Commit 52e1cf2d authored Jun 22, 2018 by Hans de Goede Committed by Ingo Molnar Jun 22, 2018

efi/libstub/tpm: Initialize efi_physical_addr_t vars to zero for mixed mode



Commit:

  79832f0b ("efi/libstub/tpm: Initialize pointer variables to zero for mixed mode")

fixes a problem with the tpm code on mixed mode (64-bit kernel on 32-bit UEFI),
where 64-bit pointer variables are not fully initialized by the 32-bit EFI code.

A similar problem applies to the efi_physical_addr_t variables which
are written by the ->get_event_log() EFI call. Even though efi_physical_addr_t
is 64-bit everywhere, it seems that some 32-bit UEFI implementations only
fill in the lower 32 bits when passed a pointer to an efi_physical_addr_t
to fill.

This commit initializes these to 0 to, to ensure the upper 32 bits are
0 in mixed mode. This fixes recent kernels sometimes hanging during
early boot on mixed mode UEFI systems.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org> # v4.16+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180622064222.11633-2-ard.biesheuvel@linaro.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 1abd8a8f

drivers/firmware/efi/libstub/tpm.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -64,7 +64,7 @@ static void efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
		efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID;
		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;
		efi_physical_addr_t log_location = 0, log_last_entry = 0;
		struct linux_efi_tpm_eventlog *log_tbl = NULL;
		unsigned long first_entry_addr, last_entry_addr;
		size_t log_size, last_entry_size;