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Builder: avoid duplicity of imports, sort imports lexicographically #78

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merged 1 commit into from
Mar 19, 2020
Merged

Builder: avoid duplicity of imports, sort imports lexicographically #78

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8 changes: 6 additions & 2 deletions include/yaramod/builder/yara_file_builder.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@

#pragma once

#include <map>
#include <memory>
#include <vector>

Expand Down Expand Up @@ -56,10 +57,13 @@ class YaraFileBuilder
YaraFileBuilder& withRule(const std::shared_ptr<Rule>& rule);
/// @}

protected:
void insertImportIntoTokenStream(TokenIt before, const std::string& moduleName);

private:
bool _lastAddedWasImport = false; ///< Flag to determine newlines
std::shared_ptr<TokenStream> _tokenStream; ///< Tokens storage
std::vector<TokenIt> _module_tokens; ///< Modules
std::map<std::string, TokenIt> _module_tokens; ///< Modules
TokenIt _newline_after_imports; ///< Always stands behind newline after last import in the TokenStream
ImportFeatures _import_features; ///< Determines which modules should be possible to load
ModulesPool _modules_pool; ///< Storage of used modules
std::vector<std::shared_ptr<Rule>> _rules; ///< Rules
Expand Down
42 changes: 29 additions & 13 deletions src/builder/yara_file_builder.cpp
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Expand Up @@ -20,7 +20,8 @@ namespace yaramod {
std::unique_ptr<YaraFile> YaraFileBuilder::get(bool recheck, ParserDriver* external_driver)
{
auto yaraFile = std::make_unique<YaraFile>(std::move(_tokenStream), _import_features);
yaraFile->addImports(_module_tokens, _modules_pool);
for (const auto& module_token : _module_tokens)
yaraFile->addImport(module_token.second, _modules_pool);
yaraFile->addRules(_rules);

_module_tokens.clear();
Expand Down Expand Up @@ -67,6 +68,14 @@ std::unique_ptr<YaraFile> YaraFileBuilder::get(bool recheck, ParserDriver* exter
return yaraFile;
}

void YaraFileBuilder::insertImportIntoTokenStream(TokenIt before, const std::string& moduleName)
{
_tokenStream->emplace(before, TokenType::IMPORT_KEYWORD, "import");
auto moduleToken = _tokenStream->emplace(before, TokenType::IMPORT_MODULE, moduleName);
_tokenStream->emplace(before, NEW_LINE, "\n");
_module_tokens.insert(std::make_pair(moduleName, moduleToken));
}

/**
* Adds module to YARA file.
*
Expand All @@ -76,16 +85,25 @@ std::unique_ptr<YaraFile> YaraFileBuilder::get(bool recheck, ParserDriver* exter
*/
YaraFileBuilder& YaraFileBuilder::withModule(const std::string& moduleName)
{
if (!_module_tokens.empty())
TokenIt moduleToken;
if (_module_tokens.empty())
{
if (!_lastAddedWasImport)
_tokenStream->emplace_back(NEW_LINE, "\n");
auto before = _tokenStream->begin();
insertImportIntoTokenStream(before, moduleName);
_newline_after_imports = _tokenStream->emplace(before, NEW_LINE, "\n");
}
_tokenStream->emplace_back(TokenType::IMPORT_KEYWORD, "import");
TokenIt moduleToken = _tokenStream->emplace_back(TokenType::IMPORT_MODULE, moduleName);
_tokenStream->emplace_back(NEW_LINE, "\n");
_module_tokens.push_back(moduleToken);
_lastAddedWasImport = true;
else
{
auto close_module = _module_tokens.lower_bound(moduleName);
if (close_module == _module_tokens.end())
insertImportIntoTokenStream(_newline_after_imports, moduleName);
else if (close_module->first != moduleName)
{
auto before = _tokenStream->findBackwards(TokenType::IMPORT_KEYWORD, close_module->second);
insertImportIntoTokenStream(before, moduleName);
}
}

return *this;
}

Expand All @@ -111,14 +129,13 @@ YaraFileBuilder& YaraFileBuilder::withRule(Rule&& rule)
*/
YaraFileBuilder& YaraFileBuilder::withRule(std::unique_ptr<Rule>&& rule)
{
if (!_rules.empty() || _lastAddedWasImport)
if (!_rules.empty())
_tokenStream->emplace_back(NEW_LINE, "\n");

