{static_,}range_map: fix overflows under ubsan

Explicitly call out where overflows are expected, and add appropriate
checking for them.

BUG=b:235999011
TEST=Unittests on CrOS and Linux

Change-Id: I999a6996183c2f4afc16a1c0188dee3bd64d7f09
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/3759630
Reviewed-by: Mike Frysinger <vapier@chromium.org>

Makefile.am

@@ -130,6 +130,7 @@ EXTRA_PROGRAMS =
 CLEANFILES =
 
 check_LIBRARIES += src/testing/libtesting.a
+check_PROGRAMS += src/common/safe_math_unittest
 
 if !SYSTEM_TEST_LIBS
 src_testing_libtesting_a_SOURCES = \
@@ -690,6 +691,15 @@ src_tools_mac_dump_syms_dump_syms_mac_CXXFLAGS= \
 src_tools_mac_dump_syms_dump_syms_mac_LDADD= \
 	$(RUSTC_DEMANGLE_LIBS)
 
+src_common_safe_math_unittest_SOURCES = \
+	src/common/safe_math.h \
+	src/common/safe_math_unittest.cc
+src_common_safe_math_unittest_CPPFLAGS = \
+	$(AM_CPPFLAGS) $(TEST_CFLAGS)
+src_common_safe_math_unittest_LDADD = \
+	$(TEST_LIBS) \
+	$(PTHREAD_CFLAGS) $(PTHREAD_LIBS)
+
 src_common_dumper_unittest_SOURCES = \
 	src/common/byte_cursor_unittest.cc \
 	src/common/convert_UTF.cc \

Makefile.in

@@ -134,7 +134,8 @@ host_triplet = @host@
 @LINUX_HOST_TRUE@am__append_3 = -fPIC
 libexec_PROGRAMS = $(am__EXEEXT_10)
 bin_PROGRAMS = $(am__EXEEXT_2) $(am__EXEEXT_3) $(am__EXEEXT_4)
-check_PROGRAMS = $(am__EXEEXT_5) $(am__EXEEXT_6) $(am__EXEEXT_7) \
+check_PROGRAMS = src/common/safe_math_unittest$(EXEEXT) \
+	$(am__EXEEXT_5) $(am__EXEEXT_6) $(am__EXEEXT_7) \
 	$(am__EXEEXT_8) $(am__EXEEXT_9)
 EXTRA_PROGRAMS = $(am__EXEEXT_1)
 @DISABLE_PROCESSOR_FALSE@am__append_4 = src/libbreakpad.a
@@ -888,6 +889,15 @@ src_common_mac_macho_reader_unittest_OBJECTS =  \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(am__DEPENDENCIES_2) \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(am__DEPENDENCIES_1) \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(am__DEPENDENCIES_1)
+am__src_common_safe_math_unittest_SOURCES_DIST =  \
+	src/common/safe_math.h src/common/safe_math_unittest.cc
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@am_src_common_safe_math_unittest_OBJECTS = src/common/safe_math_unittest-safe_math_unittest.$(OBJEXT)
+src_common_safe_math_unittest_OBJECTS =  \
+	$(am_src_common_safe_math_unittest_OBJECTS)
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@src_common_safe_math_unittest_DEPENDENCIES =  \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(am__DEPENDENCIES_2) \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(am__DEPENDENCIES_1) \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(am__DEPENDENCIES_1)
 am__src_common_test_assembler_unittest_SOURCES_DIST =  \
 	src/common/test_assembler.cc src/common/test_assembler.h \
 	src/common/test_assembler_unittest.cc
@@ -1701,6 +1711,7 @@ am__depfiles_remade = src/client/$(DEPDIR)/minidump_file_writer.Po \
 	src/common/$(DEPDIR)/processor_stackwalker_mips_unittest-test_assembler.Po \
 	src/common/$(DEPDIR)/processor_stackwalker_x86_unittest-test_assembler.Po \
 	src/common/$(DEPDIR)/processor_synth_minidump_unittest-test_assembler.Po \
+	src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Po \
 	src/common/$(DEPDIR)/string_conversion.Po \
 	src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Po \
 	src/common/$(DEPDIR)/test_assembler_unittest-test_assembler_unittest.Po \
@@ -1970,6 +1981,7 @@ SOURCES = $(src_client_linux_libbreakpad_client_a_SOURCES) \
 	$(src_common_dwarf_dwarf2reader_splitfunctions_unittest_SOURCES) \
 	$(src_common_linux_google_crashdump_uploader_test_SOURCES) \
 	$(src_common_mac_macho_reader_unittest_SOURCES) \
+	$(src_common_safe_math_unittest_SOURCES) \
 	$(src_common_test_assembler_unittest_SOURCES) \
 	$(src_processor_address_map_unittest_SOURCES) \
 	$(src_processor_basic_source_line_resolver_unittest_SOURCES) \
@@ -2026,6 +2038,7 @@ DIST_SOURCES =  \
 	$(am__src_common_dwarf_dwarf2reader_splitfunctions_unittest_SOURCES_DIST) \
 	$(am__src_common_linux_google_crashdump_uploader_test_SOURCES_DIST) \
 	$(am__src_common_mac_macho_reader_unittest_SOURCES_DIST) \
+	$(am__src_common_safe_math_unittest_SOURCES_DIST) \
 	$(am__src_common_test_assembler_unittest_SOURCES_DIST) \
 	$(am__src_processor_address_map_unittest_SOURCES_DIST) \
 	$(am__src_processor_basic_source_line_resolver_unittest_SOURCES_DIST) \
@@ -2909,6 +2922,17 @@ TESTS = $(check_PROGRAMS) $(check_SCRIPTS)
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@src_tools_mac_dump_syms_dump_syms_mac_LDADD = \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(RUSTC_DEMANGLE_LIBS)
 
