diff mbox series

[stable-v6.1,02/18] efi: efivars: prevent double registration

Message ID 20240304111937.2556102-22-ardb+git@google.com
State New
Headers show
Series efistub/x86 changes for secure boot | expand

Commit Message

Ard Biesheuvel March 4, 2024, 11:19 a.m. UTC 
From: Johan Hovold <johan+linaro@kernel.org>

[ Commit 0217a40d7ba6e71d7f3422fbe89b436e8ee7ece7 upstream ]

Add the missing sanity check to efivars_register() so that it is no
longer possible to override an already registered set of efivar ops
(without first deregistering them).

This can help debug initialisation ordering issues where drivers have so
far unknowingly been relying on overriding the generic ops.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/vars.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 0ba9f18312f5..4ca256bcd697 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -66,19 +66,28 @@  int efivars_register(struct efivars *efivars,
 		     const struct efivar_operations *ops,
 		     struct kobject *kobject)
 {
+	int rv;
+
 	if (down_interruptible(&efivars_lock))
 		return -EINTR;
 
+	if (__efivars) {
+		pr_warn("efivars already registered\n");
+		rv = -EBUSY;
+		goto out;
+	}
+
 	efivars->ops = ops;
 	efivars->kobject = kobject;
 
 	__efivars = efivars;
 
 	pr_info("Registered efivars operations\n");
-
+	rv = 0;
+out:
 	up(&efivars_lock);
 
-	return 0;
+	return rv;
 }
 EXPORT_SYMBOL_GPL(efivars_register);