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From: "Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
To: Christian Brauner <brauner@kernel.org>,
	 Seth Forshee <sforshee@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>,
	 Jan Kara <jack@suse.cz>,
	Stephen Smalley <stephen.smalley.work@gmail.com>,
	 Ondrej Mosnacek <omosnace@redhat.com>,
	 Casey Schaufler <casey@schaufler-ca.com>,
	Mimi Zohar <zohar@linux.ibm.com>,
	 Roberto Sassu <roberto.sassu@huawei.com>,
	 Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
	 Eric Snowberg <eric.snowberg@oracle.com>,
	 "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	 Jonathan Corbet <corbet@lwn.net>,
	Miklos Szeredi <miklos@szeredi.hu>,
	 Amir Goldstein <amir73il@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	 linux-security-module@vger.kernel.org, audit@vger.kernel.org,
	 selinux@vger.kernel.org, linux-integrity@vger.kernel.org,
	 linux-doc@vger.kernel.org, linux-unionfs@vger.kernel.org
Subject: [PATCH v2 18/25] fs: add vfs_set_fscaps()
Date: Wed, 21 Feb 2024 15:24:49 -0600	[thread overview]
Message-ID: <20240221-idmap-fscap-refactor-v2-18-3039364623bd@kernel.org> (raw)
In-Reply-To: <20240221-idmap-fscap-refactor-v2-0-3039364623bd@kernel.org>

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         | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h |  2 ++
 2 files changed, 81 insertions(+)

diff --git a/fs/xattr.c b/fs/xattr.c
index 10d1b1f78fc2..96de43928a51 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -245,6 +245,85 @@ 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 setxattr_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, setxattr_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
+ * @setxattr_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 setxattr_flags)
+{
+	struct inode *inode = d_inode(dentry);
+	struct inode *delegated_inode = NULL;
+	int error;
+
+retry_deleg:
+	inode_lock(inode);
+
+	error = xattr_permission(idmap, inode, XATTR_NAME_CAPS, MAY_WRITE);
+	if (error)
+		goto out_inode_unlock;
+	error = security_inode_set_fscaps(idmap, dentry, caps, setxattr_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,
+							setxattr_flags);
+		else
+			error = generic_set_fscaps(idmap, dentry, caps,
+						   setxattr_flags);
+		if (!error) {
+			fsnotify_xattr(dentry);
+			security_inode_post_set_fscaps(idmap, dentry, caps,
+						       setxattr_flags);
+		}
+	} else if (unlikely(is_bad_inode(inode))) {
+		error = -EIO;
+	} else {
+		error = -EOPNOTSUPP;
+	}
+
+out_inode_unlock:
+	inode_unlock(inode);
+
+	if (delegated_inode) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(vfs_set_fscaps);
+
 int
 __vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	       struct inode *inode, const char *name, const void *value,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d7cd2467e1ea..4f5d7ed44644 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2120,6 +2120,8 @@ extern int vfs_get_fscaps_nosec(struct mnt_idmap *idmap, struct dentry *dentry,
 				struct vfs_caps *caps);
 extern int vfs_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry,
 			  struct vfs_caps *caps);
+extern int vfs_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry,
+			  const struct vfs_caps *caps, int setxattr_flags);
 
