* [PATCHv3][REBASED] arm64: Add CONFIG_CC_STACKPROTECTOR
@ 2014-06-25 22:55 Laura Abbott
2014-06-27 9:44 ` Will Deacon
2014-07-10 9:22 ` Catalin Marinas
0 siblings, 2 replies; 3+ messages in thread
From: Laura Abbott @ 2014-06-25 22:55 UTC (permalink / raw)
To: linux-arm-kernel
arm64 currently lacks support for -fstack-protector. Add
similar functionality to arm to detect stack corruption.
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/stackprotector.h | 38 +++++++++++++++++++++++++++++++++
arch/arm64/kernel/process.c | 6 ++++++
3 files changed, 45 insertions(+)
create mode 100644 arch/arm64/include/asm/stackprotector.h
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a474de34..f865436 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -32,6 +32,7 @@ config ARM64
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
select HAVE_C_RECORDMCOUNT
+ select HAVE_CC_STACKPROTECTOR
select HAVE_DEBUG_BUGVERBOSE
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_API_DEBUG
diff --git a/arch/arm64/include/asm/stackprotector.h b/arch/arm64/include/asm/stackprotector.h
new file mode 100644
index 0000000..fe5e287
--- /dev/null
+++ b/arch/arm64/include/asm/stackprotector.h
@@ -0,0 +1,38 @@
+/*
+ * GCC stack protector support.
+ *
+ * Stack protector works by putting predefined pattern at the start of
+ * the stack frame and verifying that it hasn't been overwritten when
+ * returning from the function. The pattern is called stack canary
+ * and gcc expects it to be defined by a global variable called
+ * "__stack_chk_guard" on ARM. This unfortunately means that on SMP
+ * we cannot have a different canary value per task.
+ */
+
+#ifndef __ASM_STACKPROTECTOR_H
+#define __ASM_STACKPROTECTOR_H
+
+#include <linux/random.h>
+#include <linux/version.h>
+
+extern unsigned long __stack_chk_guard;
+
+/*
+ * Initialize the stackprotector canary value.
+ *
+ * NOTE: this must only be called from functions that never return,
+ * and it must always be inlined.
+ */
+static __always_inline void boot_init_stack_canary(void)
+{
+ unsigned long canary;
+
+ /* Try to get a semi random initial value. */
+ get_random_bytes(&canary, sizeof(canary));
+ canary ^= LINUX_VERSION_CODE;
+
+ current->stack_canary = canary;
+ __stack_chk_guard = current->stack_canary;
+}
+
+#endif /* _ASM_STACKPROTECTOR_H */
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 43b7c34..1309d64 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -51,6 +51,12 @@
#include <asm/processor.h>
#include <asm/stacktrace.h>
+#ifdef CONFIG_CC_STACKPROTECTOR
+#include <linux/stackprotector.h>
+unsigned long __stack_chk_guard __read_mostly;
+EXPORT_SYMBOL(__stack_chk_guard);
+#endif
+
static void setup_restart(void)
{
/*
--
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end of thread, other threads:[~2014-07-10 9:22 UTC | newest]
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2014-06-25 22:55 [PATCHv3][REBASED] arm64: Add CONFIG_CC_STACKPROTECTOR Laura Abbott
2014-06-27 9:44 ` Will Deacon
2014-07-10 9:22 ` Catalin Marinas
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