[45/60] kasan, arm64: unpoison stack only with CONFIG_KASAN_STACK

Commit Message

Andrew Morton Dec. 22, 2020, 8:02 p.m. UTC

From: Andrey Konovalov <[e-mail]>
Subject: kasan, arm64: unpoison stack only with CONFIG_KASAN_STACK

There's a config option CONFIG_KASAN_STACK that has to be enabled for
KASAN to use stack instrumentation and perform validity checks for
stack variables.

There's no need to unpoison stack when CONFIG_KASAN_STACK is not enabled.
Only call kasan_unpoison_task_stack[_below]() when CONFIG_KASAN_STACK is
enabled.

Note, that CONFIG_KASAN_STACK is an option that is currently always
defined when CONFIG_KASAN is enabled, and therefore has to be tested
with #if instead of #ifdef.

Link: https://lkml.kernel.org/r/d0[e-mail]
Link: https://linux-review.googlesource.com/id/If8a891e9fe01ea543e00b576852685afec0887e3
Signed-off-by: Andrey Konovalov <[e-mail]>
Reviewed-by: Marco Elver <[e-mail]>
Acked-by: Catalin Marinas <[e-mail]>
Reviewed-by: Dmitry Vyukov <[e-mail]>
Tested-by: Vincenzo Frascino <[e-mail]>
Cc: Alexander Potapenko <[e-mail]>
Cc: Andrey Ryabinin <[e-mail]>
Cc: Branislav Rankov <[e-mail]>
Cc: Evgenii Stepanov <[e-mail]>
Cc: Kevin Brodsky <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 arch/arm64/kernel/sleep.S        |    2 +-
 arch/x86/kernel/acpi/wakeup_64.S |    2 +-
 include/linux/kasan.h            |   10 ++++++----
 mm/kasan/common.c                |    2 ++
 4 files changed, 10 insertions(+), 6 deletions(-)

Patch

--- a/arch/arm64/kernel/sleep.S~kasan-arm64-unpoison-stack-only-with-config_kasan_stack
+++ a/arch/arm64/kernel/sleep.S
@@ -133,7 +133,7 @@  SYM_FUNC_START(_cpu_resume)
 	 */
 	bl	cpu_do_resume
 
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
 	mov	x0, sp
 	bl	kasan_unpoison_task_stack_below
 #endif
--- a/arch/x86/kernel/acpi/wakeup_64.S~kasan-arm64-unpoison-stack-only-with-config_kasan_stack
+++ a/arch/x86/kernel/acpi/wakeup_64.S
@@ -112,7 +112,7 @@  SYM_FUNC_START(do_suspend_lowlevel)
 	movq	pt_regs_r14(%rax), %r14
 	movq	pt_regs_r15(%rax), %r15
 
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
 	/*
 	 * The suspend path may have poisoned some areas deeper in the stack,
 	 * which we now need to unpoison.
--- a/include/linux/kasan.h~kasan-arm64-unpoison-stack-only-with-config_kasan_stack
+++ a/include/linux/kasan.h
@@ -77,8 +77,6 @@  static inline void kasan_disable_current
 
 void kasan_unpoison_range(const void *address, size_t size);
 
-void kasan_unpoison_task_stack(struct task_struct *task);
-
 void kasan_alloc_pages(struct page *page, unsigned int order);
 void kasan_free_pages(struct page *page, unsigned int order);
 
@@ -123,8 +121,6 @@  void kasan_restore_multi_shot(bool enabl
 
 static inline void kasan_unpoison_range(const void *address, size_t size) {}
 
-static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
-
 static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
 static inline void kasan_free_pages(struct page *page, unsigned int order) {}
 
@@ -176,6 +172,12 @@  static inline size_t kasan_metadata_size
 
 #endif /* CONFIG_KASAN */
 
+#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
+void kasan_unpoison_task_stack(struct task_struct *task);
+#else
+static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
+#endif
+
 #ifdef CONFIG_KASAN_GENERIC
 
 void kasan_cache_shrink(struct kmem_cache *cache);
--- a/mm/kasan/common.c~kasan-arm64-unpoison-stack-only-with-config_kasan_stack
+++ a/mm/kasan/common.c
@@ -63,6 +63,7 @@  void kasan_unpoison_range(const void *ad
 	unpoison_range(address, size);
 }
 
+#if CONFIG_KASAN_STACK
 static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
 {
 	void *base = task_stack_page(task);
@@ -89,6 +90,7 @@  asmlinkage void kasan_unpoison_task_stac
 
 	unpoison_range(base, watermark - base);
 }
+#endif /* CONFIG_KASAN_STACK */
 
 void kasan_alloc_pages(struct page *page, unsigned int order)
 {