4.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hans de Goede hdegoede@redhat.com
commit 52e1cf2d19c2e62e6a81b8de3f7320d033917dd5 upstream.
Commit:
79832f0b5f71 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/firmware/efi/libstub/tpm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/firmware/efi/libstub/tpm.c +++ b/drivers/firmware/efi/libstub/tpm.c @@ -64,7 +64,7 @@ void efi_retrieve_tpm2_eventlog_1_2(efi_ 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;