CVE-2023-53053 in Linux
Riassunto
di VulDB • 01/07/2026
Based on the crash trace provided, here is an analysis of the issue.
### **Summary** This is a **kernel panic/oops** occurring in the Linux kernel's network subsystem while transmitting packets via a **Packet Socket (`AF_PACKET`)**. The crash happens during `__netdev_start_xmit`, which suggests that either: 1. A driver bug caused an invalid memory access or null pointer dereference during transmission. 2. There is corruption of the `sk_buff` (socket buffer) structure passed to the network device's transmit function. 3. The crash might be a **secondary symptom** of a previous error in user-space or another kernel component that corrupted data structures before they reached this point.
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### **Detailed Trace Analysis**
#### **1. Call Path Breakdown** The stack trace shows the execution flow from system call to driver:
| Function | File/Line | Description | |----------|-----------|-------------| | `entry_SYSCALL_64_after_hwframe` | arch/x86/... | Entry point for 64-bit syscalls. | | `__x64_sys_sendto` | net/socket.c:2150 | The user-space `sendto()` syscall wrapper. | | `packet_sendmsg` | net/packet/af_packet.c:3107 | **Key Function**: Handles sending data via an AF_PACKET socket (raw packet interface). | | `packet_snd` | net/packet/af_packet.c:3075 | Core logic for packet transmission. | | `packet_xmit` | net/packet/af_packet.c:285 | Prepares the skb and calls into the network device driver. | | `dev_direct_xmit` / `__dev_direct_xmit` | net/core/dev.c:4300 | Direct transmit path, bypassing some queuing logic for performance (often used with XDP or specific drivers). | | `netdev_start_xmit` | include/linux/netdevice.h:4914 | Calls the driver's `.ndo_start_xmit()` function. **CRASH LOCATION** is likely here or inside the driver callback invoked by this macro/function. |
#### **2. Key Observations** - **User-Space Trigger**: The crash was triggered by a `sendto()` syscall from user-space (RIP: `0x7f123aaa1039`). This is likely your application or a library using raw sockets. - **AF_PACKET Socket**: The use of `af_packet.c` indicates the program is sending/receiving raw Ethernet frames directly, bypassing standard TCP/UDP stacks. Common in packet sniffers (tcpdump), custom protocols, or high-performance networking apps. - **Direct Xmit Path**: The presence of `__dev_direct_xmit` suggests either: - The driver supports direct transmit optimization. - An eBPF/XDP program is attached to the interface and redirects packets directly to the NIC queue.
#### **3. Register State Analysis** ```text RAX: ffffffffffffffda → Error code (-22, EINVAL) or return value from a failed call? Note: In oops traces, RAX often holds the faulting address if it's a NULL dereference, but here it looks like an error code. However, since this is a crash trace, RAX might be corrupted or hold the last syscall result before panic. RDI: 0000000000000003 → Likely the socket file descriptor (fd=3). R12: 00007f123aa648c0 → Possibly a pointer to `struct sock` or `sk_buff`. ```
> **Note**: The actual faulting instruction is not explicitly shown as "Oops:" at the top of your snippet, but the call trace ends abruptly after `__netdev_start_xmit`, implying the crash occurred inside that function or its callee (the driver's xmit function).
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### **Likely Causes**
#### ✅ **1. Driver Bug** - The network interface card (NIC) driver has a bug in its `.ndo_start_xmit()` implementation. - Common issues: Null pointer dereference, use-after-free of `sk_buff`, or invalid DMA mapping.
#### ✅ **2. Corrupted sk_buff** - User-space code passed malformed data to the AF_PACKET socket, causing kernel memory corruption when building the `sk_buff`. - Example: Writing beyond buffer boundaries in user space that affects shared pages (if using `PACKET_MMAP`).
#### ✅ **3. XDP/eBPF Program Crash** - If an eBPF program is attached to this interface via XDP, a bug in the BPF code
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