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@src_common_safe_math_unittest_SOURCES = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/common/safe_math.h \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/common/safe_math_unittest.cc
+
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@src_common_safe_math_unittest_CPPFLAGS = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(AM_CPPFLAGS) $(TEST_CFLAGS)
+
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@src_common_safe_math_unittest_LDADD = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(TEST_LIBS) \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	$(PTHREAD_CFLAGS) $(PTHREAD_LIBS)
+
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@src_common_dumper_unittest_SOURCES = \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/common/byte_cursor_unittest.cc \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/common/convert_UTF.cc \
@@ -4800,6 +4824,13 @@ src/common/tests/mac_macho_reader_unittest-file_utils.$(OBJEXT):  \
 src/common/mac/macho_reader_unittest$(EXEEXT): $(src_common_mac_macho_reader_unittest_OBJECTS) $(src_common_mac_macho_reader_unittest_DEPENDENCIES) $(EXTRA_src_common_mac_macho_reader_unittest_DEPENDENCIES) src/common/mac/$(am__dirstamp)
 	@rm -f src/common/mac/macho_reader_unittest$(EXEEXT)
 	$(AM_V_CXXLD)$(CXXLINK) $(src_common_mac_macho_reader_unittest_OBJECTS) $(src_common_mac_macho_reader_unittest_LDADD) $(LIBS)
+src/common/safe_math_unittest-safe_math_unittest.$(OBJEXT):  \
+	src/common/$(am__dirstamp) \
+	src/common/$(DEPDIR)/$(am__dirstamp)
+
+src/common/safe_math_unittest$(EXEEXT): $(src_common_safe_math_unittest_OBJECTS) $(src_common_safe_math_unittest_DEPENDENCIES) $(EXTRA_src_common_safe_math_unittest_DEPENDENCIES) src/common/$(am__dirstamp)
+	@rm -f src/common/safe_math_unittest$(EXEEXT)
+	$(AM_V_CXXLD)$(CXXLINK) $(src_common_safe_math_unittest_OBJECTS) $(src_common_safe_math_unittest_LDADD) $(LIBS)
 src/common/test_assembler_unittest-test_assembler.$(OBJEXT):  \
 	src/common/$(am__dirstamp) \
 	src/common/$(DEPDIR)/$(am__dirstamp)
@@ -5423,6 +5454,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/processor_stackwalker_mips_unittest-test_assembler.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/processor_stackwalker_x86_unittest-test_assembler.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/processor_synth_minidump_unittest-test_assembler.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/string_conversion.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@src/common/$(DEPDIR)/test_assembler_unittest-test_assembler_unittest.Po@am__quote@ # am--include-marker
@@ -7253,6 +7285,20 @@ src/common/tests/mac_macho_reader_unittest-file_utils.obj: src/common/tests/file
 @AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCXX_FALSE@	$(AM_V_CXX@am__nodep@)$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(src_common_mac_macho_reader_unittest_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o src/common/tests/mac_macho_reader_unittest-file_utils.obj `if test -f 'src/common/tests/file_utils.cc'; then $(CYGPATH_W) 'src/common/tests/file_utils.cc'; else $(CYGPATH_W) '$(srcdir)/src/common/tests/file_utils.cc'; fi`
 
