Hi Ted, On Wed, Dec 28, 2016 at 12:22:52AM -0500, Theodore Ts'o wrote: > While we allow deletes without the key, the following should not be > permitted: > > # cd /vdc/encrypted-dir-without-key > # ls -l > total 4 > -rw-r--r-- 1 root root 0 Dec 27 22:35 6,LKNRJsp209FbXoSvJWzB > -rw-r--r-- 1 root root 286 Dec 27 22:35 uRJ5vJh9gE7vcomYMqTAyD > # mv uRJ5vJh9gE7vcomYMqTAyD 6,LKNRJsp209FbXoSvJWzB > > Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> > --- > fs/ext4/namei.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > index eadba919f26b..45a5ba558074 100644 > --- a/fs/ext4/namei.c > +++ b/fs/ext4/namei.c > @@ -3525,6 +3525,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, > EXT4_I(old_dentry->d_inode)->i_projid))) > return -EXDEV; > > + if ((ext4_encrypted_inode(old_dir) && > + !fscrypt_has_encryption_key(old_dir)) || > + (ext4_encrypted_inode(new_dir) && > + !fscrypt_has_encryption_key(new_dir))) > + return -ENOKEY; > + > retval = dquot_initialize(old.dir); > if (retval) > return retval; > @@ -3725,6 +3731,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry, > int retval; > struct timespec ctime; > > + if ((ext4_encrypted_inode(old_dir) && > + !fscrypt_has_encryption_key(old_dir)) || > + (ext4_encrypted_inode(new_dir) && > + !fscrypt_has_encryption_key(new_dir))) > + return -ENOKEY; > + > if ((ext4_encrypted_inode(old_dir) || > ext4_encrypted_inode(new_dir)) && > (old_dir != new_dir) && I'm fine with this, with the understanding that it relies on ext4_lookup() calling fscrypt_get_encryption_info() (via fscrypt_has_permitted_context()) when looking up the directory. I also suggest moving the fscrypt_permitted_context() check in ext4_rename() up to be next to the new check, so that the fscrypt hooks are grouped together and are consistent with ext4_cross_rename(). I can also write/update an xfstest to test this. Something I'm thinking about is making things easier for filesystems by having functions like "fscrypt_rename_hook()" which would handle all these needed checks. It would be easy to do with out-of-line functions in fs/crypto/, but we don't want to be making ->is_encrypted() calls through the fscrypt_operations all the time, when an inlined call to ext4_encrypted_inode() (or f2fs or ubifs_encrypted_inode()) is much faster. I think it could be implemented as efficiently as now if the hooks were defined in a header and called a macro like "fs_encrypted_inode()" which filesystems would have to #define first. It would be a little ugly, but at least it would be less error-prone than having multiple filesystems replicate these increasingly complex checks. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
