compiler-rt/lib/asan/asan_flags.cpp

   1 //===-- asan_flags.cpp ------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of AddressSanitizer, an address sanity checker.
  10 //
  11 // ASan flag parsing logic.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "asan_flags.h"
  15
  16 #include "asan_activation.h"
  17 #include "asan_interface_internal.h"
  18 #include "asan_stack.h"
  19 #include "lsan/lsan_common.h"
  20 #include "sanitizer_common/sanitizer_common.h"
  21 #include "sanitizer_common/sanitizer_flag_parser.h"
  22 #include "sanitizer_common/sanitizer_flags.h"
  23 #include "sanitizer_common/sanitizer_win_interception.h"
  24 #include "ubsan/ubsan_flags.h"
  25 #include "ubsan/ubsan_platform.h"
  26
  27 namespace __asan {
  28
  29 Flags asan_flags_dont_use_directly;  // use via flags().
  30
  31 static const char *MaybeUseAsanDefaultOptionsCompileDefinition() {
  32 #ifdef ASAN_DEFAULT_OPTIONS
  33   return SANITIZER_STRINGIFY(ASAN_DEFAULT_OPTIONS);
  34 #else
  35   return "";
  36 #endif
  37 }
  38
  39 void Flags::SetDefaults() {
  40 #define ASAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
  41 #include "asan_flags.inc"
  42 #undef ASAN_FLAG
  43 }
  44
  45 static void RegisterAsanFlags(FlagParser *parser, Flags *f) {
  46 #define ASAN_FLAG(Type, Name, DefaultValue, Description) \
  47   RegisterFlag(parser, #Name, Description, &f->Name);
  48 #include "asan_flags.inc"
  49 #undef ASAN_FLAG
  50 }
  51
  52 static void DisplayHelpMessages(FlagParser *parser) {
  53   // TODO(eugenis): dump all flags at verbosity>=2?
  54   if (Verbosity()) {
  55     ReportUnrecognizedFlags();
  56   }
  57
  58   if (common_flags()->help) {
  59     parser->PrintFlagDescriptions();
  60   }
  61 }
  62
  63 static void InitializeDefaultFlags() {
  64   Flags *f = flags();
  65   FlagParser asan_parser;
  66
  67   // Set the default values and prepare for parsing ASan and common flags.
  68   SetCommonFlagsDefaults();
  69   {
  70     CommonFlags cf;
  71     cf.CopyFrom(*common_flags());
  72     cf.detect_leaks = cf.detect_leaks && CAN_SANITIZE_LEAKS;
  73     cf.external_symbolizer_path = GetEnv("ASAN_SYMBOLIZER_PATH");
  74     cf.malloc_context_size = kDefaultMallocContextSize;
  75     cf.intercept_tls_get_addr = true;
  76     cf.exitcode = 1;
  77     OverrideCommonFlags(cf);
  78   }
  79   f->SetDefaults();
  80
  81   RegisterAsanFlags(&asan_parser, f);
  82   RegisterCommonFlags(&asan_parser);
  83
  84   // Set the default values and prepare for parsing LSan and UBSan flags
  85   // (which can also overwrite common flags).
  86 #if CAN_SANITIZE_LEAKS
  87   __lsan::Flags *lf = __lsan::flags();
  88   lf->SetDefaults();
  89
  90   FlagParser lsan_parser;
  91   __lsan::RegisterLsanFlags(&lsan_parser, lf);
  92   RegisterCommonFlags(&lsan_parser);
  93 #endif
  94
  95 #if CAN_SANITIZE_UB
  96   __ubsan::Flags *uf = __ubsan::flags();
  97   uf->SetDefaults();
  98
  99   FlagParser ubsan_parser;
 100   __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
 101   RegisterCommonFlags(&ubsan_parser);
 102 #endif
 103
 104   if (SANITIZER_APPLE) {
 105     // Support macOS MallocScribble and MallocPreScribble:
 106     // <https://developer.apple.com/library/content/documentation/Performance/
 107     // Conceptual/ManagingMemory/Articles/MallocDebug.html>
 108     if (GetEnv("MallocScribble")) {
 109       f->max_free_fill_size = 0x1000;
 110     }
 111     if (GetEnv("MallocPreScribble")) {
 112       f->malloc_fill_byte = 0xaa;
 113     }
 114   }
 115
 116   // Override from ASan compile definition.
