From: Andrey Ryabinin a.ryabinin@samsung.com
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 (cherry picked from commit b8c73fc2493d42517be95cf2c89659fc6c6f4d02) Signed-off-by: Alex Shi alex.shi@linaro.org --- include/linux/kasan.h | 6 ++++++ mm/compaction.c | 2 ++ mm/kasan/kasan.c | 14 ++++++++++++++ mm/kasan/kasan.h | 2 ++ mm/kasan/report.c | 11 +++++++++++ mm/page_alloc.c | 3 +++ 6 files changed, 38 insertions(+)
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 @@ static inline void kasan_disable_current(void)
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_unpoison_shadow(const void *address, size_t size) {} 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 b47f08e..81c89c3 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 @@ -59,6 +60,7 @@ static void map_pages(struct list_head *list) 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 @@ static __always_inline void check_memory_region(unsigned long addr, 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 @@ static void print_error_description(struct kasan_access_info *info) 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_error_description(struct kasan_access_info *info)
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 c32cb64..903d2d1 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> @@ -743,6 +744,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order)
trace_mm_page_free(page, order); kmemcheck_free_shadow(page, order); + kasan_free_pages(page, order);
if (PageAnon(page)) page->mapping = NULL; @@ -922,6 +924,7 @@ static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags)
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);