_tokenStream->move_append(rule->getTokenStream());
_tokenStream->emplace_back(NEW_LINE, "\n");

_rules.emplace_back(std::move(rule));
_lastAddedWasImport = false;
return *this;
}

Expand All @@ -131,13 +148,12 @@ YaraFileBuilder& YaraFileBuilder::withRule(std::unique_ptr<Rule>&& rule)
*/
YaraFileBuilder& YaraFileBuilder::withRule(const std::shared_ptr<Rule>& rule)
{
if (!_rules.empty() || _lastAddedWasImport)
if (!_rules.empty() || !_module_tokens.empty())
_tokenStream->emplace_back(NEW_LINE, "\n");

_tokenStream->move_append(rule->getTokenStream());
_tokenStream->emplace_back(NEW_LINE, "\n");
_rules.emplace_back(rule);
_lastAddedWasImport = false;
return *this;
}

Expand Down
102 changes: 101 additions & 1 deletion tests/cpp/builder_tests.cpp
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Expand Up @@ -41,8 +41,36 @@ PureImportsWorks) {
.get(true, &driver);

ASSERT_NE(nullptr, yaraFile);
EXPECT_EQ(R"(import "pe"
EXPECT_EQ(R"(import "elf"
import "pe"
)", yaraFile->getText());
}

TEST_F(BuilderTests,
PureImportsComplicateWorks) {
YaraFileBuilder newFile;
auto yaraFile = newFile
.withModule("pe")
.withModule("cuckoo")
.withModule("elf")
.get(true, &driver);

ASSERT_NE(nullptr, yaraFile);
EXPECT_EQ(R"(import "cuckoo"
import "elf"
import "pe"
)", yaraFile->getText());

yaraFile = newFile
.withModule("cuckoo")
.withModule("pe")
.withModule("elf")
.get(true, &driver);

ASSERT_NE(nullptr, yaraFile);
EXPECT_EQ(R"(import "cuckoo"
import "elf"
import "pe"
)", yaraFile->getText());
}

Expand Down Expand Up @@ -75,6 +103,78 @@ UnnamedRuleWorks) {
)", yaraFile->getTextFormatted());
}

TEST_F(BuilderTests,
UnnamedRuleWithImportsWorks) {
YaraRuleBuilder newRule;
auto rule = newRule.get();

YaraFileBuilder newFile;
auto yaraFile = newFile
.withRule(std::move(rule))
.withModule("cuckoo")
.withModule("pe")
.withModule("cuckoo")
.withModule("elf")
.get(true);

ASSERT_NE(nullptr, yaraFile);
EXPECT_EQ(R"(import "cuckoo"
import "elf"
import "pe"
rule unknown {
condition:
true
})", yaraFile->getText());

EXPECT_EQ(R"(import "cuckoo"
import "elf"
import "pe"
rule unknown
{
condition:
true
}
)", yaraFile->getTextFormatted());
}

TEST_F(BuilderTests,
UnnamedRuleWithImportsWorks2) {
YaraRuleBuilder newRule;
auto rule = newRule.get();

YaraFileBuilder newFile;
auto yaraFile = newFile
.withModule("cuckoo")
.withModule("pe")
.withRule(std::move(rule))
.withModule("cuckoo")
.withModule("elf")
.get(true);

ASSERT_NE(nullptr, yaraFile);
EXPECT_EQ(R"(import "cuckoo"
import "elf"
import "pe"
rule unknown {
condition:
true
})", yaraFile->getText());

EXPECT_EQ(R"(import "cuckoo"
import "elf"
import "pe"
rule unknown
{
condition:
true
}
)", yaraFile->getTextFormatted());
}

TEST_F(BuilderTests,
RuleWithCustomNameWorks) {
YaraRuleBuilder newRule;
Expand Down
9 changes: 5 additions & 4 deletions tests/python/test_builder.py
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Expand Up @@ -19,13 +19,14 @@ def test_pure_imports(self):
.with_module('elf') \
.get()

self.assertEqual(yara_file.text_formatted, '''import "phish"
self.assertEqual(yara_file.text_formatted, '''import "elf"
import "pe"
import "elf"
import "phish"
''')
self.assertEqual(yara_file.text, '''import "phish"
self.assertEqual(yara_file.text, '''import "elf"
import "pe"
import "elf"
import "phish"
''')

def test_empty_rule(self):
Expand Down