fscrypt: new helper function - fscrypt_require_key()

Add a helper function which checks if an inode is encrypted, and if so,
tries to set up its encryption key.  This is a pattern which is
duplicated in multiple places in each of ext4, f2fs, and ubifs --- for
example, when a regular file is asked to be opened or truncated.

Acked-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Eric Biggers 2017-10-09 12:15:39 -07:00 committed by Theodore Ts'o
parent ffcc41829a
commit d293c3e4e0
1 changed files with 25 additions and 0 deletions

View File

@ -151,5 +151,30 @@ static inline bool fscrypt_has_encryption_key(const struct inode *inode)
#include <linux/fscrypt_notsupp.h> #include <linux/fscrypt_notsupp.h>
#endif /* __FS_HAS_ENCRYPTION */ #endif /* __FS_HAS_ENCRYPTION */
/**
* fscrypt_require_key - require an inode's encryption key
* @inode: the inode we need the key for
*
* If the inode is encrypted, set up its encryption key if not already done.
* Then require that the key be present and return -ENOKEY otherwise.
*
* No locks are needed, and the key will live as long as the struct inode --- so
* it won't go away from under you.
*
* Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
* if a problem occurred while setting up the encryption key.
*/
static inline int fscrypt_require_key(struct inode *inode)
{
if (IS_ENCRYPTED(inode)) {
int err = fscrypt_get_encryption_info(inode);
if (err)
return err;
if (!fscrypt_has_encryption_key(inode))
return -ENOKEY;
}
return 0;
}
#endif /* _LINUX_FSCRYPT_H */ #endif /* _LINUX_FSCRYPT_H */