kasan: introduce kasan_complete_mode_report_info

Add bug_type and alloc/free_track fields to kasan_report_info and add a
kasan_complete_mode_report_info() function that fills in these fields. 
This function is implemented differently for different KASAN mode.

Change the reporting code to use the filled in fields instead of invoking
kasan_get_bug_type() and kasan_get_alloc/free_track().

For the Generic mode, kasan_complete_mode_report_info() invokes these
functions instead.  For the tag-based modes, only the bug_type field is
filled in; alloc/free_track are handled in the next patch.

Using a single function that fills in these fields is required for the
tag-based modes, as the values for all three fields are determined in a
single procedure implemented in the following patch.

Link: https://lkml.kernel.org/r/8432b861054fa8d0cee79a8877dedeaf3b677ca8.1662411799.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/kasan/kasan.h

@@ -146,6 +146,13 @@ static inline bool kasan_requires_meta(void)
 #define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE)
 #define META_ROWS_AROUND_ADDR 2
 
+#define KASAN_STACK_DEPTH 64
+
+struct kasan_track {
+	u32 pid;
+	depot_stack_handle_t stack;
+};
+
 enum kasan_report_type {
 	KASAN_REPORT_ACCESS,
 	KASAN_REPORT_INVALID_FREE,
@@ -164,6 +171,11 @@ struct kasan_report_info {
 	void *first_bad_addr;
 	struct kmem_cache *cache;
 	void *object;
+
+	/* Filled in by the mode-specific reporting code. */
+	const char *bug_type;
+	struct kasan_track alloc_track;
+	struct kasan_track free_track;
 };
 
 /* Do not change the struct layout: compiler ABI. */
@@ -189,14 +201,7 @@ struct kasan_global {
 #endif
 };
 
-/* Structures for keeping alloc and free tracks. */
-
-#define KASAN_STACK_DEPTH 64
-
-struct kasan_track {
-	u32 pid;
-	depot_stack_handle_t stack;
-};
+/* Structures for keeping alloc and free meta. */
 
 #ifdef CONFIG_KASAN_GENERIC
 
@@ -270,16 +275,16 @@ static inline bool addr_has_metadata(const void *addr)
 
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
+void *kasan_find_first_bad_addr(void *addr, size_t size);
+void kasan_complete_mode_report_info(struct kasan_report_info *info);
+void kasan_metadata_fetch_row(char *buffer, void *row);
+
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 void kasan_print_tags(u8 addr_tag, const void *addr);
 #else
 static inline void kasan_print_tags(u8 addr_tag, const void *addr) { }
 #endif
 
-void *kasan_find_first_bad_addr(void *addr, size_t size);
-const char *kasan_get_bug_type(struct kasan_report_info *info);
-void kasan_metadata_fetch_row(char *buffer, void *row);
-
 #if defined(CONFIG_KASAN_STACK)
 void kasan_print_address_stack_frame(const void *addr);
 #else
@@ -314,10 +319,6 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc);
 void kasan_set_track(struct kasan_track *track, gfp_t flags);
 void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
 void kasan_save_free_info(struct kmem_cache *cache, void *object);
-struct kasan_track *kasan_get_alloc_track(struct kmem_cache *cache,
-						void *object);
-struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
-						void *object, u8 tag);
 
 #if defined(CONFIG_KASAN_GENERIC) && \
 	(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))

mm/kasan/report.c

@@ -185,8 +185,7 @@ static void print_error_description(struct kasan_report_info *info)
 		return;
 	}
 
-	pr_err("BUG: KASAN: %s in %pS\n",
-		kasan_get_bug_type(info), (void *)info->ip);
+	pr_err("BUG: KASAN: %s in %pS\n", info->bug_type, (void *)info->ip);
 	if (info->access_size)
 		pr_err("%s of size %zu at addr %px by task %s/%d\n",
 			info->is_write ? "Write" : "Read", info->access_size,
@@ -242,31 +241,25 @@ static void describe_object_addr(const void *addr, struct kmem_cache *cache,
 		(void *)(object_addr + cache->object_size));
 }
 
-static void describe_object_stacks(u8 tag, struct kasan_report_info *info)
+static void describe_object_stacks(struct kasan_report_info *info)
 {
-	struct kasan_track *alloc_track;
-	struct kasan_track *free_track;
-
-	alloc_track = kasan_get_alloc_track(info->cache, info->object);
-	if (alloc_track) {
-		print_track(alloc_track, "Allocated");
+	if (info->alloc_track.stack) {
+		print_track(&info->alloc_track, "Allocated");
 		pr_err("\n");
 	}
 
