1 /* AddressSanitizer, a fast memory error detector.
2 Copyright (C) 2011-2023 Free Software Foundation, Inc.
3 Contributed by Kostya Serebryany <kcc@google.com>
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21 #ifndef TREE_ASAN
22 #define TREE_ASAN
23
24 extern void asan_function_start (void);
25 extern void asan_finish_file (void);
26 extern rtx_insn *asan_emit_stack_protection (rtx, rtx, unsigned int,
27 HOST_WIDE_INT *, tree *, int);
28 extern rtx_insn *asan_emit_allocas_unpoison (rtx, rtx, rtx_insn *);
29 extern bool asan_protect_global (tree, bool ignore_decl_rtl_set_p = false);
30 extern void initialize_sanitizer_builtins (void);
31 extern tree asan_dynamic_init_call (bool);
32 extern bool asan_expand_check_ifn (gimple_stmt_iterator *, bool);
33 extern bool asan_expand_mark_ifn (gimple_stmt_iterator *);
34 extern bool asan_expand_poison_ifn (gimple_stmt_iterator *, bool *,
35 hash_map<tree, tree> &);
36 extern rtx asan_memfn_rtl (tree);
37
38 extern void hwasan_record_frame_init ();
39 extern void hwasan_record_stack_var (rtx, rtx, poly_int64, poly_int64);
40 extern void hwasan_emit_prologue ();
41 extern rtx_insn *hwasan_emit_untag_frame (rtx, rtx);
42 extern rtx hwasan_get_frame_extent ();
43 extern rtx hwasan_frame_base ();
44 extern void hwasan_maybe_emit_frame_base_init (void);
45 extern bool stack_vars_base_reg_p (rtx);
46 extern uint8_t hwasan_current_frame_tag ();
47 extern void hwasan_increment_frame_tag ();
48 extern rtx hwasan_truncate_to_tag_size (rtx, rtx);
49 extern void hwasan_finish_file (void);
50 extern bool hwasan_sanitize_p (void);
51 extern bool hwasan_sanitize_stack_p (void);
52 extern bool hwasan_sanitize_allocas_p (void);
53 extern bool hwasan_expand_check_ifn (gimple_stmt_iterator *, bool);
54 extern bool hwasan_expand_mark_ifn (gimple_stmt_iterator *);
55 extern bool gate_hwasan (void);
56
57 extern gimple_stmt_iterator create_cond_insert_point
58 (gimple_stmt_iterator *, bool, bool, bool, basic_block *, basic_block *);
59
60 /* Alias set for accessing the shadow memory. */
61 extern alias_set_type asan_shadow_set;
62
63 /* Hash set of labels that are either used in a goto, or their address
64 has been taken. */
65 extern hash_set <tree> *asan_used_labels;
66
67 /* Shadow memory is found at
68 (address >> ASAN_SHADOW_SHIFT) + asan_shadow_offset (). */
69 #define ASAN_SHADOW_SHIFT 3
70 #define ASAN_SHADOW_GRANULARITY (1UL << ASAN_SHADOW_SHIFT)
71
72 /* Red zone size, stack and global variables are padded by ASAN_RED_ZONE_SIZE
73 up to 2 * ASAN_RED_ZONE_SIZE - 1 bytes. */
74 #define ASAN_RED_ZONE_SIZE 32
75
76 /* Stack variable use more compact red zones. The size includes also
77 size of variable itself. */
78
79 #define ASAN_MIN_RED_ZONE_SIZE 16
80
81 /* Shadow memory values for stack protection. Left is below protected vars,
82 the first pointer in stack corresponding to that offset contains
83 ASAN_STACK_FRAME_MAGIC word, the second pointer to a string describing
84 the frame. Middle is for padding in between variables, right is
85 above the last protected variable and partial immediately after variables
86 up to ASAN_RED_ZONE_SIZE alignment. */
87 #define ASAN_STACK_MAGIC_LEFT 0xf1
88 #define ASAN_STACK_MAGIC_MIDDLE 0xf2
89 #define ASAN_STACK_MAGIC_RIGHT 0xf3
90 #define ASAN_STACK_MAGIC_USE_AFTER_RET 0xf5
91 #define ASAN_STACK_MAGIC_USE_AFTER_SCOPE 0xf8
92
93 #define ASAN_STACK_FRAME_MAGIC 0x41b58ab3
94 #define ASAN_STACK_RETIRED_MAGIC 0x45e0360e
95
96 #define ASAN_USE_AFTER_SCOPE_ATTRIBUTE "use after scope memory"
97
98 /* NOTE: The values below and the hooks under targetm.memtag define an ABI and
99 are hard-coded to these values in libhwasan, hence they can't be changed
100 independently here. */
101 /* How many bits are used to store a tag in a pointer.
102 The default version uses the entire top byte of a pointer (i.e. 8 bits). */
103 #define HWASAN_TAG_SIZE targetm.memtag.tag_size ()
104 /* Tag Granule of HWASAN shadow stack.
105 This is the size in real memory that each byte in the shadow memory refers
106 to. I.e. if a variable is X bytes long in memory then its tag in shadow
107 memory will span X / HWASAN_TAG_GRANULE_SIZE bytes.
108 Most variables will need to be aligned to this amount since two variables
109 that are neighbors in memory and share a tag granule would need to share the
110 same tag (the shared tag granule can only store one tag). */
111 #define HWASAN_TAG_GRANULE_SIZE targetm.memtag.granule_size ()
112 /* Define the tag for the stack background.
