[PATCH v16 9/9] kasan, arm64: tests supports for HW_TAGS async mode
Vincenzo Frascino
vincenzo.frascino at arm.com
Mon Mar 15 13:20:19 GMT 2021
From: Andrey Konovalov <andreyknvl at google.com>
This change adds KASAN-KUnit tests support for the async HW_TAGS mode.
In async mode, tag fault aren't being generated synchronously when a
bad access happens, but are instead explicitly checked for by the kernel.
As each KASAN-KUnit test expect a fault to happen before the test is over,
check for faults as a part of the test handler.
Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Acked-by: Andrey Konovalov <andreyknvl at google.com>
Tested-by: Andrey Konovalov <andreyknvl at google.com>
Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino at arm.com>
---
arch/arm64/include/asm/memory.h | 1 +
lib/test_kasan.c | 17 +++++++++++------
mm/kasan/hw_tags.c | 6 ++++++
mm/kasan/kasan.h | 6 ++++++
mm/kasan/report.c | 5 +++++
5 files changed, 29 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index a07923eb33c5..7d0fd4f36e23 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -246,6 +246,7 @@ static inline const void *__tag_set(const void *addr, u8 tag)
#define arch_enable_tagging_sync() mte_enable_kernel_sync()
#define arch_enable_tagging_async() mte_enable_kernel_async()
#define arch_set_tagging_report_once(state) mte_set_report_once(state)
+#define arch_force_async_tag_fault() mte_check_tfsr_exit()
#define arch_init_tags(max_tag) mte_init_tags(max_tag)
#define arch_get_random_tag() mte_get_random_tag()
#define arch_get_mem_tag(addr) mte_get_mem_tag(addr)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 929fbe06b154..0882d6c17e62 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -69,10 +69,10 @@ static void kasan_test_exit(struct kunit *test)
* resource named "kasan_data". Do not use this name for KUnit resources
* outside of KASAN tests.
*
- * For hardware tag-based KASAN, when a tag fault happens, tag checking is
- * normally auto-disabled. When this happens, this test handler reenables
- * tag checking. As tag checking can be only disabled or enabled per CPU, this
- * handler disables migration (preemption).
+ * For hardware tag-based KASAN in sync mode, when a tag fault happens, tag
+ * checking is auto-disabled. When this happens, this test handler reenables
+ * tag checking. As tag checking can be only disabled or enabled per CPU,
+ * this handler disables migration (preemption).
*
* Since the compiler doesn't see that the expression can change the fail_data
* fields, it can reorder or optimize away the accesses to those fields.
@@ -80,7 +80,8 @@ static void kasan_test_exit(struct kunit *test)
* expression to prevent that.
*/
#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
- if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
+ !kasan_async_mode_enabled()) \
migrate_disable(); \
WRITE_ONCE(fail_data.report_expected, true); \
WRITE_ONCE(fail_data.report_found, false); \
@@ -92,10 +93,14 @@ static void kasan_test_exit(struct kunit *test)
barrier(); \
expression; \
barrier(); \
+ if (kasan_async_mode_enabled()) \
+ kasan_force_async_fault(); \
+ barrier(); \
KUNIT_EXPECT_EQ(test, \
READ_ONCE(fail_data.report_expected), \
READ_ONCE(fail_data.report_found)); \
- if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
+ !kasan_async_mode_enabled()) { \
if (READ_ONCE(fail_data.report_found)) \
kasan_enable_tagging_sync(); \
migrate_enable(); \
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 1df4ce803861..4004388b4e4b 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -252,4 +252,10 @@ void kasan_enable_tagging_sync(void)
}
EXPORT_SYMBOL_GPL(kasan_enable_tagging_sync);
+void kasan_force_async_fault(void)
+{
+ hw_force_async_tag_fault();
+}
+EXPORT_SYMBOL_GPL(kasan_force_async_fault);
+
#endif
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 56b155ddaf30..f34253e29b4a 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -304,6 +304,9 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
#ifndef arch_set_tagging_report_once
#define arch_set_tagging_report_once(state)
#endif
+#ifndef arch_force_async_tag_fault
+#define arch_force_async_tag_fault()
+#endif
#ifndef arch_get_random_tag
#define arch_get_random_tag() (0xFF)
#endif
@@ -318,6 +321,7 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
#define hw_enable_tagging_async() arch_enable_tagging_async()
#define hw_init_tags(max_tag) arch_init_tags(max_tag)
#define hw_set_tagging_report_once(state) arch_set_tagging_report_once(state)
+#define hw_force_async_tag_fault() arch_force_async_tag_fault()
#define hw_get_random_tag() arch_get_random_tag()
#define hw_get_mem_tag(addr) arch_get_mem_tag(addr)
#define hw_set_mem_tag_range(addr, size, tag, init) \
@@ -335,11 +339,13 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
void kasan_set_tagging_report_once(bool state);
void kasan_enable_tagging_sync(void);
+void kasan_force_async_fault(void);
#else /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */
static inline void kasan_set_tagging_report_once(bool state) { }
static inline void kasan_enable_tagging_sync(void) { }
+static inline void kasan_force_async_fault(void) { }
#endif /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8b0843a2cdd7..14bd51ea2348 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -366,6 +366,11 @@ void kasan_report_async(void)
{
unsigned long flags;
+#if IS_ENABLED(CONFIG_KUNIT)
+ if (current->kunit_test)
+ kasan_update_kunit_status(current->kunit_test);
+#endif /* IS_ENABLED(CONFIG_KUNIT) */
+
start_report(&flags);
pr_err("BUG: KASAN: invalid-access\n");
pr_err("Asynchronous mode enabled: no access details available\n");
--
2.30.2
More information about the linux-arm-kernel
mailing list