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From: Johan Hovold <johan+linaro@kernel.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Jeremy Kerr <jk@ozlabs.org>,
	Maximilian Luz <luzmaximilian@gmail.com>,
	linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan+linaro@kernel.org>,
	Steev Klimaszewski <steev@kali.org>
Subject: [PATCH] efivarfs: fix NULL-deref on mount when no efivars
Date: Thu, 26 Jan 2023 12:21:29 +0100	[thread overview]
Message-ID: <20230126112129.4602-1-johan+linaro@kernel.org> (raw)

The VFS calls kill_sb() also in case mount fails in get_tree().

Add the missing check to make sure that efivars has been registered also
to kill_sb() to avoid dereferencing a NULL pointer when trying to remove
efivar entries.

Fixes: c3fd71b428b8 ("efivarfs: always register filesystem")
Reported-by: Steev Klimaszewski <steev@kali.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 fs/efivarfs/super.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index b67d431c861a..482d612b716b 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -246,6 +246,9 @@ static void efivarfs_kill_sb(struct super_block *sb)
 {
 	kill_litter_super(sb);
 
+	if (!efivar_is_available())
+		return;
+
 	/* Remove all entries and destroy */
 	efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
 }
-- 
2.39.1


             reply	other threads:[~2023-01-26 11:23 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-26 11:21 Johan Hovold [this message]
2023-01-26 20:32 ` [PATCH] efivarfs: fix NULL-deref on mount when no efivars Ard Biesheuvel
2023-01-27  8:28   ` Johan Hovold
2023-01-27  8:38     ` Ard Biesheuvel
2023-02-23  9:03 ` kernel test robot
2023-02-24  8:02   ` Johan Hovold
2023-02-23 10:05 ` kernel test robot

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