sanitizers.gni - mozsearch

# Copyright 2015 The Chromium Authors. All rights reserved.

# Use of this source code is governed by a BSD-style license that can be

# found in the LICENSE file.

import("//chromium/build/config/chrome_build.gni")

import("//chromium/build/config/chromecast_build.gni")

import("//chromium/build/config/chromeos/args.gni")

import("//chromium/build/config/chromeos/ui_mode.gni")

import("//chromium/build/config/profiling/profiling.gni")

import("//chromium/build/toolchain/toolchain.gni")

declare_args() {

  # Compile for Address Sanitizer to find memory bugs.

  is_asan = false

  # Compile for Hardware-Assisted Address Sanitizer to find memory bugs

  # (android/arm64 only).

  # See http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html

  is_hwasan = false

  # Compile for Leak Sanitizer to find leaks.

  is_lsan = false

  # Compile for Memory Sanitizer to find uninitialized reads.

  is_msan = false

  # Compile for Thread Sanitizer to find threading bugs.

  is_tsan = false

  # Compile for Undefined Behaviour Sanitizer to find various types of

  # undefined behaviour (excludes vptr checks).

  is_ubsan = false

  # Halt the program if a problem is detected.

  is_ubsan_no_recover = false

  # Compile for Undefined Behaviour Sanitizer's null pointer checks.

  is_ubsan_null = false

  # Track where uninitialized memory originates from. From fastest to slowest:

  # 0 - no tracking, 1 - track only the initial allocation site, 2 - track the

  # chain of stores leading from allocation site to use site.

  msan_track_origins = 2

  # Use dynamic libraries instrumented by one of the sanitizers instead of the

  # standard system libraries. Set this flag to build the libraries from source.

  use_locally_built_instrumented_libraries = false

  # Compile with Control Flow Integrity to protect virtual calls and casts.

  # See http://clang.llvm.org/docs/ControlFlowIntegrity.html

  # TODO(pcc): Remove this flag if/when CFI is enabled in all official builds.

  # Disable this on linux-chromeos to avoid using ThinLTO there;

  # crbug.com/1033839. Similarly, don't use this on ARC builds.

  # TODO(crbug.com/1159424): Reassess the validity of the next expression.

  is_cfi =

      is_official_build &&

      (((target_os == "linux" || is_chromeos_lacros) && target_cpu == "x64") ||

       ((is_chromeos_ash || is_chromeos_lacros) && is_chromeos_device))

  # Enable checks for indirect function calls via a function pointer.

  # TODO(pcc): remove this when we're ready to add these checks by default.

  # https://crbug.com/701919

  # TODO(crbug.com/1159424): Reassess the validity of the next expression.

  use_cfi_icall = (target_os == "linux" || is_chromeos_lacros) &&

                  target_cpu == "x64" && is_official_build

  # Print detailed diagnostics when Control Flow Integrity detects a violation.

  use_cfi_diag = false

  # Let Control Flow Integrity continue execution instead of crashing when

  # printing diagnostics (use_cfi_diag = true).

  use_cfi_recover = false

  # Compile for fuzzing with LLVM LibFuzzer.

  # See http://www.chromium.org/developers/testing/libfuzzer

  use_libfuzzer = false

  # Compile for fuzzing with AFL.

  use_afl = false

  # Compile for fuzzing with an external engine (e.g., Grammarinator).

  use_external_fuzzing_engine = false

  # Enables core ubsan security features. Will later be removed once it matches

  # is_ubsan.

  is_ubsan_security = false

  # Helper variable for testing builds with disabled libfuzzer.

  # Not for client use.

  disable_libfuzzer = false

  # Optimize for coverage guided fuzzing (balance between speed and number of

  # branches). Can be also used to remove non-determinism and other issues.

  optimize_for_fuzzing = false

  # Value for -fsanitize-coverage flag. Setting this causes

  # use_sanitizer_coverage to be enabled.

  # This flag is not used for libFuzzer (use_libfuzzer=true). Instead, we use:

  #     -fsanitize=fuzzer-no-link

  # Default value when unset and use_fuzzing_engine=true:

  #     trace-pc-guard

  # Default value when unset and use_sanitizer_coverage=true:

  #     trace-pc-guard,indirect-calls

  sanitizer_coverage_flags = ""

