On Thu, 22 Oct 2020 at 15:19, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > > TODO: no meaningful description here yet, please see the cover letter > for this RFC series. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Link: https://linux-review.googlesource.com/id/If7d37003875b2ed3e0935702c8015c223d6416a4 > --- > mm/kasan/common.c | 92 +++++++++++++----------- > mm/kasan/generic.c | 5 ++ > mm/kasan/hw_tags.c | 169 ++++++++++++++++++++++++++++++++++++++++++++- > mm/kasan/kasan.h | 9 +++ > mm/kasan/report.c | 14 +++- > mm/kasan/sw_tags.c | 5 ++ > 6 files changed, 250 insertions(+), 44 deletions(-) > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 1a5e6c279a72..cc129ef62ab1 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -129,35 +129,37 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > unsigned int redzone_size; > int redzone_adjust; > > - /* Add alloc meta. */ > - cache->kasan_info.alloc_meta_offset = *size; > - *size += sizeof(struct kasan_alloc_meta); > - > - /* Add free meta. */ > - if (IS_ENABLED(CONFIG_KASAN_GENERIC) && > - (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor || > - cache->object_size < sizeof(struct kasan_free_meta))) { > - cache->kasan_info.free_meta_offset = *size; > - *size += sizeof(struct kasan_free_meta); > - } > - > - redzone_size = optimal_redzone(cache->object_size); > - redzone_adjust = redzone_size - (*size - cache->object_size); > - if (redzone_adjust > 0) > - *size += redzone_adjust; > - > - *size = min_t(unsigned int, KMALLOC_MAX_SIZE, > - max(*size, cache->object_size + redzone_size)); > + if (static_branch_unlikely(&kasan_stack)) { > + /* Add alloc meta. */ > + cache->kasan_info.alloc_meta_offset = *size; > + *size += sizeof(struct kasan_alloc_meta); > + > + /* Add free meta. */ > + if (IS_ENABLED(CONFIG_KASAN_GENERIC) && > + (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor || > + cache->object_size < sizeof(struct kasan_free_meta))) { > + cache->kasan_info.free_meta_offset = *size; > + *size += sizeof(struct kasan_free_meta); > + } > > - /* > - * If the metadata doesn't fit, don't enable KASAN at all. > - */ > - if (*size <= cache->kasan_info.alloc_meta_offset || > - *size <= cache->kasan_info.free_meta_offset) { > - cache->kasan_info.alloc_meta_offset = 0; > - cache->kasan_info.free_meta_offset = 0; > - *size = orig_size; > - return; > + redzone_size = optimal_redzone(cache->object_size); > + redzone_adjust = redzone_size - (*size - cache->object_size); > + if (redzone_adjust > 0) > + *size += redzone_adjust; > + > + *size = min_t(unsigned int, KMALLOC_MAX_SIZE, > + max(*size, cache->object_size + redzone_size)); > + > + /* > + * If the metadata doesn't fit, don't enable KASAN at all. > + */ > + if (*size <= cache->kasan_info.alloc_meta_offset || > + *size <= cache->kasan_info.free_meta_offset) { > + cache->kasan_info.alloc_meta_offset = 0; > + cache->kasan_info.free_meta_offset = 0; > + *size = orig_size; > + return; > + } > } > > *flags |= SLAB_KASAN; > @@ -165,10 +167,12 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > > size_t kasan_metadata_size(struct kmem_cache *cache) > { > - return (cache->kasan_info.alloc_meta_offset ? > - sizeof(struct kasan_alloc_meta) : 0) + > - (cache->kasan_info.free_meta_offset ? > - sizeof(struct kasan_free_meta) : 0); > + if (static_branch_unlikely(&kasan_stack)) > + return (cache->kasan_info.alloc_meta_offset ? > + sizeof(struct kasan_alloc_meta) : 0) + > + (cache->kasan_info.free_meta_offset ? > + sizeof(struct kasan_free_meta) : 0); > + return 0; > } > > struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, > @@ -270,8 +274,10 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > if (!