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-rw-r--r--mm/kasan/kasan.c65
-rw-r--r--mm/kasan/kasan.h15
-rw-r--r--mm/kasan/quarantine.c19
-rw-r--r--mm/kasan/report.c85
4 files changed, 92 insertions, 92 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index b6f99e8..88af13c 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -442,11 +442,6 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object)
kasan_poison_shadow(object,
round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
KASAN_KMALLOC_REDZONE);
- if (cache->flags & SLAB_KASAN) {
- struct kasan_alloc_meta *alloc_info =
- get_alloc_info(cache, object);
- alloc_info->state = KASAN_STATE_INIT;
- }
}
static inline int in_irqentry_text(unsigned long ptr)
@@ -510,6 +505,17 @@ struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
return (void *)object + cache->kasan_info.free_meta_offset;
}
+void kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
+{
+ struct kasan_alloc_meta *alloc_info;
+
+ if (!(cache->flags & SLAB_KASAN))
+ return;
+
+ alloc_info = get_alloc_info(cache, object);
+ __memset(alloc_info, 0, sizeof(*alloc_info));
+}
+
void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
{
kasan_kmalloc(cache, object, cache->object_size, flags);
@@ -529,34 +535,26 @@ static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
bool kasan_slab_free(struct kmem_cache *cache, void *object)
{
+ s8 shadow_byte;
+
/* RCU slabs could be legally used after free within the RCU period */
if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
return false;
- if (likely(cache->flags & SLAB_KASAN)) {
- struct kasan_alloc_meta *alloc_info;
- struct kasan_free_meta *free_info;
+ shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
+ if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
+ kasan_report_double_free(cache, object, shadow_byte);
+ return true;
+ }
- alloc_info = get_alloc_info(cache, object);
- free_info = get_free_info(cache, object);
+ kasan_poison_slab_free(cache, object);
- switch (alloc_info->state) {
- case KASAN_STATE_ALLOC:
- alloc_info->state = KASAN_STATE_QUARANTINE;
- quarantine_put(free_info, cache);
- set_track(&free_info->track, GFP_NOWAIT);
- kasan_poison_slab_free(cache, object);
- return true;
- case KASAN_STATE_QUARANTINE:
- case KASAN_STATE_FREE:
- pr_err("Double free");
- dump_stack();
- break;
- default:
- break;
- }
- }
- return false;
+ if (unlikely(!(cache->flags & SLAB_KASAN)))
+ return false;
+
+ set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
+ quarantine_put(get_free_info(cache, object), cache);
+ return true;
}
void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
@@ -565,7 +563,7 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
unsigned long redzone_start;
unsigned long redzone_end;
- if (flags & __GFP_RECLAIM)
+ if (gfpflags_allow_blocking(flags))
quarantine_reduce();
if (unlikely(object == NULL))
@@ -579,14 +577,9 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
kasan_unpoison_shadow(object, size);
kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
KASAN_KMALLOC_REDZONE);
- if (cache->flags & SLAB_KASAN) {
- struct kasan_alloc_meta *alloc_info =
- get_alloc_info(cache, object);
- alloc_info->state = KASAN_STATE_ALLOC;
- alloc_info->alloc_size = size;
- set_track(&alloc_info->track, flags);
- }
+ if (cache->flags & SLAB_KASAN)
+ set_track(&get_alloc_info(cache, object)->alloc_track, flags);
}
EXPORT_SYMBOL(kasan_kmalloc);
@@ -596,7 +589,7 @@ void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
unsigned long redzone_start;
unsigned long redzone_end;
- if (flags & __GFP_RECLAIM)
+ if (gfpflags_allow_blocking(flags))
quarantine_reduce();
if (unlikely(ptr == NULL))
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 31972cd..e5c2181 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -59,13 +59,6 @@ struct kasan_global {
* Structures to keep alloc and free tracks *
*/
-enum kasan_state {
- KASAN_STATE_INIT,
- KASAN_STATE_ALLOC,
- KASAN_STATE_QUARANTINE,
- KASAN_STATE_FREE
-};
-
#define KASAN_STACK_DEPTH 64
struct kasan_track {
@@ -74,9 +67,8 @@ struct kasan_track {
};
struct kasan_alloc_meta {
- struct kasan_track track;
- u32 state : 2; /* enum kasan_state */
- u32 alloc_size : 30;
+ struct kasan_track alloc_track;
+ struct kasan_track free_track;
};
struct qlist_node {
@@ -87,7 +79,6 @@ struct kasan_free_meta {
* Otherwise it might be used for the allocator freelist.
