On Mon, Aug 12, 2019 at 08:06:44PM -0400, Theodore Y. Ts'o wrote:
> > + /* Some inodes still reference this key; try to evict them. */
> > + if (try_to_lock_encrypted_files(sb, mk) != 0)
> > + status_flags |=
> > + FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY;
> > + }
>
> try_to_lock_encrypted_files() can return other errors besides -EBUSY;
> in particular sync_filesystem() can return other errors, such as -EIO
> or -EFSCORUPTED. In that case, I think we're better off returning the
> relevant status code back to the user. We will have already wiped the
> master key, but this situation will only happen in exceptional
> conditions (e.g., user has ejected the sdcard, etc.), so it's not
> worth it to try to undo the master key wipe to try to restore things
> to the pre-ioctl execution state.
>
> So I think we should capture the return code from
> try_to_lock_encrypted_files, and if it is EBUSY, we can set FILES_BUSY
> flag and return success. Otherwise, we should return the error.
>
> If you agree, please fix that up and then feel free to add:
>
> Reviewed-by: Theodore Ts'o <[email protected]>
>
> - Ted
Yes, that makes sense. I've made the following change to this patch:
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 9901593051424b..c3423f0edc7014 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -479,6 +479,7 @@ int fscrypt_ioctl_remove_key(struct file *filp, void __user
*_uarg)
struct key *key;
struct fscrypt_master_key *mk;
u32 status_flags = 0;
+ int err;
bool dead;
if (copy_from_user(&arg, uarg, sizeof(arg)))
@@ -514,11 +515,15 @@ int fscrypt_ioctl_remove_key(struct file *filp, void
__user *_uarg)
* key object is free to be removed from the keyring.
*/
key_invalidate(key);
+ err = 0;
} else {
/* Some inodes still reference this key; try to evict them. */
- if (try_to_lock_encrypted_files(sb, mk) != 0)
+ err = try_to_lock_encrypted_files(sb, mk);
+ if (err == -EBUSY) {
status_flags |=
FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY;
+ err = 0;
+ }
}
/*
* We return 0 if we successfully did something: wiped the secret, or
@@ -527,7 +532,9 @@ int fscrypt_ioctl_remove_key(struct file *filp, void __user
*_uarg)
* including all files locked.
*/
key_put(key);
- return put_user(status_flags, &uarg->removal_status_flags);
+ if (err == 0)
+ err = put_user(status_flags, &uarg->removal_status_flags);
+ return err;
}
EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key);
