fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctl

Add a root-only variant of the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl which
removes all users' claims of the key, not just the current user's claim.
I.e., it always removes the key itself, no matter how many users have
added it.

This is useful for forcing a directory to be locked, without having to
figure out which user ID(s) the key was added under.  This is planned to
be used by a command like 'sudo fscrypt lock DIR --all-users' in the
fscrypt userspace tool (http://github.com/google/fscrypt).

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2019-08-04 19:35:47 -07:00
parent 23c688b540
commit 78a1b96bcf
3 changed files with 33 additions and 5 deletions

View file

@ -143,6 +143,8 @@ extern int fscrypt_inherit_context(struct inode *, struct inode *,
extern void fscrypt_sb_free(struct super_block *sb);
extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
extern int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
extern int fscrypt_ioctl_remove_key_all_users(struct file *filp,
void __user *arg);
extern int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
/* keysetup.c */
@ -396,6 +398,12 @@ static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
return -EOPNOTSUPP;
}
static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
void __user *arg)
{
return -EOPNOTSUPP;
}
static inline int fscrypt_ioctl_get_key_status(struct file *filp,
void __user *arg)
{