1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * This file contains common tag-based KASAN code. 4 * 5 * Copyright (c) 2018 Google, Inc. 6 * Copyright (c) 2020 Google, Inc. 7 */ 8 9 #include <linux/init.h> 10 #include <linux/kasan.h> 11 #include <linux/kernel.h> 12 #include <linux/memory.h> 13 #include <linux/mm.h> 14 #include <linux/static_key.h> 15 #include <linux/string.h> 16 #include <linux/types.h> 17 18 #include "kasan.h" 19 20 void kasan_set_free_info(struct kmem_cache *cache, 21 void *object, u8 tag) 22 { 23 struct kasan_alloc_meta *alloc_meta; 24 u8 idx = 0; 25 26 alloc_meta = kasan_get_alloc_meta(cache, object); 27 if (!alloc_meta) 28 return; 29 30 #ifdef CONFIG_KASAN_TAGS_IDENTIFY 31 idx = alloc_meta->free_track_idx; 32 alloc_meta->free_pointer_tag[idx] = tag; 33 alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS; 34 #endif 35 36 kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT); 37 } 38 39 struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, 40 void *object, u8 tag) 41 { 42 struct kasan_alloc_meta *alloc_meta; 43 int i = 0; 44 45 alloc_meta = kasan_get_alloc_meta(cache, object); 46 if (!alloc_meta) 47 return NULL; 48 49 #ifdef CONFIG_KASAN_TAGS_IDENTIFY 50 for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { 51 if (alloc_meta->free_pointer_tag[i] == tag) 52 break; 53 } 54 if (i == KASAN_NR_FREE_STACKS) 55 i = alloc_meta->free_track_idx; 56 #endif 57 58 return &alloc_meta->free_track[i]; 59 } 60