From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91E242D634; Fri, 1 Dec 2023 17:09:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jticPDpk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F30F9C433C9; Fri, 1 Dec 2023 17:09:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701450582; bh=uEyHckuH85mFToap34E21cKoNiYKQu7WvLyHdU6m5Mk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jticPDpkXPNXiHfum1CiK44sgJUxDUnC/w4iHEXmx2Xh1ucb6e2kv1iB+0JN1lOR3 AGgJVmd0mTbNI0ZGlCw8dwv0wOAd7IHSkr4nIgg4fdAezdcg0EgJEPJhoij4nUGOOj ey+JiEvigeCyf3MJ2PJ9j60r2zbSAgOJUMfagG+WBB0ZPw/erAcUg89RUU0LMrBupr dKm85sjvxIm6eM9BHPpFOebQkA6sS2/RcIal4nfGMhcojMIWP9eMz+ZiJc65xPRN4l feH/Iuax6lcUsuMVTlZzXcl1S8qNdS/iNleYZXlhxBCYFnEeTWU6TS9vesMSYvJt8/ Ph6eLHgPRM/0Q== Date: Fri, 1 Dec 2023 18:09:36 +0100 From: Christian Brauner To: "Seth Forshee (DigitalOcean)" Cc: Serge Hallyn , Paul Moore , Eric Paris , James Morris , Alexander Viro , Miklos Szeredi , Amir Goldstein , 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 08/16] fs: add vfs_get_fscaps() Message-ID: <20231201-wodurch-holen-ce9c44d8aaf5@brauner> References: <20231129-idmap-fscap-refactor-v1-0-da5a26058a5b@kernel.org> <20231129-idmap-fscap-refactor-v1-8-da5a26058a5b@kernel.org> Precedence: bulk X-Mailing-List: audit@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231129-idmap-fscap-refactor-v1-8-da5a26058a5b@kernel.org> On Wed, Nov 29, 2023 at 03:50:26PM -0600, Seth Forshee (DigitalOcean) wrote: > Provide a type-safe interface for retrieving filesystem capabilities and > a generic implementation suitable for most filesystems. Also add an > internal interface, __vfs_get_fscaps(), which skips security checks for > later use from the capability code. > > Signed-off-by: Seth Forshee (DigitalOcean) > --- > fs/xattr.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/fs.h | 4 ++++ > 2 files changed, 70 insertions(+) > > diff --git a/fs/xattr.c b/fs/xattr.c > index 09d927603433..3abaf9bef0a5 100644 > --- a/fs/xattr.c > +++ b/fs/xattr.c > @@ -181,6 +181,72 @@ xattr_supports_user_prefix(struct inode *inode) > } > EXPORT_SYMBOL(xattr_supports_user_prefix); > > +static int generic_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, > + struct vfs_caps *caps) > +{ > + struct inode *inode = d_inode(dentry); > + struct vfs_ns_cap_data *nscaps = NULL; > + int ret; > + > + ret = (int)vfs_getxattr_alloc(idmap, dentry, XATTR_NAME_CAPS, I don't think you need that case here. > + (char **)&nscaps, 0, GFP_NOFS); > + > + if (ret >= 0) > + ret = vfs_caps_from_xattr(idmap, i_user_ns(inode), caps, nscaps, ret); > + > + kfree(nscaps); > + return ret; > +} > + > +/** > + * __vfs_get_fscaps - get filesystem capabilities without security checks > + * @idmap: idmap of the mount the inode was found from > + * @dentry: the dentry from which to get filesystem capabilities > + * @caps: storage in which to return the filesystem capabilities > + * > + * This function gets the filesystem capabilities for the dentry and returns > + * them in @caps. It does not perform security checks. > + * > + * Return: 0 on success, a negative errno on error. > + */ > +int __vfs_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, > + struct vfs_caps *caps) I would rename that to vfs_get_fscaps_nosec(). We do that for vfs_getxattr_nosec() as well. It's not pretty but it's better than just slapping underscores onto it imo.