From 2603f8a78dfb1d54f62dbacc490ea44aa6d80e04 Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Mon, 15 Mar 2021 13:20:12 +0000 Subject: kasan: Add KASAN mode kernel parameter Architectures supported by KASAN_HW_TAGS can provide a sync or async mode of execution. On an MTE enabled arm64 hw for example this can be identified with the synchronous or asynchronous tagging mode of execution. In synchronous mode, an exception is triggered if a tag check fault occurs. In asynchronous mode, if a tag check fault occurs, the TFSR_EL1 register is updated asynchronously. The kernel checks the corresponding bits periodically. KASAN requires a specific kernel command line parameter to make use of this hw features. Add KASAN HW execution mode kernel command line parameter. Note: This patch adds the kasan.mode kernel parameter and the sync/async kernel command line options to enable the described features. [ Add a new var instead of exposing kasan_arg_mode to be consistent with flags for other command line arguments. ] Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Reviewed-by: Andrey Konovalov Acked-by: Catalin Marinas Acked-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Signed-off-by: Andrey Konovalov Link: https://lore.kernel.org/r/20210315132019.33202-3-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas --- mm/kasan/kasan.h | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'mm/kasan/kasan.h') diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 8c55634d6edd..a3d0d165d97d 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -21,6 +21,7 @@ static inline bool kasan_stack_collection_enabled(void) #endif extern bool kasan_flag_panic __ro_after_init; +extern bool kasan_flag_async __ro_after_init; #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) #define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) @@ -275,8 +276,11 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #ifdef CONFIG_KASAN_HW_TAGS -#ifndef arch_enable_tagging -#define arch_enable_tagging() +#ifndef arch_enable_tagging_sync +#define arch_enable_tagging_sync() +#endif +#ifndef arch_enable_tagging_async +#define arch_enable_tagging_async() #endif #ifndef arch_init_tags #define arch_init_tags(max_tag) @@ -294,7 +298,8 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #define arch_set_mem_tag_range(addr, size, tag) ((void *)(addr)) #endif -#define hw_enable_tagging() arch_enable_tagging() +#define hw_enable_tagging_sync() arch_enable_tagging_sync() +#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_get_random_tag() arch_get_random_tag() @@ -303,7 +308,8 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #else /* CONFIG_KASAN_HW_TAGS */ -#define hw_enable_tagging() +#define hw_enable_tagging_sync() +#define hw_enable_tagging_async() #define hw_set_tagging_report_once(state) #endif /* CONFIG_KASAN_HW_TAGS */ @@ -311,12 +317,12 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) void kasan_set_tagging_report_once(bool state); -void kasan_enable_tagging(void); +void kasan_enable_tagging_sync(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(void) { } +static inline void kasan_enable_tagging_sync(void) { } #endif /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */ -- cgit From 8f7b5054755e48cc7b217a41e3f1891e01338d2f Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Mon, 15 Mar 2021 13:20:14 +0000 Subject: kasan: Add report for async mode KASAN provides an asynchronous mode of execution. Add reporting functionality for this mode. Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Reviewed-by: Andrey Konovalov Acked-by: Catalin Marinas Acked-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Signed-off-by: Andrey Konovalov Link: https://lore.kernel.org/r/20210315132019.33202-5-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas --- mm/kasan/kasan.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'mm/kasan/kasan.h') diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index a3d0d165d97d..02e9656b857f 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -7,17 +7,33 @@ #include #ifdef CONFIG_KASAN_HW_TAGS + #include + DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace); +extern bool kasan_flag_async __ro_after_init; + static inline bool kasan_stack_collection_enabled(void) { return static_branch_unlikely(&kasan_flag_stacktrace); } + +static inline bool kasan_async_mode_enabled(void) +{ + return kasan_flag_async; +} #else + static inline bool kasan_stack_collection_enabled(void) { return true; } + +static inline bool kasan_async_mode_enabled(void) +{ + return false; +} + #endif extern bool kasan_flag_panic __ro_after_init; -- cgit From e80a76aa1a91018d919d2210366943f9bf17009e Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Mon, 15 Mar 2021 13:20:19 +0000 Subject: kasan, arm64: tests supports for HW_TAGS async mode 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 Acked-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Link: https://lore.kernel.org/r/20210315132019.33202-10-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas --- mm/kasan/kasan.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'mm/kasan/kasan.h') diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 02e9656b857f..2d29069ae977 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) arch_set_mem_tag_range((addr), (size), (tag)) @@ -334,11 +338,13 @@ 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 */ -- cgit