**: The code does not check if the WED device is still valid or if the flow is still associated with a live WED instance before attempting to disable offload.
### Solution
The fix involves ensuring that the correct WED reference is used when handling flow offload callbacks. This typically requires:
1. **Validating the WED pointer**: Before calling `mt76_wed_offload_disable`, check if the WED device is still valid. 2. **Using the correct WED instance**: Ensure that the flow offload callback uses the WED instance associated with the specific netdev/interface that triggered the event, rather than a global or stale pointer. 3. **Adding NULL checks**: Prevent dereferencing a NULL or invalid WED pointer.
### Patch
Below is a conceptual patch for the `mtk_wed_flow_remove` function in the MediaTek WED driver. The exact file path may vary depending on your kernel version (e.g., `drivers/net/ethernet/mediatek/mtk_wed.c` or similar).
```c // File: drivers/net/ethernet/mediatek/mtk_wed.c (or equivalent)
#include <linux/netdevice.h> #include <net/flow_offload.h> #include "mtk_wed.h" #include "mt76.h"
// ... existing code ...
static void mtk_wed_flow_remove(struct flow_offload *flow, void *data) {
struct mtk_wed_flow *wed_flow = data; struct mtk_wed *wed = wed_flow->wed; // Assuming this structure exists struct net_device *dev = wed_flow->dev; struct mt76_dev *mdev; struct mt76_wed *wed_dev;
// Check if the WED flow structure is valid if (!wed_flow || !wed) return;
// Get the mt76 device from the WED structure mdev = container_of(wed, struct mt76_dev, wed); if (!mdev) return;
// Get the WED device structure wed_dev = &mdev->wed; if (!wed_dev) return;
// Validate that the netdev is still valid and associated with this WED if (!dev || dev->reg_state != NETREG_REGISTERED) return;
// Additional check: Ensure the flow is still active in the WED hardware // This might involve checking a flag or state in the flow structure if (!wed_flow->active) return;
// Disable offload for this flow using the correct WED reference // This is the critical call that was crashing mt76_wed_offload_disable(wed_dev, flow);
// Mark the flow as inactive to prevent further processing wed_flow->active = false; }
// ... existing code ... ```
### Key Changes Explained
1. **Pointer Validation**: Added checks for `wed_flow`, `wed`, `mdev`, and `wed_dev` to ensure none of them are NULL before proceeding. 2. **Netdev State Check**: Verified that the network device (`dev`) is still registered (`NETREG_REGISTERED`). If the device has been unregistered, the WED offload should not be attempted. 3. **Flow Activity Check**: Added a check for `wed_flow->active` to ensure the flow is still considered active in the WED subsystem. This prevents disabling offload for flows that have already been cleaned up. 4. **Correct WED Reference**: Ensured that `mt76_wed_offload_disable` is called with the correct `wed_dev` pointer derived from the flow's associated WED structure, rather than a potentially stale
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