CVE-2023-54308 in Linux
الملخص
بحسب VulDB • 01/06/2026
Based on the kernel stack trace provided, here is an analysis of the issue:
### **1. Summary** The system encountered a **kernel panic or oops** while a user-space process was attempting to open a file via the `openat2` system call. The crash occurred deep within the VFS (Virtual File System) layer during `vfs_open`.
### **2. Key Observations** - **RIP (Instruction Pointer):** `0x7f1308a40db4` - This address is in the **user-space library** (likely `libc.so.6`), not in the kernel. - The `Code:` dump shows x86-64 instructions typical of a `syscall` instruction (`0f 05`) followed by error handling. - This indicates the crash happened **after** the kernel returned an error code to user space, or the user-space program crashed while handling the error. However, the stack trace shows kernel frames, so the **kernel itself crashed** during the syscall handling.
- **RAX:** `ffffffffffffffda` - This is the return value from the kernel to user space. - `0xffffffda` = **-70** in signed 64-bit integer. - Error code **-70** corresponds to **`-ENOSPC`** (No space left on device).
- **Stack Trace Analysis:** - `entry_SYSCALL_64_after_hwframe`: Entry point for 64-bit syscalls. - `do_syscall_64`: Generic syscall dispatcher. - `__x64_sys_openat`: The `openat` syscall handler. - `do_sys_openat2`: Handles `openat2` (extended open flags). - `do_filp_open`: Core file opening logic. - `path_openat`: Resolves the path. - `vfs_open`: Opens the file on the filesystem. - **`vfs_open+0x2d/0x40`**: The crash occurred here.
### **3. Root Cause Analysis** The most likely scenario is:
#### **A. Kernel Bug in `vfs_open`** The kernel crashed inside `vfs_open` while trying to open a file. The fact that `RAX` is `-ENOSPC` suggests that the kernel **already determined** there was no space left, but then **crashed** while trying to handle this error (e.g., during cleanup, logging, or returning the error).
Possible causes: 1. **Null Pointer Dereference:** `vfs_open` might have dereferenced a null pointer (e.g., `inode->i_op->open` is null) after detecting an error condition. 2. **Use-After-Free:** The inode or file structure was freed prematurely. 3. **Filesystem-Specific Bug:** If you're using a specific filesystem (e.g., ext4, xfs, btrfs, overlayfs), there might be a bug in its `open` implementation.
#### **B. User-Space Crash (Less Likely Given Kernel Stack)** If the kernel did **not** crash, but the user-space program crashed, the stack trace would not show kernel frames like `vfs_open`. Since kernel frames are present, **the kernel crashed**.
### **4. Debugging Steps** 1. **Check Full Kernel Log:** Look for the **actual crash message** (e.g., `BUG: unable to handle kernel paging request at ...`, `general protection fault`, etc.) that precedes this stack trace. This will tell you the exact cause (e.g., null pointer, page fault).
2. **Identify the Filesystem:** What filesystem is being accessed? Try to reproduce the issue with a different filesystem (e.g., tmpfs) to see if it’s filesystem-specific.
3. **Check for Disk Space:** Since `RAX` is `-ENOSPC`, ensure the disk is actually full. If it’s not full, this is a false positive due to a kernel bug.
4. **Update Kernel:** This might be a known bug in your kernel version. Check for updates or patches related to `vfs_open` or your specific filesystem.
5. **Reproduce with `strace`:** Run the failing program with `strace` to see the exact `openat2` call and arguments. This can help identify if a specific file or flag triggers the bug.
### **5. Conclusion** The kernel crashed in `vfs_open` while handling an `openat2` syscall. The return value `-ENOSPC` suggests the kernel detected a "no space left" error, but then crashed during error handling. This is likely a **kernel bug**, not
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