This is a note to let you know that I've just added the patch titled
efi: ssdt: Don't free memory if ACPI table was loaded successfully
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
efi-ssdt-don-t-free-memory-if-acpi-table-was-loaded-successfully.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4b017e59f01097f19b938f6dc4dc2c4720701610 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
Date: Fri, 14 Oct 2022 12:25:52 +0200
Subject: efi: ssdt: Don't free memory if ACPI table was loaded successfully
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From: Ard Biesheuvel <ardb@xxxxxxxxxx>
commit 4b017e59f01097f19b938f6dc4dc2c4720701610 upstream.
Amadeusz reports KASAN use-after-free errors introduced by commit
3881ee0b1edc ("efi: avoid efivars layer when loading SSDTs from
variables"). The problem appears to be that the memory that holds the
new ACPI table is now freed unconditionally, instead of only when the
ACPI core reported a failure to load the table.
So let's fix this, by omitting the kfree() on success.
Cc: <stable@xxxxxxxxxxxxxxx> # v6.0
Link: https://lore.kernel.org/all/a101a10a-4fbb-5fae-2e3c-76cf96ed8fbd@xxxxxxxxxxxxxxx/
Fixes: 3881ee0b1edc ("efi: avoid efivars layer when loading SSDTs from variables")
Reported-by: Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/efi/efi.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -269,6 +269,8 @@ static __init int efivar_ssdt_load(void)
acpi_status ret = acpi_load_table(data, NULL);
if (ret)
pr_err("failed to load table: %u\n", ret);
+ else
+ continue;
} else {
pr_err("failed to get var data: 0x%lx\n", status);
}
Patches currently in stable-queue which might be from ardb@xxxxxxxxxx are
queue-6.0/efi-ssdt-don-t-free-memory-if-acpi-table-was-loaded-successfully.patch
queue-6.0/efi-efivars-fix-variable-writes-without-query_variable_store.patch
