From: Eric Biggers <ebiggers@kernel.org>
To: linux-ext4@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org
Subject: Re: [PATCH v3] e2fsck: check for consistent encryption policies
Date: Wed, 4 Sep 2019 08:55:25 -0700 [thread overview]
Message-ID: <20190904155524.GA41757@gmail.com> (raw)
In-Reply-To: <20190823162339.186643-1-ebiggers@kernel.org>
On Fri, Aug 23, 2019 at 09:23:39AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> By design, the kernel enforces that all files in an encrypted directory
> use the same encryption policy as the directory. It's not possible to
> violate this constraint using syscalls. Lookups of files that violate
> this constraint also fail, in case the disk was manipulated.
>
> But this constraint can also be violated by accidental filesystem
> corruption. E.g., a power cut when using ext4 without a journal might
> leave new files without the encryption bit and/or xattr. Thus, it's
> important that e2fsck correct this condition.
>
> Therefore, this patch makes the following changes to e2fsck:
>
> - During pass 1 (inode table scan), create a map from inode number to
> encryption policy for all encrypted inodes. But it's optimized so
> that the full xattrs aren't saved but rather only 32-bit "policy IDs",
> since usually many inodes share the same encryption policy. Also, if
> an encryption xattr is missing, offer to clear the encrypt flag. If
> an encryption xattr is clearly corrupt, offer to clear the inode.
>
> - During pass 2 (directory structure check), use the map to verify that
> all regular files, directories, and symlinks in encrypted directories
> use the directory's encryption policy. Offer to clear any directory
> entries for which this isn't the case.
>
> Add a new test "f_bad_encryption" to test the new behavior.
>
> Due to the new checks, it was also necessary to update the existing test
> "f_short_encrypted_dirent" to add an encryption xattr to the test file,
> since it was missing one before, which is now considered invalid.
>
Any comments on this patch?
- Eric
next prev parent reply other threads:[~2019-09-04 15:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-23 16:23 [PATCH v3] e2fsck: check for consistent encryption policies Eric Biggers
2019-09-04 15:55 ` Eric Biggers [this message]
2019-09-07 4:23 ` Andreas Dilger
2019-09-07 10:06 ` Theodore Y. Ts'o
2019-09-09 17:34 ` Eric Biggers
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