efi: ssdt: Don't free memory if ACPI table was loaded successfully
authorArd Biesheuvel <ardb@kernel.org>
Fri, 14 Oct 2022 10:25:52 +0000 (12:25 +0200)
committerArd Biesheuvel <ardb@kernel.org>
Fri, 21 Oct 2022 09:09:40 +0000 (11:09 +0200)
commit4b017e59f01097f19b938f6dc4dc2c4720701610
tree403cdf74e256b38e383983ad6e8b99675c3076de
parentf57fb375a203e28bf7c08ca01d5ee72028b391d9
efi: ssdt: Don't free memory if ACPI table was loaded successfully

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@vger.kernel.org> # v6.0
Link: https://lore.kernel.org/all/a101a10a-4fbb-5fae-2e3c-76cf96ed8fbd@linux.intel.com/
Fixes: 3881ee0b1edc ("efi: avoid efivars layer when loading SSDTs from variables")
Reported-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
drivers/firmware/efi/efi.c