safe-redirect

function visit(node, filename, code) {
  if (!useImportFrom(node.context.imports, "django.http", "HttpResponseRedirect") && !useImportFrom(node.context.imports, "django.http", "HttpResponse")) {
    return;
  }

  if (!node.parameters) {
    return;
  }

  if (node.parameters.values.length !== 1) {
    return;
  }

  const firstParameterName = node.parameters.values[0].name;
  if (firstParameterName.astType !== "string") {
    return;
  }

  const requestVariableName = firstParameterName.value;

  const userVariablesFromRequest = [];
  const responsesVariables = [];

  const checkRedirectCall = (element, variables) => {
    if (element.astType === "return") {
      checkRedirectCall(element.value, variables);
    }

    if (element.astType === "assignment") {
      checkRedirectCall(element.right, variables);
    }


    if (element.astType === "functioncall") {
      if (element.functionName.value === "HttpResponseRedirect") {
        if (element.arguments.values && element.arguments.values.length === 1) {
          const firstArgument = element.arguments.values[0].value;
          if (firstArgument.astType === "string" && variables.includes(firstArgument.value)) {
            const error = buildError(element.start.line, element.start.col,
              element.end.line, element.end.col,
              "do not use user-input", "CRITICAL", "SECURITY");

            const edit = buildEditUpdate(firstArgument.start.line, firstArgument.start.col, firstArgument.end.line, firstArgument.end.col, `url_for(${firstArgument.value})`);

            addError(error);
          }
        }
      }
    }
  };


  node.content.elements && node.content.elements.forEach(e => {
    console.log(e.astType);
    // First, find variables inferred from the requests
    if (e.astType === "assignment") {
      if (e.left.astType === "string" && e.right.astType === "functioncall" && e.right.functionName.value === "get" && e.right.moduleOrObject && e.right.moduleOrObject.value === `${requestVariableName}.GET`) {
        userVariablesFromRequest.push(e.left.value);
        console.log(`pushing ${e.left.value}`);
      }
    }

    // Check if we build a response object
    if (e.astType === "assignment") {
      if (e.left.astType === "string" && e.right.astType === "functioncall" && e.right.functionName.value === "HttpResponse") {
        console.log("pushing");
        console.log(e.left.value);
        responsesVariables.push(e.left.value);
      }
    }

    // Check if we assign to a response
    if (e.astType === "assignment" && e.left.astType === "variableindex" && e.right.astType === "string" && userVariablesFromRequest.includes(e.right.value)) {
      const vi = e.left;
      if (responsesVariables.includes(vi.variable.value) && vi.index.value === "'Location'") {
        const error = buildError(e.start.line, e.start.col,
          e.end.line, e.end.col,
          "do not use user-input", "CRITICAL", "SECURITY");
        addError(error);

      }
    }

    // check if we have a redirect call
    checkRedirectCall(e, userVariablesFromRequest);
  });
}