Commit 1aad932c authored by Antonio Nino Diaz's avatar Antonio Nino Diaz

rpi3: Add support for the stack protector

It uses the hardware RNG in a similar way as Juno (it gets 128 bits of
entropy and does xor on them).

It is disabled by default.

Change-Id: I8b3adb61f5a5623716e0e8b6799404c68dd94c60
Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
parent 4ad2696d
......@@ -212,6 +212,9 @@ instructions in `Setup SD card`_.
The following build options are supported:
- ``ENABLE_STACK_PROTECTOR``: Disabled by default. It uses the hardware RNG of
the board.
- ``PRELOADED_BL33_BASE``: Specially useful because the file ``kernel8.img`` can
be loaded anywhere by modifying the file ``config.txt``. It doesn't have to
contain a kernel, it could have any arbitrary payload.
......
......@@ -90,6 +90,9 @@ WORKAROUND_CVE_2017_5715 := 0
# Disable the PSCI platform compatibility layer by default
ENABLE_PLAT_COMPAT := 0
# Disable stack protector by default
ENABLE_STACK_PROTECTOR := 0
# Reset to BL31 isn't supported
RESET_TO_BL31 := 0
......@@ -146,6 +149,11 @@ ifeq (${ARCH},aarch32)
$(error Error: AArch32 not supported on rpi3)
endif
ifneq ($(ENABLE_STACK_PROTECTOR), 0)
PLAT_BL_COMMON_SOURCES += plat/rpi3/rpi3_rng.c \
plat/rpi3/rpi3_stack_protector.c
endif
ifeq (${SPD},opteed)
BL2_SOURCES += \
lib/optee/optee_utils.c
......
/*
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <sys/types.h>
#include <utils.h>
#include "rpi3_private.h"
/* Get 128 bits of entropy and fuse the values together to form the canary. */
#define TRNG_NBYTES 16U
u_register_t plat_get_stack_protector_canary(void)
{
size_t i;
u_register_t buf[TRNG_NBYTES / sizeof(u_register_t)];
u_register_t ret = 0U;
rpi3_rng_read(buf, sizeof(buf));
for (i = 0U; i < ARRAY_SIZE(buf); i++)
ret ^= buf[i];
return ret;
}
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