diff options
| author | Jamie Liu <jamieliu@google.com> | 2019-04-25 16:03:32 -0700 |
|---|---|---|
| committer | Shentubot <shentubot@google.com> | 2019-04-25 16:05:13 -0700 |
| commit | 6b76c172b48ecb2c342882c0fe6474b2b973dad0 (patch) | |
| tree | 61295be888beb8cb9c024aad03b9debe44fc2e32 /pkg/sentry/fs/dirent.go | |
| parent | 72197810405a462386ded05d3c7c60c320289223 (diff) | |
Don't enforce NAME_MAX in fs.Dirent.walk().
Maximum filename length is filesystem-dependent, and obtained via
statfs::f_namelen. This limit is usually 255 bytes (NAME_MAX), but not
always. For example, VFAT supports filenames of up to 255... UCS-2
characters, which Linux conservatively takes to mean UTF-8-encoded
bytes: fs/fat/inode.c:fat_statfs(), FAT_LFN_LEN * NLS_MAX_CHARSET_SIZE.
As a result, Linux's VFS does not enforce NAME_MAX:
$ rg --maxdepth=1 '\WNAME_MAX\W' fs/ include/linux/
fs/libfs.c
38: buf->f_namelen = NAME_MAX;
64: if (dentry->d_name.len > NAME_MAX)
include/linux/relay.h
74: char base_filename[NAME_MAX]; /* saved base filename */
include/linux/fscrypt.h
149: * filenames up to NAME_MAX bytes, since base64 encoding expands the length.
include/linux/exportfs.h
176: * understanding that it is already pointing to a a %NAME_MAX+1 sized
Remove this check from core VFS, and add it to ramfs (and by extension
tmpfs), where it is actually applicable:
mm/shmem.c:shmem_dir_inode_operations.lookup == simple_lookup *does*
enforce NAME_MAX.
PiperOrigin-RevId: 245324748
Change-Id: I17567c4324bfd60e31746a5270096e75db963fac
Diffstat (limited to 'pkg/sentry/fs/dirent.go')
| -rw-r--r-- | pkg/sentry/fs/dirent.go | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go index 4870e7d40..4bcdf530a 100644 --- a/pkg/sentry/fs/dirent.go +++ b/pkg/sentry/fs/dirent.go @@ -459,11 +459,6 @@ func (d *Dirent) walk(ctx context.Context, root *Dirent, name string, walkMayUnl return nil, syscall.ENOTDIR } - // The component must be less than NAME_MAX. - if len(name) > linux.NAME_MAX { - return nil, syscall.ENAMETOOLONG - } - if name == "" || name == "." { d.IncRef() return d, nil |