commit b306e90ffabdaa7e3b3350dbcd19b7663e71ab17
From: Amir Goldstein <amir73il@gmail.com>
Author: Amir Goldstein <amir73il@gmail.com>
Date: Mon Oct 17 17:06:38 2022 +0200
Git-commit: b306e90ffabdaa7e3b3350dbcd19b7663e71ab17
Patch-mainline: v6.2-rc1
References: git-fixes
Subject: ovl: remove privs in ovl_copyfile()

    ovl: remove privs in ovl_copyfile()
    
    Underlying fs doesn't remove privs because copy_range/remap_range are
    called with privileged mounter credentials.
    
    This fixes some failures in fstest generic/673.
    
Fixes: 8ede205541ff ("ovl: add reflink/copyfile/dedup support")
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index a1a22f58ba18..755a11c63596 100644

--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -567,14 +567,23 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 	const struct cred *old_cred;
 	loff_t ret;
 
+	inode_lock(inode_out);
+	if (op != OVL_DEDUPE) {
+		/* Update mode */
+		ovl_copyattr(file_inode(file_in), inode_out);
+		ret = file_remove_privs(file_out);
+		if (ret)
+			goto out_unlock;
+	}
+
 	ret = ovl_real_fdget(file_out, &real_out);
 	if (ret)
-		return ret;
+		goto out_unlock;
 
 	ret = ovl_real_fdget(file_in, &real_in);
 	if (ret) {
 		fdput(real_out);
-		return ret;
+		goto out_unlock;
 	}
 
 	old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
@@ -603,6 +612,9 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 	fdput(real_in);
 	fdput(real_out);
 
+out_unlock:
+	inode_unlock(inode_out);
+
 	return ret;
 }