mm: page_alloc: add kasan hooks on alloc and free paths
Add kernel address sanitizer hooks to mark allocated page's addresses as
accessible in corresponding shadow region. Mark freed pages as
inaccessible.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 9102fda..f00c15c 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -34,6 +34,9 @@
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);
+
#else /* CONFIG_KASAN */
static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
@@ -41,6 +44,9 @@
static inline void kasan_enable_current(void) {}
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) {}
+
#endif /* CONFIG_KASAN */
#endif /* LINUX_KASAN_H */
diff --git a/mm/compaction.c b/mm/compaction.c
index d50d6de..8c0d945 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -16,6 +16,7 @@
#include <linux/sysfs.h>
#include <linux/balloon_compaction.h>
#include <linux/page-isolation.h>
+#include <linux/kasan.h>
#include "internal.h"
#ifdef CONFIG_COMPACTION
@@ -72,6 +73,7 @@
list_for_each_entry(page, list, lru) {
arch_alloc_page(page, 0);
kernel_map_pages(page, 1, 1);
+ kasan_alloc_pages(page, 0);
}
}
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index def8110..b516eb8 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -254,6 +254,20 @@
kasan_report(addr, size, write, _RET_IP_);
}
+void kasan_alloc_pages(struct page *page, unsigned int order)
+{
+ if (likely(!PageHighMem(page)))
+ kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
+}
+
+void kasan_free_pages(struct page *page, unsigned int order)
+{
+ if (likely(!PageHighMem(page)))
+ kasan_poison_shadow(page_address(page),
+ PAGE_SIZE << order,
+ KASAN_FREE_PAGE);
+}
+
#define DEFINE_ASAN_LOAD_STORE(size) \
void __asan_load##size(unsigned long addr) \
{ \
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 648b9c0..d3c90d5 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -6,6 +6,8 @@
#define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
#define KASAN_SHADOW_MASK (KASAN_SHADOW_SCALE_SIZE - 1)
+#define KASAN_FREE_PAGE 0xFF /* page was freed */
+
struct kasan_access_info {
const void *access_addr;
const void *first_bad_addr;
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 5835d69..fab8e78 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -54,6 +54,9 @@
shadow_val = *(u8 *)kasan_mem_to_shadow(info->first_bad_addr);
switch (shadow_val) {
+ case KASAN_FREE_PAGE:
+ bug_type = "use after free";
+ break;
case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
bug_type = "out of bounds access";
break;
@@ -69,6 +72,14 @@
static void print_address_description(struct kasan_access_info *info)
{
+ const void *addr = info->access_addr;
+
+ if ((addr >= (void *)PAGE_OFFSET) &&
+ (addr < high_memory)) {
+ struct page *page = virt_to_head_page(addr);
+ dump_page(page, "kasan: bad access detected");
+ }
+
dump_stack();
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cb47582..a47f0b2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -25,6 +25,7 @@
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/kmemcheck.h>
+#include <linux/kasan.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
@@ -787,6 +788,7 @@
trace_mm_page_free(page, order);
kmemcheck_free_shadow(page, order);
+ kasan_free_pages(page, order);
if (PageAnon(page))
page->mapping = NULL;
@@ -970,6 +972,7 @@
arch_alloc_page(page, order);
kernel_map_pages(page, 1 << order, 1);
+ kasan_alloc_pages(page, order);
if (gfp_flags & __GFP_ZERO)
prep_zero_page(page, order, gfp_flags);