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arm64: Add CONFIG_CC_STACKPROTECTOR

PATCH Superseded Laura Abbott 3 participants 5 messages Jan 30, 2014 – Jun 25, 2014 arm64

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Laura Abbott

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#0 lore raw

PATCH v3 1/1 arm64: Add CONFIG_CC_STACKPROTECTOR

arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption.

Cc Will Deacon <[email protected]>
Cc Catalin Marinas <[email protected]>
Signed-off-by Laura Abbott <[email protected]>

---
I realized today that the patch I gave before was not going to work for recent trees because of changes to CC_STACKPROTECTOR that were not in my working tree before. This should be the patch to actually work against recent kernels.

---
 arch/arm64/Kconfig                      |    1 +
 arch/arm64/include/asm/stackprotector.h |   38 +++++++++++++++++++++++++++++++
 arch/arm64/kernel/process.c             |    6 +++++
 3 files changed, 45 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm64/include/asm/stackprotector.h
arch/arm64/Kconfig +1 -0
index dd4327f..2ebf522 100644
@@ -27,6 +27,7 @@ config ARM64
 	select HARDIRQS_SW_RESEND
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_CC_STACKPROTECTOR
 	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_API_DEBUG
arch/arm64/include/asm/stackprotector.h new file +38 -0
new file mode 100644
index 0000000..fe5e287
@@ -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 */
arch/arm64/kernel/process.c +6 -0
index 1e5a178..89c301d 100644
@@ -50,6 +50,12 @@
 #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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#2 lore raw

PATCH v3 1/1 arm64: Add CONFIG_CC_STACKPROTECTOR

Quoted 11 lines · Kees Cook
Quoted 6 lines · Laura Abbott

arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption.

Cc Will Deacon <[email protected]>
Cc Catalin Marinas <[email protected]>
Signed-off-by Laura Abbott <[email protected]>

Thanks!

Acked-by Kees Cook <[email protected]>

Hi again,

This patch never got applied any where. Who can take this?

Thanks!

-Kees

Signature · 2 lines
Kees Cook
Chrome OS Security
#3 lore raw

PATCH v3 1/1 arm64: Add CONFIG_CC_STACKPROTECTOR

Quoted 9 lines · Kees Cook
Quoted 8 lines · Kees Cook
Quoted 6 lines · Laura Abbott

arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption.

Cc Will Deacon <[email protected]>
Cc Catalin Marinas <[email protected]>
Signed-off-by Laura Abbott <[email protected]>
Quoted 7 lines
Quoted 3 lines

Thanks!

Acked-by Kees Cook <[email protected]>

Hi again,

This patch never got applied any where. Who can take this?

We can take this via the arm64 tree. Laura, is the patch still valid against current mainline?

Will

author
#4 lore raw

PATCH v3 1/1 arm64: Add CONFIG_CC_STACKPROTECTOR

Quoted 12 lines · Will Deacon
Quoted 11 lines · Kees Cook
Quoted 10 lines · Kees Cook
Quoted 6 lines · Laura Abbott

arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption.

Cc Will Deacon <[email protected]>
Cc Catalin Marinas <[email protected]>
Signed-off-by Laura Abbott <[email protected]>

Thanks!

Quoted 9 lines
Quoted 5 lines
Quoted 1 line
Acked-by Kees Cook <[email protected]>

Hi again,

This patch never got applied any where. Who can take this?

We can take this via the arm64 tree. Laura, is the patch still valid against current mainline?

Apparently not. I will send out a rebased version.

Thanks,
Laura

Signature · 2 lines
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation