From: Gabriel Krisman Bertazi <krisman@suse.de>
To: Eric Biggers <ebiggers@kernel.org>
Cc: viro@zeniv.linux.org.uk, jaegeuk@kernel.org, tytso@mit.edu,
linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-fsdevel@vger.kernel.org, amir73il@gmail.com
Subject: Re: [PATCH v3 02/10] fscrypt: Share code between functions that prepare lookup
Date: Thu, 25 Jan 2024 17:18:00 -0300 [thread overview]
Message-ID: <87a5otxj47.fsf@mailhost.krisman.be> (raw)
In-Reply-To: <20240125030530.GB52073@sol.localdomain> (Eric Biggers's message of "Wed, 24 Jan 2024 19:05:30 -0800")
Eric Biggers <ebiggers@kernel.org> writes:
> On Fri, Jan 19, 2024 at 03:47:34PM -0300, Gabriel Krisman Bertazi wrote:
>> To make the patch simpler, we now call fscrypt_get_encryption_info twice
>> for fscrypt_prepare_lookup, once inside fscrypt_setup_filename and once
>> inside fscrypt_prepare_lookup_dentry. It seems safe to do, and
>> considering it will bail early in the second lookup and most lookups
>> should go to the dcache anyway, it doesn't seem problematic for
>> performance. In addition, we add a function call for the unencrypted
>> case, also during lookup.
>
> Unfortunately I don't think it's correct. This is basically undoing my fix
> b01531db6cec ("fscrypt: fix race where ->lookup() marks plaintext dentry as
> ciphertext") from several years ago.
>
> When a lookup is done, the filesystem needs to either treat the name being
> looked up as a no-key name *or* as a regular name, depending on whether the
> directory's key is present. We shouldn't enable race conditions where, due to
> the key being concurrently added, the name is treated as a no-key name for
> filename matching purposes but a regular name for dentry validation purposes.
> That can result in an anomaly where a file that exists ends up with a negative
> dentry that doesn't get invalidated.
>
> Basically, the boolean fscrypt_name::is_nokey_name that's produced by
> fscrypt_setup_filename() should continue to be propagated to DCACHE_NOKEY_NAME.
I see your point. I'll drop this patch and replace it with a patch that
just merges the DCACHE_NOKEY_NAME configuration. Sadly, we gotta keep
the two variants I think.
thanks for the review
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2024-01-25 20:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-19 18:47 [PATCH v3 00/10] Set casefold/fscrypt dentry operations through sb->s_d_op Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 01/10] ovl: Reject mounting case-insensitive filesystems Gabriel Krisman Bertazi
2024-01-25 2:51 ` Eric Biggers
2024-01-25 16:55 ` Gabriel Krisman Bertazi
2024-01-27 7:08 ` Eric Biggers
2024-01-19 18:47 ` [PATCH v3 02/10] fscrypt: Share code between functions that prepare lookup Gabriel Krisman Bertazi
2024-01-25 3:05 ` Eric Biggers
2024-01-25 20:18 ` Gabriel Krisman Bertazi [this message]
2024-01-19 18:47 ` [PATCH v3 03/10] fscrypt: Drop d_revalidate for valid dentries during lookup Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 04/10] fscrypt: Drop d_revalidate once the key is added Gabriel Krisman Bertazi
2024-01-25 3:12 ` Eric Biggers
2024-01-25 20:20 ` Gabriel Krisman Bertazi
2024-01-27 7:17 ` Eric Biggers
2024-01-29 19:34 ` Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 05/10] libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 06/10] libfs: Add helper to choose dentry operations at mount Gabriel Krisman Bertazi
2024-01-25 3:13 ` Eric Biggers
2024-01-19 18:47 ` [PATCH v3 07/10] ext4: Configure dentry operations at dentry-creation time Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 08/10] f2fs: " Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 09/10] ubifs: " Gabriel Krisman Bertazi
2024-01-19 18:47 ` [PATCH v3 10/10] libfs: Drop generic_set_encrypted_ci_d_ops Gabriel Krisman Bertazi
-- strict thread matches above, loose matches on Subject: below --
2024-01-11 22:58 [PATCH v3 00/10] Set casefold/fscrypt dentry operations through sb->s_d_op Gabriel Krisman Bertazi
2024-01-11 22:58 ` [PATCH v3 02/10] fscrypt: Share code between functions that prepare lookup Gabriel Krisman Bertazi
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