 117   const char *asan_compile_def = MaybeUseAsanDefaultOptionsCompileDefinition();
 118   asan_parser.ParseString(asan_compile_def);
 119
 120   // Override from user-specified string.
 121   const char *asan_default_options = __asan_default_options();
 122   asan_parser.ParseString(asan_default_options);
 123 #if CAN_SANITIZE_UB
 124   const char *ubsan_default_options = __ubsan_default_options();
 125   ubsan_parser.ParseString(ubsan_default_options);
 126 #endif
 127 #if CAN_SANITIZE_LEAKS
 128   const char *lsan_default_options = __lsan_default_options();
 129   lsan_parser.ParseString(lsan_default_options);
 130 #endif
 131
 132   // Override from command line.
 133   asan_parser.ParseStringFromEnv("ASAN_OPTIONS");
 134 #if CAN_SANITIZE_LEAKS
 135   lsan_parser.ParseStringFromEnv("LSAN_OPTIONS");
 136 #endif
 137 #if CAN_SANITIZE_UB
 138   ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
 139 #endif
 140
 141   InitializeCommonFlags();
 142
 143   // TODO(samsonov): print all of the flags (ASan, LSan, common).
 144   DisplayHelpMessages(&asan_parser);
 145 }
 146
 147 static void ProcessFlags() {
 148   Flags *f = flags();
 149
 150   // Flag validation:
 151   if (!CAN_SANITIZE_LEAKS && common_flags()->detect_leaks) {
 152     Report("%s: detect_leaks is not supported on this platform.\n",
 153            SanitizerToolName);
 154     Die();
 155   }
 156   // Ensure that redzone is at least ASAN_SHADOW_GRANULARITY.
 157   if (f->redzone < (int)ASAN_SHADOW_GRANULARITY)
 158     f->redzone = ASAN_SHADOW_GRANULARITY;
 159   // Make "strict_init_order" imply "check_initialization_order".
 160   // TODO(samsonov): Use a single runtime flag for an init-order checker.
 161   if (f->strict_init_order) {
 162     f->check_initialization_order = true;
 163   }
 164   CHECK_LE((uptr)common_flags()->malloc_context_size, kStackTraceMax);
 165   CHECK_LE(f->min_uar_stack_size_log, f->max_uar_stack_size_log);
 166   CHECK_GE(f->redzone, 16);
 167   CHECK_GE(f->max_redzone, f->redzone);
 168   CHECK_LE(f->max_redzone, 2048);
 169   CHECK(IsPowerOfTwo(f->redzone));
 170   CHECK(IsPowerOfTwo(f->max_redzone));
 171
 172   // quarantine_size is deprecated but we still honor it.
 173   // quarantine_size can not be used together with quarantine_size_mb.
 174   if (f->quarantine_size >= 0 && f->quarantine_size_mb >= 0) {
 175     Report("%s: please use either 'quarantine_size' (deprecated) or "
 176            "quarantine_size_mb, but not both\n", SanitizerToolName);
 177     Die();
 178   }
 179   if (f->quarantine_size >= 0)
 180     f->quarantine_size_mb = f->quarantine_size >> 20;
 181   if (f->quarantine_size_mb < 0) {
 182     const int kDefaultQuarantineSizeMb =
 183         (ASAN_LOW_MEMORY) ? 1UL << 4 : 1UL << 8;
 184     f->quarantine_size_mb = kDefaultQuarantineSizeMb;
 185   }
 186   if (f->thread_local_quarantine_size_kb < 0) {
 187     const u32 kDefaultThreadLocalQuarantineSizeKb =
 188         // It is not advised to go lower than 64Kb, otherwise quarantine batches
 189         // pushed from thread local quarantine to global one will create too
 190         // much overhead. One quarantine batch size is 8Kb and it  holds up to
 191         // 1021 chunk, which amounts to 1/8 memory overhead per batch when
 192         // thread local quarantine is set to 64Kb.
