1/* @title: Address sanitization */
2#include <err.h>
3#include <log.h>
4#include <math/bit.h>
5#include <stdbool.h>
6#include <stddef.h>
7#include <stdint.h>
8#include <types/types.h>
9
10#define ASAN_SHADOW_SCALE 3ULL /* 1 shadow byte per 8 real bytes */
11#define ASAN_SHADOW_OFFSET 0xDFFFFE0000000000
12
13/*
14 * offset = SHADOW_REGION_START - (COVERED_START >> SHADOW_SCALE)
15 * shadow = (addr >> scale) + offset */
16#define ASAN_SHADOW_ADDR(a) \
17 ((uintptr_t) (((uintptr_t) (a) >> ASAN_SHADOW_SCALE) + ASAN_SHADOW_OFFSET))
18#define ASAN_GRANULE ((uintptr_t) BIT(ASAN_SHADOW_SCALE))
19#define ASAN_REDZONE 16 /* optional redzone per allocation */
20
21/* Shadow byte encoding, one per ASAN_GRANULE bytes of memory:
22 *
23 * 0 - whole granule accessible
24 * 1..7 first k bytes accessible
25 * >= 0x80 nothing in granule accessible */
26#define ASAN_POISON_VALUE 0xFF /* generic: never handed out */
27#define ASAN_POISON_HEAP_REDZONE 0xFA /* slack around/inside a live slot */
28#define ASAN_POISON_HEAP_FREED 0xFD /* was live, has been freed */
29
30static inline bool asan_shadow_is_poison(uint8_t s) {
31 return s >= 0x80;
32}
33
34#define ASAN_ABORT_IF_NOT_READY() \
35 do { \
36 if (!asan_ready) \
37 return; \
38 } while (0)
39
40LOG_SITE_EXTERN(asan);
41LOG_HANDLE_EXTERN(asan);
42
43#define asan_log(lvl, fmt, ...) \
44 log(LOG_SITE(asan), LOG_HANDLE(asan), lvl, fmt, ##__VA_ARGS__)
45
46#define asan_err(fmt, ...) asan_log(LOG_ERROR, fmt, ##__VA_ARGS__)
47#define asan_warn(fmt, ...) asan_log(LOG_WARN, fmt, ##__VA_ARGS__)
48#define asan_info(fmt, ...) asan_log(LOG_INFO, fmt, ##__VA_ARGS__)
49#define asan_debug(fmt, ...) asan_log(LOG_DEBUG, fmt, ##__VA_ARGS__)
50#define asan_trace(fmt, ...) asan_log(LOG_TRACE, fmt, ##__VA_ARGS__)
51
52#ifdef DEBUG_ASAN
53
54void asan_init(void);
55
56/* Shadow backing at the slab chunk granularity, which must happen before any
57 * object in the chunk is handed off */
58enum err asan_shadow_install(vaddr_t base, size_t len);
59void asan_shadow_release(vaddr_t base, size_t len);
60
61void asan_alloc(void *addr, size_t requested, size_t slot);
62void asan_free(void *addr, size_t slot);
63void asan_poison(void *addr, size_t size);
64void asan_unpoison(void *addr, size_t size);
65
66#else
67
68static inline void asan_init(void) {}
69
70static inline enum err asan_shadow_install(vaddr_t base, size_t len) {
71 cc_ignore(base, len);
72 return ERR_OK;
73}
74
75static inline void asan_shadow_release(vaddr_t base, size_t len) {
76 cc_ignore(base, len);
77}
78
79static inline void asan_alloc(void *addr, size_t requested, size_t slot) {
80 cc_ignore(addr, requested, slot);
81}
82
83static inline void asan_free(void *addr, size_t slot) {
84 cc_ignore(addr, slot);
85}
86
87static inline void asan_poison(void *addr, size_t size) {
88 cc_ignore(addr, size);
89}
90
91static inline void asan_unpoison(void *addr, size_t size) {
92 cc_ignore(addr, size);
93}
94
95#endif
96