ModSecurity/src/rule.cc
2017-08-16 23:42:13 -03:00

865 lines
26 KiB
C++

/*
* ModSecurity, http://www.modsecurity.org/
* Copyright (c) 2015 Trustwave Holdings, Inc. (http://www.trustwave.com/)
*
* You may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* If any of the files related to licensing are missing or if you have any
* other questions related to licensing please contact Trustwave Holdings, Inc.
* directly using the email address security@modsecurity.org.
*
*/
#include "modsecurity/rule.h"
#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <cstring>
#include <list>
#include <utility>
#include "src/operators/operator.h"
#include "modsecurity/actions/action.h"
#include "modsecurity/modsecurity.h"
#include "src/actions/transformations/none.h"
#include "src/actions/tag.h"
#include "src/utils/string.h"
#include "modsecurity/rules.h"
#include "modsecurity/rule_message.h"
#include "src/macro_expansion.h"
#include "src/actions/msg.h"
#include "src/actions/log_data.h"
#include "src/actions/severity.h"
#include "src/variables/variable.h"
namespace modsecurity {
using operators::Operator;
using actions::Action;
using Variables::Variable;
using actions::transformations::None;
Rule::Rule(std::string marker)
: m_accuracy(0),
m_actionsConf(),
m_actionsRuntimePos(),
m_actionsRuntimePre(),
m_chained(false),
m_chainedRule(NULL),
m_fileName(""),
m_lineNumber(0),
m_logData(""),
m_marker(marker),
m_maturity(0),
m_op(NULL),
m_phase(-1),
m_rev(""),
m_ruleId(0),
m_secMarker(true),
m_variables(NULL),
m_ver(""),
m_unconditional(false),
m_referenceCount(1) { }
Rule::Rule(Operator *_op,
std::vector<Variable *> *_variables,
std::vector<Action *> *actions,
std::string fileName,
int lineNumber)
: m_accuracy(0),
m_actionsConf(),
m_actionsRuntimePos(),
m_actionsRuntimePre(),
m_chained(false),
m_chainedRule(NULL),
m_fileName(fileName),
m_lineNumber(lineNumber),
m_logData(""),
m_marker(""),
m_maturity(0),
m_op(_op),
m_phase(-1),
m_rev(""),
m_ruleId(0),
m_secMarker(false),
m_variables(_variables),
m_ver(""),
m_unconditional(false),
m_referenceCount(1) {
if (actions != NULL) {
for (Action *a : *actions) {
if (a->action_kind == Action::ConfigurationKind) {
m_actionsConf.push_back(a);
a->evaluate(this, NULL);
} else if (a->action_kind
== Action::RunTimeBeforeMatchAttemptKind) {
m_actionsRuntimePre.push_back(a);
} else if (a->action_kind == Action::RunTimeOnlyIfMatchKind) {
m_actionsRuntimePos.push_back(a);
} else {
std::cout << "General failure, action: " << a->m_name;
std::cout << " has an unknown type." << std::endl;
delete a;
}
}
}
/**
* If phase is not entered, we assume phase 2. For historical reasons.
