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authorLaura Abbott <lauraa@codeaurora.org>2014-06-25 23:55:03 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2014-07-09 12:23:48 +0100
commitc0c264ae5112d1cdb7d37d4e208b7a7e766a7418 (patch)
tree6e9de5e48ed2b0b91e4a371d53eda59ff578a5f9
parent4e6f7084096c08e37f909d7b075a91b72580405f (diff)
downloadlinux-c0c264ae5112d1cdb7d37d4e208b7a7e766a7418.tar.gz
arm64: Add CONFIG_CC_STACKPROTECTOR
arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Laura Abbott <lauraa@codeaurora.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/stackprotector.h38
-rw-r--r--arch/arm64/kernel/process.c6
3 files changed, 45 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a474de346be6..f865436096b6 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 000000000000..fe5e287dc56b
--- /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 43b7c34f92cb..1309d64aa926 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)
{
/*