(cache->flags & SLAB_KASAN)) > return (void *)object; > > - alloc_meta = kasan_get_alloc_meta(cache, object); > - __memset(alloc_meta, 0, sizeof(*alloc_meta)); > + if (static_branch_unlikely(&kasan_stack)) { > + 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)); > @@ -308,15 +314,19 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE); > kasan_poison_memory(object, rounded_up_size, KASAN_KMALLOC_FREE); > > - if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) || > - unlikely(!(cache->flags & SLAB_KASAN))) > - return false; > + if (static_branch_unlikely(&kasan_stack)) { > + if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) || > + unlikely(!(cache->flags & SLAB_KASAN))) > + return false; > + > + kasan_set_free_info(cache, object, tag); > > - kasan_set_free_info(cache, object, tag); > + quarantine_put(cache, object); > > - quarantine_put(cache, object); > + return IS_ENABLED(CONFIG_KASAN_GENERIC); > + } > > - return IS_ENABLED(CONFIG_KASAN_GENERIC); > + return false; > } > > bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) > @@ -355,7 +365,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start, > KASAN_KMALLOC_REDZONE); > > - if (cache->flags & SLAB_KASAN) > + if (static_branch_unlikely(&kasan_stack) && (cache->flags & SLAB_KASAN)) > set_alloc_info(cache, (void *)object, flags); > > return set_tag(object, tag); > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > index d259e4c3aefd..20a1e753e0c5 100644 > --- a/mm/kasan/generic.c > +++ b/mm/kasan/generic.c > @@ -33,6 +33,11 @@ > #include "kasan.h" > #include "../slab.h" > > +/* See the comments in hw_tags.c */ > +DEFINE_STATIC_KEY_TRUE_RO(kasan_enabled); > +EXPORT_SYMBOL(kasan_enabled); > +DEFINE_STATIC_KEY_TRUE_RO(kasan_stack); > + > /* > * All functions below always inlined so compiler could > * perform better optimizations in each of __asan_loadX/__assn_storeX > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > index 915142da6b57..bccd781011ad 100644 > --- a/mm/kasan/hw_tags.c > +++ b/mm/kasan/hw_tags.c > @@ -8,6 +8,8 @@ > > #define pr_fmt(fmt) "kasan: " fmt > > +#include <linux/init.h> > +#include <linux/jump_label.h> > #include <linux/kasan.h> > #include <linux/kernel.h> > #include <linux/memory.h> > @@ -17,10 +19,175 @@ > > #include "kasan.h" > > +enum kasan_arg_mode { > + KASAN_ARG_MODE_OFF, > + KASAN_ARG_MODE_PROD, > + KASAN_ARG_MODE_FULL, > +}; > + > +enum kasan_arg_stack { > + KASAN_ARG_STACK_DEFAULT, > + KASAN_ARG_STACK_OFF, > + KASAN_ARG_STACK_ON, > +}; > + > +enum kasan_arg_trap { > + KASAN_ARG_TRAP_DEFAULT, > + KASAN_ARG_TRAP_ASYNC, > + KASAN_ARG_TRAP_SYNC, > +}; > + > +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_stack kasan_arg_stack __ro_after_init; > +static enum kasan_arg_fault kasan_arg_fault __ro_after_init; > +static enum kasan_arg_trap kasan_arg_trap __ro_after_init; > + > +/* Whether KASAN is enabled at all. */ > +DEFINE_STATIC_KEY_FALSE_RO(kasan_enabled); > +EXPORT_SYMBOL(kasan_enabled); > + > +/* Whether to collect alloc/free stack traces. */ > +DEFINE_STATIC_KEY_FALSE_RO(kasan_stack); > + > +/* Whether to use synchronous or asynchronous tag checking. */ > +static bool kasan_sync __ro_after_init; > + > +/* Whether panic or disable tag checking on fault. */ > +bool kasan_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_stack(char *arg) > +{ > + if (!arg) > + return -EINVAL; > + > + if (!strcmp(arg, "off")) > + kasan_arg_stack = KASAN_ARG_STACK_OFF; > + else if (!strcmp(arg, "on")) > + kasan_arg_stack = KASAN_ARG_STACK_ON; > + else > + return -EINVAL; > + > + return 0; > +} > +early_param("kasan.stack", early_kasan_stack); > + > +/* kasan.trap=sync/async */ > +static int __init early_kasan_trap(char *arg) > +{ > + if (!arg) > + return -EINVAL; > + > + if (!strcmp(arg, "ASYNC")) Why is this "ASYNC" and not "async"? > + kasan_arg_trap = KASAN_ARG_TRAP_ASYNC; > + else if (!strcmp(arg, "sync")) > + kasan_arg_trap = KASAN_ARG_TRAP_SYNC; > + else > + return -EINVAL; > + > + return 0; > +} > +early_param("kasan.trap", early_kasan_trap); > + > +/* 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); > + > void __init kasan_init_tags(void) > { > - init_tags(KASAN_TAG_MAX); > + if (!cpu_supports_tags()) > + return; > + > + /* First, preset values based on the mode. */ > + > + switch (kasan_arg_mode) { > + case KASAN_ARG_MODE_OFF: > + return; > + case KASAN_ARG_MODE_PROD: > + static_branch_enable(&kasan_enabled); > + break; > + case KASAN_ARG_MODE_FULL: > + static_branch_enable(&kasan_enabled); > + static_branch_enable(&kasan_stack); > + kasan_sync = true; > + break; > + } > + > + /* Now, optionally override the presets. */ > > + switch (kasan_arg_stack) { > + case KASAN_ARG_STACK_OFF: > + static_branch_disable(&kasan_stack); > + break; > + case KASAN_ARG_STACK_ON: > + static_branch_enable(&kasan_stack); > + break; > + default: > + break; > + } > + > + switch (kasan_arg_trap) { > + case KASAN_ARG_TRAP_ASYNC: > + kasan_sync = false; > + break; > + case KASAN_ARG_TRAP_SYNC: > + kasan_sync = true; > + break; > + default: > + break; > + } > + > + switch (kasan_arg_fault) { > + case KASAN_ARG_FAULT_REPORT: > + kasan_panic = false; > + break; > + case KASAN_ARG_FAULT_PANIC: > + kasan_panic = true; > + break; > + default: > + break; > + } > + > + /* TODO: choose between sync and async based on kasan_sync. */ > + init_tags(KASAN_TAG_MAX); > pr_info("KernelAddressSanitizer initialized\n"); > } > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index f7ae0c23f023..00b47bc753aa 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -2,9 +2,18 @@ > #ifndef __MM_KASAN_KASAN_H > #define __MM_KASAN_KASAN_H > > +#include <linux/jump_label.h> > #include <linux/kasan.h> > #include <linux/stackdepot.h> > > +#ifdef CONFIG_KASAN_HW_TAGS > +DECLARE_STATIC_KEY_FALSE(kasan_stack); > +#else > +DECLARE_STATIC_KEY_TRUE(kasan_stack); > +#endif > + > +extern bool kasan_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 dee5350b459c..426dd1962d3c 100644 > --- a/mm/kasan/report.c > +++ b/mm/kasan/report.c > @@ -97,6 +97,10 @@ static void end_report(unsigned long *flags) > panic_on_warn = 0; > panic("panic_on_warn set ...\n"); > } > +#ifdef CONFIG_KASAN_HW_TAGS > + if (kasan_panic) > + panic("kasan.fault=panic set ...\n"); > +#endif > kasan_enable_current(); > } > > @@ -159,8 +163,8 @@ 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); > > @@ -188,7 +192,13 @@ 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 (static_branch_unlikely(&kasan_stack)) > + describe_object_stacks(cache, object, addr, tag); > describe_object_addr(cache, object, addr); > } > > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c > index 4db41f274702..b6d185adf2c5 100644 > --- a/mm/kasan/sw_tags.c > +++ b/mm/kasan/sw_tags.c > @@ -33,6 +33,11 @@ > #include "kasan.h" > #include "../slab.h" > > +/* See the comments in hw_tags.c */ > +DEFINE_STATIC_KEY_TRUE_RO(kasan_enabled); > +EXPORT_SYMBOL(kasan_enabled); > +DEFINE_STATIC_KEY_TRUE_RO(kasan_stack); > + > static DEFINE_PER_CPU(u32, prng_state); > > void __init kasan_init_tags(void) > -- > 2.29.0.rc1.297.gfa9743e501-goog >
