From d1d6b7ea58aa5a80a4c4d0666b49460056c8ef0a Mon Sep 17 00:00:00 2001
From: B Horn <b@horn.uk>
Date: Sun, 12 May 2024 06:03:58 +0100
Subject: [PATCH 20/73] fs/xfs: Ensuring failing to mount sets a grub_errno

It was previously possible for grub_xfs_mount() to return NULL without
setting grub_errno if the XFS version was invalid. This resulted in it
being possible for grub_dl_unref() to be called twice allowing the XFS
module to be unloaded while there were still references to it.

Fixing this problem in general by ensuring a grub_errno is set if the
fail label is reached.

Reported-by: B Horn <b@horn.uk>
Signed-off-by: B Horn <b@horn.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/fs/xfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c
index 82ea33f40..8c0d60f7d 100644
--- a/grub-core/fs/xfs.c
+++ b/grub-core/fs/xfs.c
@@ -327,6 +327,8 @@ static int grub_xfs_sb_valid(struct grub_xfs_data *data)
 	}
       return 1;
     }
+
+  grub_error (GRUB_ERR_BAD_FS, "unsupported XFS filesystem version");
   return 0;
 }
 
@@ -1068,7 +1070,7 @@ grub_xfs_mount (grub_disk_t disk)
   return data;
  fail:
 
-  if (grub_errno == GRUB_ERR_OUT_OF_RANGE)
+  if (grub_errno == GRUB_ERR_OUT_OF_RANGE || grub_errno == GRUB_ERR_NONE)
     grub_error (GRUB_ERR_BAD_FS, "not an XFS filesystem");
 
   grub_free (data);
-- 
2.33.0