CVE-2025-71236 in Linux
요약
\~에 의해 VulDB • 2026. 06. 29.
Based on the kernel crash log provided, here is an analysis of the issue and the suggested fix.
### **Analysis**
1. **Crash Type**: The system crashed with a **Page Fault** (`CR2: 0x...f8` indicates access to address `0xf8`, which is clearly invalid/null-like dereference). 2. **Faulting Function**: The call trace points directly to the function: ```c ? qla_fab_async_scan.part.0+0x40b/0x870 [qla2xxx]
``` 3. **Root Cause Hypothesis**: As you suggested, this is highly likely a **NULL pointer dereference** where the code attempts to free memory or access fields of a structure (`sp`) that was not properly initialized or has already been freed elsewhere (use-after-free).
### **Recommended Fix**
You need to locate the `qla_fab_async_scan` function in the Linux kernel source tree under `drivers/scsi/qla2xxx/`. Specifically, look at offset `+0x40b` within that function.
The fix involves adding a NULL check before any operation on the pointer (likely named `sp`, which usually stands for "SCSI Pointer" or similar in this context).
#### **Example Patch Structure**
Assuming the problematic code looks something like this: ```c // BEFORE FIX (Vulnerable) kfree(sp->some_field); // Or sp->func(), etc. ```
It should be changed to: ```c // AFTER FIX (Safe) if (!sp) {
ql_log(ql_log_warn, vha, 0x7xxx, "NULL pointer 'sp' detected in %s\n", __func__); return; // Or handle error appropriately based on context }
kfree(sp->some_field); // Now safe to access sp ```
### **Steps to Implement**
1. **Locate the Source File**: ```bash find /lib/modules/$(uname -r)/build/drivers/scsi/qla2xxx -name "*.c" | xargs grep -l "qla_fab_async_scan" ``` *(Typically `drivers/scsi/qla2xxx/qla_os.c` or similar)*
2. **Identify the Exact Line**: Use `objdump` or readelf to map offset `+0x40b` in `qla_fab_async_scan.part.0` back to source lines, or simply search for recent changes involving memory freeing within that function.
3. **Add NULL Check**: Insert a check like: ```c if (sp == NULL) {
// Log warning and return early ql_log(ql_log_warn, vha, 0x7xxx, "NULL sp in async scan\n"); return; } ```
4. **Recompile and Test**: Recompile the `qla2xxx` module with this fix and test under load to ensure no further crashes occur during fabric scans.
### **Additional Debugging Tip**
If you have access to kernel debugging tools, enable dynamic tracing for this function: ```bash echo 'p qla_fab_async_scan.part.0' > /sys/kernel/debug/dynamic_debug/control dmesg -w | grep "qla2xxx" ``` This will help confirm if `sp` is indeed NULL at the point of failure and whether it’s a race condition or initialization bug.
Let me know if you need help locating the exact source line in your kernel version!
If you want to get best quality of vulnerability data, you may have to visit VulDB.