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 
25 namespace __asan {
26 
27 Flags asan_flags_dont_use_directly;  // use via flags().
28 
29 static const char *MaybeUseAsanDefaultOptionsCompileDefinition() {
30 #ifdef ASAN_DEFAULT_OPTIONS
31   return SANITIZER_STRINGIFY(ASAN_DEFAULT_OPTIONS);
32 #else
33   return "";
34 #endif
35 }
36 
37 void Flags::SetDefaults() {
38 #define ASAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
39 #include "asan_flags.inc"
40 #undef ASAN_FLAG
41 }
42 
43 static 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 
50 void 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_MAC) {
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 
204 SANITIZER_INTERFACE_WEAK_DEF(const char*, __asan_default_options, void) {
205   return "";
206 }
207