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1 : : /* AddressSanitizer, a fast memory error detector.
2 : : Copyright (C) 2011-2024 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 : 7102 : asan_red_zone_size (unsigned int size)
145 : : {
146 : 7102 : unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1);
147 : 7102 : 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 : 2511 : asan_var_and_redzone_size (unsigned HOST_WIDE_INT size)
155 : : {
156 : 2511 : if (size <= 4)
157 : : return 16;
158 : 1604 : else if (size <= 16)
159 : : return 32;
160 : 844 : else if (size <= 128)
161 : 638 : return size + 32;
162 : 206 : else if (size <= 512)
163 : 83 : return size + 64;
164 : 123 : else if (size <= 4096)
165 : 40 : return size + 128;
166 : : else
167 : 83 : 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 : 21226 : asan_intercepted_p (enum built_in_function fcode)
187 : : {
188 : : /* This list should be kept up-to-date with upstream's version at
189 : : compiler-rt/lib/hwasan/hwasan_platform_interceptors.h. */
190 : 21226 : if (hwasan_sanitize_p ())
191 : 644 : return fcode == BUILT_IN_MEMCMP
192 : : || fcode == BUILT_IN_MEMCPY
193 : 644 : || fcode == BUILT_IN_MEMMOVE
194 : 644 : || fcode == BUILT_IN_MEMSET;
195 : :
196 : 20582 : return fcode == BUILT_IN_INDEX
197 : : || fcode == BUILT_IN_MEMCHR
198 : : || fcode == BUILT_IN_MEMCMP
199 : : || fcode == BUILT_IN_MEMCPY
200 : 20582 : || fcode == BUILT_IN_MEMMOVE
201 : 20582 : || fcode == BUILT_IN_MEMSET
202 : : || fcode == BUILT_IN_STRCASECMP
203 : : || fcode == BUILT_IN_STRCAT
204 : : || fcode == BUILT_IN_STRCHR
205 : : || fcode == BUILT_IN_STRCMP
206 : : || fcode == BUILT_IN_STRCPY
207 : : || fcode == BUILT_IN_STRDUP
208 : : || fcode == BUILT_IN_STRLEN
209 : : || fcode == BUILT_IN_STRNCASECMP
210 : : || fcode == BUILT_IN_STRNCAT
211 : : || fcode == BUILT_IN_STRNCMP
212 : : || fcode == BUILT_IN_STRCSPN
213 : : || fcode == BUILT_IN_STRPBRK
214 : : || fcode == BUILT_IN_STRSPN
215 : : || fcode == BUILT_IN_STRSTR
216 : : || fcode == BUILT_IN_STRNCPY;
217 : : }
218 : :
219 : : /* Return TRUE if we should instrument for use-after-scope sanity checking. */
220 : :
221 : : inline bool
222 : 20608752 : asan_sanitize_use_after_scope (void)
223 : : {
224 : 20608752 : return (flag_sanitize_address_use_after_scope
225 : 20608752 : && (asan_sanitize_stack_p () || hwasan_sanitize_stack_p ()));
226 : : }
227 : :
228 : : /* Return true if DECL should be guarded on the stack. */
229 : :
230 : : inline bool
231 : 5400 : asan_protect_stack_decl (tree decl)
232 : : {
233 : 5400 : return DECL_P (decl)
234 : 5400 : && (!DECL_ARTIFICIAL (decl)
235 : 1464 : || (asan_sanitize_use_after_scope () && TREE_ADDRESSABLE (decl)));
236 : : }
237 : :
238 : : /* Return true when flag_sanitize & FLAG is non-zero. If FN is non-null,
239 : : remove all flags mentioned in "no_sanitize" of DECL_ATTRIBUTES. */
240 : :
241 : : inline bool
242 : 621367220 : sanitize_flags_p (unsigned int flag, const_tree fn = current_function_decl)
243 : : {
244 : 621367220 : unsigned int result_flags = flag_sanitize & flag;
245 : 621367220 : if (result_flags == 0)
246 : : return false;
247 : :
248 : 718090 : if (fn != NULL_TREE)
249 : : {
250 : 711866 : tree value = lookup_attribute ("no_sanitize", DECL_ATTRIBUTES (fn));
251 : 711866 : if (value)
252 : 2755 : result_flags &= ~tree_to_uhwi (TREE_VALUE (value));
253 : : }
254 : :
255 : 718090 : return result_flags;
256 : : }
257 : :
258 : : /* Return true when coverage sanitization should happend for FN function. */
259 : :
260 : : inline bool
261 : 58228622 : sanitize_coverage_p (const_tree fn = current_function_decl)
262 : : {
263 : 58228622 : return (flag_sanitize_coverage
264 : 58228622 : && (fn == NULL_TREE
265 : 307 : || lookup_attribute ("no_sanitize_coverage",
266 : 307 : DECL_ATTRIBUTES (fn)) == NULL_TREE));
267 : : }
268 : :
269 : : #endif /* TREE_ASAN */
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