+src/common/safe_math_unittest-safe_math_unittest.o: src/common/safe_math_unittest.cc
+@am__fastdepCXX_TRUE@	$(AM_V_CXX)$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(src_common_safe_math_unittest_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT src/common/safe_math_unittest-safe_math_unittest.o -MD -MP -MF src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Tpo -c -o src/common/safe_math_unittest-safe_math_unittest.o `test -f 'src/common/safe_math_unittest.cc' || echo '$(srcdir)/'`src/common/safe_math_unittest.cc
+@am__fastdepCXX_TRUE@	$(AM_V_at)$(am__mv) src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Tpo src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Po
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	$(AM_V_CXX)source='src/common/safe_math_unittest.cc' object='src/common/safe_math_unittest-safe_math_unittest.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCXX_FALSE@	$(AM_V_CXX@am__nodep@)$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(src_common_safe_math_unittest_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o src/common/safe_math_unittest-safe_math_unittest.o `test -f 'src/common/safe_math_unittest.cc' || echo '$(srcdir)/'`src/common/safe_math_unittest.cc
+
+src/common/safe_math_unittest-safe_math_unittest.obj: src/common/safe_math_unittest.cc
+@am__fastdepCXX_TRUE@	$(AM_V_CXX)$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(src_common_safe_math_unittest_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT src/common/safe_math_unittest-safe_math_unittest.obj -MD -MP -MF src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Tpo -c -o src/common/safe_math_unittest-safe_math_unittest.obj `if test -f 'src/common/safe_math_unittest.cc'; then $(CYGPATH_W) 'src/common/safe_math_unittest.cc'; else $(CYGPATH_W) '$(srcdir)/src/common/safe_math_unittest.cc'; fi`
+@am__fastdepCXX_TRUE@	$(AM_V_at)$(am__mv) src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Tpo src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Po
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	$(AM_V_CXX)source='src/common/safe_math_unittest.cc' object='src/common/safe_math_unittest-safe_math_unittest.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCXX_FALSE@	$(AM_V_CXX@am__nodep@)$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(src_common_safe_math_unittest_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o src/common/safe_math_unittest-safe_math_unittest.obj `if test -f 'src/common/safe_math_unittest.cc'; then $(CYGPATH_W) 'src/common/safe_math_unittest.cc'; else $(CYGPATH_W) '$(srcdir)/src/common/safe_math_unittest.cc'; fi`
+
 src/common/test_assembler_unittest-test_assembler.o: src/common/test_assembler.cc
 @am__fastdepCXX_TRUE@	$(AM_V_CXX)$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(src_common_test_assembler_unittest_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT src/common/test_assembler_unittest-test_assembler.o -MD -MP -MF src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Tpo -c -o src/common/test_assembler_unittest-test_assembler.o `test -f 'src/common/test_assembler.cc' || echo '$(srcdir)/'`src/common/test_assembler.cc
 @am__fastdepCXX_TRUE@	$(AM_V_at)$(am__mv) src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Tpo src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Po
@@ -8846,6 +8892,13 @@ recheck: all $(check_PROGRAMS) $(check_LIBRARIES) $(check_SCRIPTS)
 	        am__force_recheck=am--force-recheck \
 	        TEST_LOGS="$$log_list"; \
 	exit $$?
+src/common/safe_math_unittest.log: src/common/safe_math_unittest$(EXEEXT)
+	@p='src/common/safe_math_unittest$(EXEEXT)'; \
+	b='src/common/safe_math_unittest'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
 src/common/test_assembler_unittest.log: src/common/test_assembler_unittest$(EXEEXT)
 	@p='src/common/test_assembler_unittest$(EXEEXT)'; \
 	b='src/common/test_assembler_unittest'; \
@@ -9508,6 +9561,7 @@ distclean: distclean-am
 	-rm -f src/common/$(DEPDIR)/processor_stackwalker_mips_unittest-test_assembler.Po
 	-rm -f src/common/$(DEPDIR)/processor_stackwalker_x86_unittest-test_assembler.Po
 	-rm -f src/common/$(DEPDIR)/processor_synth_minidump_unittest-test_assembler.Po
+	-rm -f src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Po
 	-rm -f src/common/$(DEPDIR)/string_conversion.Po
 	-rm -f src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Po
 	-rm -f src/common/$(DEPDIR)/test_assembler_unittest-test_assembler_unittest.Po
@@ -9853,6 +9907,7 @@ maintainer-clean: maintainer-clean-am
 	-rm -f src/common/$(DEPDIR)/processor_stackwalker_mips_unittest-test_assembler.Po
 	-rm -f src/common/$(DEPDIR)/processor_stackwalker_x86_unittest-test_assembler.Po
 	-rm -f src/common/$(DEPDIR)/processor_synth_minidump_unittest-test_assembler.Po
+	-rm -f src/common/$(DEPDIR)/safe_math_unittest-safe_math_unittest.Po
 	-rm -f src/common/$(DEPDIR)/string_conversion.Po
 	-rm -f src/common/$(DEPDIR)/test_assembler_unittest-test_assembler.Po
 	-rm -f src/common/$(DEPDIR)/test_assembler_unittest-test_assembler_unittest.Po

