The commit is pushed to "branch-rh7-3.10.0-693.1.1.vz7.37.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.1.1.vz7.37.4
------>
commit 6f5821e22508780d9c2c3731670e44ce16a46318
Author: Alexander Potapenko <gli...@google.com>
Date: Fri Sep 15 17:14:46 2017 +0300
mm, kasan: SLAB support
Add KASAN hooks to SLAB allocator.
This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.
Signed-off-by: Alexander Potapenko <gli...@google.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: Pekka Enberg <penb...@kernel.org>
Cc: David Rientjes <rient...@google.com>
Cc: Joonsoo Kim <iamjoonsoo....@lge.com>
Cc: Andrey Konovalov <adech...@gmail.com>
Cc: Dmitry Vyukov <dvyu...@google.com>
Cc: Andrey Ryabinin <ryabinin....@gmail.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Konstantin Serebryany <k...@google.com>
Cc: Dmitry Chernenkov <dmit...@google.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
https://jira.sw.ru/browse/PSBM-69081
(cherry picked from commit 0295fd5d570626817d10deadf5a2ad5e49c36a1d)
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
Documentation/kasan.txt | 7 ++--
include/linux/kasan.h | 12 ++++++
include/linux/slab.h | 6 +++
include/linux/slab_def.h | 14 +++++++
include/linux/slub_def.h | 11 +++++
lib/Kconfig.kasan | 8 ++--
mm/Makefile | 1 +
mm/kasan/kasan.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++
mm/kasan/kasan.h | 34 ++++++++++++++++
mm/kasan/report.c | 54 ++++++++++++++++++++-----
mm/slab.c | 39 +++++++++++++++---
mm/slub.c | 2 +-
12 files changed, 266 insertions(+), 24 deletions(-)
diff --git a/Documentation/kasan.txt b/Documentation/kasan.txt
index 3107467..7dd95b3 100644
--- a/Documentation/kasan.txt
+++ b/Documentation/kasan.txt
@@ -12,8 +12,7 @@ KASAN uses compile-time instrumentation for checking every
memory access,
therefore you will need a GCC version 4.9.2 or later. GCC 5.0 or later is
required for detection of out-of-bounds accesses to stack or global variables.
-Currently KASAN is supported only for x86_64 architecture and requires the
-kernel to be built with the SLUB allocator.
+Currently KASAN is supported only for x86_64 architecture.
1. Usage
========
@@ -27,8 +26,8 @@ inline are compiler instrumentation types. The former
produces smaller binary
the latter is 1.1 - 2 times faster. Inline instrumentation requires a GCC
version 5.0 or later.
-Currently KASAN works only with the SLUB memory allocator.
-For better bug detection and nicer report and enable CONFIG_STACKTRACE.
+KASAN works with both SLUB and SLAB memory allocators.
+For better bug detection and nicer reporting, enable CONFIG_STACKTRACE.
To disable instrumentation for specific files or directories, add a line
similar to the following to the respective kernel Makefile:
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 5486d77..f55c31b 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -38,6 +38,9 @@ void kasan_unpoison_shadow(const void *address, size_t size);
void kasan_alloc_pages(struct page *page, unsigned int order);
void kasan_free_pages(struct page *page, unsigned int order);
+void kasan_cache_create(struct kmem_cache *cache, size_t *size,
+ unsigned long *flags);
+
void kasan_poison_slab(struct page *page);
void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
void kasan_poison_object_data(struct kmem_cache *cache, void *object);
@@ -51,6 +54,11 @@ void kasan_krealloc(const void *object, size_t new_size);
void kasan_slab_alloc(struct kmem_cache *s, void *object);
void kasan_slab_free(struct kmem_cache *s, void *object);
+struct kasan_cache {
+ int alloc_meta_offset;
+ int free_meta_offset;
+};
+
int kasan_module_alloc(void *addr, size_t size);
void kasan_free_shadow(const struct vm_struct *vm);
@@ -64,6 +72,10 @@ static inline void kasan_disable_current(void) {}
static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
static inline void kasan_free_pages(struct page *page, unsigned int order) {}
+static inline void kasan_cache_create(struct kmem_cache *cache,
+ size_t *size,
+ unsigned long *flags) {}
+
static inline void kasan_poison_slab(struct page *page) {}