-	free_track = kasan_get_free_track(info->cache, info->object, tag);
-	if (free_track) {
-		print_track(free_track, "Freed");
+	if (info->free_track.stack) {
+		print_track(&info->free_track, "Freed");
 		pr_err("\n");
 	}
 
 	kasan_print_aux_stacks(info->cache, info->object);
 }
 
-static void describe_object(const void *addr, u8 tag,
-			    struct kasan_report_info *info)
+static void describe_object(const void *addr, struct kasan_report_info *info)
 {
 	if (kasan_stack_collection_enabled())
-		describe_object_stacks(tag, info);
+		describe_object_stacks(info);
 	describe_object_addr(addr, info->cache, info->object);
 }
 
@@ -295,7 +288,7 @@ static void print_address_description(void *addr, u8 tag,
 	pr_err("\n");
 
 	if (info->cache && info->object) {
-		describe_object(addr, tag, info);
+		describe_object(addr, info);
 		pr_err("\n");
 	}
 
@@ -426,6 +419,9 @@ static void complete_report_info(struct kasan_report_info *info)
 		info->object = nearest_obj(info->cache, slab, addr);
 	} else
 		info->cache = info->object = NULL;
+
+	/* Fill in mode-specific report info fields. */
+	kasan_complete_mode_report_info(info);
 }
 
 void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_type type)
@@ -443,6 +439,7 @@ void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_ty
 
 	start_report(&flags, true);
 
+	memset(&info, 0, sizeof(info));
 	info.type = type;
 	info.access_addr = ptr;
 	info.access_size = 0;
@@ -477,6 +474,7 @@ bool kasan_report(unsigned long addr, size_t size, bool is_write,
 
 	start_report(&irq_flags, true);
 
+	memset(&info, 0, sizeof(info));
 	info.type = KASAN_REPORT_ACCESS;
 	info.access_addr = ptr;
 	info.access_size = size;

mm/kasan/report_generic.c

@@ -109,7 +109,7 @@ static const char *get_wild_bug_type(struct kasan_report_info *info)
 	return bug_type;
 }
 
-const char *kasan_get_bug_type(struct kasan_report_info *info)
+static const char *get_bug_type(struct kasan_report_info *info)
 {
 	/*
 	 * If access_size is a negative number, then it has reason to be
@@ -127,25 +127,27 @@ const char *kasan_get_bug_type(struct kasan_report_info *info)
 	return get_wild_bug_type(info);
 }
 
-struct kasan_track *kasan_get_alloc_track(struct kmem_cache *cache,
-						void *object)
+void kasan_complete_mode_report_info(struct kasan_report_info *info)
 {
 	struct kasan_alloc_meta *alloc_meta;
+	struct kasan_free_meta *free_meta;
 
-	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (!alloc_meta)
-		return NULL;
+	info->bug_type = get_bug_type(info);
 
-	return &alloc_meta->alloc_track;
-}
+	if (!info->cache || !info->object)
+		return;
 
-struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
-						void *object, u8 tag)
-{
-	if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_SLAB_FREETRACK)
-		return NULL;
-	/* Free meta must be present with KASAN_SLAB_FREETRACK. */
-	return &kasan_get_free_meta(cache, object)->free_track;
+	alloc_meta = kasan_get_alloc_meta(info->cache, info->object);
+	if (alloc_meta)
+		memcpy(&info->alloc_track, &alloc_meta->alloc_track,
+		       sizeof(info->alloc_track));
+
+	if (*(u8 *)kasan_mem_to_shadow(info->object) == KASAN_SLAB_FREETRACK) {
+		/* Free meta must be present with KASAN_SLAB_FREETRACK. */
+		free_meta = kasan_get_free_meta(info->cache, info->object);
+		memcpy(&info->free_track, &free_meta->free_track,
+		       sizeof(info->free_track));
+	}
 }
 
 void kasan_metadata_fetch_row(char *buffer, void *row)

mm/kasan/report_tags.c

@@ -6,7 +6,7 @@
 
 #include "kasan.h"
 
-const char *kasan_get_bug_type(struct kasan_report_info *info)
+static const char *get_bug_type(struct kasan_report_info *info)
 {
 	/*
 	 * If access_size is a negative number, then it has reason to be
@@ -22,14 +22,7 @@ const char *kasan_get_bug_type(struct kasan_report_info *info)
 	return "invalid-access";
 }
 
-struct kasan_track *kasan_get_alloc_track(struct kmem_cache *cache,
-						void *object)
+void kasan_complete_mode_report_info(struct kasan_report_info *info)
 {
-	return NULL;
-}
-
-struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
-						void *object, u8 tag)
-{
-	return NULL;
+	info->bug_type = get_bug_type(info);
 }