*
*/
if (m_phase == -1) {
m_phase = modsecurity::Phases::RequestHeadersPhase;
}
if (m_op == NULL) {
m_unconditional = true;
}
delete actions;
}
Rule::~Rule() {
if (m_op != NULL) {
delete m_op;
}
while (m_actionsConf.empty() == false) {
auto *a = m_actionsConf.back();
m_actionsConf.pop_back();
delete a;
}
while (m_actionsRuntimePre.empty() == false) {
auto *a = m_actionsRuntimePre.back();
m_actionsRuntimePre.pop_back();
delete a;
}
while (m_actionsRuntimePos.empty() == false) {
auto *a = m_actionsRuntimePos.back();
m_actionsRuntimePos.pop_back();
delete a;
}
while (m_variables != NULL && m_variables->empty() == false) {
auto *a = m_variables->back();
m_variables->pop_back();
delete a;
}
if (m_variables != NULL) {
delete m_variables;
}
if (m_chainedRule != NULL) {
delete m_chainedRule;
}
}
std::vector<std::string> Rule::getActionNames() {
std::vector<std::string> a;
for (auto &z : this->m_actionsRuntimePos) {
a.push_back(z->m_name);
}
for (auto &z : this->m_actionsRuntimePre) {
a.push_back(z->m_name);
}
for (auto &z : this->m_actionsConf) {
a.push_back(z->m_name);
}
return a;
}
bool Rule::evaluateActions(Transaction *trans) {
return true;
}
void Rule::updateMatchedVars(Transaction *trans, std::string key,
std::string value) {
trans->debug(9, "Matched vars updated.");
trans->m_variableMatchedVar.set(value, trans->m_variableOffset);
trans->m_variableMatchedVarName.set(key, trans->m_variableOffset);
trans->m_variableMatchedVars.set(key, value, trans->m_variableOffset);
trans->m_variableMatchedVarsNames.set(key, key, trans->m_variableOffset);
}
void Rule::cleanMatchedVars(Transaction *trans) {
trans->debug(9, "Matched vars cleaned.");
trans->m_variableMatchedVar.unset();
trans->m_variableMatchedVars.unset();
trans->m_variableMatchedVarName.unset();
trans->m_variableMatchedVarsNames.unset();
}
void Rule::updateRulesVariable(Transaction *trans) {
if (m_ruleId != 0) {
trans->m_variableRule.set("id",
std::to_string(m_ruleId), 0);
}
if (m_rev.empty() == false) {
trans->m_variableRule.set("rev",
m_rev, 0);
}
if (getActionsByName("msg").size() > 0) {
actions::Msg *msg = dynamic_cast<actions::Msg*>(
getActionsByName("msg")[0]);
trans->m_variableRule.set("msg",
msg->data(trans), 0);
}
if (getActionsByName("logdata").size() > 0) {
actions::LogData *data = dynamic_cast<actions::LogData*>(
getActionsByName("logdata")[0]);
trans->m_variableRule.set("logdata",
data->data(trans), 0);
}
if (getActionsByName("severity").size() > 0) {
actions::Severity *data = dynamic_cast<actions::Severity*>(
getActionsByName("severity")[0]);
trans->m_variableRule.set("severity",
std::to_string(data->m_severity), 0);
}
}
std::string Rule::resolveMatchMessage(std::string key, std::string value) {
std::string ret = this->m_op->m_match_message;
if (ret.empty() == true) {
ret = "Matched \"Operator `" + this->m_op->m_op + "' with parameter `" +
utils::string::limitTo(200, this->m_op->m_param) +
"' against variable `" + key + "' (Value: `" +
utils::string::limitTo(100, utils::string::toHexIfNeeded(value)) +
"' )";
}
return ret;
}
void Rule::executeActionsIndependentOfChainedRuleResult(Transaction *trans,
bool *containsDisruptive, std::shared_ptr<RuleMessage> ruleMessage) {
for (Action *a : this->m_actionsRuntimePos) {
if (a->isDisruptive() == true) {
if (a->m_name == "pass") {
