Vulnerability Database

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to avoid out-of-boundary access in devs.path

• touch /mnt/f2fs/012345678901234567890123456789012345678901234567890123
• truncate -s $((102410241024))
  /mnt/f2fs/012345678901234567890123456789012345678901234567890123
• touch /mnt/f2fs/file
• truncate -s $((102410241024)) /mnt/f2fs/file
• mkfs.f2fs /mnt/f2fs/012345678901234567890123456789012345678901234567890123
  -c /mnt/f2fs/file
• mount /mnt/f2fs/012345678901234567890123456789012345678901234567890123
  /mnt/f2fs/loop

[16937.192225] F2FS-fs (loop0): Mount Device [ 0]: /mnt/f2fs/012345678901234567890123456789012345678901234567890123\xff\x01, 511, 0 - 3ffff [16937.192268] F2FS-fs (loop0): Failed to find devices

If device path length equals to MAX_PATH_LEN, sbi->devs.path[] may not end up w/ null character due to path array is fully filled, So accidently, fields locate after path[] may be treated as part of device path, result in parsing wrong device path.

struct f2fs_dev_info { ... char path[MAX_PATH_LEN]; ... };

Let's add one byte space for sbi->devs.path[] to store null character of device path string.