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1# Copyright 2015 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import("//build/config/coverage/coverage.gni")
6import("//build/toolchain/toolchain.gni")
7
8declare_args() {
9  # Compile for Address Sanitizer to find memory bugs.
10  is_asan = false
11
12  # Customize asan detection.
13  asan_detector = false
14
15  # Compile for Leak Sanitizer to find leaks.
16  is_lsan = false
17
18  # Compile for Memory Sanitizer to find uninitialized reads.
19  is_msan = false
20
21  # Compile for Thread Sanitizer to find threading bugs.
22  is_tsan = false
23
24  # Compile for Undefined Behavior Sanitizer to find various types of
25  # undefined behavior (excludes vptr checks).
26  is_ubsan = false
27
28  # Halt the program if a problem is detected.
29  is_ubsan_no_recover = false
30
31  # Compile for Undefined Behavior Sanitizer's null pointer checks.
32  is_ubsan_null = false
33
34  # Compile for Undefined Behavior Sanitizer's vptr checks.
35  is_ubsan_vptr = false
36
37  # Compile with SafeStack shadow stack support.
38  is_safestack = false
39
40  # Track where uninitialized memory originates from. From fastest to slowest:
41  # 0 - no tracking, 1 - track only the initial allocation site, 2 - track the
42  # chain of stores leading from allocation site to use site.
43  msan_track_origins = 2
44
45  # Use dynamic libraries instrumented by one of the sanitizers instead of the
46  # standard system libraries. Set this flag to download prebuilt binaries from
47  # GCS.
48  use_prebuilt_instrumented_libraries = false
49
50  # Use dynamic libraries instrumented by one of the sanitizers instead of the
51  # standard system libraries. Set this flag to build the libraries from source.
52  use_locally_built_instrumented_libraries = false
53
54  # Compile with Control Flow Integrity to protect virtual calls and casts.
55  # See http://clang.llvm.org/docs/ControlFlowIntegrity.html
56  is_cfi = target_os == "linux" && !is_chromeos && target_cpu == "x64" &&
57           is_official_build
58
59  # Enable checks for bad casts: derived cast and unrelated cast.
60  use_cfi_cast = false
61
62  # Enable checks for indirect function calls via a function pointer.
63  use_cfi_icall = target_os == "linux" && !is_chromeos && target_cpu == "x64" &&
64                  is_official_build
65
66  # Print detailed diagnostics when Control Flow Integrity detects a violation.
67  use_cfi_diag = false
68
69  # Let Control Flow Integrity continue execution instead of crashing when
70  # printing diagnostics (use_cfi_diag = true).
71  use_cfi_recover = false
72
73  # Compile for fuzzing with LLVM LibFuzzer.
74  # See http://www.chromium.org/developers/testing/libfuzzer
75  use_libfuzzer = false
76
77  # Compile for fuzzing with AFL.
78  use_afl = false
79
80  # Enables core ubsan security features. Will later be removed once it matches
81  # is_ubsan.
82  is_ubsan_security = false
83
84  # Compile for fuzzing with Dr. Fuzz
85  # See http://www.chromium.org/developers/testing/dr-fuzz
86  use_drfuzz = false
87
88  # Helper variable for testing builds with disabled libfuzzer.
89  # Not for client use.
90  disable_libfuzzer = false
91
92  # Optimize for coverage guided fuzzing (balance between speed and number of
93  # branches). Can be also used to remove non-determinism and other issues.
94  optimize_for_fuzzing = false
95
96  # Value for -fsanitize-coverage flag. Setting this causes
97  # use_sanitizer_coverage to be enabled.
98  # This flag is not used for libFuzzer (use_libfuzzer=true) unless we are on
99  # Mac. Instead, we use:
100  #     -fsanitize=fuzzer-no-link
101  # Default value when unset and use_fuzzing_engine=true:
102  #     trace-pc-guard
103  # Default value when unset and use_sanitizer_coverage=true:
104  #     trace-pc-guard,indirect-calls
105  sanitizer_coverage_flags = ""
106}
107
108is_v8_host_toolchain =
109    current_toolchain == "//build/toolchain/linux:clang_x64_v8_arm64" ||
110    current_toolchain == "//build/toolchain/linux:clang_x86_v8_arm"
111
112# Disable sanitizers for non-default toolchains.
113if (current_toolchain == host_toolchain || is_v8_host_toolchain) {
114  is_asan = false
115  is_cfi = false
116  is_lsan = false
117  is_msan = false
118  is_tsan = false
119  is_ubsan = false
120  is_ubsan_null = false
121  is_ubsan_no_recover = false
122  is_ubsan_security = false
123  is_ubsan_vptr = false
124  msan_track_origins = 0
125  sanitizer_coverage_flags = ""
126  use_afl = false
127  use_cfi_diag = false
128  use_cfi_recover = false
129  use_drfuzz = false
130  use_libfuzzer = false
131  use_prebuilt_instrumented_libraries = false
132  use_locally_built_instrumented_libraries = false
133  use_sanitizer_coverage = false
134}
135
136# Whether we are doing a fuzzer build. Normally this should be checked instead
137# of checking "use_libfuzzer || use_afl" because often developers forget to
138# check for "use_afl".