static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
void *object) {}
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 1d95666..7dc1b73 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -85,6 +85,12 @@
# define SLAB_ACCOUNT 0x00000000UL
#endif
+#ifdef CONFIG_KASAN
+#define SLAB_KASAN 0x08000000UL
+#else
+#define SLAB_KASAN 0x00000000UL
+#endif
+
/* The following flags affect the page allocator grouping pages by mobility */
#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are
reclaimable */
#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are
short-lived */
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index bf41210..13c72b3 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -70,6 +70,9 @@ struct kmem_cache {
#ifdef CONFIG_MEMCG_KMEM
struct memcg_cache_params memcg_params;
#endif
+#ifdef CONFIG_KASAN
+ struct kasan_cache kasan_info;
+#endif
/* 6) per-cpu/per-node data, touched during every alloc/free */
/*
@@ -90,4 +93,15 @@ struct kmem_cache {
*/
};
+static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+ void *x) {
+ void *object = x - (x - page->s_mem) % cache->size;
+ void *last_object = page->s_mem + (cache->num - 1) * cache->size;
+
+ if (unlikely(object > last_object))
+ return last_object;
+ else
+ return object;
+}
+
#endif /* _LINUX_SLAB_DEF_H */
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 89bcb9e..7188ba0 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -142,4 +142,15 @@ static inline void *virt_to_obj(struct kmem_cache *s,
void object_err(struct kmem_cache *s, struct page *page,
u8 *object, char *reason);
+static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+ void *x) {
+ void *object = x - (x - page_address(page)) % cache->size;
+ void *last_object = page_address(page) +
+ (page->objects - 1) * cache->size;
+ if (unlikely(object > last_object))
+ return last_object;
+ else
+ return object;
+}
+
#endif /* _LINUX_SLUB_DEF_H */
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 777eda7..6471d77 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -5,7 +5,7 @@ if HAVE_ARCH_KASAN
config KASAN
bool "KASan: runtime memory debugger"
- depends on SLUB_DEBUG
+ depends on SLUB_DEBUG || (SLAB && !DEBUG_SLAB)
select CONSTRUCTORS
help
Enables kernel address sanitizer - runtime memory debugger,
@@ -15,8 +15,10 @@ config KASAN
global variables requires gcc 5.0 or later.
This feature consumes about 1/8 of available memory and brings about
~x3 performance slowdown.
- For better error detection enable CONFIG_STACKTRACE,
- and add slub_debug=U to boot cmdline.
+
+ For better error detection enable CONFIG_STACKTRACE.
+ Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
+ (the resulting kernel does not boot).
config KASAN_SHADOW_OFFSET
hex
diff --git a/mm/Makefile b/mm/Makefile
index 97178a8..65d9bcc 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -3,6 +3,7 @@
#
KASAN_SANITIZE_slab_common.o := n
+KASAN_SANITIZE_slab.o := n
KASAN_SANITIZE_slub.o := n
# These files are disabled because they produce non-interesting and/or
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 3873c2c..2e1a640 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -311,6 +311,59 @@ void kasan_free_pages(struct page *page, unsigned int
order)
KASAN_FREE_PAGE);
}
+#ifdef CONFIG_SLAB
+/*
+ * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
+ * For larger allocations larger redzones are used.
+ */
+static size_t optimal_redzone(size_t object_size)
+{
+ int rz =
+ object_size <= 64 - 16 ? 16 :
+ object_size <= 128 - 32 ? 32 :
+ object_size <= 512 - 64 ? 64 :
+ object_size <= 4096 - 128 ? 128 :
+ object_size <= (1 << 14) - 256 ? 256 :
+ object_size <= (1 << 15) - 512 ? 512 :
+ object_size <= (1 << 16) - 1024 ? 1024 : 2048;
+ return rz;
+}
+
+void kasan_cache_create(struct kmem_cache *cache, size_t *size,
+ unsigned long *flags)
+{
+ int redzone_adjust;
+ /* Make sure the adjusted size is still less than
+ * KMALLOC_MAX_CACHE_SIZE.
+ * TODO: this check is only useful for SLAB, but not SLUB. We'll need
+ * to skip it for SLUB when it starts using kasan_cache_create().
