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