From: Amir Goldstein <amir73il@gmail.com>
To: "Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>,
Serge Hallyn <serge@hallyn.com>, Paul Moore <paul@paul-moore.com>,
Eric Paris <eparis@redhat.com>, James Morris <jmorris@namei.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Miklos Szeredi <miklos@szeredi.hu>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org, audit@vger.kernel.org,
linux-unionfs@vger.kernel.org
Subject: Re: [PATCH 09/16] fs: add vfs_set_fscaps()
Date: Thu, 30 Nov 2023 10:01:55 +0200 [thread overview]
Message-ID: <CAOQ4uxjhFKmHSUKiFOraDZojD0qGC=ChJJwtfrncuvTYi9NTKw@mail.gmail.com> (raw)
In-Reply-To: <20231129-idmap-fscap-refactor-v1-9-da5a26058a5b@kernel.org>
On Wed, Nov 29, 2023 at 11:50 PM Seth Forshee (DigitalOcean)
<sforshee@kernel.org> wrote:
>
> Provide a type-safe interface for setting filesystem capabilities and a
> generic implementation suitable for most filesystems.
>
> Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
> ---
> fs/xattr.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/fs.h | 2 ++
> 2 files changed, 89 insertions(+)
>
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 3abaf9bef0a5..03cc824e4f87 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -247,6 +247,93 @@ int vfs_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry,
> }
> EXPORT_SYMBOL(vfs_get_fscaps);
>
> +static int generic_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry,
> + const struct vfs_caps *caps, int flags)
> +{
> + struct inode *inode = d_inode(dentry);
> + struct vfs_ns_cap_data nscaps;
> + int size;
> +
> + size = vfs_caps_to_xattr(idmap, i_user_ns(inode), caps,
> + &nscaps, sizeof(nscaps));
> + if (size < 0)
> + return size;
> +
> + return __vfs_setxattr_noperm(idmap, dentry, XATTR_NAME_CAPS,
> + &nscaps, size, flags);
> +}
> +
> +/**
> + * vfs_set_fscaps - set filesystem capabilities
> + * @idmap: idmap of the mount the inode was found from
> + * @dentry: the dentry on which to set filesystem capabilities
> + * @caps: the filesystem capabilities to be written
> + * @flags: setxattr flags to use when writing the capabilities xattr
> + *
> + * This function writes the supplied filesystem capabilities to the dentry.
> + *
> + * Return: 0 on success, a negative errno on error.
> + */
> +int vfs_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry,
> + const struct vfs_caps *caps, int flags)
> +{
> + struct inode *inode = d_inode(dentry);
> + struct inode *delegated_inode = NULL;
> + struct vfs_ns_cap_data nscaps;
> + int size, error;
> +
> + /*
> + * Unfortunately EVM wants to have the raw xattr value to compare to
> + * the on-disk version, so we need to pass the raw xattr to the
> + * security hooks. But we also want to do security checks before
> + * breaking leases, so that means a conversion to the raw xattr here
> + * which will usually be reduntant with the conversion we do for
> + * writing the xattr to disk.
> + */
> + size = vfs_caps_to_xattr(idmap, i_user_ns(inode), caps, &nscaps,
> + sizeof(nscaps));
> + if (size < 0)
> + return size;
> +
> +retry_deleg:
> + inode_lock(inode);
> +
> + error = xattr_permission(idmap, inode, XATTR_NAME_CAPS, MAY_WRITE);
> + if (error)
> + goto out_inode_unlock;
> + error = security_inode_setxattr(idmap, dentry, XATTR_NAME_CAPS, &nscaps,
> + size, flags);
> + if (error)
> + goto out_inode_unlock;
> +
> + error = try_break_deleg(inode, &delegated_inode);
> + if (error)
> + goto out_inode_unlock;
> +
> + if (inode->i_opflags & IOP_XATTR) {
> + if (inode->i_op->set_fscaps)
> + error = inode->i_op->set_fscaps(idmap, dentry, caps, flags);
> + else
> + error = generic_set_fscaps(idmap, dentry, caps, flags);
I think the non-generic case is missing fsnotify_xattr().