src/common/common.gyp

@@ -163,6 +163,7 @@
         'memory_range.h',
         'module.cc',
         'module.h',
+        'safe_math.h',
         'scoped_ptr.h',
         'simple_string_dictionary.cc',
         'simple_string_dictionary.h',
@@ -233,6 +234,7 @@
         'memory_allocator_unittest.cc',
         'memory_range_unittest.cc',
         'module_unittest.cc',
+        'safe_math_unittest.cc',
         'simple_string_dictionary_unittest.cc',
         'stabs_reader_unittest.cc',
         'stabs_to_module_unittest.cc',

src/common/safe_math.h

@@ -0,0 +1,82 @@
+// Copyright (c) 2022, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// safe_math.h: Helpful math functions.
+#ifndef SAFE_MATH_H__
+#define SAFE_MATH_H__
+
+#include <utility>
+
+namespace google_breakpad {
+
+// Adds `a` and `b`, returning a pair of:
+// - The result after any truncation.
+// - Whether an overflow/underflow occurred.
+template <typename T>
+std::pair<T, bool> AddWithOverflowCheck(T a, T b) {
+#ifdef _WIN32
+  // Since C++11, unsigned overflow is well-defined; do everything unsigned,
+  // assuming 2's complement.
+  if (std::is_unsigned<T>::value) {
+    T result = a + b;
+    // Since we're adding two values >= 0, having a smaller value implies
+    // overflow.
+    bool overflow = result < a;
+    return {result, overflow};
+  }
+
+  using TUnsigned = typename std::make_unsigned<T>::type;
+  T result = TUnsigned(a) + TUnsigned(b);
+  bool overflow;
+  if ((a >= 0) == (b >= 0)) {
+    if (a >= 0) {
+      overflow = result < a;
+    } else {
+      overflow = result > a;
+    }
+  } else {
+    // If signs are different, it's impossible for overflow to happen.
+    overflow = false;
+  }
+  return {result, overflow};
+#else
+  T result;
+  bool overflow = __builtin_add_overflow(a, b, &result);
+  return {result, overflow};
+#endif
+}
+
+template <typename T>
+T AddIgnoringOverflow(T a, T b) {
+  return AddWithOverflowCheck(a, b).first;
+}
+
+}  // namespace google_breakpad
+
+#endif  // SAFE_MATH_H__