 /**
  * enum freeze_holder - holder of the freeze

-- 
2.43.0


  parent reply	other threads:[~2024-02-21 21:25 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-21 21:24 [PATCH v2 00/25] fs: use type-safe uid representation for filesystem capabilities Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 01/25] mnt_idmapping: split out core vfs[ug]id_t definitions into vfsid.h Seth Forshee (DigitalOcean)
2024-02-22 14:09   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 02/25] mnt_idmapping: include cred.h Seth Forshee (DigitalOcean)
2024-02-22 14:12   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 03/25] capability: add static asserts for comapatibility of vfs_cap_data and vfs_ns_cap_data Seth Forshee (DigitalOcean)
2024-02-22 14:23   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 04/25] capability: rename cpu_vfs_cap_data to vfs_caps Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 05/25] capability: use vfsuid_t for vfs_caps rootids Seth Forshee (DigitalOcean)
2024-02-22 14:25   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 06/25] capability: provide helpers for converting between xattrs and vfs_caps Seth Forshee (DigitalOcean)
2024-02-22 15:20   ` Christian Brauner
2024-02-22 15:38     ` Seth Forshee (DigitalOcean)
2024-02-23  8:08       ` Christian Brauner
2024-03-01 16:30   ` Roberto Sassu
2024-03-01 19:00     ` Seth Forshee (DigitalOcean)
2024-03-04  8:33       ` Roberto Sassu
2024-03-04 14:24         ` Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 07/25] capability: provide a helper for converting vfs_caps to xattr for userspace Seth Forshee (DigitalOcean)
2024-02-22 15:22   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 08/25] xattr: add is_fscaps_xattr() helper Seth Forshee (DigitalOcean)
2024-02-23  8:09   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 09/25] commoncap: use is_fscaps_xattr() Seth Forshee (DigitalOcean)
2024-02-23  8:10   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 10/25] xattr: " Seth Forshee (DigitalOcean)
2024-02-23  8:10   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 11/25] security: add hooks for set/get/remove of fscaps Seth Forshee (DigitalOcean)
2024-02-21 23:31   ` Paul Moore
2024-02-22  0:07     ` Seth Forshee (DigitalOcean)
2024-02-23  8:23   ` Christian Brauner
2024-03-01 15:59   ` Roberto Sassu
2024-03-01 18:50     ` Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 12/25] selinux: add hooks for fscaps operations Seth Forshee (DigitalOcean)
2024-02-21 23:38   ` Paul Moore
2024-02-22  0:10     ` Seth Forshee (DigitalOcean)
2024-02-22  0:19       ` Paul Moore
2024-02-22  0:28         ` Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 13/25] smack: " Seth Forshee (DigitalOcean)
2024-02-21 22:52   ` Casey Schaufler
2024-02-22  0:11     ` Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 14/25] evm: add support for fscaps security hooks Seth Forshee (DigitalOcean)
2024-03-01  9:19   ` Roberto Sassu
2024-03-01 12:54     ` Christian Brauner
2024-03-01 13:19       ` Roberto Sassu
2024-03-01 13:39         ` Christian Brauner
2024-03-01 14:39     ` Seth Forshee (DigitalOcean)
2024-03-01 15:04       ` Roberto Sassu
2024-03-04 15:01   ` Roberto Sassu
2024-02-21 21:24 ` [PATCH v2 15/25] security: call evm fscaps hooks from generic " Seth Forshee (DigitalOcean)
2024-02-21 23:43   ` Paul Moore
2024-02-22  0:20     ` Seth Forshee (DigitalOcean)
2024-02-22  0:37       ` Paul Moore
2024-02-21 21:24 ` [PATCH v2 16/25] fs: add inode operations to get/set/remove fscaps Seth Forshee (DigitalOcean)
2024-02-23  8:25   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 17/25] fs: add vfs_get_fscaps() Seth Forshee (DigitalOcean)
2024-02-23  8:28   ` Christian Brauner
2024-02-21 21:24 ` Seth Forshee (DigitalOcean) [this message]
2024-02-23  8:38   ` [PATCH v2 18/25] fs: add vfs_set_fscaps() Christian Brauner
2024-02-21 21:24 ` [PATCH v2 19/25] fs: add vfs_remove_fscaps() Seth Forshee (DigitalOcean)
2024-02-23  8:40   ` Christian Brauner
2024-02-21 21:24 ` [PATCH v2 20/25] ovl: add fscaps handlers Seth Forshee (DigitalOcean)
2024-02-23  9:04   ` Christian Brauner
2024-02-27 13:28   ` Amir Goldstein
2024-02-27 14:57     ` Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 21/25] ovl: use vfs_{get,set}_fscaps() for copy-up Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 22/25] fs: use vfs interfaces for capabilities xattrs Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 23/25] commoncap: remove cap_inode_getsecurity() Seth Forshee (DigitalOcean)
2024-02-21 21:24 ` [PATCH v2 24/25] commoncap: use vfs fscaps interfaces Seth Forshee (DigitalOcean)
2024-03-04 10:19   ` Roberto Sassu
2024-03-04 15:31     ` Seth Forshee (DigitalOcean)
2024-03-04 16:17       ` Roberto Sassu
2024-03-04 16:56         ` Seth Forshee (DigitalOcean)
2024-03-05  9:12           ` Christian Brauner
2024-03-05 12:46             ` Roberto Sassu
2024-03-05 16:26               ` Christian Brauner
2024-03-05 16:35                 ` Roberto Sassu
2024-03-05 17:03                   ` Seth Forshee (DigitalOcean)
2024-03-05 17:08                     ` Roberto Sassu
2024-03-05 17:11               ` Roberto Sassu
2024-03-05 20:17                 ` Seth Forshee (DigitalOcean)
2024-03-06  8:30                   ` Roberto Sassu
2024-03-06  2:17                 ` Mimi Zohar
2024-03-06  8:25                   ` Roberto Sassu
2024-03-06 12:56                     ` Mimi Zohar
2024-02-21 21:24 ` [PATCH v2 25/25] vfs: return -EOPNOTSUPP for fscaps from vfs_*xattr() Seth Forshee (DigitalOcean)
2024-02-22 15:27 ` [PATCH v2 00/25] fs: use type-safe uid representation for filesystem capabilities Christian Brauner
2024-02-22 16:28   ` Seth Forshee (DigitalOcean)

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