trans->debug(9, "Rule contains a `pass' action");
} else {
*containsDisruptive = true;
}
} else {
if (a->m_name == "setvar" || a->m_name == "msg" || a->m_name == "log") {
trans->debug(4, "Running [independent] (non-disruptive) action: " + a->m_name);
a->evaluate(this, trans, ruleMessage);
}
}
}
}
bool Rule::executeOperatorAt(Transaction *trans, std::string key,
std::string value, std::shared_ptr<RuleMessage> ruleMessage) {
#if MSC_EXEC_CLOCK_ENABLED
clock_t begin = clock();
clock_t end;
double elapsed_s = 0;
#endif
bool ret;
trans->debug(9, "Target value: \"" + utils::string::limitTo(80,
utils::string::toHexIfNeeded(value)) \
+ "\" (Variable: " + key + ")");
ret = this->m_op->evaluateInternal(trans, this, value, ruleMessage);
if (ret == false) {
return false;
}
#if MSC_EXEC_CLOCK_ENABLED
end = clock();
elapsed_s = static_cast<double>(end - begin) / CLOCKS_PER_SEC;
trans->debug(5, "Operator completed in " + \
std::to_string(elapsed_s) + " seconds");
#endif
return ret;
}
std::list<std::pair<std::shared_ptr<std::string>,
std::shared_ptr<std::string>>>
Rule::executeDefaultTransformations(
Transaction *trans, const std::string &in, bool multiMatch) {
int none = 0;
int transformations = 0;
std::list<std::pair<std::shared_ptr<std::string>,
std::shared_ptr<std::string>>> ret;
std::shared_ptr<std::string> value =
std::shared_ptr<std::string>(new std::string(in));
std::shared_ptr<std::string> newValue;
std::shared_ptr<std::string> transStr =
std::shared_ptr<std::string>(new std::string());
if (multiMatch == true) {
ret.push_back(std::make_pair(
std::shared_ptr<std::string>(value),
std::shared_ptr<std::string>(transStr)));
ret.push_back(std::make_pair(
std::shared_ptr<std::string>(value),
std::shared_ptr<std::string>(transStr)));
}
for (Action *a : this->m_actionsRuntimePre) {
if (a->m_isNone) {
none++;
}
}
// Check for transformations on the SecDefaultAction
// Notice that first we make sure that won't be a t:none
// on the target rule.
if (none == 0) {
for (Action *a : trans->m_rules->m_defaultActions[this->m_phase]) {
if (a->action_kind \
== actions::Action::RunTimeBeforeMatchAttemptKind) {
newValue = std::unique_ptr<std::string>(
new std::string(a->evaluate(*value, trans)));
if (multiMatch == true) {
if (*newValue != *value) {
ret.push_back(std::make_pair(
newValue,
transStr));
}
}
value = std::shared_ptr<std::string>(newValue);
if (transStr->empty()) {
transStr->append(a->m_name);
} else {
transStr->append("," + a->m_name);
}
trans->debug(9, "(SecDefaultAction) T (" + \
std::to_string(transformations) + ") " + \
a->m_name + ": \"" + \
utils::string::limitTo(80, *value) +"\"");
transformations++;
}
}
}
for (Action *a : this->m_actionsRuntimePre) {
if (none == 0) {
newValue = std::shared_ptr<std::string>(
new std::string(a->evaluate(*value, trans)));
if (multiMatch == true) {
if (*value != *newValue) {
ret.push_back(std::make_pair(
newValue,
transStr));
value = newValue;
}
}
value = newValue;
trans->debug(9, " T (" + \
std::to_string(transformations) + ") " + \
a->m_name + ": \"" + \
utils::string::limitTo(80, *value) + "\"");
if (transStr->empty()) {
transStr->append(a->m_name);
} else {
transStr->append("," + a->m_name);
}
transformations++;
}
if (a->m_isNone) {
none--;
}
}
if (multiMatch == true) {
// v2 checks the last entry twice. Don't know why.
