From: "Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
To: 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>,
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,
linux-unionfs@vger.kernel.org,
"Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
Subject: [PATCH 08/16] fs: add vfs_get_fscaps()
Date: Wed, 29 Nov 2023 15:50:26 -0600 [thread overview]
Message-ID: <20231129-idmap-fscap-refactor-v1-8-da5a26058a5b@kernel.org> (raw)
In-Reply-To: <20231129-idmap-fscap-refactor-v1-0-da5a26058a5b@kernel.org>
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) <sforshee@kernel.org>
---
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,
+ (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)
+{
+ struct inode *inode = d_inode(dentry);
+
+ if (inode->i_op->get_fscaps)
+ return inode->i_op->get_fscaps(idmap, dentry, caps);
+ return generic_get_fscaps(idmap, dentry, caps);
+}
+
+/**
+ * vfs_get_fscaps - get filesystem capabilities
+ * @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.
+ *
+ * Return: 0 on success, a negative errno on error.
+ */
+int vfs_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct vfs_caps *caps)
+{
+ int error;
+
+ /*
+ * The VFS has no restrictions on reading security.* xattrs, so
+ * xattr_permission() isn't needed. Only LSMs get a say.
+ */
+ error = security_inode_getxattr(dentry, XATTR_NAME_CAPS);
+ if (error)
+ return error;
+
+ return __vfs_get_fscaps(idmap, dentry, caps);
+}
+EXPORT_SYMBOL(vfs_get_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 a0a77f67b999..e25b39e4017a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2055,6 +2055,10 @@ extern int vfs_dedupe_file_range(struct file *file,
extern loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
struct file *dst_file, loff_t dst_pos,
loff_t len, unsigned int remap_flags);
+extern int __vfs_get_fscaps(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);
enum freeze_holder {
FREEZE_HOLDER_KERNEL = (1U << 0),
--
2.43.0
next prev parent reply other threads:[~2023-11-29 21:51 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 ` Seth Forshee (DigitalOcean) [this message]
2023-12-01 17:09 ` [PATCH 08/16] fs: add vfs_get_fscaps() 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
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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