1 /* AddressSanitizer, a fast memory error detector.
2 Copyright (C) 2011-2021 Free Software Foundation, Inc.
3 Contributed by Kostya Serebryany <kcc@google.com>
5 This file is part of GCC.
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
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
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/>. */
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
> &);
37 extern void hwasan_record_frame_init ();
38 extern void hwasan_record_stack_var (rtx
, rtx
, poly_int64
, poly_int64
);
39 extern void hwasan_emit_prologue ();
40 extern rtx_insn
*hwasan_emit_untag_frame (rtx
, rtx
);
41 extern rtx
hwasan_get_frame_extent ();
42 extern rtx
hwasan_frame_base ();
43 extern void hwasan_maybe_emit_frame_base_init (void);
44 extern bool stack_vars_base_reg_p (rtx
);
45 extern uint8_t hwasan_current_frame_tag ();
46 extern void hwasan_increment_frame_tag ();
47 extern rtx
hwasan_truncate_to_tag_size (rtx
, rtx
);
48 extern void hwasan_finish_file (void);
49 extern bool hwasan_sanitize_p (void);
50 extern bool hwasan_sanitize_stack_p (void);
51 extern bool hwasan_sanitize_allocas_p (void);
52 extern bool hwasan_expand_check_ifn (gimple_stmt_iterator
*, bool);
53 extern bool hwasan_expand_mark_ifn (gimple_stmt_iterator
*);
54 extern bool gate_hwasan (void);
56 extern gimple_stmt_iterator create_cond_insert_point
57 (gimple_stmt_iterator
*, bool, bool, bool, basic_block
*, basic_block
*);
59 /* Alias set for accessing the shadow memory. */
60 extern alias_set_type asan_shadow_set
;
62 /* Hash set of labels that are either used in a goto, or their address
64 extern hash_set
<tree
> *asan_used_labels
;
66 /* Shadow memory is found at
67 (address >> ASAN_SHADOW_SHIFT) + asan_shadow_offset (). */
68 #define ASAN_SHADOW_SHIFT 3
69 #define ASAN_SHADOW_GRANULARITY (1UL << ASAN_SHADOW_SHIFT)
71 /* Red zone size, stack and global variables are padded by ASAN_RED_ZONE_SIZE
72 up to 2 * ASAN_RED_ZONE_SIZE - 1 bytes. */
73 #define ASAN_RED_ZONE_SIZE 32
75 /* Stack variable use more compact red zones. The size includes also
76 size of variable itself. */
78 #define ASAN_MIN_RED_ZONE_SIZE 16
80 /* Shadow memory values for stack protection. Left is below protected vars,
81 the first pointer in stack corresponding to that offset contains
82 ASAN_STACK_FRAME_MAGIC word, the second pointer to a string describing
83 the frame. Middle is for padding in between variables, right is
84 above the last protected variable and partial immediately after variables
85 up to ASAN_RED_ZONE_SIZE alignment. */
86 #define ASAN_STACK_MAGIC_LEFT 0xf1
87 #define ASAN_STACK_MAGIC_MIDDLE 0xf2
88 #define ASAN_STACK_MAGIC_RIGHT 0xf3
89 #define ASAN_STACK_MAGIC_USE_AFTER_RET 0xf5
90 #define ASAN_STACK_MAGIC_USE_AFTER_SCOPE 0xf8
92 #define ASAN_STACK_FRAME_MAGIC 0x41b58ab3
93 #define ASAN_STACK_RETIRED_MAGIC 0x45e0360e
95 #define ASAN_USE_AFTER_SCOPE_ATTRIBUTE "use after scope memory"
97 /* NOTE: The values below and the hooks under targetm.memtag define an ABI and
98 are hard-coded to these values in libhwasan, hence they can't be changed
99 independently here. */
100 /* How many bits are used to store a tag in a pointer.
101 The default version uses the entire top byte of a pointer (i.e. 8 bits). */
102 #define HWASAN_TAG_SIZE targetm.memtag.tag_size ()
103 /* Tag Granule of HWASAN shadow stack.
104 This is the size in real memory that each byte in the shadow memory refers
105 to. I.e. if a variable is X bytes long in memory then its tag in shadow
106 memory will span X / HWASAN_TAG_GRANULE_SIZE bytes.
107 Most variables will need to be aligned to this amount since two variables
108 that are neighbors in memory and share a tag granule would need to share the
109 same tag (the shared tag granule can only store one tag). */
110 #define HWASAN_TAG_GRANULE_SIZE targetm.memtag.granule_size ()
111 /* Define the tag for the stack background.