ret.push_back(ret.back());
trans->debug(9, "multiMatch is enabled. " \
+ std::to_string(ret.size()) + \
" values to be tested.");
} else {
ret.push_back(std::make_pair(
std::shared_ptr<std::string>(value),
std::shared_ptr<std::string>(transStr)));
}
return ret;
}
std::vector<std::unique_ptr<collection::Variable>> Rule::getFinalVars(
Transaction *trans) {
std::list<const std::string*> exclusions;
std::list<const std::string*> exclusions_update_by_tag_remove;
std::list<const std::string*> exclusions_update_by_id_remove;
std::vector<Variables::Variable *> variables;
std::vector<std::unique_ptr<collection::Variable>> finalVars;
std::copy (m_variables->begin(), m_variables->end(), std::back_inserter(variables));
for (auto &a : trans->m_rules->m_exceptions.m_variable_update_target_by_tag) {
if (containsTag(a.first, trans) == false) {
continue;
}
if (a.second->m_isExclusion) {
std::vector<const collection::Variable *> z;
a.second->evaluateInternal(trans, this, &z);
for (auto &y : z) {
exclusions_update_by_tag_remove.push_back(y->m_key);
}
exclusions_update_by_tag_remove.push_back(&a.second->m_name);
} else {
Variable *b = a.second.get();
variables.push_back(b);
}
}
for (auto &a : trans->m_rules->m_exceptions.m_variable_update_target_by_id) {
if (m_ruleId != a.first) {
continue;
}
if (a.second->m_isExclusion) {
std::vector<const collection::Variable *> z;
a.second->evaluateInternal(trans, this, &z);
for (auto &y : z) {
exclusions_update_by_id_remove.push_back(y->m_key);
}
exclusions_update_by_id_remove.push_back(&a.second->m_name);
} else {
Variable *b = a.second.get();
variables.push_back(b);
}
}
for (int i = 0; i < variables.size(); i++) {
Variable *variable = variables.at(i);
if (variable->m_isExclusion) {
std::vector<const collection::Variable *> z;
variable->evaluateInternal(trans, this, &z);
for (auto &y : z) {
exclusions.push_back(y->m_key);
}
exclusions.push_back(&variable->m_name);
}
}
for (int i = 0; i < variables.size(); i++) {
Variable *variable = variables.at(i);
std::vector<const collection::Variable *> e;
bool ignoreVariable = false;
if (variable->m_isExclusion) {
continue;
}
variable->evaluateInternal(trans, this, &e);
for (const collection::Variable *v : e) {
const std::string *key = v->m_key;
if (std::find_if(exclusions.begin(), exclusions.end(),
[key](const std::string *m) -> bool { return *key == *m; })
!= exclusions.end()) {
#ifndef NO_LOGS
trans->debug(9, "Variable: " + *key +
" is part of the exclusion list, skipping...");
#endif
if (v->m_dynamic) {
delete v;
v = NULL;
}
continue;
}
if (std::find_if(exclusions_update_by_tag_remove.begin(),
exclusions_update_by_tag_remove.end(),
[key](const std::string *m) -> bool { return *key == *m; })
!= exclusions_update_by_tag_remove.end()) {
#ifndef NO_LOGS
trans->debug(9, "Variable: " + *key +
" is part of the exclusion list (from update by tag" +
"), skipping...");
#endif
if (v->m_dynamic) {
delete v;
v = NULL;
}
continue;
}
if (std::find_if(exclusions_update_by_id_remove.begin(),
exclusions_update_by_id_remove.end(),
[key](const std::string *m) -> bool { return *key == *m; })
!= exclusions_update_by_id_remove.end()) {
#ifndef NO_LOGS
trans->debug(9, "Variable: " + *key +
" is part of the exclusion list (from update by ID), skipping...");
#endif
if (v->m_dynamic) {
delete v;
v = NULL;
}
continue;
}
for (auto &i : trans->m_ruleRemoveTargetByTag) {
std::string tag = i.first;
std::string args = i.second;
size_t posa = key->find(":");
if (containsTag(tag, trans) == false) {
continue;
}
if (args == *key) {
trans->debug(9, "Variable: " + *key +
