diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/stack_protector/aarch32/asm_stack_protector.S | 34 | ||||
| -rw-r--r-- | lib/stack_protector/aarch64/asm_stack_protector.S | 34 | ||||
| -rw-r--r-- | lib/stack_protector/stack_protector.c | 32 | ||||
| -rw-r--r-- | lib/stack_protector/stack_protector.mk | 28 |
4 files changed, 128 insertions, 0 deletions
diff --git a/lib/stack_protector/aarch32/asm_stack_protector.S b/lib/stack_protector/aarch32/asm_stack_protector.S new file mode 100644 index 0000000..19b7525 --- /dev/null +++ b/lib/stack_protector/aarch32/asm_stack_protector.S @@ -0,0 +1,34 @@ +/* + * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <arch.h> +#include <asm_macros.S> +#include <assert_macros.S> + + .globl update_stack_protector_canary + +/* ----------------------------------------------------------------------- + * void update_stack_protector_canary(void) + * + * Change the value of the canary used for stack smashing attacks protection. + * Note: This must be called when it is safe to call C code, but this cannot be + * called by C code. Doing this will make the check fail when the calling + * function returns. + * ----------------------------------------------------------------------- + */ + +func update_stack_protector_canary + /* Use r4 as it is callee-saved */ + mov r4, lr + bl plat_get_stack_protector_canary + + /* Update the canary with the returned value */ + ldr r1, =__stack_chk_guard + str r0, [r1] + bx r4 +endfunc update_stack_protector_canary + + diff --git a/lib/stack_protector/aarch64/asm_stack_protector.S b/lib/stack_protector/aarch64/asm_stack_protector.S new file mode 100644 index 0000000..c2245d3 --- /dev/null +++ b/lib/stack_protector/aarch64/asm_stack_protector.S @@ -0,0 +1,34 @@ +/* + * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <arch.h> +#include <asm_macros.S> +#include <assert_macros.S> + + .globl update_stack_protector_canary + +/* ----------------------------------------------------------------------- + * void update_stack_protector_canary(void) + * + * Change the value of the canary used for stack smashing attacks protection. + * Note: This must be called when it is safe to call C code, but this cannot be + * called by C code. Doing this will make the check fail when the calling + * function returns. + * ----------------------------------------------------------------------- + */ + +func update_stack_protector_canary + /* Use x19 as it is callee-saved */ + mov x19, x30 + bl plat_get_stack_protector_canary + + /* Update the canary with the returned value */ + adrp x1, __stack_chk_guard + str x0, [x1, #:lo12:__stack_chk_guard] + ret x19 +endfunc update_stack_protector_canary + + diff --git a/lib/stack_protector/stack_protector.c b/lib/stack_protector/stack_protector.c new file mode 100644 index 0000000..3ff74fc --- /dev/null +++ b/lib/stack_protector/stack_protector.c @@ -0,0 +1,32 @@ +/* + * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <stdint.h> + +#include <common/debug.h> +#include <plat/common/platform.h> + +/* + * Canary value used by the compiler runtime checks to detect stack corruption. + * + * Force the canary to be in .data to allow predictable memory layout relatively + * to the stacks. + */ +u_register_t __attribute__((section(".data.stack_protector_canary"))) + __stack_chk_guard = (u_register_t) 3288484550995823360ULL; + +/* + * Function called when the stack's canary check fails, which means the stack + * was corrupted. It must not return. + */ +void __dead2 __stack_chk_fail(void) +{ +#if DEBUG + ERROR("Stack corruption detected\n"); +#endif + panic(); +} + diff --git a/lib/stack_protector/stack_protector.mk b/lib/stack_protector/stack_protector.mk new file mode 100644 index 0000000..b5aba15 --- /dev/null +++ b/lib/stack_protector/stack_protector.mk @@ -0,0 +1,28 @@ +# +# Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved. +# +# SPDX-License-Identifier: BSD-3-Clause +# + +# Boolean macro to be used in C code +STACK_PROTECTOR_ENABLED := 0 + +ifeq (${ENABLE_STACK_PROTECTOR},0) + ENABLE_STACK_PROTECTOR := none +endif + +ifeq (${ENABLE_STACK_PROTECTOR},none) + TF_CFLAGS += -fno-stack-protector +else + STACK_PROTECTOR_ENABLED := 1 + BL_COMMON_SOURCES += lib/stack_protector/stack_protector.c \ + lib/stack_protector/${ARCH}/asm_stack_protector.S + + ifeq (${ENABLE_STACK_PROTECTOR},default) + TF_CFLAGS += -fstack-protector + else + TF_CFLAGS += -fstack-protector-${ENABLE_STACK_PROTECTOR} + endif +endif + +$(eval $(call add_define,STACK_PROTECTOR_ENABLED)) |