From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-mtd@lists.infradead.org, linux-api@vger.kernel.org,
linux-crypto@vger.kernel.org, keyrings@vger.kernel.org,
Paul Crowley <paulcrowley@google.com>,
Satya Tangirala <satyat@google.com>
Subject: Re: [PATCH v7 08/16] fscrypt: add FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl
Date: Sun, 28 Jul 2019 15:30:12 -0400 [thread overview]
Message-ID: <20190728193012.GH6088@mit.edu> (raw)
In-Reply-To: <20190726224141.14044-9-ebiggers@kernel.org>
On Fri, Jul 26, 2019 at 03:41:33PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> Add a new fscrypt ioctl, FS_IOC_GET_ENCRYPTION_KEY_STATUS. Given a key
> specified by 'struct fscrypt_key_specifier' (the same way a key is
> specified for the other fscrypt key management ioctls), it returns
> status information in a 'struct fscrypt_get_key_status_arg'.
>
> The main motivation for this is that applications need to be able to
> check whether an encrypted directory is "unlocked" or not, so that they
> can add the key if it is not, and avoid adding the key (which may
> involve prompting the user for a passphrase) if it already is.
>
> It's possible to use some workarounds such as checking whether opening a
> regular file fails with ENOKEY, or checking whether the filenames "look
> like gibberish" or not. However, no workaround is usable in all cases.
>
> Like the other key management ioctls, the keyrings syscalls may seem at
> first to be a good fit for this. Unfortunately, they are not. Even if
> we exposed the keyring ID of the ->s_master_keys keyring and gave
> everyone Search permission on it (note: currently the keyrings
> permission system would also allow everyone to "invalidate" the keyring
> too), the fscrypt keys have an additional state that doesn't map cleanly
> to the keyrings API: the secret can be removed, but we can be still
> tracking the files that were using the key, and the removal can be
> re-attempted or the secret added again.
>
> After later patches, some applications will also need a way to determine
> whether a key was added by the current user vs. by some other user.
> Reserved fields are included in fscrypt_get_key_status_arg for this and
> other future extensions.
>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Looks good, feel free to add:
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
next prev parent reply other threads:[~2019-07-28 19:30 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 22:41 [PATCH v7 00/16] fscrypt: key management improvements Eric Biggers
2019-07-26 22:41 ` [PATCH v7 01/16] fs, fscrypt: move uapi definitions to new header <linux/fscrypt.h> Eric Biggers
2019-07-28 15:08 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 02/16] fscrypt: use FSCRYPT_ prefix for uapi constants Eric Biggers
2019-07-26 22:41 ` [PATCH v7 03/16] fscrypt: use FSCRYPT_* definitions, not FS_* Eric Biggers
2019-07-26 22:41 ` [PATCH v7 04/16] fscrypt: add ->ci_inode to fscrypt_info Eric Biggers
2019-07-28 15:09 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 05/16] fscrypt: refactor v1 policy key setup into keysetup_legacy.c Eric Biggers
2019-07-28 15:40 ` Theodore Y. Ts'o
2019-07-29 19:37 ` Eric Biggers
2019-07-26 22:41 ` [PATCH v7 06/16] fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl Eric Biggers
2019-07-28 18:50 ` Theodore Y. Ts'o
2019-07-29 19:46 ` Eric Biggers
2019-07-29 20:14 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 07/16] fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY ioctl Eric Biggers
2019-07-28 19:24 ` Theodore Y. Ts'o
2019-07-29 19:58 ` Eric Biggers
2019-07-31 18:38 ` Eric Biggers
2019-07-31 23:38 ` Theodore Y. Ts'o
2019-08-01 1:11 ` [f2fs-dev] " Eric Biggers
2019-08-01 5:31 ` Theodore Y. Ts'o
2019-08-01 18:35 ` Eric Biggers
2019-08-01 18:46 ` Eric Biggers
2019-08-01 22:04 ` Eric Biggers
2019-08-02 4:38 ` Eric Biggers
2019-08-12 14:16 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 08/16] fscrypt: add FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl Eric Biggers
2019-07-28 19:30 ` Theodore Y. Ts'o [this message]
2019-07-26 22:41 ` [PATCH v7 09/16] fscrypt: add an HKDF-SHA512 implementation Eric Biggers
2019-07-28 19:39 ` Theodore Y. Ts'o
2019-07-29 20:29 ` Eric Biggers
2019-07-29 21:42 ` James Bottomley
2019-07-26 22:41 ` [PATCH v7 10/16] fscrypt: v2 encryption policy support Eric Biggers
2019-07-28 21:17 ` Theodore Y. Ts'o
2019-07-29 20:46 ` Eric Biggers
2019-07-26 22:41 ` [PATCH v7 11/16] fscrypt: allow unprivileged users to add/remove keys for v2 policies Eric Biggers
2019-07-28 21:22 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 12/16] fscrypt: require that key be added when setting a v2 encryption policy Eric Biggers
2019-07-28 21:24 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 13/16] ext4: wire up new fscrypt ioctls Eric Biggers
2019-07-28 21:24 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 14/16] f2fs: " Eric Biggers
2019-07-30 0:36 ` Jaegeuk Kim
2019-08-02 8:10 ` Chao Yu
2019-08-02 17:31 ` Eric Biggers
2019-08-04 9:42 ` [f2fs-dev] " Chao Yu
2019-07-26 22:41 ` [PATCH v7 15/16] ubifs: " Eric Biggers
2019-07-30 0:39 ` Theodore Y. Ts'o
2019-07-26 22:41 ` [PATCH v7 16/16] fscrypt: document the new ioctls and policy version Eric Biggers
2019-07-29 2:00 ` Theodore Y. Ts'o
2019-07-29 21:36 ` Eric Biggers
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