linux-kernel - [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <ded454eeff88f631dc08eef76f0ad9f2daff0085.1603372719.git.andreyknvl@google.com>
Date:   Thu, 22 Oct 2020 15:18:56 +0200
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>
Cc:     Evgenii Stepanov <eugenis@...gle.com>,
        Kostya Serebryany <kcc@...gle.com>,
        Peter Collingbourne <pcc@...gle.com>,
        Serban Constantinescu <serbanc@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Elena Petrova <lenaptr@...gle.com>,
        Branislav Rankov <Branislav.Rankov@....com>,
        Kevin Brodsky <kevin.brodsky@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        kasan-dev@...glegroups.com, linux-arm-kernel@...ts.infradead.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: [PATCH RFC v2 04/21] kasan: 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.

Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
Link: https://linux-review.googlesource.com/id/If8a891e9fe01ea543e00b576852685afec0887e3
---
 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(-)

diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index ba40d57757d6..bdadfa56b40e 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/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
diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index c8daa92f38dc..5d3a0b8fd379 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/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.
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 3f3f541e5d5f..7be9fb9146ac 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -68,8 +68,6 @@ static inline void kasan_disable_current(void) {}
 
 void kasan_unpoison_memory(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);
 
@@ -114,8 +112,6 @@ void kasan_restore_multi_shot(bool enabled);
 
 static inline void kasan_unpoison_memory(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) {}
 
@@ -167,6 +163,12 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
 #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);
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index a880e5a547ed..a3e67d49b893 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -58,6 +58,7 @@ void kasan_disable_current(void)
 }
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
+#if CONFIG_KASAN_STACK
 static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
 {
 	void *base = task_stack_page(task);
@@ -84,6 +85,7 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
 
 	kasan_unpoison_memory(base, watermark - base);
 }
+#endif /* CONFIG_KASAN_STACK */
 
 void kasan_alloc_pages(struct page *page, unsigned int order)
 {
-- 
2.29.0.rc1.297.gfa9743e501-goog