diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 780ec27459ab043f21267c294820982eaf45813e..219c2979bd3e6c5e30364c70c0a969ab79fb290d 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -134,6 +134,11 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, unsigned int redzone_size; int redzone_adjust; + if (!kasan_stack_collection_enabled()) { + *flags |= SLAB_KASAN; + return; + } + /* Add alloc meta. */ cache->kasan_info.alloc_meta_offset = *size; *size += sizeof(struct kasan_alloc_meta); @@ -170,6 +175,8 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, size_t kasan_metadata_size(struct kmem_cache *cache) { + if (!kasan_stack_collection_enabled()) + return 0; return (cache->kasan_info.alloc_meta_offset ? sizeof(struct kasan_alloc_meta) : 0) + (cache->kasan_info.free_meta_offset ? @@ -262,11 +269,13 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, { struct kasan_alloc_meta *alloc_meta; - if (!(cache->flags & SLAB_KASAN)) - return (void *)object; + if (kasan_stack_collection_enabled()) { + if (!(cache->flags & SLAB_KASAN)) + return (void *)object; - alloc_meta = kasan_get_alloc_meta(cache, object); - __memset(alloc_meta, 0, sizeof(*alloc_meta)); + alloc_meta = kasan_get_alloc_meta(cache, object); + __memset(alloc_meta, 0, sizeof(*alloc_meta)); + } if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) object = set_tag(object, assign_tag(cache, object, true, false)); @@ -303,6 +312,9 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE); poison_range(object, rounded_up_size, KASAN_KMALLOC_FREE); + if (!kasan_stack_collection_enabled()) + return false; + if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) || unlikely(!(cache->flags & SLAB_KASAN))) return false; @@ -350,7 +362,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, poison_range((void *)redzone_start, redzone_end - redzone_start, KASAN_KMALLOC_REDZONE); - if (cache->flags & SLAB_KASAN) + if (kasan_stack_collection_enabled() && (cache->flags & SLAB_KASAN)) set_alloc_info(cache, (void *)object, flags); return set_tag(object, tag); diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 863fed4edd3ffce305eb5dffb2b4e836d5bfc4f5..4ccc3c873c82fc7f58ebe5b67718b08d85e6e0aa 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -8,18 +8,115 @@ #define pr_fmt(fmt) "kasan: " fmt +#include #include #include #include #include +#include #include #include #include "kasan.h" +enum kasan_arg_mode { + KASAN_ARG_MODE_DEFAULT, + KASAN_ARG_MODE_OFF, + KASAN_ARG_MODE_PROD, + KASAN_ARG_MODE_FULL, +}; + +enum kasan_arg_stacktrace { + KASAN_ARG_STACKTRACE_DEFAULT, + KASAN_ARG_STACKTRACE_OFF, + KASAN_ARG_STACKTRACE_ON, +}; + +enum kasan_arg_fault { + KASAN_ARG_FAULT_DEFAULT, + KASAN_ARG_FAULT_REPORT, + KASAN_ARG_FAULT_PANIC, +}; + +static enum kasan_arg_mode kasan_arg_mode __ro_after_init; +static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init; +static enum kasan_arg_fault kasan_arg_fault __ro_after_init; + +/* Whether KASAN is enabled at all. */ +DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); +EXPORT_SYMBOL(kasan_flag_enabled); + +/* Whether to collect alloc/free stack traces. */ +DEFINE_STATIC_KEY_FALSE(kasan_flag_stacktrace); + +/* Whether panic or disable tag checking on fault. */ +bool kasan_flag_panic __ro_after_init; + +/* kasan.mode=off/prod/full */ +static int __init early_kasan_mode(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "off")) + kasan_arg_mode = KASAN_ARG_MODE_OFF; + else if (!strcmp(arg, "prod")) + kasan_arg_mode = KASAN_ARG_MODE_PROD; + else if (!strcmp(arg, "full")) + kasan_arg_mode = KASAN_ARG_MODE_FULL; + else + return -EINVAL; + + return 0; +} +early_param("kasan.mode", early_kasan_mode); + +/* kasan.stack=off/on */ +static int __init early_kasan_flag_stacktrace(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "off")) + kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF; + else if (!strcmp(arg, "on")) + kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON; + else + return -EINVAL; + + return 0; +} +early_param("kasan.stacktrace", early_kasan_flag_stacktrace); + +/* kasan.fault=report/panic */ +static int __init