112 This defines what tag the stack pointer will be and hence what tag all
113 variables that are not given special tags are (e.g. spilled registers,
114 and parameters passed on the stack). */
115 #define HWASAN_STACK_BACKGROUND gen_int_mode (0, QImode)
117 /* Various flags for Asan builtins. */
118 enum asan_check_flags
120 ASAN_CHECK_STORE
= 1 << 0,
121 ASAN_CHECK_SCALAR_ACCESS
= 1 << 1,
122 ASAN_CHECK_NON_ZERO_LEN
= 1 << 2,
123 ASAN_CHECK_LAST
= 1 << 3
126 /* Flags for Asan check builtins. */
127 #define IFN_ASAN_MARK_FLAGS DEF(POISON), DEF(UNPOISON)
131 #define DEF(X) ASAN_MARK_##X
136 /* Return true if STMT is ASAN_MARK with FLAG as first argument. */
137 extern bool asan_mark_p (gimple
*stmt
, enum asan_mark_flags flag
);
139 /* Return the size of padding needed to insert after a protected
142 static inline unsigned int
143 asan_red_zone_size (unsigned int size
)
145 unsigned int c
= size
& (ASAN_RED_ZONE_SIZE
- 1);
146 return c
? 2 * ASAN_RED_ZONE_SIZE
- c
: ASAN_RED_ZONE_SIZE
;
149 /* Return how much a stack variable occupis on a stack
150 including a space for red zone. */
152 static inline unsigned HOST_WIDE_INT
153 asan_var_and_redzone_size (unsigned HOST_WIDE_INT size
)
159 else if (size
<= 128)
161 else if (size
<= 512)
163 else if (size
<= 4096)
169 extern bool set_asan_shadow_offset (const char *);
171 extern bool asan_shadow_offset_set_p ();
173 extern void set_sanitized_sections (const char *);
175 extern bool asan_sanitize_stack_p (void);
177 extern bool asan_sanitize_allocas_p (void);
179 extern hash_set
<tree
> *asan_handled_variables
;
181 /* Return TRUE if builtin with given FCODE will be intercepted by
185 asan_intercepted_p (enum built_in_function fcode
)
187 if (hwasan_sanitize_p ())
190 return fcode
== BUILT_IN_INDEX
191 || fcode
== BUILT_IN_MEMCHR
192 || fcode
== BUILT_IN_MEMCMP
193 || fcode
== BUILT_IN_MEMCPY
194 || fcode
== BUILT_IN_MEMMOVE
195 || fcode
== BUILT_IN_MEMSET
196 || fcode
== BUILT_IN_STRCASECMP
197 || fcode
== BUILT_IN_STRCAT
198 || fcode
== BUILT_IN_STRCHR
199 || fcode
== BUILT_IN_STRCMP
200 || fcode
== BUILT_IN_STRCPY
201 || fcode
== BUILT_IN_STRDUP
202 || fcode
== BUILT_IN_STRLEN
203 || fcode
== BUILT_IN_STRNCASECMP
204 || fcode
== BUILT_IN_STRNCAT
205 || fcode
== BUILT_IN_STRNCMP
206 || fcode
== BUILT_IN_STRCSPN
207 || fcode
== BUILT_IN_STRPBRK
208 || fcode
== BUILT_IN_STRSPN
209 || fcode
== BUILT_IN_STRSTR
210 || fcode
== BUILT_IN_STRNCPY
;
213 /* Return TRUE if we should instrument for use-after-scope sanity checking. */
216 asan_sanitize_use_after_scope (void)
218 return (flag_sanitize_address_use_after_scope
219 && (asan_sanitize_stack_p () || hwasan_sanitize_stack_p ()));
222 /* Return true if DECL should be guarded on the stack. */
225 asan_protect_stack_decl (tree decl
)
228 && (!DECL_ARTIFICIAL (decl
)
229 || (asan_sanitize_use_after_scope () && TREE_ADDRESSABLE (decl
)));
232 /* Return true when flag_sanitize & FLAG is non-zero. If FN is non-null,
233 remove all flags mentioned in "no_sanitize" of DECL_ATTRIBUTES. */
236 sanitize_flags_p (unsigned int flag
, const_tree fn
= current_function_decl
)
238 unsigned int result_flags
= flag_sanitize
& flag
;
239 if (result_flags
== 0)
244 tree value
= lookup_attribute ("no_sanitize", DECL_ATTRIBUTES (fn
));
246 result_flags
&= ~tree_to_uhwi (TREE_VALUE (value
));
252 /* Return true when coverage sanitization should happend for FN function. */
255 sanitize_coverage_p (const_tree fn
= current_function_decl
)
257 return (flag_sanitize_coverage
258 && lookup_attribute ("no_sanitize_coverage",
259 DECL_ATTRIBUTES (fn
)) == NULL_TREE
);
262 #endif /* TREE_ASAN */