[PATCH v10 18/46] richacl: Add richacl xattr handler

Andreas Gruenbacher
2015-10-11T23:01:17Z

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 | 78 +++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl_xattr.h | 2 ++
2 files changed, 80 insertions(+)

diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
index cd9979d..dc529dc 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");

@@ -161,6 +163,82 @@ richacl_to_xattr(struct user_namespace *user_ns,
}
EXPORT_SYMBOL_GPL(richacl_to_xattr);

+static size_t
+richacl_xattr_list(struct dentry *dentry, char *list, size_t list_len,
+ const char *name, size_t name_len, int handler_flags)
+{
+ const size_t size = sizeof(XATTR_NAME_RICHACL);
+
+ if (!IS_RICHACL(d_backing_inode(dentry)))
+ return 0;
+ if (list && size <= list_len)
+ memcpy(list, XATTR_NAME_RICHACL, size);
+ return size;
+}
+
+static int
+richacl_xattr_get(struct dentry *dentry, const char *name, void *buffer,
+ size_t buffer_size, int handler_flags)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct richacl *acl;
+ int error;
+
+ if (strcmp(name, "") != 0)
+ 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(&init_user_ns, acl, buffer, buffer_size);
+ richacl_put(acl);
+ return error;
+}
+
+static int
+richacl_xattr_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags, int handler_flags)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct richacl *acl = NULL;
+ int ret;
+
+ if (strcmp(name, "") != 0)
+ 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(&init_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 = {
+ .prefix = XATTR_NAME_RICHACL,
+ .list = richacl_xattr_list,
+ .get = richacl_xattr_get,
+ .set = richacl_xattr_set,
+};
+EXPORT_SYMBOL(richacl_xattr_handler);
+
/*
* Fix up the uids and gids in richacl extended attributes in place.
*/
diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
index f84cc21..dac4e32 100644
--- a/include/linux/richacl_xattr.h
+++ b/include/linux/richacl_xattr.h
@@ -59,4 +59,6 @@ static inline void richacl_fix_xattr_to_user(void *value, size_t size)
}
#endif

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