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efi: ssdt: Don't free memory if ACPI table was loaded successfully

Message ID 20221014103134.2612781-1-ardb@kernel.org
State Accepted
Commit 4b017e59f01097f19b938f6dc4dc2c4720701610
Headers show
Series efi: ssdt: Don't free memory if ACPI table was loaded successfully | expand

Commit Message

Ard Biesheuvel Oct. 14, 2022, 10:31 a.m. UTC
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.

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 | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 9624735f1575..3ecdc43a3f2b 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -271,6 +271,8 @@  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);
 		}