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_activation.h"
15#include "asan_flags.h"
16#include "asan_interface_internal.h"
17#include "asan_stack.h"
18#include "lsan/lsan_common.h"
19#include "sanitizer_common/sanitizer_common.h"
20#include "sanitizer_common/sanitizer_flags.h"
21#include "sanitizer_common/sanitizer_flag_parser.h"
22#include "ubsan/ubsan_flags.h"
23#include "ubsan/ubsan_platform.h"
24
25namespace __asan {
26
27Flags asan_flags_dont_use_directly;  // use via flags().
28
29static const char *MaybeCallAsanDefaultOptions() {
30  return (&__asan_default_options) ? __asan_default_options() : "";
31}
32
33static const char *MaybeUseAsanDefaultOptionsCompileDefinition() {
34#ifdef ASAN_DEFAULT_OPTIONS
35  return SANITIZER_STRINGIFY(ASAN_DEFAULT_OPTIONS);
36#else
37  return "";
38#endif
39}
40
41void Flags::SetDefaults() {
42#define ASAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
43#include "asan_flags.inc"
44#undef ASAN_FLAG
45}
46
47static void RegisterAsanFlags(FlagParser *parser, Flags *f) {
48#define ASAN_FLAG(Type, Name, DefaultValue, Description) \
49  RegisterFlag(parser, #Name, Description, &f->Name);
50#include "asan_flags.inc"
51#undef ASAN_FLAG
52}
53
54void InitializeFlags() {
55  // Set the default values and prepare for parsing ASan and common flags.
56  SetCommonFlagsDefaults();
57  {
58    CommonFlags cf;
59    cf.CopyFrom(*common_flags());
60    cf.detect_leaks = cf.detect_leaks && CAN_SANITIZE_LEAKS;
61    cf.external_symbolizer_path = GetEnv("ASAN_SYMBOLIZER_PATH");
62    cf.malloc_context_size = kDefaultMallocContextSize;
63    cf.intercept_tls_get_addr = true;
64    cf.exitcode = 1;
65    OverrideCommonFlags(cf);
66  }
67  Flags *f = flags();
68  f->SetDefaults();
69
70  FlagParser asan_parser;
71  RegisterAsanFlags(&asan_parser, f);
72  RegisterCommonFlags(&asan_parser);
73
74  // Set the default values and prepare for parsing LSan and UBSan flags
75  // (which can also overwrite common flags).
76#if CAN_SANITIZE_LEAKS
77  __lsan::Flags *lf = __lsan::flags();
78  lf->SetDefaults();
79
80  FlagParser lsan_parser;
81  __lsan::RegisterLsanFlags(&lsan_parser, lf);
82  RegisterCommonFlags(&lsan_parser);
83#endif
84
85#if CAN_SANITIZE_UB
86  __ubsan::Flags *uf = __ubsan::flags();
87  uf->SetDefaults();
88
89  FlagParser ubsan_parser;
90  __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
91  RegisterCommonFlags(&ubsan_parser);
92#endif
93
94  if (SANITIZER_MAC) {
95    // Support macOS MallocScribble and MallocPreScribble:
96    // <https://developer.apple.com/library/content/documentation/Performance/
97    // Conceptual/ManagingMemory/Articles/MallocDebug.html>
98    if (GetEnv("MallocScribble")) {
99      f->max_free_fill_size = 0x1000;
100    }
101    if (GetEnv("MallocPreScribble")) {
102      f->malloc_fill_byte = 0xaa;
103    }
104  }
105
106  // Override from ASan compile definition.
107  const char *asan_compile_def = MaybeUseAsanDefaultOptionsCompileDefinition();
108  asan_parser.ParseString(asan_compile_def);
109
110  // Override from user-specified string.
111  const char *asan_default_options = MaybeCallAsanDefaultOptions();
112  asan_parser.ParseString(asan_default_options);
113#if CAN_SANITIZE_UB
114  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
115  ubsan_parser.ParseString(ubsan_default_options);
116#endif
117#if CAN_SANITIZE_LEAKS
118  const char *lsan_default_options = __lsan::MaybeCallLsanDefaultOptions();
119  lsan_parser.ParseString(lsan_default_options);
120#endif
121
122  // Override from command line.
