[PATCH 5.10 033/545] fs: Add missing umask strip in vfs_tmpfile

[Greg Kroah-Hartman]

From: Yang Xu <xuyang2018.jy@xxxxxxxxxxx>

commit ac6800e279a22b28f4fc21439843025a0d5bf03e upstream.

All creation paths except for O_TMPFILE handle umask in the vfs directly
if the filesystem doesn't support or enable POSIX ACLs. If the filesystem
does then umask handling is deferred until posix_acl_create().
Because, O_TMPFILE misses umask handling in the vfs it will not honor
umask settings. Fix this by adding the missing umask handling.

Link: https://lore.kernel.org/r/1657779088-2242-2-git-send-email-xuyang2018.jy@xxxxxxxxxxx
Fixes: 60545d0d4610 ("[O_TMPFILE] it's still short a few helpers, but infrastructure should be OK now...")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.19+
Reported-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-and-Tested-by: Jeff Layton <jlayton@xxxxxxxxxx>
Acked-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
Signed-off-by: Yang Xu <xuyang2018.jy@xxxxxxxxxxx>
Signed-off-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/namei.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3272,6 +3272,8 @@ struct dentry *vfs_tmpfile(struct dentry
 	child = d_alloc(dentry, &slash_name);
 	if (unlikely(!child))
 		goto out_err;
+	if (!IS_POSIXACL(dir))
+		mode &= ~current_umask();
 	error = dir->i_op->tmpfile(dir, child, mode);
 	if (error)
 		goto out_err;