" was excluded by ruleRemoteTargetByTag...");
ignoreVariable = true;
break;
}
if (posa != std::string::npos) {
std::string var = std::string(*key, posa);
if (var == args) {
trans->debug(9, "Variable: " + *key +
" was excluded by ruleRemoteTargetByTag...");
ignoreVariable = true;
break;
}
}
}
if (ignoreVariable) {
if (v->m_dynamic) {
delete v;
v = NULL;
}
continue;
}
for (auto &i : trans->m_ruleRemoveTargetById) {
int id = i.first;
std::string args = i.second;
size_t posa = key->find(":");
if (m_ruleId != id) {
continue;
}
if (args == *key) {
trans->debug(9, "Variable: " + *key +
" was excluded by ruleRemoveTargetById...");
ignoreVariable = true;
break;
}
if (posa != std::string::npos) {
if (key->size() > posa) {
std::string var = std::string(*key, 0, posa);
if (var == args) {
trans->debug(9, "Variable: " + var +
" was excluded by ruleRemoveTargetById...");
ignoreVariable = true;
break;
}
}
}
}
if (ignoreVariable) {
if (v->m_dynamic) {
delete v;
v = NULL;
}
continue;
}
std::unique_ptr<collection::Variable> var(new collection::Variable(
new std::string(*v->m_key),
new std::string(*v->m_value)));
var->m_dynamic_value = true;
var->m_dynamic_key = true;
for (auto &i : v->m_orign) {
std::unique_ptr<VariableOrigin> origin(new VariableOrigin());
origin->m_offset = i->m_offset;
origin->m_length = i->m_length;
var->m_orign.push_back(std::move(origin));
}
if (v->m_dynamic) {
delete v;
v = NULL;
}
finalVars.push_back(std::move(var));
}
}
return finalVars;
}
void Rule::executeActionsAfterFullMatch(Transaction *trans,
bool containsDisruptive, std::shared_ptr<RuleMessage> ruleMessage) {
for (Action *a : trans->m_rules->m_defaultActions[this->m_phase]) {
if (a->action_kind != actions::Action::RunTimeOnlyIfMatchKind) {
continue;
}
if (a->isDisruptive() == false) {
trans->debug(9, "(SecDefaultAction) Running " \
"action: " + a->m_name);
a->evaluate(this, trans, ruleMessage);
continue;
}
if (containsDisruptive) {
trans->debug(4, "(SecDefaultAction) ignoring " \
"action: " + a->m_name + \
" (rule contains a disruptive action)");
continue;
}
if (trans->getRuleEngineState() == Rules::EnabledRuleEngine) {
trans->debug(4, "(SecDefaultAction) " \
"Running action: " + a->m_name + \
" (rule does not contain a disruptive action)");
a->evaluate(this, trans, ruleMessage);
continue;
}
trans->debug(4, "(SecDefaultAction) Not running action: " \
+ a->m_name + ". Rule does not contain a disruptive action,"\
+ " but SecRuleEngine is not On.");
}
for (Action *a : this->m_actionsRuntimePos) {
if (a->isDisruptive() == false) {
if (a->m_name != "setvar" && a->m_name != "log"
&& a->m_name != "msg") {
trans->debug(4, "Running (non-disruptive) action: " + a->m_name);
a->evaluate(this, trans, ruleMessage);
}
continue;
}
if (trans->getRuleEngineState() == Rules::EnabledRuleEngine) {
trans->debug(4, "Running (disruptive) action: " + a->m_name);
a->evaluate(this, trans, ruleMessage);
continue;
}
trans->debug(4, "Not running disruptive action: " + \
a->m_name + ". SecRuleEngine is not On");
}
}
bool Rule::evaluate(Transaction *trans,
std::shared_ptr<RuleMessage> ruleMessage) {
bool globalRet = false;
std::vector<Variable *> *variables = this->m_variables;
bool recursiveGlobalRet;
bool containsDisruptive = false;
std::vector<std::unique_ptr<collection::Variable>> finalVars;
std::string eparam;
if (ruleMessage == NULL) {
ruleMessage = std::shared_ptr<RuleMessage>(
new RuleMessage(this, trans));
}
trans->m_matched.clear();
if (m_secMarker == true) {
return true;
}
if (m_unconditional == true) {
trans->debug(4, "(Rule: " + std::to_string(m_ruleId) \
+ ") Executing unconditional rule...");