113 This defines what tag the stack pointer will be and hence what tag all
114 variables that are not given special tags are (e.g. spilled registers,
115 and parameters passed on the stack). */
116 #define HWASAN_STACK_BACKGROUND gen_int_mode (0, QImode)
117
118 /* Various flags for Asan builtins. */
119 enum asan_check_flags
120 {
121 ASAN_CHECK_STORE = 1 << 0,
122 ASAN_CHECK_SCALAR_ACCESS = 1 << 1,
123 ASAN_CHECK_NON_ZERO_LEN = 1 << 2,
124 ASAN_CHECK_LAST = 1 << 3
125 };
126
127 /* Flags for Asan check builtins. */
128 #define IFN_ASAN_MARK_FLAGS DEF(POISON), DEF(UNPOISON)
129
130 enum asan_mark_flags
131 {
132 #define DEF(X) ASAN_MARK_##X
133 IFN_ASAN_MARK_FLAGS
134 #undef DEF
135 };
136
137 /* Return true if STMT is ASAN_MARK with FLAG as first argument. */
138 extern bool asan_mark_p (gimple *stmt, enum asan_mark_flags flag);
139
140 /* Return the size of padding needed to insert after a protected
141 decl of SIZE. */
142
143 inline unsigned int
144 asan_red_zone_size (unsigned int size)
145 {
146 unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1);
147 return c ? 2 * ASAN_RED_ZONE_SIZE - c : ASAN_RED_ZONE_SIZE;
148 }
149
150 /* Return how much a stack variable occupis on a stack
151 including a space for red zone. */
152
153 inline unsigned HOST_WIDE_INT
154 asan_var_and_redzone_size (unsigned HOST_WIDE_INT size)
155 {
156 if (size <= 4)
157 return 16;
158 else if (size <= 16)
159 return 32;
160 else if (size <= 128)
161 return size + 32;
162 else if (size <= 512)
163 return size + 64;
164 else if (size <= 4096)
165 return size + 128;
166 else
167 return size + 256;
168 }
169
170 extern bool set_asan_shadow_offset (const char *);
171
172 extern bool asan_shadow_offset_set_p ();
173
174 extern void set_sanitized_sections (const char *);
175
176 extern bool asan_sanitize_stack_p (void);
177
178 extern bool asan_sanitize_allocas_p (void);
179
180 extern hash_set<tree> *asan_handled_variables;
181
182 /* Return TRUE if builtin with given FCODE will be intercepted by
183 libasan. */
184
185 inline bool
186 asan_intercepted_p (enum built_in_function fcode)
187 {
188 if (hwasan_sanitize_p ())
189 return false;
190
191 return fcode == BUILT_IN_INDEX
192 || fcode == BUILT_IN_MEMCHR
193 || fcode == BUILT_IN_MEMCMP
194 || fcode == BUILT_IN_MEMCPY
195 || fcode == BUILT_IN_MEMMOVE
196 || fcode == BUILT_IN_MEMSET
197 || fcode == BUILT_IN_STRCASECMP
198 || fcode == BUILT_IN_STRCAT
199 || fcode == BUILT_IN_STRCHR
200 || fcode == BUILT_IN_STRCMP
201 || fcode == BUILT_IN_STRCPY
202 || fcode == BUILT_IN_STRDUP
203 || fcode == BUILT_IN_STRLEN
204 || fcode == BUILT_IN_STRNCASECMP
205 || fcode == BUILT_IN_STRNCAT
206 || fcode == BUILT_IN_STRNCMP
207 || fcode == BUILT_IN_STRCSPN
208 || fcode == BUILT_IN_STRPBRK
209 || fcode == BUILT_IN_STRSPN
210 || fcode == BUILT_IN_STRSTR
211 || fcode == BUILT_IN_STRNCPY;
212 }
213
214 /* Return TRUE if we should instrument for use-after-scope sanity checking. */
215
216 inline bool
217 asan_sanitize_use_after_scope (void)
218 {
219 return (flag_sanitize_address_use_after_scope
220 && (asan_sanitize_stack_p () || hwasan_sanitize_stack_p ()));
221 }
222
223 /* Return true if DECL should be guarded on the stack. */
224
225 inline bool
226 asan_protect_stack_decl (tree decl)
227 {
228 return DECL_P (decl)
229 && (!DECL_ARTIFICIAL (decl)
230 || (asan_sanitize_use_after_scope () && TREE_ADDRESSABLE (decl)));
231 }
232
233 /* Return true when flag_sanitize & FLAG is non-zero. If FN is non-null,
234 remove all flags mentioned in "no_sanitize" of DECL_ATTRIBUTES. */
235
236 inline bool
237 sanitize_flags_p (unsigned int flag, const_tree fn = current_function_decl)
238 {
239 unsigned int result_flags = flag_sanitize & flag;
240 if (result_flags == 0)
241 return false;
242
243 if (fn != NULL_TREE)
244 {
245 tree value = lookup_attribute ("no_sanitize", DECL_ATTRIBUTES (fn));
246 if (value)
247 result_flags &= ~tree_to_uhwi (TREE_VALUE (value));
248 }
249
250 return result_flags;
251 }
252
253 /* Return true when coverage sanitization should happend for FN function. */
254
255 inline bool
256 sanitize_coverage_p (const_tree fn = current_function_decl)
257 {
258 return (flag_sanitize_coverage
259 && (fn == NULL_TREE
260 || lookup_attribute ("no_sanitize_coverage",
261 DECL_ATTRIBUTES (fn)) == NULL_TREE));
262 }
263
264 #endif /* TREE_ASAN */