ovl: properly handle large files in ovl_security_fileattr

BugLink: https://bugs.launchpad.net/bugs/2095283

commit 3b6b99e upstream.

dentry_open in ovl_security_fileattr fails for any file
larger than 2GB if open method of the underlying filesystem
calls generic_file_open (e.g. fusefs).

The issue can be reproduce using the following script:
(passthrough_ll is an example app from libfuse).

  $ D=/opt/test/mnt
  $ mkdir -p ${D}/{source,base,top/uppr,top/work,ovlfs}
  $ dd if=/dev/zero of=${D}/source/zero.bin bs=1G count=2
  $ passthrough_ll -o source=${D}/source ${D}/base
  $ mount -t overlay overlay \
      -olowerdir=${D}/base,upperdir=${D}/top/uppr,workdir=${D}/top/work \
      ${D}/ovlfs
  $ chmod 0777 ${D}/mnt/ovlfs/zero.bin

Running this script results in "Value too large for defined data type"
error message from chmod.

Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Fixes: 72db821 ("ovl: copy up sync/noatime fileattr flags")
Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>

Author: gonzoua

fs/overlayfs/inode.c

@@ -519,8 +519,13 @@ static int ovl_security_fileattr(struct path *realpath, struct fileattr *fa,
 	struct file *file;
 	unsigned int cmd;
 	int err;
+	unsigned int flags;
+
+	flags = O_RDONLY;
+	if (force_o_largefile())
+		flags |= O_LARGEFILE;
 
-	file = dentry_open(realpath, O_RDONLY, current_cred());
+	file = dentry_open(realpath, flags, current_cred());
 	if (IS_ERR(file))
 		return PTR_ERR(file);