From: Eric Biggers <ebiggers@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: linux-fscrypt@vger.kernel.org,
Satya Tangirala <satyat@google.com>,
linux-api@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net, keyrings@vger.kernel.org,
linux-mtd@lists.infradead.org, linux-crypto@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
Paul Crowley <paulcrowley@google.com>
Subject: Re: [RFC PATCH v3 00/18] fscrypt: key management improvements
Date: Wed, 20 Feb 2019 10:36:20 -0800 [thread overview]
Message-ID: <20190220183619.GA177939@gmail.com> (raw)
In-Reply-To: <14023.1550686042@warthog.procyon.org.uk>
Hi David,
On Wed, Feb 20, 2019 at 06:07:22PM +0000, David Howells wrote:
> I have a couple of patches that add ACLs to keyrings, that you can find at the
> top of the branch here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-acl
>
> I have other patches that allow tags to be used as subjects in the ACL, with a
> container supplying a tag, e.g.:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit/?h=container&id=e0fdc5613a32b9475b025f58e7a2267329b3f3a4
>
> Might something similar be of use to you here, perhaps specifying a tag
> referring to the blockdev of interest rather than the container?
>
> David
I don't think so. The main point of adding keys directly to the filesystem is
that it's generally inappropriate to apply OS-level access control or
process-based visibility restrictions to fscrypt keys given that:
- The unlocked/locked status of files is already filesystem-level.
- The purpose of encryption is orthogonal to OS-level access control.
The ioctl based interface also makes it *much* easier to implement all the
semantics needed for removing fscrypt keys.
I don't see how key ACLs would be appropriate here, except that key ACLs would
allow userspace to opt-in to fixing the denial of service vulnerability where
keyctl_invalidate() only requires Search permission. But for fscrypt that's
addressed by my proposal too, and is just one of many problems it addresses.
- Eric
prev parent reply other threads:[~2019-02-20 18:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 6:52 [RFC PATCH v3 00/18] fscrypt: key management improvements Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 01/18] fs, fscrypt: move uapi definitions to new header <linux/fscrypt.h> Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 02/18] fscrypt: use FSCRYPT_ prefix for uapi constants Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 03/18] fscrypt: use FSCRYPT_* definitions, not FS_* Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 04/18] fs: add ->s_master_keys to struct super_block Eric Biggers
2019-02-20 23:19 ` Richard Weinberger
2019-02-20 6:52 ` [RFC PATCH v3 05/18] fscrypt: add ->ci_inode to fscrypt_info Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 06/18] fscrypt: refactor v1 policy key setup into keysetup_legacy.c Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 07/18] fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl Eric Biggers
2019-02-20 23:52 ` Richard Weinberger
2019-02-21 5:49 ` Eric Biggers
2019-02-21 9:33 ` Richard Weinberger
2019-02-21 18:42 ` Eric Biggers
2019-03-18 23:08 ` Eric Biggers
2019-03-22 22:02 ` Richard Weinberger
2019-02-20 6:52 ` [RFC PATCH v3 08/18] fs/dcache.c: add shrink_dcache_inode() Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 09/18] fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY ioctl Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 10/18] fscrypt: add FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 11/18] fscrypt: add an HKDF-SHA512 implementation Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 12/18] fscrypt: v2 encryption policy support Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 13/18] fscrypt: allow unprivileged users to add/remove keys for v2 policies Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 14/18] fscrypt: require that key be added when setting a v2 encryption policy Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 15/18] ext4: wire up new fscrypt ioctls Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 16/18] f2fs: " Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 17/18] ubifs: " Eric Biggers
2019-02-20 6:52 ` [RFC PATCH v3 18/18] fscrypt: document the new ioctls and policy version Eric Biggers
2019-02-20 7:18 ` [RFC PATCH v3 00/18] fscrypt: key management improvements Andreas Dilger
2019-02-20 7:54 ` Eric Biggers
2019-02-20 18:07 ` David Howells
2019-02-20 18:36 ` Eric Biggers [this message]
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