linux-kernel - Re: [PATCH v2 11/25] security: add hooks for set/get/remove of fscaps

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Date: Wed, 21 Feb 2024 18:31:42 -0500
From: Paul Moore <paul@...l-moore.com>
To: "Seth Forshee (DigitalOcean)" <sforshee@...nel.org>
Cc: Christian Brauner <brauner@...nel.org>, Serge Hallyn <serge@...lyn.com>, Eric Paris <eparis@...hat.com>, 
	James Morris <jmorris@...ei.org>, Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>, 
	Stephen Smalley <stephen.smalley.work@...il.com>, Ondrej Mosnacek <omosnace@...hat.com>, 
	Casey Schaufler <casey@...aufler-ca.com>, Mimi Zohar <zohar@...ux.ibm.com>, 
	Roberto Sassu <roberto.sassu@...wei.com>, Dmitry Kasatkin <dmitry.kasatkin@...il.com>, 
	Eric Snowberg <eric.snowberg@...cle.com>, "Matthew Wilcox (Oracle)" <willy@...radead.org>, 
	Jonathan Corbet <corbet@....net>, Miklos Szeredi <miklos@...redi.hu>, Amir Goldstein <amir73il@...il.com>, 
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-security-module@...r.kernel.org, audit@...r.kernel.org, 
	selinux@...r.kernel.org, linux-integrity@...r.kernel.org, 
	linux-doc@...r.kernel.org, linux-unionfs@...r.kernel.org
Subject: Re: [PATCH v2 11/25] security: add hooks for set/get/remove of fscaps

On Wed, Feb 21, 2024 at 4:26 PM Seth Forshee (DigitalOcean)
<sforshee@...nel.org> wrote:
>
> In preparation for moving fscaps out of the xattr code paths, add new
> security hooks. These hooks are largely needed because common kernel
> code will pass around struct vfs_caps pointers, which EVM will need to
> convert to raw xattr data for verification and updates of its hashes.
>
> Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@...nel.org>
> ---
>  include/linux/lsm_hook_defs.h |  7 +++++
>  include/linux/security.h      | 33 +++++++++++++++++++++
>  security/security.c           | 69 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 109 insertions(+)

One minor problem below, but assuming you fix that, this looks okay to me.

Acked-by: Paul Moore <paul@...l-moore.com>

> diff --git a/security/security.c b/security/security.c
> index 3aaad75c9ce8..0d210da9862c 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2351,6 +2351,75 @@ int security_inode_remove_acl(struct mnt_idmap *idmap,

..

> +/**
> + * security_inode_get_fscaps() - Check if reading fscaps is allowed
> + * @dentry: file

You are missing an entry for the @idmap parameter.

> + * Check permission before getting fscaps.
> + *
> + * Return: Returns 0 if permission is granted.
> + */
> +int security_inode_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry)
> +{
> +       if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> +               return 0;
> +       return call_int_hook(inode_get_fscaps, 0, idmap, dentry);
> +}

-- 
paul-moore.com