From 79832f0b5f718e0023d9dd73e6845310609a564d Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 13 Mar 2018 14:09:21 +0000 Subject: efi/libstub/tpm: Initialize pointer variables to zero for mixed mode As reported by Jeremy Cline, running the new TPM libstub code in mixed mode (i.e., 64-bit kernel on 32-bit UEFI) results in hangs when invoking the TCG2 protocol, or when accessing the log_tbl pool allocation. The reason turns out to be that in both cases, the 64-bit pointer variables are not fully initialized by the 32-bit EFI code, and so we should take care to zero initialize these variables beforehand, or we'll end up dereferencing bogus pointers. Reported-by: Jeremy Cline Signed-off-by: Ard Biesheuvel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: hdegoede@redhat.com Cc: jarkko.sakkinen@linux.intel.com Cc: javierm@redhat.com Cc: linux-efi@vger.kernel.org Cc: tweek@google.com Link: http://lkml.kernel.org/r/20180313140922.17266-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- drivers/firmware/efi/libstub/tpm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c index da661bf8cb96..13c1edd37e96 100644 --- a/drivers/firmware/efi/libstub/tpm.c +++ b/drivers/firmware/efi/libstub/tpm.c @@ -68,11 +68,11 @@ void efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) efi_guid_t linux_eventlog_guid = LINUX_EFI_TPM_EVENT_LOG_GUID; efi_status_t status; efi_physical_addr_t log_location, log_last_entry; - struct linux_efi_tpm_eventlog *log_tbl; + struct linux_efi_tpm_eventlog *log_tbl = NULL; unsigned long first_entry_addr, last_entry_addr; size_t log_size, last_entry_size; efi_bool_t truncated; - void *tcg2_protocol; + void *tcg2_protocol = NULL; status = efi_call_early(locate_protocol, &tcg2_guid, NULL, &tcg2_protocol); -- cgit v1.2.3-55-g7522