1 files changed, 17 insertions, 0 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 16fefd373fc2..a21d5a938a17 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -25,6 +25,7 @@
 #include <linux/async.h>
 #include <linux/posix_acl.h>
 #include <linux/ima.h>
+#include <linux/cred.h>
 
 /*
  * This is needed for the following functions:
@@ -1733,3 +1734,19 @@ void inode_init_owner(struct inode *inode, const struct inode *dir,
         inode->i_mode = mode;
 }
 EXPORT_SYMBOL(inode_init_owner);
+
+/*
+ * return true if current either has CAP_FOWNER to the
+ * file, or owns the file.
+ */
+bool is_owner_or_cap(const struct inode *inode)
+{
+        struct user_namespace *ns = inode_userns(inode);
+
+        if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
+                return true;
+        if (ns_capable(ns, CAP_FOWNER))
+                return true;
+        return false;
+}
+EXPORT_SYMBOL(is_owner_or_cap);