[SYCL] fix for std::locale::global interfering with allowlist check (#18550)

`std::locale::global()` is a very common way for apps to initialize
string localization for numeric and monetary values. Unfortunately, it
is global.
In this very limited fix, we are preventing it from interfering with the
allowlist check which uses `std::stringstream`. The insertion of commas
into numbers for the locale support messes with the expected values.
We'll probably have to audit the other uses of std streams to see if
they would be similarly vulnerable.

---------

Signed-off-by: Chris Perkins <[email protected]>

Author: cperkinsintel

sycl/source/detail/allowlist.cpp

@@ -428,6 +428,8 @@ void applyAllowList(std::vector<ur_device_handle_t> &UrDevices,
     uint32_t DeviceVendorIdUInt =
         DeviceImpl.get_info<info::device::vendor_id>();
     std::stringstream DeviceVendorIdHexStringStream;
+    // To avoid commas or other locale-specific modifications, call imbue().
+    DeviceVendorIdHexStringStream.imbue(std::locale::classic());
     DeviceVendorIdHexStringStream << "0x" << std::hex << DeviceVendorIdUInt;
     const auto &DeviceVendorIdValue = DeviceVendorIdHexStringStream.str();
     DeviceDesc[DeviceVendorIdKeyName] = DeviceVendorIdValue;

sycl/unittests/allowlist/DeviceIsAllowed.cpp

@@ -7,9 +7,14 @@
 //===----------------------------------------------------------------------===//
 
 #include <detail/allowlist.hpp>
+#include <sycl/platform.hpp>
 
 #include <gtest/gtest.h>
 
+#ifdef _WIN32
+#include <windows.h> // SetEnvironmentVariable
+#endif
+
 constexpr char SyclDeviceAllowList[] =
     "BackendName:opencl,DeviceType:gpu,DeviceVendorId:0x8086,DriverVersion:{{("
     "19\\.(4[3-9]|[5-9]\\d)\\..*)|([2-9][0-9]\\.\\d+\\..*)|(\\d+\\.\\d+\\."
@@ -85,6 +90,35 @@ TEST(DeviceIsAllowedTests, CheckSupportedOpenCLGPUDeviceIsAllowed) {
   EXPECT_EQ(Actual, true);
 }
 
+TEST(DeviceIsAllowedTests, CheckLocalizationDoesNotImpact) {
+  // The localization can affect std::stringstream output.
+  // We want to make sure that DeviceVenderId doesn't have a comma
+  // inserted (ie "0x8,086" ), which will break the platform retrieval.
+
+  try {
+    auto previous = std::locale::global(std::locale("en_US.UTF-8"));
+#ifdef _WIN32
+    SetEnvironmentVariableA("SYCL_DEVICE_ALLOWLIST", SyclDeviceAllowList);
+#else
+    setenv("SYCL_DEVICE_ALLOWLIST", SyclDeviceAllowList, 1);
+#endif
+
+    auto post_platforms = sycl::platform::get_platforms();
+    std::locale::global(previous);
+#ifdef _WIN32
+    SetEnvironmentVariableA("SYCL_DEVICE_ALLOWLIST", nullptr);
+#else
+    unsetenv("SYCL_DEVICE_ALLOWLIST");
+#endif
+
+    EXPECT_NE(size_t{0}, post_platforms.size());
+  } catch (...) {
+    // It is possible that the en_US locale is not available.
+    // In this case, we just skip the test.
+    GTEST_SKIP() << "Locale en_US.UTF-8 not available.";
+  }
+}
+
 TEST(DeviceIsAllowedTests, CheckSupportedOpenCLCPUDeviceIsAllowed) {
   bool Actual = sycl::detail::deviceIsAllowed(
       OpenCLCPUDeviceDesc, sycl::detail::parseAllowList(SyclDeviceAllowList));