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From: "Theodore Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-unionfs@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org,
	Sarthak Kukreti <sarthakkukreti@chromium.org>,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries
Date: Wed, 17 Apr 2019 10:07:01 -0400	[thread overview]
Message-ID: <20190417140701.GD4686@mit.edu> (raw)
In-Reply-To: <20190320183913.12686-5-ebiggers@kernel.org>

On Wed, Mar 20, 2019 at 11:39:12AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Plaintext dentries are always valid, so only set fscrypt_d_ops on
> ciphertext dentries.
> 
> Besides marginally improved performance, this allows overlayfs to use an
> fscrypt-encrypted upperdir, provided that all the following are true:
> 
>     (1) The fscrypt encryption key is placed in the keyring before
> 	mounting overlayfs, and remains while the overlayfs is mounted.
> 
>     (2) The overlayfs workdir uses the same encryption policy.
> 
>     (3) No dentries for the ciphertext names of subdirectories have been
> 	created in the upperdir or workdir yet.  (Since otherwise
> 	d_splice_alias() will reuse the old dentry with ->d_op set.)
> 
> One potential use case is using an ephemeral encryption key to encrypt
> all files created or changed by a container, so that they can be
> securely erased ("crypto-shredded") after the container stops.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Looks good, applied.

					- Ted

WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-mtd@lists.infradead.org, linux-unionfs@vger.kernel.org,
	Sarthak Kukreti <sarthakkukreti@chromium.org>,
	Gao Xiang <gaoxiang25@huawei.com>
Subject: Re: [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries
Date: Wed, 17 Apr 2019 10:07:01 -0400	[thread overview]
Message-ID: <20190417140701.GD4686@mit.edu> (raw)
In-Reply-To: <20190320183913.12686-5-ebiggers@kernel.org>

On Wed, Mar 20, 2019 at 11:39:12AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Plaintext dentries are always valid, so only set fscrypt_d_ops on
> ciphertext dentries.
> 
> Besides marginally improved performance, this allows overlayfs to use an
> fscrypt-encrypted upperdir, provided that all the following are true:
> 
>     (1) The fscrypt encryption key is placed in the keyring before
> 	mounting overlayfs, and remains while the overlayfs is mounted.
> 
>     (2) The overlayfs workdir uses the same encryption policy.
> 
>     (3) No dentries for the ciphertext names of subdirectories have been
> 	created in the upperdir or workdir yet.  (Since otherwise
> 	d_splice_alias() will reuse the old dentry with ->d_op set.)
> 
> One potential use case is using an ephemeral encryption key to encrypt
> all files created or changed by a container, so that they can be
> securely erased ("crypto-shredded") after the container stops.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Looks good, applied.

					- Ted

WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Gao Xiang <gaoxiang25@huawei.com>,
	linux-unionfs@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org,
	Sarthak Kukreti <sarthakkukreti@chromium.org>,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries
Date: Wed, 17 Apr 2019 10:07:01 -0400	[thread overview]
Message-ID: <20190417140701.GD4686@mit.edu> (raw)
In-Reply-To: <20190320183913.12686-5-ebiggers@kernel.org>

On Wed, Mar 20, 2019 at 11:39:12AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Plaintext dentries are always valid, so only set fscrypt_d_ops on
> ciphertext dentries.
> 
> Besides marginally improved performance, this allows overlayfs to use an
> fscrypt-encrypted upperdir, provided that all the following are true:
> 
>     (1) The fscrypt encryption key is placed in the keyring before
> 	mounting overlayfs, and remains while the overlayfs is mounted.
> 
>     (2) The overlayfs workdir uses the same encryption policy.
> 
>     (3) No dentries for the ciphertext names of subdirectories have been
> 	created in the upperdir or workdir yet.  (Since otherwise
> 	d_splice_alias() will reuse the old dentry with ->d_op set.)
> 
> One potential use case is using an ephemeral encryption key to encrypt
> all files created or changed by a container, so that they can be
> securely erased ("crypto-shredded") after the container stops.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Looks good, applied.

					- Ted

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

  reply	other threads:[~2019-04-17 14:07 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-20 18:39 [PATCH v2 0/5] fscrypt: d_revalidate fixes and cleanups Eric Biggers
2019-03-20 18:39 ` Eric Biggers
2019-03-20 18:39 ` Eric Biggers
2019-03-20 18:39 ` [PATCH v2 1/5] fscrypt: clean up and improve dentry revalidation Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` [f2fs-dev] " Eric Biggers
2019-04-16 23:08   ` Theodore Ts'o
2019-04-16 23:08     ` Theodore Ts'o
2019-04-17  0:10     ` Eric Biggers
2019-04-17  0:10       ` Eric Biggers
2019-04-17  0:10       ` Eric Biggers
2019-04-17  0:10       ` [f2fs-dev] " Eric Biggers
2019-04-17 13:50       ` Theodore Ts'o
2019-04-17 13:50         ` Theodore Ts'o
2019-04-17 13:50         ` Theodore Ts'o
2019-03-20 18:39 ` [PATCH v2 2/5] fscrypt: fix race allowing rename() and link() of ciphertext dentries Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` [f2fs-dev] " Eric Biggers
2019-04-17 13:53   ` Theodore Ts'o
2019-04-17 13:53     ` Theodore Ts'o
2019-04-17 13:53     ` Theodore Ts'o
2019-03-20 18:39 ` [PATCH v2 3/5] fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-04-17 14:06   ` Theodore Ts'o
2019-04-17 14:06     ` Theodore Ts'o
2019-03-20 18:39 ` [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` [f2fs-dev] " Eric Biggers
2019-04-17 14:07   ` Theodore Ts'o [this message]
2019-04-17 14:07     ` Theodore Ts'o
2019-04-17 14:07     ` Theodore Ts'o
2019-03-20 18:39 ` [PATCH v2 5/5] fscrypt: fix race where ->lookup() marks plaintext dentry as ciphertext Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` Eric Biggers
2019-03-20 18:39   ` [f2fs-dev] " Eric Biggers
2019-04-17 14:24   ` Theodore Ts'o
2019-04-17 14:24     ` Theodore Ts'o
2019-04-17 14:24     ` Theodore Ts'o
2019-04-01 17:11 ` [PATCH v2 0/5] fscrypt: d_revalidate fixes and cleanups Eric Biggers
2019-04-01 17:11   ` Eric Biggers
2019-04-01 17:11   ` Eric Biggers
2019-04-01 17:11   ` [f2fs-dev] " Eric Biggers
2019-04-08  8:22   ` Richard Weinberger
2019-04-08  8:22     ` Richard Weinberger
2019-04-08  8:22     ` Richard Weinberger

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