  # When enabled, only relevant sanitizer defines are set, but compilation

  # happens with no extra flags. This is useful when in component build

  # enabling sanitizers only in some of the components.

  use_sanitizer_configs_without_instrumentation = false

  # When true, seed corpora archives are built.

  archive_seed_corpus = true

declare_args() {

  # Enable checks for bad casts: derived cast and unrelated cast.

  # TODO(krasin): remove this, when we're ready to add these checks by default.

  # https://crbug.com/626794

  use_cfi_cast = is_cfi && (is_chromeos_ash || is_chromeos_lacros)

  # Compile for Undefined Behaviour Sanitizer's vptr checks.

  is_ubsan_vptr = is_ubsan_security

assert(!is_hwasan || (target_os == "android" && target_cpu == "arm64"),

       "HWASan only supported on Android ARM64 builds.")

# Disable sanitizers for non-target toolchains.

if (!is_a_target_toolchain) {

  is_asan = false

  is_cfi = false

  is_hwasan = false

  is_lsan = false

  is_msan = false

  is_tsan = false

  is_ubsan = false

  is_ubsan_null = false

  is_ubsan_no_recover = false

  is_ubsan_security = false

  is_ubsan_vptr = false

  msan_track_origins = 0

  sanitizer_coverage_flags = ""

  use_afl = false

  use_cfi_diag = false

  use_cfi_recover = false

  use_libfuzzer = false

  use_locally_built_instrumented_libraries = false

  use_sanitizer_coverage = false

} else if (target_cpu != "arm64") {

  is_hwasan = false

# Use dynamic libraries instrumented by one of the sanitizers instead of the

# standard system libraries. We have instrumented system libraries for msan,

# which requires them to prevent false positives.

# TODO(thakis): Maybe remove this variable.

use_prebuilt_instrumented_libraries = is_msan

# Whether we are doing a fuzzer build. Normally this should be checked instead

# of checking "use_libfuzzer || use_afl" because often developers forget to

# check for "use_afl".

use_fuzzing_engine = use_libfuzzer || use_afl || use_external_fuzzing_engine

# Args that are in turn dependent on other args must be in a separate

# declare_args block. User overrides are only applied at the end of a

# declare_args block.

declare_args() {

  # Generates an owners file for each fuzzer test.

  # TODO(crbug.com/1194183): Remove this arg when finding OWNERS is faster.

  generate_fuzzer_owners = use_fuzzing_engine

  use_sanitizer_coverage =

      !use_clang_coverage &&

      (use_fuzzing_engine || sanitizer_coverage_flags != "")

  # https://crbug.com/1002058: Code coverage works inside the sandbox via the

  # help of several helper IPCs. Unfortunately, the sandbox-only path does not

  # work well for fuzzing builds. Since fuzzing builds already disable the

  # sandbox when dumping coverage, limit the sandbox-only path to non-fuzzing

  # builds.

  # Everything is IPC on Fuchsia, so this workaround for code coverage inside

  # the sandbox does not apply.

  use_clang_profiling_inside_sandbox =

      use_clang_profiling && !use_fuzzing_engine && !is_fuchsia

if (use_fuzzing_engine && sanitizer_coverage_flags == "") {

  sanitizer_coverage_flags = "trace-pc-guard"

} else if (use_sanitizer_coverage && sanitizer_coverage_flags == "") {

  sanitizer_coverage_flags = "trace-pc-guard,indirect-calls"

# Whether we are linking against a sanitizer runtime library. Among other

# things, this changes the default symbol level and other settings in order to

# prepare to create stack traces "live" using the sanitizer runtime.

using_sanitizer = is_asan || is_hwasan || is_lsan || is_tsan || is_msan ||

                  is_ubsan || is_ubsan_null || is_ubsan_vptr ||

                  is_ubsan_security || use_sanitizer_coverage || use_cfi_diag

assert(!using_sanitizer || is_clang,

       "Sanitizers (is_*san) require setting is_clang = true in 'gn args'")

assert(!is_cfi || is_clang,

       "is_cfi requires setting is_clang = true in 'gn args'")