*/
struct qlist_node quarantine_link;
- struct kasan_track track;
};
struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
@@ -108,6 +99,8 @@ static inline bool kasan_report_enabled(void)
void kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
+void kasan_report_double_free(struct kmem_cache *cache, void *object,
+ s8 shadow);
#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)
void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index 65793f1..b6728a3 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -144,13 +144,15 @@ static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache)
static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
{
void *object = qlink_to_object(qlink, cache);
- struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
unsigned long flags;
- local_irq_save(flags);
- alloc_info->state = KASAN_STATE_FREE;
+ if (IS_ENABLED(CONFIG_SLAB))
+ local_irq_save(flags);
+
___cache_free(cache, object, _THIS_IP_);
- local_irq_restore(flags);
+
+ if (IS_ENABLED(CONFIG_SLAB))
+ local_irq_restore(flags);
}
static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
@@ -196,7 +198,7 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
void quarantine_reduce(void)
{
- size_t new_quarantine_size;
+ size_t new_quarantine_size, percpu_quarantines;
unsigned long flags;
struct qlist_head to_free = QLIST_INIT;
size_t size_to_free = 0;
@@ -214,7 +216,12 @@ void quarantine_reduce(void)
*/
new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
QUARANTINE_FRACTION;
- new_quarantine_size -= QUARANTINE_PERCPU_SIZE * num_online_cpus();
+ percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
+ if (WARN_ONCE(new_quarantine_size < percpu_quarantines,
+ "Too little memory, disabling global KASAN quarantine.\n"))
+ new_quarantine_size = 0;
+ else
+ new_quarantine_size -= percpu_quarantines;
WRITE_ONCE(quarantine_size, new_quarantine_size);
last = global_quarantine.head;
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 861b977..24c1211 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -116,6 +116,26 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
+static DEFINE_SPINLOCK(report_lock);
+
+static void kasan_start_report(unsigned long *flags)
+{
+ /*
+ * Make sure we don't end up in loop.
+ */
+ kasan_disable_current();
+ spin_lock_irqsave(&report_lock, *flags);
+ pr_err("==================================================================\n");
+}
+
+static void kasan_end_report(unsigned long *flags)
+{
+ pr_err("==================================================================\n");
+ add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
+ spin_unlock_irqrestore(&report_lock, *flags);
+ kasan_enable_current();
+}
+
static void print_track(struct kasan_track *track)
{
pr_err("PID = %u\n", track->pid);
@@ -129,37 +149,33 @@ static void print_track(struct kasan_track *track)
}
}
-static void kasan_object_err(struct kmem_cache *cache, struct page *page,
- void *object, char *unused_reason)
+static void kasan_object_err(struct kmem_cache *cache, void *object)
{
struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
- struct kasan_free_meta *free_info;
dump_stack();
- pr_err("Object at %p, in cache %s\n", object, cache->name);
+ pr_err("Object at %p, in cache %s size: %d\n", object, cache->name,
+ cache->object_size);
+
if (!(cache->flags & SLAB_KASAN))
return;
- switch (alloc_info->state) {
- case KASAN_STATE_INIT:
- pr_err("Object not allocated yet\n");
- break;
- case KASAN_STATE_ALLOC:
- pr_err("Object allocated with size %u bytes.\n",
- alloc_info->alloc_size);
- pr_err("Allocation:\n");
- print_track(&alloc_info->track);
- break;
- case KASAN_STATE_FREE:
- case KASAN_STATE_QUARANTINE:
- pr_err("Object freed, allocated with size %u bytes\n",
- alloc_info->alloc_size);
- free_info = get_free_info(cache, object);
- pr_err("Allocation:\n");
- print_track(&alloc_info->track);
- pr_err("Deallocation:\n");
- print_track(&free_info->track);
- break;
- }
+
+ pr_err("Allocated:\n");
+ print_track(&alloc_info->alloc_track);
+ pr_err("Freed:\n");
+ print_track(&alloc_info->free_track);
+}
+
+void kasan_report_double_free(struct kmem_cache *cache, void *object,
+ s8 shadow)
+{
+ unsigned long flags;
+
+ kasan_start_report(&flags);
+ pr_err("BUG: Double free or freeing an invalid pointer\n");
+ pr_err("Unexpected shadow byte: 0x%hhX\n", shadow);
+ kasan_object_err(cache, object);
+ kasan_end_report(&flags);
}
static void print_address_description(struct kasan_access_info *info)
@@ -175,8 +191,7 @@ static void print_address_description(struct kasan_access_info *info)
struct kmem_cache *cache = page->slab_cache;
object = nearest_obj(cache, page,
(void *)info->access_addr);
- kasan_object_err(cache, page, object,
- "kasan: bad access detected");
+ kasan_object_err(cache, object);
return;
}
dump_page(page, "kasan: bad access detected");
@@ -241,19 +256,13 @@ static void print_shadow_for_address(const void *addr)
}
}
-static DEFINE_SPINLOCK(report_lock);
-
static void kasan_report_error(struct kasan_access_info *info)
{
unsigned long flags;
const char *bug_type;
- /*
- * Make sure we don't end up in loop.
- */
- kasan_disable_current();
- spin_lock_irqsave(&report_lock, flags);
- pr_err("==================================================================\n");
+ kasan_start_report(&flags);
+
if (info->access_addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START)) {
if ((unsigned long)info->access_addr < PAGE_SIZE)
@@ -274,10 +283,8 @@ static void kasan_report_error(struct kasan_access_info *info)
print_address_description(info);
print_shadow_for_address(info->first_bad_addr);
}
- pr_err("==================================================================\n");
- add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
- spin_unlock_irqrestore(&report_lock, flags);
- kasan_enable_current();
+
+ kasan_end_report(&flags);
}
void kasan_report(unsigned long addr, size_t size,