Fix ASan-reported heap-buffer-overflow in GIUH tests

[PhilMiller]

Identified in #536

$ ./test/test_giuh --gtest_filter=GIUH_Test.TestInit0

Running main() from /Users/phil/Code/noaa/ngen/test/googletest/googletest/src/gtest_main.cc
Note: Google Test filter = GIUH_Test.TestInit0
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from GIUH_Test
[ RUN      ] GIUH_Test.TestInit0
=================================================================
==72208==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x000109d001f8 at pc 0x00010249fd50 bp 0x00016dac8b10 sp 0x00016dac8b08
READ of size 8 at 0x000109d001f8 thread T0
    #0 0x10249fd4c in giuh::giuh_kernel_impl::interpolate_regularized_cdf() GIUH.cpp:134
    #1 0x102364074 in giuh::giuh_kernel_impl::giuh_kernel_impl(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::vector<double, std::__1::allocator<double> >, std::__1::vector<double, std::__1::allocator<double> >, unsigned int) GIUH.hpp:102
    #2 0x102340028 in giuh::giuh_kernel_impl::giuh_kernel_impl(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::vector<double, std::__1::allocator<double> >, std::__1::vector<double, std::__1::allocator<double> >, unsigned int) GIUH.hpp:98
    #3 0x10233c190 in giuh::giuh_kernel_impl::giuh_kernel_impl(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::vector<double, std::__1::allocator<double> >, std::__1::vector<double, std::__1::allocator<double> >) GIUH.hpp:124
    #4 0x1024abab0 in giuh::GiuhJsonReader::build_giuh_kernel(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, boost::property_tree::basic_ptree<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >) GiuhJsonReader.cpp:16
    #5 0x1024ae4ec in giuh::GiuhJsonReader::get_giuh_kernel_for_id(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) GiuhJsonReader.cpp:78
    #6 0x102338dc4 in GIUH_Test_TestInit0_Test::TestBody() GIUH_Test.cpp:71
    #7 0x10247d810 in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) gtest.cc:2599
    #8 0x1023e0d90 in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) gtest.cc:2635
    #9 0x1023e0960 in testing::Test::Run() gtest.cc:2674
    #10 0x1023e3200 in testing::TestInfo::Run() gtest.cc:2853
    #11 0x1023e6194 in testing::TestSuite::Run() gtest.cc:3012
    #12 0x10240a418 in testing::internal::UnitTestImpl::RunAllTests() gtest.cc:5870
    #13 0x10248b224 in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) gtest.cc:2599
    #14 0x1024094d8 in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) gtest.cc:2635
    #15 0x102408fe8 in testing::UnitTest::Run() gtest.cc:5444
    #16 0x10249e23c in RUN_ALL_TESTS() gtest.h:2293
    #17 0x10249e198 in main gtest_main.cc:51
    #18 0x1029b1088 in start+0x204 (dyld:arm64e+0x5088)

