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From: Eric Biggers <ebiggers@kernel.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	Richard Weinberger <richard@nod.at>,
	linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	overlayfs <linux-unionfs@vger.kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: overlayfs vs. fscrypt
Date: Wed, 13 Mar 2019 09:33:49 -0700	[thread overview]
Message-ID: <20190313163348.GD703@sol.localdomain> (raw)
In-Reply-To: <20190313161147.GS2217@ZenIV.linux.org.uk>

On Wed, Mar 13, 2019 at 04:11:48PM +0000, Al Viro wrote:
> On Wed, Mar 13, 2019 at 08:01:27AM -0700, Eric Biggers wrote:
> 
> > What do you think about this?
> 
> That fscrypt might have some very deep flaws.  I'll need to RTFS and
> review its model, but what I've seen in this thread so far is not
> promising anything good.
> 
> It's not just overlayfs - there are all kinds of interesting trouble
> possible just with fscrypt, unless I'm misparsing what had been said
> so far.

FYI, there *is* a known bug I was very recently made aware of and am planning to
fix.  When ->lookup() finds the plaintext name for a directory and the
ciphertext name is already in the dcache, d_splice_alias() will __d_move() the
existing dentry to the plaintext name.  But it doesn't set
DCACHE_ENCRYPTED_WITH_KEY, so the dentry incorrectly is still marked as a
ciphertext name and will be invalidated on the next lookup.  That's especially
problematic if the lookup that caused the __d_move() came from sys_mount().

I'm thinking the best fix is to have __d_move() propagate
DCACHE_ENCRYPTED_WITH_KEY from 'target' to 'dentry'.

- Eric

      reply	other threads:[~2019-03-13 16:33 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-13 12:31 overlayfs vs. fscrypt Richard Weinberger
2019-03-13 12:36 ` Miklos Szeredi
2019-03-13 12:47   ` Richard Weinberger
2019-03-13 12:58     ` Miklos Szeredi
2019-03-13 13:00       ` Richard Weinberger
2019-03-13 13:24         ` Miklos Szeredi
2019-03-13 13:32           ` Richard Weinberger
2019-03-13 14:26             ` Amir Goldstein
2019-03-13 15:16               ` Theodore Ts'o
2019-03-13 15:30                 ` Richard Weinberger
2019-03-13 15:36                 ` James Bottomley
2019-03-13 15:51                   ` Eric Biggers
2019-03-13 16:13                     ` James Bottomley
2019-03-13 16:24                       ` Richard Weinberger
2019-03-13 16:44                   ` Theodore Ts'o
2019-03-13 17:45                     ` James Bottomley
2019-03-13 18:58                       ` Theodore Ts'o
2019-03-13 19:17                         ` James Bottomley
2019-03-13 19:57                           ` Eric Biggers
2019-03-13 20:06                             ` James Bottomley
2019-03-13 20:25                               ` Eric Biggers
2019-03-13 21:04                                 ` James Bottomley
2019-03-13 22:13                                   ` Eric Biggers
2019-03-13 22:29                                     ` James Bottomley
2019-03-13 22:58                                       ` Eric Biggers
2019-03-13 16:06                 ` Al Viro
2019-03-13 16:44                   ` Eric Biggers
2019-03-13 19:19                     ` Al Viro
2019-03-13 19:43                       ` Eric Biggers
2019-03-13 15:30               ` Eric Biggers
2019-03-13 20:33               ` Richard Weinberger
2019-03-13 22:26                 ` Eric Biggers
2019-03-13 22:42                   ` Richard Weinberger
2019-03-14  7:34                     ` Miklos Szeredi
2019-03-14 17:15                       ` [RFC] fscrypt_key_required mount option Richard Weinberger
2019-03-14 17:15                         ` [PATCH 1/4] fscrypt: Implement FS_CFLG_OWN_D_OPS Richard Weinberger
2019-03-14 17:15                         ` [PATCH 2/4] fscrypt: Export fscrypt_d_ops Richard Weinberger
2019-03-14 17:15                         ` [PATCH 3/4] ubifs: Simplify fscrypt_get_encryption_info() error handling Richard Weinberger
2019-03-14 17:15                         ` [PATCH 4/4] ubifs: Implement new mount option, fscrypt_key_required Richard Weinberger
2019-03-14 17:49                           ` Eric Biggers
2019-03-14 20:54                             ` Richard Weinberger
2019-03-14 23:07                               ` Theodore Ts'o
2019-03-15  7:48                                 ` Richard Weinberger
2019-03-15 13:51                                   ` Theodore Ts'o
2019-03-15 13:59                                     ` Richard Weinberger
2019-03-14 23:15                           ` James Bottomley
2019-03-14 23:42                             ` Theodore Ts'o
2019-03-14 23:55                               ` James Bottomley
2019-03-13 15:01           ` overlayfs vs. fscrypt Eric Biggers
2019-03-13 16:11             ` Al Viro
2019-03-13 16:33               ` Eric Biggers [this message]

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