Set SystemDrive env var on osquery command

pkg/osquery/runtime/osqueryinstance.go

@@ -802,6 +802,14 @@ func (i *OsqueryInstance) createOsquerydCommand(osquerydBinary string, paths *os
 	// https://github.com/osquery/osquery/pull/6824
 	cmd.Env = append(cmd.Env, "SYSTEM_VERSION_COMPAT=0")
 
+	// On Windows, we want the `SystemDrive` environment variable to be set to ensure paths can be resolved appropriately.
+	// The cmd handles setting `SystemRoot` for us.
+	if runtime.GOOS == "windows" {
+		if systemDrive, found := os.LookupEnv("SystemDrive"); found {
+			cmd.Env = append(cmd.Env, fmt.Sprintf("SystemDrive=%s", systemDrive))
+		}
+	}
+
 	return cmd, nil
 }
 

pkg/osquery/runtime/osqueryinstance_windows_test.go

@@ -0,0 +1,50 @@
+//go:build windows
+// +build windows
+
+package runtime
+
+import (
+	"strings"
+	"testing"
+
+	typesMocks "github.com/kolide/launcher/ee/agent/types/mocks"
+	"github.com/kolide/launcher/pkg/log/multislogger"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateOsqueryCommandEnvVars(t *testing.T) {
+	t.Parallel()
+
+	osquerydPath := testOsqueryBinaryDirectory
+
+	k := typesMocks.NewKnapsack(t)
+	k.On("WatchdogEnabled").Return(true)
+	k.On("WatchdogMemoryLimitMB").Return(150)
+	k.On("WatchdogUtilizationLimitPercent").Return(20)
+	k.On("WatchdogDelaySec").Return(120)
+	k.On("OsqueryVerbose").Return(true)
+	k.On("OsqueryFlags").Return([]string{})
+	k.On("Slogger").Return(multislogger.NewNopLogger())
+
+	i := newInstance(defaultRegistrationId, k, mockServiceClient())
+
+	cmd, err := i.createOsquerydCommand(osquerydPath, &osqueryFilePaths{
+		pidfilePath:           "/foo/bar/osquery-abcd.pid",
+		databasePath:          "/foo/bar/osquery.db",
+		extensionSocketPath:   "/foo/bar/osquery.sock",
+		extensionAutoloadPath: "/foo/bar/osquery.autoload",
+	})
+	require.NoError(t, err)
+
+	systemDriveEnvVarFound := false
+	for _, envVar := range cmd.Env {
+		if strings.Contains(envVar, "SystemDrive") {
+			systemDriveEnvVarFound = true
+			break
+		}
+	}
+
+	require.True(t, systemDriveEnvVarFound, "SystemDrive env var missing from command")
+
+	k.AssertExpectations(t)
+}