1 /* AddressSanitizer, a fast memory error detector.
2 Copyright (C) 2011-2020 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
37 extern gimple_stmt_iterator create_cond_insert_point
38 (gimple_stmt_iterator *, bool, bool, bool, basic_block *, basic_block *);
39
40 /* Alias set for accessing the shadow memory. */
41 extern alias_set_type asan_shadow_set;
42
43 /* Hash set of labels that are either used in a goto, or their address
44 has been taken. */
45 extern hash_set <tree> *asan_used_labels;
46
47 /* Shadow memory is found at
48 (address >> ASAN_SHADOW_SHIFT) + asan_shadow_offset (). */
49 #define ASAN_SHADOW_SHIFT 3
50 #define ASAN_SHADOW_GRANULARITY (1UL << ASAN_SHADOW_SHIFT)
51
52 /* Red zone size, stack and global variables are padded by ASAN_RED_ZONE_SIZE
53 up to 2 * ASAN_RED_ZONE_SIZE - 1 bytes. */
54 #define ASAN_RED_ZONE_SIZE 32
55
56 /* Stack variable use more compact red zones. The size includes also
57 size of variable itself. */
58
59 #define ASAN_MIN_RED_ZONE_SIZE 16
60
61 /* Shadow memory values for stack protection. Left is below protected vars,
62 the first pointer in stack corresponding to that offset contains
63 ASAN_STACK_FRAME_MAGIC word, the second pointer to a string describing
64 the frame. Middle is for padding in between variables, right is
65 above the last protected variable and partial immediately after variables
66 up to ASAN_RED_ZONE_SIZE alignment. */
67 #define ASAN_STACK_MAGIC_LEFT 0xf1
68 #define ASAN_STACK_MAGIC_MIDDLE 0xf2
69 #define ASAN_STACK_MAGIC_RIGHT 0xf3
70 #define ASAN_STACK_MAGIC_USE_AFTER_RET 0xf5
71 #define ASAN_STACK_MAGIC_USE_AFTER_SCOPE 0xf8
72
73 #define ASAN_STACK_FRAME_MAGIC 0x41b58ab3
74 #define ASAN_STACK_RETIRED_MAGIC 0x45e0360e
75
76 #define ASAN_USE_AFTER_SCOPE_ATTRIBUTE "use after scope memory"
77
78 /* Various flags for Asan builtins. */
79 enum asan_check_flags
80 {
81 ASAN_CHECK_STORE = 1 << 0,
82 ASAN_CHECK_SCALAR_ACCESS = 1 << 1,
83 ASAN_CHECK_NON_ZERO_LEN = 1 << 2,
84 ASAN_CHECK_LAST = 1 << 3
85 };
86
87 /* Flags for Asan check builtins. */
88 #define IFN_ASAN_MARK_FLAGS DEF(POISON), DEF(UNPOISON)
89
90 enum asan_mark_flags
91 {
92 #define DEF(X) ASAN_MARK_##X
93 IFN_ASAN_MARK_FLAGS
94 #undef DEF
95 };
96
97 /* Return true if STMT is ASAN_MARK with FLAG as first argument. */
98 extern bool asan_mark_p (gimple *stmt, enum asan_mark_flags flag);
99
100 /* Return the size of padding needed to insert after a protected
101 decl of SIZE. */
102
103 static inline unsigned int
asan_red_zone_size(unsigned int size)104 asan_red_zone_size (unsigned int size)
105 {
106 unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1);
107 return c ? 2 * ASAN_RED_ZONE_SIZE - c : ASAN_RED_ZONE_SIZE;
108 }
109
110 /* Return how much a stack variable occupis on a stack
111 including a space for red zone. */
112
113 static inline unsigned HOST_WIDE_INT
asan_var_and_redzone_size(unsigned HOST_WIDE_INT size)114 asan_var_and_redzone_size (unsigned HOST_WIDE_INT size)
115 {
116 if (size <= 4)
117 return 16;
118 else if (size <= 16)
119 return 32;
120 else if (size <= 128)
121 return size + 32;
122 else if (size <= 512)
123 return size + 64;
124 else if (size <= 4096)
125 return size + 128;
126 else
127 return size + 256;
128 }
129
130 extern bool set_asan_shadow_offset (const char *);
131
132 extern bool asan_shadow_offset_set_p ();
133
134 extern void set_sanitized_sections (const char *);
135
136 extern bool asan_sanitize_stack_p (void);
137
138 extern bool asan_sanitize_allocas_p (void);
139
140 extern hash_set<tree> *asan_handled_variables;
141
142 /* Return TRUE if builtin with given FCODE will be intercepted by
143 libasan. */
144
145 static inline bool
asan_intercepted_p(enum built_in_function fcode)146 asan_intercepted_p (enum built_in_function fcode)
147 {
148 return fcode == BUILT_IN_INDEX
149 || fcode == BUILT_IN_MEMCHR
150 || fcode == BUILT_IN_MEMCMP
151 || fcode == BUILT_IN_MEMCPY
152 || fcode == BUILT_IN_MEMMOVE
153 || fcode == BUILT_IN_MEMSET
154 || fcode == BUILT_IN_STRCASECMP
155 || fcode == BUILT_IN_STRCAT
156 || fcode == BUILT_IN_STRCHR
157 || fcode == BUILT_IN_STRCMP
158 || fcode == BUILT_IN_STRCPY
159 || fcode == BUILT_IN_STRDUP
160 || fcode == BUILT_IN_STRLEN
161 || fcode == BUILT_IN_STRNCASECMP
162 || fcode == BUILT_IN_STRNCAT
163 || fcode == BUILT_IN_STRNCMP
164 || fcode == BUILT_IN_STRCSPN
165 || fcode == BUILT_IN_STRPBRK
166 || fcode == BUILT_IN_STRSPN
167 || fcode == BUILT_IN_STRSTR
168 || fcode == BUILT_IN_STRNCPY;
169 }
170
171 /* Return TRUE if we should instrument for use-after-scope sanity checking. */
172
173 static inline bool
asan_sanitize_use_after_scope(void)174 asan_sanitize_use_after_scope (void)
175 {
176 return (flag_sanitize_address_use_after_scope && asan_sanitize_stack_p ());
177 }
178
179 /* Return true if DECL should be guarded on the stack. */
180
181 static inline bool
asan_protect_stack_decl(tree decl)182 asan_protect_stack_decl (tree decl)
183 {
184 return DECL_P (decl)
185 && (!DECL_ARTIFICIAL (decl)
186 || (asan_sanitize_use_after_scope () && TREE_ADDRESSABLE (decl)));
187 }
188
189 /* Return true when flag_sanitize & FLAG is non-zero. If FN is non-null,
190 remove all flags mentioned in "no_sanitize" of DECL_ATTRIBUTES. */
191
192 static inline bool
193 sanitize_flags_p (unsigned int flag, const_tree fn = current_function_decl)
194 {
195 unsigned int result_flags = flag_sanitize & flag;
196 if (result_flags == 0)
197 return false;
198
199 if (fn != NULL_TREE)
200 {
201 tree value = lookup_attribute ("no_sanitize", DECL_ATTRIBUTES (fn));
202 if (value)
203 result_flags &= ~tree_to_uhwi (TREE_VALUE (value));
204 }
205
206 return result_flags;
207 }
208
209 #endif /* TREE_ASAN */
210