kasan, arm64: only use kasan_depth for software modes

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode. Hardware tag-based KASAN won't use kasan_depth. Only define and use it when one of the software KASAN modes are enabled. No functional changes for software modes. Link: https://lkml.kernel.org/r/e16f15aeda90bc7fb4dfc2e243a14b74cc5c8219.1606161801.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <[email protected]> Signed-off-by: Vincenzo Frascino <[email protected]> Reviewed-by: Catalin Marinas <[email protected]> Reviewed-by: Alexander Potapenko <[email protected]> Tested-by: Vincenzo Frascino <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Branislav Rankov <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Evgenii Stepanov <[email protected]> Cc: Kevin Brodsky <[email protected]> Cc: Marco Elver <[email protected]> Cc: Vasily Gorbik <[email protected]> Cc: Will Deacon <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
LoveHeat · Dec 22, 2020 · d73b493 · d73b493
1 parent afe6ef8
commit d73b493
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Showing 6 changed files with 23 additions and 14 deletions.
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
@@ -273,17 +273,22 @@ static void __init kasan_init_shadow(void)
 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 }
 
+static void __init kasan_init_depth(void)
+{
+	init_task.kasan_depth = 0;
+}
+
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) */
 
 static inline void __init kasan_init_shadow(void) { }
 
+static inline void __init kasan_init_depth(void) { }
+
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 void __init kasan_init(void)
 {
 	kasan_init_shadow();
-
-	/* At this point kasan is fully initialized. Enable error messages */
-	init_task.kasan_depth = 0;
+	kasan_init_depth();
 	pr_info("KernelAddressSanitizer initialized\n");
 }
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
@@ -52,6 +52,12 @@ static inline void *kasan_mem_to_shadow(const void *addr)
 int kasan_add_zero_shadow(void *start, unsigned long size);
 void kasan_remove_zero_shadow(void *start, unsigned long size);
 
+/* Enable reporting bugs after kasan_disable_current() */
+extern void kasan_enable_current(void);
+
+/* Disable reporting bugs for current task */
+extern void kasan_disable_current(void);
+
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 static inline int kasan_add_zero_shadow(void *start, unsigned long size)
@@ -62,16 +68,13 @@ static inline void kasan_remove_zero_shadow(void *start,
 					unsigned long size)
 {}
 
+static inline void kasan_enable_current(void) {}
+static inline void kasan_disable_current(void) {}
+
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 #ifdef CONFIG_KASAN
 
-/* Enable reporting bugs after kasan_disable_current() */
-extern void kasan_enable_current(void);
-
-/* Disable reporting bugs for current task */
-extern void kasan_disable_current(void);
-
 void kasan_unpoison_range(const void *address, size_t size);
 
 void kasan_unpoison_task_stack(struct task_struct *task);
@@ -122,9 +125,6 @@ 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_enable_current(void) {}
-static inline void kasan_disable_current(void) {}
-
 static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
 static inline void kasan_free_pages(struct page *page, unsigned int order) {}
 

diff --git a/include/linux/sched.h b/include/linux/sched.h
@@ -1234,7 +1234,7 @@ struct task_struct {
 	u64				timer_slack_ns;
 	u64				default_timer_slack_ns;
 
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 	unsigned int			kasan_depth;
 #endif
 

diff --git a/init/init_task.c b/init/init_task.c
@@ -176,7 +176,7 @@ struct task_struct init_task
 	.numa_group	= NULL,
 	.numa_faults	= NULL,
 #endif
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 	.kasan_depth	= 1,
 #endif
 #ifdef CONFIG_KCSAN

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
@@ -46,6 +46,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags)
 	track->stack = kasan_save_stack(flags);
 }
 
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 void kasan_enable_current(void)
 {
 	current->kasan_depth++;
@@ -55,6 +56,7 @@ void kasan_disable_current(void)
 {
 	current->kasan_depth--;
 }
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 void kasan_unpoison_range(const void *address, size_t size)
 {

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
@@ -292,8 +292,10 @@ static void print_shadow_for_address(const void *addr)
 
 static bool report_enabled(void)
 {
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 	if (current->kasan_depth)
 		return false;
+#endif
 	if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
 		return true;
 	return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);