CVE-2025-38716 in Linux
요약
\~에 의해 VulDB • 2026. 06. 30.
Based on the kernel log snippet provided, here is an analysis of what happened:
### **Summary** The system attempted to mount a filesystem using the `hfs` (Hierarchical File System) driver. The operation failed during the superblock initialization phase (`hfs_fill_super`). While this specific stack trace does not show the final error code or panic message, it indicates that something went wrong while setting up the HFS metadata structures.
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### **Detailed Breakdown**
1. **Context**: - The process (TID `9787`) is executing a mount system call (`__x64_sys_mount`). - It calls into the VFS layer: `vfs_get_tree` → `get_tree_bdev_flags`. - This triggers the filesystem-specific initialization function: **`hfs_fill_super`**.
2. **Key Function**: - **`hfs_fill_super+0x38e/0x720`**: This is where HFS sets up its superblock, reads metadata nodes (MDB), and initializes internal structures. The offset `0x38e` suggests the failure occurred roughly halfway through this function.
3. **Potential Causes for Failure in `hfs_fill_super`**: - **Corrupted or Invalid Superblock/MDB**: HFS relies on a Master Directory Block (MDB). If the image/file is truncated, corrupted, or not actually an HFS volume, reading it will fail. - **Unsupported Format**: The disk might be HFS+ (HFS Plus) but mounted with an old `hfs` driver that doesn’t support newer features, or vice versa. Note: Modern Linux kernels often use the `hfsplus` module for Mac OS Extended volumes. Using `hfs` on an HFS+ volume will fail. - **Checksum Mismatch**: The MDB checksum validation failed. - **Invalid Volume Size/Block Count**: Inconsistent metadata values in the superblock.
4. **Why No Panic/Oops?** - This is likely a **graceful error return** (e.g., `-EINVAL`, `-EIO`) rather than a kernel crash. The mount syscall returns an error to userspace, and `dmesg` logs the stack trace for debugging purposes if debug options are enabled or if it’s part of a broader failure report.
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### **How to Diagnose Further**
1. **Check Full dmesg Output**: Look at lines *before* this snippet for an actual error message like: ``` hfs: unable to find HFS+ superblock hfs: invalid MDB checksum hfs: wrong magic number (expected 0x424d, got ...) ```
2. **Verify Filesystem Type**: - If you’re trying to mount a Mac OS Extended volume, ensure you are using the `hfsplus` module, not `hfs`. ```bash # Check if hfsplus is loaded lsmod | grep hfsplus
# Try mounting with explicit type (if supported) sudo mount -t hfsplus /dev/sdXN /mnt/point ```
3. **Check Image Integrity**: If this is a disk image file: ```bash file your_image.img hexdump -C your_image.img | head -n 20 # Check for HFS magic bytes (0x4572 at offset 1024) ```
4. **Enable Kernel Debugging**: If you need more details, recompile the kernel with `CONFIG_HFS_FS_DEBUG=y` or use `ftrace` to trace into `hfs_fill_super`.
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### **Conclusion** The mount failed during HFS superblock initialization due to invalid/corrupted metadata. Most commonly, this is caused by: - Using the wrong driver (`hfs` vs `hfsplus`). - A corrupted or non-HFS disk image.
Check your full `dmesg` output for specific error codes and verify you are using the correct filesystem type for your volume.
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