gcc/asan.h

   1 /* AddressSanitizer, a fast memory error detector.
   2    Copyright (C) 2011-2017 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);
  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 /* Shadow memory values for stack protection.  Left is below protected vars,
  57    the first pointer in stack corresponding to that offset contains
  58    ASAN_STACK_FRAME_MAGIC word, the second pointer to a string describing
  59    the frame.  Middle is for padding in between variables, right is
  60    above the last protected variable and partial immediately after variables
  61    up to ASAN_RED_ZONE_SIZE alignment.  */
  62 #define ASAN_STACK_MAGIC_LEFT             0xf1
  63 #define ASAN_STACK_MAGIC_MIDDLE           0xf2
  64 #define ASAN_STACK_MAGIC_RIGHT            0xf3
  65 #define ASAN_STACK_MAGIC_USE_AFTER_RET    0xf5
  66 #define ASAN_STACK_MAGIC_USE_AFTER_SCOPE  0xf8
  67
  68 #define ASAN_STACK_FRAME_MAGIC          0x41b58ab3
  69 #define ASAN_STACK_RETIRED_MAGIC        0x45e0360e
  70
  71 #define ASAN_USE_AFTER_SCOPE_ATTRIBUTE  "use after scope memory"
  72
  73 /* Various flags for Asan builtins.  */
  74 enum asan_check_flags
  75 {
  76   ASAN_CHECK_STORE = 1 << 0,
  77   ASAN_CHECK_SCALAR_ACCESS = 1 << 1,
  78   ASAN_CHECK_NON_ZERO_LEN = 1 << 2,
  79   ASAN_CHECK_LAST = 1 << 3
  80 };
  81
  82 /* Flags for Asan check builtins.  */
  83 #define IFN_ASAN_MARK_FLAGS DEF(POISON), DEF(UNPOISON)
  84
  85 enum asan_mark_flags
  86 {
  87 #define DEF(X) ASAN_MARK_##X
  88   IFN_ASAN_MARK_FLAGS
  89 #undef DEF
  90 };
  91
  92 /* Return true if STMT is ASAN_MARK with FLAG as first argument.  */
  93 extern bool asan_mark_p (gimple *stmt, enum asan_mark_flags flag);
  94
  95 /* Return the size of padding needed to insert after a protected
  96    decl of SIZE.  */
  97
  98 static inline unsigned int
  99 asan_red_zone_size (unsigned int size)
 100 {
 101   unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1);
 102   return c ? 2 * ASAN_RED_ZONE_SIZE - c : ASAN_RED_ZONE_SIZE;
 103 }
 104
 105 extern bool set_asan_shadow_offset (const char *);
 106
 107 extern void set_sanitized_sections (const char *);
 108
 109 extern bool asan_sanitize_stack_p (void);
 110
 111 extern bool asan_sanitize_allocas_p (void);
 112
 113 /* Return TRUE if builtin with given FCODE will be intercepted by
 114    libasan.  */
 115
 116 static inline bool
 117 asan_intercepted_p (enum built_in_function fcode)
 118 {
 119   return fcode == BUILT_IN_INDEX
 120          || fcode == BUILT_IN_MEMCHR
 121          || fcode == BUILT_IN_MEMCMP
 122          || fcode == BUILT_IN_MEMCPY
 123          || fcode == BUILT_IN_MEMMOVE
 124          || fcode == BUILT_IN_MEMSET
 125          || fcode == BUILT_IN_STRCASECMP
 126          || fcode == BUILT_IN_STRCAT
 127          || fcode == BUILT_IN_STRCHR
 128          || fcode == BUILT_IN_STRCMP
 129          || fcode == BUILT_IN_STRCPY
 130          || fcode == BUILT_IN_STRDUP
 131          || fcode == BUILT_IN_STRLEN
 132          || fcode == BUILT_IN_STRNCASECMP
 133          || fcode == BUILT_IN_STRNCAT
 134          || fcode == BUILT_IN_STRNCMP
 135          || fcode == BUILT_IN_STRCSPN
 136          || fcode == BUILT_IN_STRPBRK
 137          || fcode == BUILT_IN_STRSPN
 138          || fcode == BUILT_IN_STRSTR
 139          || fcode == BUILT_IN_STRNCPY;
 140 }
 141
 142 /* Return TRUE if we should instrument for use-after-scope sanity checking.  */
 143
 144 static inline bool
 145 asan_sanitize_use_after_scope (void)
 146 {
 147   return (flag_sanitize_address_use_after_scope && asan_sanitize_stack_p ());
 148 }
 149
 150 /* Return true if DECL should be guarded on the stack.  */
 151
 152 static inline bool
 153 asan_protect_stack_decl (tree decl)
 154 {
 155   return DECL_P (decl)
 156     && (!DECL_ARTIFICIAL (decl)
 157         || (asan_sanitize_use_after_scope () && TREE_ADDRESSABLE (decl)));
 158 }
 159
 160 /* Return true when flag_sanitize & FLAG is non-zero.  If FN is non-null,
 161    remove all flags mentioned in "no_sanitize" of DECL_ATTRIBUTES.  */
 162
 163 static inline bool
 164 sanitize_flags_p (unsigned int flag, const_tree fn = current_function_decl)
 165 {
 166   unsigned int result_flags = flag_sanitize & flag;
 167   if (result_flags == 0)
 168     return false;
 169
 170   if (fn != NULL_TREE)
 171     {
 172       tree value = lookup_attribute ("no_sanitize", DECL_ATTRIBUTES (fn));
 173       if (value)
 174         result_flags &= ~tree_to_uhwi (TREE_VALUE (value));
 175     }
 176
 177   return result_flags;
 178 }
 179
 180 #endif /* TREE_ASAN */