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

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 $((1024*1024*1024)) \ /mnt/f2fs/012345678901234567890123456789012345678901234567890123 - touch /mnt/f2fs/file - truncate -s $((1024*1024*1024)) /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.