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