See vfs_set_acl() for comparison.
Thanks,
Amir.
next prev parent reply other threads:[~2023-11-30 8:02 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-29 21:50 [PATCH 00/16] fs: use type-safe uid representation for filesystem capabilities Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 01/16] mnt_idmapping: split out core vfs[ug]id_t definitions into vfsid.h Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 02/16] mnt_idmapping: include cred.h Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 03/16] capability: rename cpu_vfs_cap_data to vfs_caps Seth Forshee (DigitalOcean)
2023-12-01 15:50 ` Christian Brauner
2023-12-05 21:25 ` [PATCH 3/16] " Paul Moore
2023-11-29 21:50 ` [PATCH 04/16] capability: use vfsuid_t for vfs_caps rootids Seth Forshee (DigitalOcean)
2023-12-05 21:25 ` [PATCH 4/16] " Paul Moore
2023-11-29 21:50 ` [PATCH 05/16] capability: provide helpers for converting between xattrs and vfs_caps Seth Forshee (DigitalOcean)
2023-12-01 16:41 ` Christian Brauner
2023-12-01 17:09 ` Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 06/16] capability: provide a helper for converting vfs_caps to xattr for userspace Seth Forshee (DigitalOcean)
2023-12-01 16:57 ` Christian Brauner
2023-12-01 17:23 ` Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 07/16] fs: add inode operations to get/set/remove fscaps Seth Forshee (DigitalOcean)
2023-11-30 5:32 ` Amir Goldstein
2023-11-30 15:36 ` Seth Forshee (DigitalOcean)
2023-12-01 17:02 ` Christian Brauner
2023-12-01 17:38 ` Seth Forshee (DigitalOcean)
2023-12-05 11:50 ` Christian Brauner
2023-11-29 21:50 ` [PATCH 08/16] fs: add vfs_get_fscaps() Seth Forshee (DigitalOcean)
2023-12-01 17:09 ` Christian Brauner
2023-12-01 17:41 ` Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 09/16] fs: add vfs_set_fscaps() Seth Forshee (DigitalOcean)
2023-11-30 8:01 ` Amir Goldstein [this message]
2023-11-30 15:38 ` Seth Forshee (DigitalOcean)
2023-12-01 17:39 ` Christian Brauner
2023-12-01 18:18 ` Seth Forshee (DigitalOcean)
2023-12-07 14:42 ` Seth Forshee (DigitalOcean)
2023-12-10 16:41 ` Amir Goldstein
2023-11-29 21:50 ` [PATCH 10/16] fs: add vfs_remove_fscaps() Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 11/16] ovl: add fscaps handlers Seth Forshee (DigitalOcean)
2023-11-30 5:56 ` Amir Goldstein
2023-11-30 16:01 ` Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 12/16] ovl: use vfs_{get,set}_fscaps() for copy-up Seth Forshee (DigitalOcean)
2023-11-30 6:23 ` Amir Goldstein
2023-11-30 16:43 ` Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 13/16] fs: use vfs interfaces for capabilities xattrs Seth Forshee (DigitalOcean)
2023-11-29 21:50 ` [PATCH 14/16] commoncap: remove cap_inode_getsecurity() Seth Forshee (DigitalOcean)
2023-12-05 21:25 ` Paul Moore
2023-11-29 21:50 ` [PATCH 15/16] commoncap: use vfs fscaps interfaces for killpriv checks Seth Forshee (DigitalOcean)
2023-12-11 7:57 ` kernel test robot
2023-11-29 21:50 ` [PATCH 16/16] vfs: return -EOPNOTSUPP for fscaps from vfs_*xattr() Seth Forshee (DigitalOcean)
2023-11-30 6:10 ` Amir Goldstein
2023-11-30 16:40 ` Seth Forshee (DigitalOcean)
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