123  asan_parser.ParseStringFromEnv("ASAN_OPTIONS");
124#if CAN_SANITIZE_LEAKS
125  lsan_parser.ParseStringFromEnv("LSAN_OPTIONS");
126#endif
127#if CAN_SANITIZE_UB
128  ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
129#endif
130
131  InitializeCommonFlags();
132
133  // TODO(eugenis): dump all flags at verbosity>=2?
134  if (Verbosity()) ReportUnrecognizedFlags();
135
136  if (common_flags()->help) {
137    // TODO(samsonov): print all of the flags (ASan, LSan, common).
138    asan_parser.PrintFlagDescriptions();
139  }
140
141  // Flag validation:
142  if (!CAN_SANITIZE_LEAKS && common_flags()->detect_leaks) {
143    Report("%s: detect_leaks is not supported on this platform.\n",
144           SanitizerToolName);
145    Die();
146  }
147  // Ensure that redzone is at least SHADOW_GRANULARITY.
148  if (f->redzone < (int)SHADOW_GRANULARITY)
149    f->redzone = SHADOW_GRANULARITY;
150  // Make "strict_init_order" imply "check_initialization_order".
151  // TODO(samsonov): Use a single runtime flag for an init-order checker.
152  if (f->strict_init_order) {
153    f->check_initialization_order = true;
154  }
155  CHECK_LE((uptr)common_flags()->malloc_context_size, kStackTraceMax);
156  CHECK_LE(f->min_uar_stack_size_log, f->max_uar_stack_size_log);
157  CHECK_GE(f->redzone, 16);
158  CHECK_GE(f->max_redzone, f->redzone);
159  CHECK_LE(f->max_redzone, 2048);
160  CHECK(IsPowerOfTwo(f->redzone));
161  CHECK(IsPowerOfTwo(f->max_redzone));
162  if (SANITIZER_RTEMS) {
163    CHECK(!f->unmap_shadow_on_exit);
164    CHECK(!f->protect_shadow_gap);
165  }
166
167  // quarantine_size is deprecated but we still honor it.
168  // quarantine_size can not be used together with quarantine_size_mb.
169  if (f->quarantine_size >= 0 && f->quarantine_size_mb >= 0) {
170    Report("%s: please use either 'quarantine_size' (deprecated) or "
171           "quarantine_size_mb, but not both\n", SanitizerToolName);
172    Die();
173  }
174  if (f->quarantine_size >= 0)
175    f->quarantine_size_mb = f->quarantine_size >> 20;
176  if (f->quarantine_size_mb < 0) {
177    const int kDefaultQuarantineSizeMb =
178        (ASAN_LOW_MEMORY) ? 1UL << 4 : 1UL << 8;
179    f->quarantine_size_mb = kDefaultQuarantineSizeMb;
180  }
181  if (f->thread_local_quarantine_size_kb < 0) {
182    const u32 kDefaultThreadLocalQuarantineSizeKb =
183        // It is not advised to go lower than 64Kb, otherwise quarantine batches
184        // pushed from thread local quarantine to global one will create too
185        // much overhead. One quarantine batch size is 8Kb and it  holds up to
186        // 1021 chunk, which amounts to 1/8 memory overhead per batch when
187        // thread local quarantine is set to 64Kb.
188        (ASAN_LOW_MEMORY) ? 1 << 6 : FIRST_32_SECOND_64(1 << 8, 1 << 10);
189    f->thread_local_quarantine_size_kb = kDefaultThreadLocalQuarantineSizeKb;
190  }
191  if (f->thread_local_quarantine_size_kb == 0 && f->quarantine_size_mb > 0) {
192    Report("%s: thread_local_quarantine_size_kb can be set to 0 only when "
193           "quarantine_size_mb is set to 0\n", SanitizerToolName);
194    Die();
195  }
196  if (!f->replace_str && common_flags()->intercept_strlen) {
197    Report("WARNING: strlen interceptor is enabled even though replace_str=0. "
198           "Use intercept_strlen=0 to disable it.");
199  }
200  if (!f->replace_str && common_flags()->intercept_strchr) {
201    Report("WARNING: strchr* interceptors are enabled even though "
202           "replace_str=0. Use intercept_strchr=0 to disable them.");
203  }
204  if (!f->replace_str && common_flags()->intercept_strndup) {
205    Report("WARNING: strndup* interceptors are enabled even though "
206           "replace_str=0. Use intercept_strndup=0 to disable them.");
207  }
208}
209
210}  // namespace __asan
211
212SANITIZER_INTERFACE_WEAK_DEF(const char*, __asan_default_options, void) {
213  return "";
214}
215