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authorJisheng Zhang2024-06-24 07:53:16 +0800
committerPalmer Dabbelt2024-07-26 05:50:47 -0700
commitb5db73fb18257cd5d9cb59bc4b779fffa629566a (patch)
tree775ebd49b77381b1fc47d4e03e1bdbc7b2c40814
parent1d20e5d437cfebefb5e6f4d652c3a1561fc23fc7 (diff)
riscv: enable HAVE_ARCH_STACKLEAK
Add support for the stackleak feature. Whenever the kernel returns to user space the kernel stack is filled with a poison value. At the same time, disables the plugin in EFI stub code because EFI stub is out of scope for the protection. Tested on qemu and milkv duo: / # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT [ 38.675575] lkdtm: Performing direct entry STACKLEAK_ERASING [ 38.678448] lkdtm: stackleak stack usage: [ 38.678448] high offset: 288 bytes [ 38.678448] current: 496 bytes [ 38.678448] lowest: 1328 bytes [ 38.678448] tracked: 1328 bytes [ 38.678448] untracked: 448 bytes [ 38.678448] poisoned: 14312 bytes [ 38.678448] low offset: 8 bytes [ 38.689887] lkdtm: OK: the rest of the thread stack is properly erased Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Link: https://lore.kernel.org/r/20240623235316.2010-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
-rw-r--r--arch/riscv/Kconfig1
-rw-r--r--arch/riscv/include/asm/thread_info.h1
-rw-r--r--arch/riscv/kernel/entry.S4
-rw-r--r--drivers/firmware/efi/libstub/Makefile3
4 files changed, 8 insertions, 1 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 34ae39ecb898..19ca402e6f26 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -123,6 +123,7 @@ config RISCV
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
select HAVE_ARCH_SECCOMP_FILTER
+ select HAVE_ARCH_STACKLEAK
select HAVE_ARCH_THREAD_STRUCT_WHITELIST
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 5d473343634b..fca5c6be2b81 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -10,6 +10,7 @@
#include <asm/page.h>
#include <linux/const.h>
+#include <linux/sizes.h>
/* thread information allocation */
#define THREAD_SIZE_ORDER CONFIG_THREAD_SIZE_ORDER
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index c933460ed3e9..ac2e908d4418 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -133,6 +133,10 @@ SYM_CODE_START_NOALIGN(ret_from_exception)
#endif
bnez s0, 1f
+#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+ call stackleak_erase_on_task_stack
+#endif
+
/* Save unwound kernel stack pointer in thread_info */
addi s0, sp, PT_SIZE_ON_STACK
REG_S s0, TASK_TI_KERNEL_SP(tp)
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 1f32d6cf98d6..f23ba62ce127 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -28,7 +28,8 @@ cflags-$(CONFIG_ARM) += -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \
-DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \
-DEFI_HAVE_STRCMP -fno-builtin -fpic \
$(call cc-option,-mno-single-pic-base)
-cflags-$(CONFIG_RISCV) += -fpic -DNO_ALTERNATIVE -mno-relax
+cflags-$(CONFIG_RISCV) += -fpic -DNO_ALTERNATIVE -mno-relax \
+ $(DISABLE_STACKLEAK_PLUGIN)
cflags-$(CONFIG_LOONGARCH) += -fpie
cflags-$(CONFIG_EFI_PARAMS_FROM_FDT) += -I$(srctree)/scripts/dtc/libfdt