+ */
+ if (*size > KMALLOC_MAX_CACHE_SIZE -
+ sizeof(struct kasan_alloc_meta) -
+ sizeof(struct kasan_free_meta))
+ return;
+ *flags |= SLAB_KASAN;
+ /* Add alloc meta. */
+ cache->kasan_info.alloc_meta_offset = *size;
+ *size += sizeof(struct kasan_alloc_meta);
+
+ /* Add free meta. */
+ if (cache->flags & SLAB_DESTROY_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_adjust = optimal_redzone(cache->object_size) -
+ (*size - cache->object_size);
+ if (redzone_adjust > 0)
+ *size += redzone_adjust;
+ *size = min(KMALLOC_MAX_CACHE_SIZE,
+ max(*size,
+ cache->object_size +
+ optimal_redzone(cache->object_size)));
+}
+#endif
+
void kasan_poison_slab(struct page *page)
{
kasan_poison_shadow(page_address(page),
@@ -328,8 +381,36 @@ 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);
+#ifdef CONFIG_SLAB
+ if (cache->flags & SLAB_KASAN) {
+ struct kasan_alloc_meta *alloc_info =
+ get_alloc_info(cache, object);
+ alloc_info->state = KASAN_STATE_INIT;
+ }
+#endif
+}
+
+static inline void set_track(struct kasan_track *track)
+{
+ track->cpu = raw_smp_processor_id();
+ track->pid = current->pid;
+ track->when = jiffies;
}
+#ifdef CONFIG_SLAB
+struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
+ const void *object)
+{
+ return (void *)object + cache->kasan_info.alloc_meta_offset;
+}
+
+struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
+ const void *object)
+{
+ return (void *)object + cache->kasan_info.free_meta_offset;
+}
+#endif
+
void kasan_slab_alloc(struct kmem_cache *cache, void *object)
{
kasan_kmalloc(cache, object, cache->object_size);
@@ -344,6 +425,17 @@ void kasan_slab_free(struct kmem_cache *cache, void
*object)
if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
return;
+#ifdef CONFIG_SLAB
+ if (cache->flags & SLAB_KASAN) {
+ struct kasan_free_meta *free_info =
+ get_free_info(cache, object);
+ struct kasan_alloc_meta *alloc_info =
+ get_alloc_info(cache, object);
+ alloc_info->state = KASAN_STATE_FREE;
+ set_track(&free_info->track);
+ }
+#endif
+
kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
}
@@ -363,6 +455,16 @@ 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);
+#ifdef CONFIG_SLAB
+ 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);
+ }
+#endif
}
EXPORT_SYMBOL(kasan_kmalloc);
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 14cdff3..e781de9 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -55,6 +55,40 @@ struct kasan_global {
#endif
};
+/**
+ * Structures to keep alloc and free tracks *
+ */
+
+enum kasan_state {
+ KASAN_STATE_INIT,
+ KASAN_STATE_ALLOC,
+ KASAN_STATE_FREE
+};
+
+struct kasan_track {
+ u64 cpu : 6; /* for NR_CPUS = 64 */
+ u64 pid : 16; /* 65536 processes */
+ u64 when : 42; /* ~140 years */
+};
+
+struct kasan_alloc_meta {
+ u32 state : 2; /* enum kasan_state */
+ u32 alloc_size : 30;
+ struct kasan_track track;
+};
+
+struct kasan_free_meta {
+ /* Allocator freelist pointer, unused by KASAN. */
+ void **freelist;
+ struct kasan_track track;
+};
+
+struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
+ const void *object);
+struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
+ const void *object);
+
+
static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
{
return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 515ab38..e1a4b41 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -97,6 +97,46 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
+#ifdef CONFIG_SLAB
+static void print_track(struct kasan_track *track)
+{
+ pr_err("PID = %u, CPU = %u, timestamp = %lu\n", track->pid,
+ track->cpu, (unsigned long)track->when);
+}
+
+static void object_err(struct kmem_cache *cache, struct page *page,
+ void *object, char *unused_reason)
+{
+ 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);
+ 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:
+ 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;
+ }
+}
+#endif
+
static void print_address_description(struct kasan_access_info *info)
{
const void *addr = info->access_addr;
@@ -108,17 +148,10 @@ static void print_address_description(struct
kasan_access_info *info)
if (PageSlab(page)) {
void *object;
struct kmem_cache *cache = page->slab_cache;
- void *last_object;
-
- object = virt_to_obj(cache, page_address(page), addr);
- last_object = page_address(page) +
- page->objects * cache->size;
-
- if (unlikely(object > last_object))
- object = last_object; /* we hit into padding */
-
+ object = nearest_obj(cache, page,
+ (void *)info->access_addr);
object_err(cache, page, object,
- "kasan: bad access detected");
+ "kasan: bad access detected");
return;
}
dump_page(page, "kasan: bad access detected");
@@ -128,7 +161,6 @@ static void print_address_description(struct
kasan_access_info *info)
if (!init_task_stack_addr(addr))
pr_err("Address belongs to variable %pS\n", addr);
}
-
dump_stack();
}
diff --git a/mm/slab.c b/mm/slab.c
index 74944fe..b64c86b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2316,6 +2316,8 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned
long flags)
#endif
#endif
+ kasan_cache_create(cachep, &size, &flags);
+
/*
* Determine if the slab management is 'on' or 'off' slab.
* (bootstrapping cannot cope with offslab caches so don't do
@@ -2638,8 +2640,13 @@ static void cache_init_objs(struct kmem_cache *cachep,
* cache which they are a constructor for. Otherwise, deadlock.
