[PATCH v17 19/22] richacl: Add richacl xattr handler

Andreas Gruenbacher
2016-01-11T15:24:12Z

Add richacl xattr handler implementing the xattr operations based on the
get_richacl and set_richacl inode operations.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/richacl_xattr.c | 73 +++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl_xattr.h | 2 ++
2 files changed, 75 insertions(+)

diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
index a273139..afa2859 100644
--- a/fs/richacl_xattr.c
+++ b/fs/richacl_xattr.c
@@ -18,7 +18,9 @@
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/xattr.h>
#include <linux/richacl_xattr.h>
+#include <uapi/linux/xattr.h>

MODULE_LICENSE("GPL");

@@ -160,3 +162,74 @@ richacl_to_xattr(struct user_namespace *user_ns,
return real_size;
}
EXPORT_SYMBOL_GPL(richacl_to_xattr);
+
+static bool
+richacl_xattr_list(struct dentry *dentry)
+{
+ return IS_RICHACL(d_backing_inode(dentry));
+}
+
+static int
+richacl_xattr_get(const struct xattr_handler *handler,
+ struct dentry *dentry, const char *name, void *buffer,
+ size_t buffer_size)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct richacl *acl;
+ int error;
+
+ if (*name)
+ return -EINVAL;
+ if (!IS_RICHACL(inode))
+ return -EOPNOTSUPP;
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+ acl = get_richacl(inode);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl == NULL)
+ return -ENODATA;
+ error = richacl_to_xattr(current_user_ns(), acl, buffer, buffer_size);
+ richacl_put(acl);
+ return error;
+}
+
+static int
+richacl_xattr_set(const struct xattr_handler *handler,
+ struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct richacl *acl = NULL;
+ int ret;
+
+ if (*name)
+ return -EINVAL;
+ if (!IS_RICHACL(inode))
+ return -EOPNOTSUPP;
+ if (!inode->i_op->set_richacl)
+ return -EOPNOTSUPP;
+
+ if (!uid_eq(current_fsuid(), inode->i_uid) &&
+ inode_permission(inode, MAY_CHMOD) &&
+ !capable(CAP_FOWNER))
+ return -EPERM;
+
+ if (value) {
+ acl = richacl_from_xattr(current_user_ns(), value, size);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ }
+
+ ret = inode->i_op->set_richacl(inode, acl);
+ richacl_put(acl);
+ return ret;
+}
+
+struct xattr_handler richacl_xattr_handler = {
+ .name = XATTR_NAME_RICHACL,
+ .list = richacl_xattr_list,
+ .get = richacl_xattr_get,
+ .set = richacl_xattr_set,
+};
+EXPORT_SYMBOL(richacl_xattr_handler);
diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
index ab67af2..ad4a56e 100644
--- a/include/linux/richacl_xattr.h
+++ b/include/linux/richacl_xattr.h
@@ -26,4 +26,6 @@ extern size_t richacl_xattr_size(const struct richacl *);
extern int richacl_to_xattr(struct user_namespace *, const struct richacl *,
void *, size_t);

+extern struct xattr_handler richacl_xattr_handler;
+
#endif /* __RICHACL_XATTR_H */