1 files changed, 29 insertions, 0 deletions

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 81b70e665bf0..887b5ba8c9b5 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -20,6 +20,7 @@
 #include <linux/signal.h>
 #include <linux/rcupdate.h>
 #include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
 
 #include <asm/poll.h>
 #include <asm/siginfo.h>
@@ -340,6 +341,31 @@ static int f_getown_ex(struct file *filp, unsigned long arg)
         return ret;
 }
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int f_getowner_uids(struct file *filp, unsigned long arg)
+{
+        struct user_namespace *user_ns = current_user_ns();
+        uid_t * __user dst = (void * __user)arg;
+        uid_t src[2];
+        int err;
+
+        read_lock(&filp->f_owner.lock);
+        src[0] = from_kuid(user_ns, filp->f_owner.uid);
+        src[1] = from_kuid(user_ns, filp->f_owner.euid);
+        read_unlock(&filp->f_owner.lock);
+
+        err  = put_user(src[0], &dst[0]);
+        err |= put_user(src[1], &dst[1]);
+
+        return err;
+}
+#else
+static int f_getowner_uids(struct file *filp, unsigned long arg)
+{
+        return -EINVAL;
+}
+#endif
+
 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
                 struct file *filp)
 {
@@ -396,6 +422,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
         case F_SETOWN_EX:
                 err = f_setown_ex(filp, arg);
                 break;
+        case F_GETOWNER_UIDS:
+                err = f_getowner_uids(filp, arg);
+                break;
         case F_GETSIG:
                 err = filp->f_owner.signum;
                 break;