executeActionsIndependentOfChainedRuleResult(trans,
&containsDisruptive, ruleMessage);
goto end_exec;
}
for (auto &i : trans->m_ruleRemoveById) {
if (m_ruleId != i) {
continue;
}
trans->debug(9, "Rule id: " + std::to_string(m_ruleId) +
" was skipped due to an ruleRemoveById action...");
return true;
}
eparam = MacroExpansion::expand(this->m_op->m_param, trans);
if (this->m_op->m_param != eparam) {
eparam = "\"" + eparam + "\" Was: \"" + this->m_op->m_param + "\"";
} else {
eparam = "\"" + eparam + "\"";
}
trans->debug(4, "(Rule: " + std::to_string(m_ruleId) \
+ ") Executing operator \"" + this->m_op->m_op \
+ "\" with param " \
+ eparam \
+ " against " \
+ Variable::to_s(variables) + ".");
updateRulesVariable(trans);
finalVars = getFinalVars(trans);
for (auto &v : finalVars) {
const std::string value = *(v->m_value);
const std::string key = *(v->m_key);
std::list<std::pair<std::shared_ptr<std::string>,
std::shared_ptr<std::string>>> values;
bool multiMatch = getActionsByName("multimatch").size() > 0;
values = executeDefaultTransformations(trans, value,
multiMatch);
for (const auto &valueTemp : values) {
bool ret;
std::string valueAfterTrans = std::move(*valueTemp.first);
ret = executeOperatorAt(trans, key, valueAfterTrans, ruleMessage);
if (ret == true) {
ruleMessage->m_match = resolveMatchMessage(key, value);
for (auto &i : v->m_orign) {
ruleMessage->m_reference.append(i->toText());
}
ruleMessage->m_reference.append(*valueTemp.second);
updateMatchedVars(trans, key, value);
executeActionsIndependentOfChainedRuleResult(trans,
&containsDisruptive, ruleMessage);
globalRet = true;
}
}
}
if (globalRet == false) {
trans->debug(4, "Rule returned 0.");
cleanMatchedVars(trans);
goto end_clean;
}
trans->debug(4, "Rule returned 1.");
if (this->m_chained == false) {
goto end_exec;
}
if (this->m_chainedRule == NULL) {
trans->debug(4, "Rule is marked as chained but there " \
"isn't a subsequent rule.");
goto end_clean;
}
trans->debug(4, "Executing chained rule.");
recursiveGlobalRet = this->m_chainedRule->evaluate(trans, ruleMessage);
if (recursiveGlobalRet == true) {
goto end_exec;
}
end_clean:
return false;
end_exec:
executeActionsAfterFullMatch(trans, containsDisruptive, ruleMessage);
if (m_ruleId != 0 && ruleMessage->m_saveMessage != false) {
trans->serverLog(ruleMessage);
trans->m_rulesMessages.push_back(*ruleMessage);
}
return true;
}
bool Rule::containsDisruptiveAction() {
for (Action *a : m_actionsRuntimePos) {
if (a->isDisruptive() == true) {
return true;
}
}
for (Action *a : m_actionsRuntimePre) {
if (a->isDisruptive() == true) {
return true;
}
}
for (Action *a : m_actionsConf) {
if (a->isDisruptive() == true) {
return true;
}
}
return false;
}
std::vector<actions::Action *> Rule::getActionsByName(const std::string& name) {
std::vector<actions::Action *> ret;
for (auto &z : m_actionsRuntimePos) {
if (z->m_name == name) {
ret.push_back(z);
}
}
for (auto &z : m_actionsRuntimePre) {
if (z->m_name == name) {
ret.push_back(z);
}
}
for (auto &z : m_actionsConf) {
if (z->m_name == name) {
ret.push_back(z);
}
}
return ret;
}
bool Rule::containsTag(const std::string& name, Transaction *t) {
for (auto &z : this->m_actionsRuntimePos) {
actions::Tag *tag = dynamic_cast<actions::Tag *> (z);
if (tag != NULL && tag->getName(t) == name) {
return true;
}
}
return false;
}
bool Rule::containsMsg(const std::string& name, Transaction *t) {
for (auto &z : this->m_actionsRuntimePos) {
actions::Msg *msg = dynamic_cast<actions::Msg *> (z);
if (msg != NULL && msg->data(t) == name) {
return true;
}
}
return false;
}
} // namespace modsecurity