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 bool asan_protect_global (tree);
  29 extern void initialize_sanitizer_builtins (void);
  30 extern tree asan_dynamic_init_call (bool);
  31 extern bool asan_expand_check_ifn (gimple_stmt_iterator *, bool);
  32 extern bool asan_expand_mark_ifn (gimple_stmt_iterator *);
  33 extern bool asan_expand_poison_ifn (gimple_stmt_iterator *, bool *,
  34                                     hash_map<tree, tree> &);
  35
  36 extern gimple_stmt_iterator create_cond_insert_point
  37      (gimple_stmt_iterator *, bool, bool, bool, basic_block *, basic_block *);
  38
  39 /* Alias set for accessing the shadow memory.  */
  40 extern alias_set_type asan_shadow_set;
  41
  42 /* Hash set of labels that are either used in a goto, or their address
  43    has been taken.  */
  44 extern hash_set <tree> *asan_used_labels;
  45
  46 /* Shadow memory is found at
  47    (address >> ASAN_SHADOW_SHIFT) + asan_shadow_offset ().  */
  48 #define ASAN_SHADOW_SHIFT       3
  49 #define ASAN_SHADOW_GRANULARITY (1UL << ASAN_SHADOW_SHIFT)
  50
  51 /* Red zone size, stack and global variables are padded by ASAN_RED_ZONE_SIZE
  52    up to 2 * ASAN_RED_ZONE_SIZE - 1 bytes.  */
  53 #define ASAN_RED_ZONE_SIZE      32
  54
  55 /* Shadow memory values for stack protection.  Left is below protected vars,
  56    the first pointer in stack corresponding to that offset contains
  57    ASAN_STACK_FRAME_MAGIC word, the second pointer to a string describing
  58    the frame.  Middle is for padding in between variables, right is
  59    above the last protected variable and partial immediately after variables
  60    up to ASAN_RED_ZONE_SIZE alignment.  */
  61 #define ASAN_STACK_MAGIC_LEFT             0xf1
  62 #define ASAN_STACK_MAGIC_MIDDLE           0xf2
  63 #define ASAN_STACK_MAGIC_RIGHT            0xf3
  64 #define ASAN_STACK_MAGIC_USE_AFTER_RET    0xf5
  65 #define ASAN_STACK_MAGIC_USE_AFTER_SCOPE  0xf8
  66
  67 #define ASAN_STACK_FRAME_MAGIC          0x41b58ab3
  68 #define ASAN_STACK_RETIRED_MAGIC        0x45e0360e
  69
  70 #define ASAN_USE_AFTER_SCOPE_ATTRIBUTE  "use after scope memory"
  71
  72 /* Various flags for Asan builtins.  */
  73 enum asan_check_flags
  74 {
  75   ASAN_CHECK_STORE = 1 << 0,
  76   ASAN_CHECK_SCALAR_ACCESS = 1 << 1,
  77   ASAN_CHECK_NON_ZERO_LEN = 1 << 2,
  78   ASAN_CHECK_LAST = 1 << 3
  79 };
  80
  81 /* Flags for Asan check builtins.  */
  82 #define IFN_ASAN_MARK_FLAGS DEF(POISON), DEF(UNPOISON)
  83
  84 enum asan_mark_flags
  85 {
  86 #define DEF(X) ASAN_MARK_##X
  87   IFN_ASAN_MARK_FLAGS
  88 #undef DEF
  89 };
  90
  91 /* Return true if STMT is ASAN_MARK with FLAG as first argument.  */
  92 extern bool asan_mark_p (gimple *stmt, enum asan_mark_flags flag);
  93
  94 /* Return the size of padding needed to insert after a protected
  95    decl of SIZE.  */
  96
  97 static inline unsigned int
  98 asan_red_zone_size (unsigned int size)
  99 {
 100   unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1);
 101   return c ? 2 * ASAN_RED_ZONE_SIZE - c : ASAN_RED_ZONE_SIZE;
 102 }
 103
 104 extern bool set_asan_shadow_offset (const char *);
 105
 106 extern void set_sanitized_sections (const char *);
 107
 108 extern bool asan_sanitize_stack_p (void);
 109
 110 /* Return TRUE if builtin with given FCODE will be intercepted by
 111    libasan.  */
 112
 113 static inline bool
 114 asan_intercepted_p (enum built_in_function fcode)
 115 {
 116   return fcode == BUILT_IN_INDEX
 117          || fcode == BUILT_IN_MEMCHR
 118          || fcode == BUILT_IN_MEMCMP
 119          || fcode == BUILT_IN_MEMCPY
 120          || fcode == BUILT_IN_MEMMOVE
 121          || fcode == BUILT_IN_MEMSET
 122          || fcode == BUILT_IN_STRCASECMP
 123          || fcode == BUILT_IN_STRCAT
 124          || fcode == BUILT_IN_STRCHR
 125          || fcode == BUILT_IN_STRCMP
 126          || fcode == BUILT_IN_STRCPY
 127          || fcode == BUILT_IN_STRDUP
 128          || fcode == BUILT_IN_STRLEN
 129          || fcode == BUILT_IN_STRNCASECMP
 130          || fcode == BUILT_IN_STRNCAT
 131          || fcode == BUILT_IN_STRNCMP
 132          || fcode == BUILT_IN_STRCSPN
 133          || fcode == BUILT_IN_STRPBRK
 134          || fcode == BUILT_IN_STRSPN
 135          || fcode == BUILT_IN_STRSTR
 136          || fcode == BUILT_IN_STRNCPY;
 137 }
 138
 139 /* Return TRUE if we should instrument for use-after-scope sanity checking.  */
 140
 141 static inline bool
 142 asan_sanitize_use_after_scope (void)
 143 {
 144   return (flag_sanitize_address_use_after_scope && asan_sanitize_stack_p ());
 145 }
 146
 147 /* Return true if DECL should be guarded on the stack.  */
 148
 149 static inline bool
 150 asan_protect_stack_decl (tree decl)
 151 {
 152   return DECL_P (decl)
 153     && (!DECL_ARTIFICIAL (decl)
 154         || (asan_sanitize_use_after_scope () && TREE_ADDRESSABLE (decl)));
 155 }
 156
 157 /* Return true when flag_sanitize & FLAG is non-zero.  If FN is non-null,
 158    remove all flags mentioned in "no_sanitize" of DECL_ATTRIBUTES.  */
 159
 160 static inline bool
 161 sanitize_flags_p (unsigned int flag, const_tree fn = current_function_decl)
 162 {
 163   unsigned int result_flags = flag_sanitize & flag;
 164   if (result_flags == 0)
 165     return false;
 166
 167   if (fn != NULL_TREE)
 168     {
 169       tree value = lookup_attribute ("no_sanitize", DECL_ATTRIBUTES (fn));
 170       if (value)
 171         result_flags &= ~tree_to_uhwi (TREE_VALUE (value));
 172     }
 173
 174   return result_flags;
 175 }
 176
 177 #endif /* TREE_ASAN */