From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Steve McIntyre <steve@einval.com>
Date: Tue, 6 Dec 2022 01:45:11 +0000
Subject: [PATCH] kern/file: Fix error handling in grub_file_open()

grub_file_open() calls grub_file_get_device_name(), but doesn't check
the return. Instead, it checks if grub_errno is set.

However, nothing initialises grub_errno here when grub_file_open()
starts. This means that trying to open one file that doesn't exist and
then trying to open another file that does will (incorrectly) also
fail to open that second file.

Let's fix that.

Signed-off-by: Steve McIntyre <steve@einval.com>
---
 grub-core/kern/file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/kern/file.c b/grub-core/kern/file.c
index 58454458c4..5b58f45cfd 100644
--- a/grub-core/kern/file.c
+++ b/grub-core/kern/file.c
@@ -66,6 +66,9 @@ grub_file_open (const char *name, enum grub_file_type type)
   const char *file_name;
   grub_file_filter_id_t filter;
 
+  /* Reset grub_errno before we start */
+  grub_errno = GRUB_ERR_NONE;
+
   device_name = grub_file_get_device_name (name);
   if (grub_errno)
     goto fail;