0x000109d001f8 is located 8 bytes to the left of 22256-byte region [0x000109d00200,0x000109d058f0)
allocated by thread T0 here:
    #0 0x102dddef0 in wrap__Znwm+0x74 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x4def0)
    #1 0x1023490bc in void* std::__1::__libcpp_operator_new<unsigned long>(unsigned long) new:235
    #2 0x102348fe0 in std::__1::__libcpp_allocate(unsigned long, unsigned long) new:261
    #3 0x1023669bc in std::__1::allocator<double>::allocate(unsigned long) allocator.h:108
    #4 0x102366804 in std::__1::allocator_traits<std::__1::allocator<double> >::allocate(std::__1::allocator<double>&, unsigned long) allocator_traits.h:262
    #5 0x102365e48 in std::__1::vector<double, std::__1::allocator<double> >::__vallocate(unsigned long) vector:1015
    #6 0x10236a060 in std::__1::vector<double, std::__1::allocator<double> >::vector(std::__1::vector<double, std::__1::allocator<double> > const&) vector:1280
    #7 0x10233bf98 in std::__1::vector<double, std::__1::allocator<double> >::vector(std::__1::vector<double, std::__1::allocator<double> > const&) vector:1273
    #8 0x1024aba84 in giuh::GiuhJsonReader::build_giuh_kernel(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, boost::property_tree::basic_ptree<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >) GiuhJsonReader.cpp:16
    #9 0x1024ae4ec in giuh::GiuhJsonReader::get_giuh_kernel_for_id(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) GiuhJsonReader.cpp:78
    #10 0x102338dc4 in GIUH_Test_TestInit0_Test::TestBody() GIUH_Test.cpp:71
    #11 0x10247d810 in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) gtest.cc:2599
    #12 0x1023e0d90 in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) gtest.cc:2635
    #13 0x1023e0960 in testing::Test::Run() gtest.cc:2674
    #14 0x1023e3200 in testing::TestInfo::Run() gtest.cc:2853
    #15 0x1023e6194 in testing::TestSuite::Run() gtest.cc:3012
    #16 0x10240a418 in testing::internal::UnitTestImpl::RunAllTests() gtest.cc:5870
    #17 0x10248b224 in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) gtest.cc:2599
    #18 0x1024094d8 in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) gtest.cc:2635
    #19 0x102408fe8 in testing::UnitTest::Run() gtest.cc:5444
    #20 0x10249e23c in RUN_ALL_TESTS() gtest.h:2293
    #21 0x10249e198 in main gtest_main.cc:51
    #22 0x1029b1088 in start+0x204 (dyld:arm64e+0x5088)

SUMMARY: AddressSanitizer: heap-buffer-overflow GIUH.cpp:134 in giuh::giuh_kernel_impl::interpolate_regularized_cdf()
Shadow bytes around the buggy address:
  0x0070213bffe0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0070213bfff0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0070213c0000: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0070213c0010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0070213c0020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0070213c0030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa[fa]
  0x0070213c0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0070213c0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0070213c0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0070213c0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0070213c0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==72208==ABORTING
Abort trap: 6

[PhilMiller]

(lldb) f 5
frame #5: 0x0000000100c28ed8 test_all`giuh::giuh_kernel_impl::interpolate_regularized_cdf(this=0x000000016fdfd330) at GIUH.cpp:134:62
   131 	        cdf_times_index_for_iteration--;
   132 	
   133 	        // Then apply equation from spreadsheet
-> 134 	        double result = (time_for_ordinate - this->cdf_times.at(cdf_times_index_for_iteration)) /
   135 	                        (this->cdf_times[cdf_times_index_for_iteration + 1] -
   136 	                         this->cdf_times[cdf_times_index_for_iteration]) *
   137 	                        (this->cdf_cumulative_freqs[cdf_times_index_for_iteration + 1] -

(lldb) p cdf_times_index_for_iteration 
(int) $0 = -1

@robertbartel looks like the decrement leaves us with an index of -1 in some cases

[robertbartel]

Looking quickly, I think we are prevented from coming across that case because of what the values are and how they are used. But I am pretty sure we can just do this to make the sanitizer happy:

diff --git a/src/core/catchment/giuh/GIUH.cpp b/src/core/catchment/giuh/GIUH.cpp
index c86143e09..cab60f7ed 100644
--- a/src/core/catchment/giuh/GIUH.cpp
+++ b/src/core/catchment/giuh/GIUH.cpp
@@ -123,7 +123,7 @@ void giuh_kernel_impl::interpolate_regularized_cdf()
 
         // Find index 'i' of largest CDF time less than the time for the current ordinate
         // Start by getting the index of the first time greater than time_for_ordinate
-        int cdf_times_index_for_iteration = 0;
+        int cdf_times_index_for_iteration = 1;
         while (this->cdf_times[cdf_times_index_for_iteration] < regularized_times_s.back()) {
             cdf_times_index_for_iteration++;
         }

[PhilMiller]

To be clear, ASan is a dynamic runtime analysis, not a static analyzer. This isn't a false positive - the case in question actually happened in our tests, and the code actually threw the exception when I changed [] to .at()