 193         (ASAN_LOW_MEMORY) ? 1 << 6 : FIRST_32_SECOND_64(1 << 8, 1 << 10);
 194     f->thread_local_quarantine_size_kb = kDefaultThreadLocalQuarantineSizeKb;
 195   }
 196   if (f->thread_local_quarantine_size_kb == 0 && f->quarantine_size_mb > 0) {
 197     Report("%s: thread_local_quarantine_size_kb can be set to 0 only when "
 198            "quarantine_size_mb is set to 0\n", SanitizerToolName);
 199     Die();
 200   }
 201   if (!f->replace_str && common_flags()->intercept_strlen) {
 202     Report("WARNING: strlen interceptor is enabled even though replace_str=0. "
 203            "Use intercept_strlen=0 to disable it.");
 204   }
 205   if (!f->replace_str && common_flags()->intercept_strchr) {
 206     Report("WARNING: strchr* interceptors are enabled even though "
 207            "replace_str=0. Use intercept_strchr=0 to disable them.");
 208   }
 209   if (!f->replace_str && common_flags()->intercept_strndup) {
 210     Report("WARNING: strndup* interceptors are enabled even though "
 211            "replace_str=0. Use intercept_strndup=0 to disable them.");
 212   }
 213 }
 214
 215 void InitializeFlags() {
 216   InitializeDefaultFlags();
 217   ProcessFlags();
 218
 219 #if SANITIZER_WINDOWS
 220   // On Windows, weak symbols are emulated by having the user program
 221   // register which weak functions are defined.
 222   // The ASAN DLL will initialize flags prior to user module initialization,
 223   // so __asan_default_options will not point to the user definition yet.
 224   // We still want to ensure we capture when options are passed via
 225   // __asan_default_options, so we add a callback to be run
 226   // when it is registered with the runtime.
 227
 228   // There is theoretically time between the initial ProcessFlags and
 229   // registering the weak callback where a weak function could be added and we
 230   // would miss it, but in practice, InitializeFlags will always happen under
 231   // the loader lock (if built as a DLL) and so will any calls to
 232   // __sanitizer_register_weak_function.
 233   AddRegisterWeakFunctionCallback(
 234       reinterpret_cast<uptr>(__asan_default_options), []() {
 235         FlagParser asan_parser;
 236
 237         RegisterAsanFlags(&asan_parser, flags());
 238         RegisterCommonFlags(&asan_parser);
 239         asan_parser.ParseString(__asan_default_options());
 240
 241         DisplayHelpMessages(&asan_parser);
 242         ProcessFlags();
 243       });
 244
 245 #  if CAN_SANITIZE_UB
 246   AddRegisterWeakFunctionCallback(
 247       reinterpret_cast<uptr>(__ubsan_default_options), []() {
 248         FlagParser ubsan_parser;
 249
 250         __ubsan::RegisterUbsanFlags(&ubsan_parser, __ubsan::flags());
 251         RegisterCommonFlags(&ubsan_parser);
 252         ubsan_parser.ParseString(__ubsan_default_options());
 253
 254         // To match normal behavior, do not print UBSan help.
 255         ProcessFlags();
 256       });
 257 #  endif
 258
 259 #  if CAN_SANITIZE_LEAKS
 260   AddRegisterWeakFunctionCallback(
 261       reinterpret_cast<uptr>(__lsan_default_options), []() {
 262         FlagParser lsan_parser;
 263
 264         __lsan::RegisterLsanFlags(&lsan_parser, __lsan::flags());
 265         RegisterCommonFlags(&lsan_parser);
 266         lsan_parser.ParseString(__lsan_default_options());
 267
 268         // To match normal behavior, do not print LSan help.
 269         ProcessFlags();
 270       });
 271 #  endif
 272
 273 #endif
 274 }
 275
 276 }  // namespace __asan
 277
 278 SANITIZER_INTERFACE_WEAK_DEF(const char*, __asan_default_options, void) {
 279   return "";
 280 }