linux-ext4 - Re: [PATCH v2 3/5] fs, fscrypt: clear DCACHE_ENCRYPTED

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Date:   Wed, 17 Apr 2019 10:06:10 -0400
From:   "Theodore Ts'o" <tytso@....edu>
To:     Eric Biggers <ebiggers@...nel.org>
Cc:     linux-fscrypt@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        linux-mtd@...ts.infradead.org, linux-unionfs@...r.kernel.org,
        Sarthak Kukreti <sarthakkukreti@...omium.org>,
        Gao Xiang <gaoxiang25@...wei.com>
Subject: Re: [PATCH v2 3/5] fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when
 unaliasing directory

On Wed, Mar 20, 2019 at 11:39:11AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@...gle.com>
> 
> Make __d_move() clear DCACHE_ENCRYPTED_NAME on the source dentry.  This
> is needed for when d_splice_alias() moves a directory's encrypted alias
> to its decrypted alias as a result of the encryption key being added.
> 
> Otherwise, the decrypted alias will incorrectly be invalidated on the
> next lookup, causing problems such as unmounting a mount the user just
> mount()ed there.
> 
> Note that we don't have to support arbitrary moves of this flag because
> fscrypt doesn't allow dentries with DCACHE_ENCRYPTED_NAME to be the
> source or target of a rename().
> 
> Fixes: 28b4c263961c ("ext4 crypto: revalidate dentry after adding or removing the key")
> Reported-by: Sarthak Kukreti <sarthakkukreti@...omium.org>
> Signed-off-by: Eric Biggers <ebiggers@...gle.com>

Looks good, applied.

					- Ted