* They must also be threaded.
*/
- if (cachep->ctor && !(cachep->flags & SLAB_POISON))
+ if (cachep->ctor && !(cachep->flags & SLAB_POISON)) {
+ kasan_unpoison_object_data(cachep,
+ objp + obj_offset(cachep));
cachep->ctor(objp + obj_offset(cachep));
+ kasan_poison_object_data(
+ cachep, objp + obj_offset(cachep));
+ }
if (cachep->flags & SLAB_RED_ZONE) {
if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
@@ -2654,8 +2661,11 @@ static void cache_init_objs(struct kmem_cache *cachep,
kernel_map_pages(virt_to_page(objp),
cachep->size / PAGE_SIZE, 0);
#else
- if (cachep->ctor)
+ if (cachep->ctor) {
+ kasan_unpoison_object_data(cachep, objp);
cachep->ctor(objp);
+ kasan_poison_object_data(cachep, objp);
+ }
#endif
slab_bufctl(slabp)[i] = i + 1;
}
@@ -2794,6 +2804,7 @@ static int cache_grow(struct kmem_cache *cachep,
slab_map_pages(cachep, slabp, objp);
+ kasan_poison_slab(slabp);
cache_init_objs(cachep, slabp);
if (local_flags & __GFP_WAIT)
@@ -3571,6 +3582,8 @@ static inline void __cache_free(struct kmem_cache
*cachep, void *objp,
{
struct array_cache *ac = cpu_cache_get(cachep);
+ kasan_slab_free(cachep, objp);
+
check_irq_off();
kmemleak_free_recursive(objp, cachep->flags);
objp = cache_free_debugcheck(cachep, objp, caller);
@@ -3609,6 +3622,7 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t
flags)
{
void *ret = slab_alloc(cachep, flags, _RET_IP_);
+ kasan_slab_alloc(cachep, ret);
trace_kmem_cache_alloc(_RET_IP_, ret,
cachep->object_size, cachep->size, flags);
@@ -3637,6 +3651,7 @@ kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t
flags, size_t size)
ret = slab_alloc(cachep, flags, _RET_IP_);
+ kasan_kmalloc(cachep, ret, size);
trace_kmalloc(_RET_IP_, ret,
size, cachep->size, flags);
return ret;
@@ -3649,6 +3664,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *cachep,
gfp_t flags, int nodeid)
{
void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
+ kasan_slab_alloc(cachep, ret);
trace_kmem_cache_alloc_node(_RET_IP_, ret,
cachep->object_size, cachep->size,
flags, nodeid);
@@ -3666,7 +3682,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache
*cachep,
void *ret;
ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
-
+ kasan_kmalloc(cachep, ret, size);
trace_kmalloc_node(_RET_IP_, ret,
size, cachep->size,
flags, nodeid);
@@ -3679,11 +3695,15 @@ static __always_inline void *
__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
{
struct kmem_cache *cachep;
+ void *ret;
cachep = kmalloc_slab(size, flags);
if (unlikely(ZERO_OR_NULL_PTR(cachep)))
return cachep;
- return kmem_cache_alloc_node_trace(cachep, flags, node, size);
+ ret = kmem_cache_alloc_node_trace(cachep, flags, node, size);
+ kasan_kmalloc(cachep, ret, size);
+
+ return ret;
}
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
@@ -3730,6 +3750,7 @@ static __always_inline void *__do_kmalloc(size_t size,
gfp_t flags,
return cachep;
ret = slab_alloc(cachep, flags, caller);
+ kasan_kmalloc(cachep, ret, size);
trace_kmalloc(caller, ret,
size, cachep->size, flags);
@@ -4550,10 +4571,18 @@ module_init(slab_proc_init);
*/
size_t ksize(const void *objp)
{
+ size_t size;
+
BUG_ON(!objp);
if (unlikely(objp == ZERO_SIZE_PTR))
return 0;
- return virt_to_cache(objp)->object_size;
+ size = virt_to_cache(objp)->object_size;
+ /* We assume that ksize callers could use the whole allocated area,
+ * so we need to unpoison this area.
+ */
+ kasan_krealloc(objp, size);
+
+ return size;
}
EXPORT_SYMBOL(ksize);
diff --git a/mm/slub.c b/mm/slub.c
index 2f9d5a1..4292050 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -166,7 +166,7 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
*/
#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
- SLAB_FAILSLAB)
+ SLAB_FAILSLAB | SLAB_KASAN)
#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
SLAB_CACHE_DMA | SLAB_NOTRACK | SLAB_ACCOUNT)
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