gcc/asan.h

   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 */