linux-kernel - Re: [PATCH 01/29] fscrypt: Add in-place encryption mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20161115181455.GA127180@google.com>
Date:   Tue, 15 Nov 2016 10:14:55 -0800
From:   Eric Biggers <ebiggers@...gle.com>
To:     Richard Weinberger <richard@....at>
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, dedekind1@...il.com,
        adrian.hunter@...el.com, tytso@....edu, jaegeuk@...nel.org,
        david@...ma-star.at, wd@...x.de, sbabic@...x.de,
        dengler@...utronix.de, mhalcrow@...gle.com, hch@...radead.org
Subject: Re: [PATCH 01/29] fscrypt: Add in-place encryption mode

Hi,

On Sun, Nov 13, 2016 at 10:20:44PM +0100, Richard Weinberger wrote:
> From: David Gstir <david@...ma-star.at>
> 
> ext4 and f2fs require a bounce page when encrypting pages. However, not
> all filesystems will need that (eg. UBIFS). This is handled via a
> flag on fscrypt_operations where a fs implementation can select in-place
> encryption over using a bounce page (which is the default).
> 
> Signed-off-by: David Gstir <david@...ma-star.at>
> Signed-off-by: Richard Weinberger <richard@....at>

The comment for fscrypt_encrypt_page() still says the following:

 * Called on the page write path.  The caller must call
 * fscrypt_restore_control_page() on the returned ciphertext page to
 * release the bounce buffer and the encryption context.

It seems this isn't correct anymore.  It also looks like the fscrypt_context
never gets released in the case where the page is encrypted in-place.

Additionally, after this change the name of the flag FS_WRITE_PATH_FL is
misleading, since it now really indicates the presence of a bounce buffer rather
than the "write path".

Eric