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From: Stefan Berger <stefanb@linux.ibm.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com,
	zohar@linux.ibm.com, roberto.sassu@huawei.com, miklos@szeredi.hu
Subject: Re: [PATCH 0/5] evm: Support signatures on stacked filesystem
Date: Wed, 31 Jan 2024 09:52:44 -0500	[thread overview]
Message-ID: <015c3a14-0d23-43ba-9593-3d4ff588f1bb@linux.ibm.com> (raw)
In-Reply-To: <CAOQ4uxg9VQ9LksxX5eFFg7E1VO_iFZNmNBaC3pED+a2=ixOhdw@mail.gmail.com>



On 1/31/24 08:18, Amir Goldstein wrote:
> On Tue, Jan 30, 2024 at 11:46 PM Stefan Berger <stefanb@linux.ibm.com> wrote:
>>
>> EVM has recently been completely disabled on unsupported (e.g.,
>> overlayfs). This series now enables copy-up of "portable and immutable"
>> signatures on those filesystems and enables the enforcement of
>> "portable and immutable" as well as the "original" signatures on
>> previously unsupported filesystem when EVM is enabled with EVM_INIT_X509.
>> HMAC verification and generation remains disabled on those filesystems.
>>
> 
> I am missing a high level description of what is in those "portable
> and immutable"
> signatures and how those signatures remain valid across copy up.
> 

 From 2/5:
"Portable and immutable EVM signatures can be copied up by stacked file-
system since the metadata their signature covers does not include file-
system-specific data such as a file's inode number, generation, and UUID."

Instead, the signatures cover file metadata such as file mode bits, uid, 
and gid as well as xattrs, which can all be preserved unchanged across a 
copy-up.

Reference: 
https://elixir.bootlin.com/linux/v6.7.2/source/security/integrity/evm/evm_crypto.c#L169


> Thanks,
> Amir.
> 

      reply	other threads:[~2024-01-31 14:55 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-30 21:46 [PATCH 0/5] evm: Support signatures on stacked filesystem Stefan Berger
2024-01-30 21:46 ` [PATCH 1/5] security: allow finer granularity in permitting copy-up of security xattrs Stefan Berger
2024-01-31 13:25   ` Amir Goldstein
2024-01-31 14:25     ` Christian Brauner
2024-01-31 14:56       ` Stefan Berger
2024-02-01 13:35         ` Christian Brauner
2024-02-01 14:18           ` Amir Goldstein
2024-02-02 11:58             ` Christian Brauner
2024-02-01 15:41     ` Stefan Berger
2024-01-31 16:47   ` kernel test robot
2024-01-31 19:06   ` kernel test robot
2024-01-30 21:46 ` [PATCH 2/5] evm: Implement per signature type decision in security_inode_copy_up_xattr Stefan Berger
2024-01-31 13:28   ` Amir Goldstein
2024-01-30 21:46 ` [PATCH 3/5] ima: Reset EVM status upon detecting changes to overlay backing file Stefan Berger
2024-01-31 13:56   ` Amir Goldstein
2024-01-31 14:46     ` Stefan Berger
2024-01-30 21:46 ` [PATCH 4/5] evm: Use the real inode's metadata to calculate metadata hash Stefan Berger
2024-01-31  2:10   ` Stefan Berger
2024-01-31 13:16     ` Amir Goldstein
2024-01-31 14:40       ` Stefan Berger
2024-01-31 15:54         ` Amir Goldstein
2024-01-31 17:23           ` Amir Goldstein
2024-01-31 17:46             ` Stefan Berger
2024-02-01 12:10               ` Amir Goldstein
2024-02-01 13:36                 ` Stefan Berger
2024-02-01 14:11                   ` Amir Goldstein
2024-02-01 20:35                     ` Stefan Berger
2024-02-02  9:24                       ` Amir Goldstein
2024-02-02 14:59                         ` Stefan Berger
2024-02-02 15:51                           ` Amir Goldstein
2024-02-02 16:06                             ` Stefan Berger
2024-02-02 16:17                               ` Amir Goldstein
2024-02-02 16:30                                 ` Stefan Berger
2024-01-31 17:25           ` Stefan Berger
2024-01-30 21:46 ` [PATCH 5/5] evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509 Stefan Berger
2024-01-31 14:06   ` Amir Goldstein
2024-02-01 17:53     ` Mimi Zohar
2024-01-31 13:18 ` [PATCH 0/5] evm: Support signatures on stacked filesystem Amir Goldstein
2024-01-31 14:52   ` Stefan Berger [this message]

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