3 files changed, 99 insertions, 0 deletions

diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 799c52b9826c..78fee632a7ee 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -22,6 +22,7 @@
 #include <linux/memblock.h>
 #include <linux/memory.h>
 #include <linux/mm.h>
+#include <linux/module.h>
 #include <linux/printk.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
@@ -395,6 +396,57 @@ void kasan_kfree_large(const void *ptr)
 			KASAN_FREE_PAGE);
 }
 
+int kasan_module_alloc(void *addr, size_t size)
+{
+	void *ret;
+	size_t shadow_size;
+	unsigned long shadow_start;
+
+	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
+	shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
+			PAGE_SIZE);
+
+	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
+		return -EINVAL;
+
+	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
+			shadow_start + shadow_size,
+			GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
+			__builtin_return_address(0));
+	return ret ? 0 : -ENOMEM;
+}
+
+void kasan_module_free(void *addr)
+{
+	vfree(kasan_mem_to_shadow(addr));
+}
+
+static void register_global(struct kasan_global *global)
+{
+	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
+
+	kasan_unpoison_shadow(global->beg, global->size);
+
+	kasan_poison_shadow(global->beg + aligned_size,
+		global->size_with_redzone - aligned_size,
+		KASAN_GLOBAL_REDZONE);
+}
+
+void __asan_register_globals(struct kasan_global *globals, size_t size)
+{
+	int i;
+
+	for (i = 0; i < size; i++)
+		register_global(&globals[i]);
+}
+EXPORT_SYMBOL(__asan_register_globals);
+
+void __asan_unregister_globals(struct kasan_global *globals, size_t size)
+{
+}
+EXPORT_SYMBOL(__asan_unregister_globals);
+
 #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 1fcc1d81a9cf..4986b0acab21 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -11,6 +11,7 @@
 #define KASAN_PAGE_REDZONE      0xFE  /* redzone for kmalloc_large allocations */
 #define KASAN_KMALLOC_REDZONE   0xFC  /* redzone inside slub object */
 #define KASAN_KMALLOC_FREE      0xFB  /* object was freed (kmem_cache_free/kfree) */
+#define KASAN_GLOBAL_REDZONE    0xFA  /* redzone for global variable */
 
 /*
  * Stack redzone shadow values
@@ -21,6 +22,10 @@
 #define KASAN_STACK_RIGHT       0xF3
 #define KASAN_STACK_PARTIAL     0xF4
 
+/* Don't break randconfig/all*config builds */
+#ifndef KASAN_ABI_VERSION
+#define KASAN_ABI_VERSION 1
+#endif
 
 struct kasan_access_info {
 	const void *access_addr;
@@ -30,6 +35,26 @@ struct kasan_access_info {
 	unsigned long ip;
 };
 
+/* The layout of struct dictated by compiler */
+struct kasan_source_location {
+	const char *filename;
+	int line_no;
+	int column_no;
+};
+
+/* The layout of struct dictated by compiler */
+struct kasan_global {
+	const void *beg;		/* Address of the beginning of the global variable. */
+	size_t size;			/* Size of the global variable. */
+	size_t size_with_redzone;	/* Size of the variable + size of the red zone. 32 bytes aligned */
+	const void *name;
+	const void *module_name;	/* Name of the module where the global variable is declared. */
+	unsigned long has_dynamic_init;	/* This needed for C++ */
+#if KASAN_ABI_VERSION >= 4
+	struct kasan_source_location *location;
+#endif
+};
+
 void kasan_report_error(struct kasan_access_info *info);
 void kasan_report_user_access(struct kasan_access_info *info);
 
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 866732ef3db3..680ceedf810a 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -23,6 +23,8 @@
 #include <linux/types.h>
 #include <linux/kasan.h>
 
+#include <asm/sections.h>
+
 #include "kasan.h"
 #include "../slab.h"
 
@@ -61,6 +63,7 @@ static void print_error_description(struct kasan_access_info *info)
 		break;
 	case KASAN_PAGE_REDZONE:
 	case KASAN_KMALLOC_REDZONE:
+	case KASAN_GLOBAL_REDZONE:
 	case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
 		bug_type = "out of bounds access";
 		break;
@@ -80,6 +83,20 @@ static void print_error_description(struct kasan_access_info *info)
 		info->access_size, current->comm, task_pid_nr(current));
 }
 
+static inline bool kernel_or_module_addr(const void *addr)
+{
+	return (addr >= (void *)_stext && addr < (void *)_end)
+		|| (addr >= (void *)MODULES_VADDR
+			&& addr < (void *)MODULES_END);
+}
+
+static inline bool init_task_stack_addr(const void *addr)
+{
+	return addr >= (void *)&init_thread_union.stack &&
+		(addr <= (void *)&init_thread_union.stack +
+			sizeof(init_thread_union.stack));
+}
+
 static void print_address_description(struct kasan_access_info *info)
 {
 	const void *addr = info->access_addr;
@@ -107,6 +124,11 @@ static void print_address_description(struct kasan_access_info *info)
 		dump_page(page, "kasan: bad access detected");
 	}
 
+	if (kernel_or_module_addr(addr)) {
+		if (!init_task_stack_addr(addr))
+			pr_err("Address belongs to variable %pS\n", addr);
+	}
+
 	dump_stack();
 }