prebuilt_instrumented_libraries_available =

    is_msan && (msan_track_origins == 0 || msan_track_origins == 2)

if (use_libfuzzer && (is_linux || is_chromeos)) {

  if (is_asan) {

    # We do leak checking with libFuzzer on Linux. Set is_lsan for code that

    # relies on LEAK_SANITIZER define to avoid false positives.

    is_lsan = true

# MSan only links Chrome properly in release builds (brettw -- 9/1/2015). The

# same is possibly true for the other non-ASan sanitizers. But regardless of

# whether it links, one would normally never run a sanitizer in debug mode.

# Running in debug mode probably indicates you forgot to set the "is_debug =

# false" flag in the build args. ASan seems to run fine in debug mode.

# If you find a use-case where you want to compile a sanitizer in debug mode

# and have verified it works, ask brettw and we can consider removing it from

# this condition. We may also be able to find another way to enable your case

# without having people accidentally get broken builds by compiling an

# unsupported or unadvisable configurations.

# For one-off testing, just comment this assertion out.

assert(!is_debug || !(is_msan || is_ubsan || is_ubsan_null || is_ubsan_vptr),

       "Sanitizers should generally be used in release (set is_debug=false).")

assert(!is_msan || ((is_linux || is_chromeos) && target_cpu == "x64"),

       "MSan currently only works on 64-bit Linux and ChromeOS builds.")

assert(!is_lsan || is_asan, "is_lsan = true requires is_asan = true also.")

# ASAN build on Windows is not working in debug mode. Intercepting memory

# allocation functions is hard on Windows and not yet implemented in LLVM.

assert(!is_win || !is_debug || !is_asan,

       "ASan on Windows doesn't work in debug (set is_debug=false).")

# libFuzzer targets can fail to build or behave incorrectly when built without

# ASAN on Windows.

assert(!is_win || !use_libfuzzer || is_asan,

       "use_libfuzzer on Windows requires setting is_asan = true")

# Make sure that if we recover on detection (i.e. not crash), diagnostics are

# printed.

assert(!use_cfi_recover || use_cfi_diag,

       "Only use CFI recovery together with diagnostics.")

# TODO(crbug.com/753445): the use_sanitizer_coverage arg is currently

# not supported by the Chromium mac_clang_x64 toolchain on iOS distribution.

# The coverage works with iOS toolchain but it is broken when the mac

# toolchain is used as a secondary one on iOS distribution. E.g., it should be

# possible to build the "net" target for iOS with the sanitizer coverage

# enabled.

assert(

    !(use_sanitizer_coverage && is_mac && target_os == "ios"),

    "crbug.com/753445: use_sanitizer_coverage=true is not supported by the " +

        "Chromium mac_clang_x64 toolchain on iOS distribution. Please set " +

        "the argument value to false.")

# Use these lists of configs to disable instrumenting code that is part of a

# fuzzer, but which isn't being targeted (such as libprotobuf-mutator, *.pb.cc

# and libprotobuf when they are built as part of a proto fuzzer). Adding or

# removing these lists does not have any effect if use_libfuzzer or use_afl are

# not passed as arguments to gn.

not_fuzzed_remove_configs = []

not_fuzzed_remove_nonasan_configs = []

if (use_fuzzing_engine) {

  # Removing coverage should always just work.

  not_fuzzed_remove_configs += [ "//chromium/build/config/coverage:default_coverage" ]

  not_fuzzed_remove_nonasan_configs +=

      [ "//chromium/build/config/coverage:default_coverage" ]

  if (!is_msan) {

    # Allow sanitizer instrumentation to be removed if we are not using MSan

    # since binaries cannot be partially instrumented with MSan.

    not_fuzzed_remove_configs +=

        [ "//chromium/build/config/sanitizers:default_sanitizer_flags" ]

    # Certain parts of binaries must be instrumented with ASan if the rest of

    # the binary is. For these, only remove non-ASan sanitizer instrumentation.

    if (!is_asan) {

      not_fuzzed_remove_nonasan_configs +=

          [ "//chromium/build/config/sanitizers:default_sanitizer_flags" ]

      assert(not_fuzzed_remove_nonasan_configs == not_fuzzed_remove_configs)

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