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Date: Wed, 21 Feb 2024 18:10:44 -0600
From: "Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
To: Paul Moore <paul@paul-moore.com>
Cc: Christian Brauner <brauner@kernel.org>, Serge Hallyn <serge@hallyn.com>,
	Eric Paris <eparis@redhat.com>, James Morris <jmorris@namei.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
	Stephen Smalley <stephen.smalley.work@gmail.com>,
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Subject: Re: [PATCH v2 12/25] selinux: add hooks for fscaps operations
Message-ID: <ZdaRBBU6K3nvklPI@do-x1extreme>
References: <20240221-idmap-fscap-refactor-v2-0-3039364623bd@kernel.org>
 <20240221-idmap-fscap-refactor-v2-12-3039364623bd@kernel.org>
 <CAHC9VhTgHP=3Te4=t6chGte15CA_tMoVjFuzBwh+FxQ6Ri4mQQ@mail.gmail.com>
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On Wed, Feb 21, 2024 at 06:38:33PM -0500, Paul Moore wrote:
> On Wed, Feb 21, 2024 at 4:25 PM Seth Forshee (DigitalOcean)
> <sforshee@kernel.org> wrote:
> >
> > Add hooks for set/get/remove fscaps operations which perform the same
> > checks as the xattr hooks would have done for XATTR_NAME_CAPS.
> >
> > Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
> > ---
> >  security/selinux/hooks.c | 26 ++++++++++++++++++++++++++
> >  1 file changed, 26 insertions(+)
> >
> > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> > index a6bf90ace84c..da129a387b34 100644
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -3367,6 +3367,29 @@ static int selinux_inode_removexattr(struct mnt_idmap *idmap,
> >         return -EACCES;
> >  }
> >
> > +static int selinux_inode_set_fscaps(struct mnt_idmap *idmap,
> > +                                   struct dentry *dentry,
> > +                                   const struct vfs_caps *caps, int flags)
> > +{
> > +       return dentry_has_perm(current_cred(), dentry, FILE__SETATTR);
> > +}
> 
> The selinux_inode_setxattr() code also has a cap_inode_setxattr()
> check which is missing here.  Unless you are handling this somewhere
> else, I would expect the function above to look similar to
> selinux_inode_remove_fscaps(), but obviously tweaked for setting the
> fscaps and not removing them.

Right, but cap_inode_setxattr() doesn't do anything for fscaps, so I
omitted the call. Unless you think the call should be included in case
cap_inode_setxattr() changes in the future, which is a reasonable
position.

Thanks,
Seth