early_kasan_fault(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "report")) + kasan_arg_fault = KASAN_ARG_FAULT_REPORT; + else if (!strcmp(arg, "panic")) + kasan_arg_fault = KASAN_ARG_FAULT_PANIC; + else + return -EINVAL; + + return 0; +} +early_param("kasan.fault", early_kasan_fault); + /* kasan_init_hw_tags_cpu() is called for each CPU. */ void kasan_init_hw_tags_cpu(void) { + /* + * There's no need to check that the hardware is MTE-capable here, + * as this function is only called for MTE-capable hardware. + */ + + /* If KASAN is disabled, do nothing. */ + if (kasan_arg_mode == KASAN_ARG_MODE_OFF) + return; + hw_init_tags(KASAN_TAG_MAX); hw_enable_tagging(); } @@ -27,6 +124,60 @@ void kasan_init_hw_tags_cpu(void) /* kasan_init_hw_tags() is called once on boot CPU. */ void __init kasan_init_hw_tags(void) { + /* If hardware doesn't support MTE, do nothing. */ + if (!system_supports_mte()) + return; + + /* Choose KASAN mode if kasan boot parameter is not provided. */ + if (kasan_arg_mode == KASAN_ARG_MODE_DEFAULT) { + if (IS_ENABLED(CONFIG_DEBUG_KERNEL)) + kasan_arg_mode = KASAN_ARG_MODE_FULL; + else + kasan_arg_mode = KASAN_ARG_MODE_PROD; + } + + /* Preset parameter values based on the mode. */ + switch (kasan_arg_mode) { + case KASAN_ARG_MODE_DEFAULT: + /* Shouldn't happen as per the check above. */ + WARN_ON(1); + return; + case KASAN_ARG_MODE_OFF: + /* If KASAN is disabled, do nothing. */ + return; + case KASAN_ARG_MODE_PROD: + static_branch_enable(&kasan_flag_enabled); + break; + case KASAN_ARG_MODE_FULL: + static_branch_enable(&kasan_flag_enabled); + static_branch_enable(&kasan_flag_stacktrace); + break; + } + + /* Now, optionally override the presets. */ + + switch (kasan_arg_stacktrace) { + case KASAN_ARG_STACKTRACE_DEFAULT: + break; + case KASAN_ARG_STACKTRACE_OFF: + static_branch_disable(&kasan_flag_stacktrace); + break; + case KASAN_ARG_STACKTRACE_ON: + static_branch_enable(&kasan_flag_stacktrace); + break; + } + + switch (kasan_arg_fault) { + case KASAN_ARG_FAULT_DEFAULT: + break; + case KASAN_ARG_FAULT_REPORT: + kasan_flag_panic = false; + break; + case KASAN_ARG_FAULT_PANIC: + kasan_flag_panic = true; + break; + } + pr_info("KernelAddressSanitizer initialized\n"); } diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 6e811d0f6242bfba829a50b988c81142393cb5b5..ca43de9811de54efcc2f08cb87ed370ee81e6e29 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -5,6 +5,22 @@ #include #include +#ifdef CONFIG_KASAN_HW_TAGS +#include +DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace); +static inline bool kasan_stack_collection_enabled(void) +{ + return static_branch_unlikely(&kasan_flag_stacktrace); +} +#else +static inline bool kasan_stack_collection_enabled(void) +{ + return true; +} +#endif + +extern bool kasan_flag_panic __ro_after_init; + #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) #define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) #else diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 00c590efdaeab5758789cbdd6f0b60c4bb3d2f40..ed9555a814df027d24f5de264ab5787deb6503f7 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -99,6 +99,10 @@ static void end_report(unsigned long *flags) panic_on_warn = 0; panic("panic_on_warn set ...\n"); } +#ifdef CONFIG_KASAN_HW_TAGS + if (kasan_flag_panic) + panic("kasan.fault=panic set ...\n"); +#endif kasan_enable_current(); } @@ -161,8 +165,8 @@ static void describe_object_addr(struct kmem_cache *cache, void *object, (void *)(object_addr + cache->object_size)); } -static void describe_object(struct kmem_cache *cache, void *object, - const void *addr, u8 tag) +static void describe_object_stacks(struct kmem_cache *cache, void *object, + const void *addr, u8 tag) { struct kasan_alloc_meta *alloc_meta = kasan_get_alloc_meta(cache, object); @@ -190,7 +194,13 @@ static void describe_object(struct kmem_cache *cache, void *object, } #endif } +} +static void describe_object(struct kmem_cache *cache, void *object, + const void *addr, u8 tag) +{ + if (kasan_stack_collection_enabled()) + describe_object_stacks(cache, object, addr, tag); describe_object_addr(cache, object, addr); }