src/common/safe_math_unittest.cc

@@ -0,0 +1,73 @@
+// Copyright (c) 2022 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// safe_math_unittest.cc: Unit tests for SafeMath
+
+#include "safe_math.h"
+#include "breakpad_googletest_includes.h"
+
+namespace {
+
+using google_breakpad::AddIgnoringOverflow;
+using google_breakpad::AddWithOverflowCheck;
+
+TEST(SafeMath, AddOverflowWorksAsIntended) {
+  EXPECT_EQ(AddWithOverflowCheck<uint8_t>(0, 0),
+            std::make_pair<uint8_t>(0, false));
+  EXPECT_EQ(AddWithOverflowCheck<uint8_t>(0, 255),
+            std::make_pair<uint8_t>(255, false));
+  EXPECT_EQ(AddWithOverflowCheck<uint8_t>(1, 255),
+            std::make_pair<uint8_t>(0, true));
+
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(-128, 127),
+            std::make_pair<int8_t>(-1, false));
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, -128),
+            std::make_pair<int8_t>(-1, false));
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(1, -128),
+            std::make_pair<int8_t>(-127, false));
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, -1),
+            std::make_pair<int8_t>(126, false));
+
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(-128, -1),
+            std::make_pair<int8_t>(127, true));
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(-128, -128),
+            std::make_pair<int8_t>(0, true));
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, 1),
+            std::make_pair<int8_t>(-128, true));
+  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, 127),
+            std::make_pair<int8_t>(-2, true));
+}
+
+TEST(SafeMath, AddIgnoringOverflowWorksAsIntended) {
+  EXPECT_EQ(AddIgnoringOverflow<uint8_t>(0, 0), 0);
+  EXPECT_EQ(AddIgnoringOverflow<uint8_t>(0, 255), 255);
+  EXPECT_EQ(AddIgnoringOverflow<uint8_t>(1, 255), 0);
+}
+
+}  // namespace

src/processor/range_map-inl.h

@@ -39,6 +39,7 @@
 
 #include <assert.h>
 
+#include "common/safe_math.h"
 #include "processor/range_map.h"
 #include "processor/linked_ptr.h"
 #include "processor/logging.h"
@@ -57,10 +58,15 @@ template<typename AddressType, typename EntryType>
 bool RangeMap<AddressType, EntryType>::StoreRangeInternal(
     const AddressType& base, const AddressType& delta,
     const AddressType& size, const EntryType& entry) {
-  AddressType high = base + (size - 1);
+  AddressType high;
-
+  bool high_ok = false;
+  if (size > 0) {
+    std::pair<AddressType, bool> result = AddWithOverflowCheck(base, size - 1);
+    high = result.first;
+    high_ok = !result.second;
+  }
   // Check for undersize or overflow.
-  if (size <= 0 || high < base) {
+  if (!high_ok) {
     // The processor will hit this case too frequently with common symbol
     // files in the size == 0 case, which is more suited to a DEBUG channel.
     // Filter those out since there's no DEBUG channel at the moment.

src/processor/range_map_unittest.cc

@@ -43,11 +43,10 @@
 
 namespace {
 
-
+using google_breakpad::AddIgnoringOverflow;
 using google_breakpad::linked_ptr;
-using google_breakpad::scoped_ptr;
 using google_breakpad::RangeMap;
-
+using google_breakpad::scoped_ptr;
 
 // A CountedObject holds an int.  A global (not thread safe!) count of
 // allocated CountedObjects is maintained to help test memory management.
@@ -148,10 +147,10 @@ static bool RetrieveTest(TestMap* range_map, const RangeTest* range_test) {
     }
 
     for (AddressType offset = low_offset; offset <= high_offset; ++offset) {
-      AddressType address =
+      AddressType address = AddIgnoringOverflow(
-          offset +
+          offset, (!side ? range_test->address
-          (!side ? range_test->address :
+                         : AddIgnoringOverflow(range_test->address,
-                   range_test->address + range_test->size - 1);
+                                               range_test->size - 1)));
 
       bool expected_result = false;  // This is correct for tests not stored.
       if (range_test->expect_storable) {

src/processor/static_range_map_unittest.cc

@@ -228,10 +228,10 @@ void TestStaticRangeMap::RetrieveTest(TestMap* range_map,
     }
 
     for (AddressType offset = low_offset; offset <= high_offset; ++offset) {
-      AddressType address =
+      AddressType address = AddIgnoringOverflow(
-          offset +
+          offset, (!side ? range_test->address
-          (!side ? range_test->address :
+                         : AddIgnoringOverflow(range_test->address,
-                   range_test->address + range_test->size - 1);
+                                               range_test->size - 1)));
 
       bool expected_result = false;  // This is correct for tests not stored.
       if (range_test->expect_storable) {