CVE-2024-36907 in Linux
الملخص
بحسب VulDB • 28/05/2026
Based on the kernel log provided, here is an analysis of the crash.
### **Summary** This is a **kernel panic/oops** occurring in the **SunRPC subsystem** (`sunrpc`) while attempting to set up a **TLS-enabled TCP connection** (`xs_tcp_tls_setup_socket`). The crash happens during the initialization of an RPC transport, specifically when probing or establishing TLS support.
---
### **Key Details from the Log**
#### **1. Crash Location** - **Function:** `call_start` (offset `0x74/0x138`) - **Module:** `[sunrpc]`
- **Call Trace:** ``` call_start+0x74/0x138 [sunrpc]
__rpc_execute+0xb8/0x3e0 [sunrpc]
rpc_execute+0x160/0x1d8 [sunrpc]
rpc_run_task+0x148/0x1f8 [sunrpc]
tls_probe+0x80/0xd0 [sunrpc] <-- Key function: TLS probing
rpc_ping+0x28/0x80 [sunrpc]
rpc_create_xprt+0x134/0x1a0 [sunrpc]
rpc_create+0x128/0x2a0 [sunrpc]
xs_tcp_tls_setup_socket+0xdc/0x508 [sunrpc] <-- TLS socket setup
```
#### **2. Triggering Context** - The crash occurs in a **kernel worker thread** (`worker_thread`), likely handling an RPC task. - The task was initiated by `rpc_create`, which is creating a new RPC transport. - The transport is being set up with **TLS support** (`xs_tcp_tls_setup_socket`). - The function `tls_probe` is called, which attempts to verify if TLS is supported or to initialize TLS context.
#### **3. Register State Analysis** - **x0-x2:** Point to kernel memory addresses (`ffff00009a509d00`, etc.), likely pointers to RPC task structures or socket contexts. - **x17:** `733d4d4554535953` → ASCII `"SYS=MS"` (likely part of a string or identifier). - **x16:** `42555300312d746e` → ASCII `"n-t1SUB"` (reversed, likely `"n-t1SUB"` or similar). - **x11:** `0101010101010101` → This is a **magic value** often used for debugging or marking uninitialized/invalid memory. Its presence in a register during a crash can indicate: - A pointer to invalid/uninitialized memory. - A corrupted structure. - A deliberate pattern used by the kernel for debugging (e.g., `KASAN` or `SLUB` poisoning).
#### **4. Code Snippet at Crash** ``` Code: f0ffffc2 911fe042 aa1403e1 aa1303e0 (b9401c83) ``` - This is ARM64 assembly. - `b9401c83` is the instruction that caused the fault. - `b9401c83` decodes to `ldr w3, [x0, #0x1c]` (load word from memory address in `x0` + offset `0x1c`).
- **Interpretation:** The CPU tried to read from memory address `x0 + 0x1c`, but this memory was **invalid** (e.g., NULL pointer dereference, use-after-free, or corrupted pointer).
---
### **Root Cause Hypothesis**
1. **NULL Pointer Dereference or Invalid Pointer:** - The `x0` register likely contains a pointer to an RPC task or socket context. - The code tried to access an offset (`0x1c`) within this structure, but the base pointer `x0` was invalid or pointed to freed/corrupted memory.
2. **TLS Initialization Bug:** - The crash occurs in `tls_probe` → `call_start`. - This suggests a bug in how the kernel probes or initializes TLS for an RPC transport. - Possible causes: - A NULL pointer passed to `tls_probe`. - A race condition where the socket/task is freed before TLS setup completes. - A bug in the TLS library integration within Sun
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