linux-ext4 - Re: [PATCH v2 2/5] fscrypt: fix race allowing rename() and link() of ciphertext dentries

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Message-ID: <20190417135319.GB4686@mit.edu>
Date:   Wed, 17 Apr 2019 09:53:19 -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 2/5] fscrypt: fix race allowing rename() and link() of
 ciphertext dentries

On Wed, Mar 20, 2019 at 11:39:10AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@...gle.com>
> 
> Close some race conditions where fscrypt allowed rename() and link() on
> ciphertext dentries that had been looked up just prior to the key being
> concurrently added.  It's better to return -ENOKEY in this case.
> 
> This avoids doing the nonsensical thing of encrypting the names a second
> time when searching for the actual on-disk dir entries.  It also
> guarantees that DCACHE_ENCRYPTED_NAME dentries are never rename()d, so
> the dcache won't have support all possible combinations of moving
> DCACHE_ENCRYPTED_NAME around during __d_move().
> 
> Signed-off-by: Eric Biggers <ebiggers@...gle.com>

Looks good, applied.

					- Ted