139use_fuzzing_engine = use_libfuzzer || use_afl
140
141# Args that are in turn dependent on other args must be in a separate
142# declare_args block. User overrides are only applied at the end of a
143# declare_args block.
144declare_args() {
145  use_sanitizer_coverage =
146      !use_clang_coverage &&
147      (use_fuzzing_engine || sanitizer_coverage_flags != "")
148
149  # Detect overflow/underflow for global objects.
150  #
151  # Mac: http://crbug.com/352073
152  asan_globals = !is_mac
153}
154
155if (use_fuzzing_engine && sanitizer_coverage_flags == "") {
156  sanitizer_coverage_flags = "trace-pc-guard"
157} else if (use_sanitizer_coverage && sanitizer_coverage_flags == "") {
158  sanitizer_coverage_flags = "trace-pc-guard,indirect-calls"
159}
160
161# Whether we are linking against a debugging sanitizer runtime library. Among
162# other things, this changes the default symbol level and other settings in
163# order to prepare to create stack traces "live" using the sanitizer runtime.
164using_sanitizer =
165    is_asan || is_lsan || is_tsan || is_msan || is_ubsan || is_ubsan_null ||
166    is_ubsan_vptr || is_ubsan_security || use_sanitizer_coverage || use_cfi_diag
167
168if (!is_ohos) {
169  using_sanitizer = false
170}
171
172assert(!using_sanitizer || is_clang,
173       "Sanitizers (is_*san) require setting is_clang = true in 'gn args'")
174
175assert(!is_cfi || is_clang,
176       "is_cfi requires setting is_clang = true in 'gn args'")
177
178assert(!is_safestack || is_clang,
179       "is_safestack requires setting is_clang = true in 'gn args'")
180
181prebuilt_instrumented_libraries_available =
182    is_msan && (msan_track_origins == 0 || msan_track_origins == 2)
183
184if (use_libfuzzer && is_linux) {
185  if (is_asan) {
186    # We do leak checking with libFuzzer on Linux. Set is_lsan for code that
187    # relies on LEAK_SANITIZER define to avoid false positives.
188    is_lsan = true
189  }
190  if (is_msan) {
191    use_prebuilt_instrumented_libraries = true
192  }
193}
194
195# MSan only links Chrome properly in release builds (brettw -- 9/1/2015). The
196# same is possibly true for the other non-ASan sanitizers. But regardless of
197# whether it links, one would normally never run a sanitizer in debug mode.
198# Running in debug mode probably indicates you forgot to set the "is_debug =
199# false" flag in the build args. ASan seems to run fine in debug mode.
200#
201# If you find a use-case where you want to compile a sanitizer in debug mode
202# and have verified it works, ask brettw and we can consider removing it from
203# this condition. We may also be able to find another way to enable your case
204# without having people accidentally get broken builds by compiling an
205# unsupported or unadvisable configurations.
206#
207# For one-off testing, just comment this assertion out.
208assert(!is_debug || !(is_msan || is_ubsan || is_ubsan_null || is_ubsan_vptr),
209       "Sanitizers should generally be used in release (set is_debug=false).")
210
211assert(!is_msan || (is_linux && current_cpu == "x64"),
212       "MSan currently only works on 64-bit Linux and ChromeOS builds.")
213
214assert(!is_lsan || is_asan, "is_lsan = true requires is_asan = true also.")
215
216# ASAN build on Windows is not working in debug mode. Intercepting memory
217# allocation functions is hard on Windows and not yet implemented in LLVM.
218assert(!is_win || !is_debug || !is_asan,
219       "ASan on Windows doesn't work in debug (set is_debug=false).")
220
221# Make sure that if we recover on detection (i.e. not crash), diagnostics are
222# printed.
223assert(!use_cfi_recover || use_cfi_diag,
224       "Only use CFI recovery together with diagnostics.")
225
226assert(
227    !(use_sanitizer_coverage && is_mac && target_os == "ios"),
228    "crbug.com/753445: use_sanitizer_coverage=true is not supported by the " +
229        "Chromium mac_clang_x64 toolchain on iOS distribution. Please set " +
230        "the argument value to false.")
231
232# Use these lists of configs to disable instrumenting code that is part of a
233# fuzzer, but which isn't being targeted (such as libprotobuf-mutator, *.pb.cc
234# and libprotobuf when they are built as part of a proto fuzzer). Adding or
235# removing these lists does not have any effect if use_libfuzzer or use_afl are
236# not passed as arguments to gn.
237not_fuzzed_remove_configs = []
238not_fuzzed_remove_nonasan_configs = []
239
240if (use_fuzzing_engine) {
241  # Removing coverage should always just work.
242  not_fuzzed_remove_configs += [ "//build/config/coverage:default_coverage" ]
243  not_fuzzed_remove_nonasan_configs +=
244      [ "//build/config/coverage:default_coverage" ]
245
246  if (!is_msan) {
247    # Allow sanitizer instrumentation to be removed if we are not using MSan
248    # since binaries cannot be partially instrumented with MSan.
249    not_fuzzed_remove_configs +=
250        [ "//build/config/sanitizers:default_sanitizer_flags" ]
251
252    # Certain parts of binaries must be instrumented with ASan if the rest of
253    # the binary is. For these, only remove non-ASan sanitizer instrumentation.
254    if (!is_asan) {
255      not_fuzzed_remove_nonasan_configs +=
256          [ "//build/config/sanitizers:default_sanitizer_flags" ]
257      assert(not_fuzzed_remove_nonasan_configs == not_fuzzed_remove_configs)
258    }
259  }
260}
261
262template("ohos_sanitizer_config") {
263  config(target_name) {
264    forward_variables_from(invoker, [ "sanitize" ])
265    if (defined(sanitize)) {
266      configs = [ "//build/config/sanitizers:sanitizer_trap_all_flags" ]
267      _mode = "release"
268      _debug = (defined(sanitize.debug) && sanitize.debug) || is_asan
269      if (_debug) {
270        _mode = "debug"
271      }
272      _cfi = defined(sanitize.cfi) && sanitize.cfi && !is_asan
273      if (_cfi) {
274        if (defined(sanitize.cfi_cross_dso) && sanitize.cfi_cross_dso) {
275          configs += [ "//build/config/sanitizers:cfi_cross_dso_" + _mode ]
276        } else {
277          configs += [ "//build/config/sanitizers:cfi_config_" + _mode ]
278        }
279      }
280      _scudo = defined(sanitize.scudo) && sanitize.scudo && !is_asan && !is_tsan
281      if (_scudo) {
282        configs += [ "//build/config/sanitizers:scudo_config" ]
283      }
284      _ubsan = defined(sanitize.ubsan) && sanitize.ubsan && !is_asan
285      if (_ubsan) {
286        configs +=
287            [ "//build/config/sanitizers:undefined_behavior_sanitize_config_" +
288              _mode ]
289      }
290      _all_ubsan = defined(sanitize.all_ubsan) && sanitize.all_ubsan && !is_asan
291      if (_all_ubsan) {
292        configs += [
293          "//build/config/sanitizers:all_undefined_behavior_sanitize_config_" +
294              _mode,
295        ]
296      }
297      _scs = defined(sanitize.scs) && sanitize.scs
298      if (_scs) {
299        configs += [ "//build/config/sanitizers:shadow_call_stack_config" ]
300      }
301      _boundary_sanitize = defined(sanitize.boundary_sanitize) &&
302                           sanitize.boundary_sanitize && !is_asan
303      if (_boundary_sanitize) {
304        configs +=
305            [ "//build/config/sanitizers:boundary_sanitize_config_" + _mode ]
306      }
307
308      _integer_overflow = defined(sanitize.integer_overflow) &&
309                          sanitize.integer_overflow && !is_asan
310      _unsigned_integer_overflow =
311          defined(sanitize.unsigned_integer_overflow) &&
312          sanitize.unsigned_integer_overflow && !is_asan
313      _signed_integer_overflow = defined(sanitize.signed_integer_overflow) &&
314                                 sanitize.signed_integer_overflow && !is_asan
315      if (_unsigned_integer_overflow || _integer_overflow) {
316        configs +=
317            [ "//build/config/sanitizers:unsigned_integer_overflow_config" ]
318      }
319      if (_signed_integer_overflow || _integer_overflow) {
320        configs +=
321            [ "//build/config/sanitizers:signed_integer_overflow_config" ]
322      }
323      if (_integer_overflow || _unsigned_integer_overflow ||
324          _signed_integer_overflow) {
325        configs +=
326            [ "//build/config/sanitizers:common_integer_overflow_config_" +
327              _mode ]
328      }
329
330      if (defined(sanitize.blocklist)) {
331        cflags = [ "-fsanitize-blacklist=" +
332                   rebase_path(get_path_info(sanitize.blocklist, "abspath"),
333                               root_build_dir) ]
334      }
335      configs += [ "//build/config/sanitizers:compiler_rt_" + _mode ]
336    }
337  }
338}
339