cppcheck/lib/exprengine.cpp

2649 lines
105 KiB
C++

/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2020 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @brief This is the ExprEngine component in Cppcheck. Its job is to
* convert the C/C++ code into expressions that the Z3 prover understands.
* We can then ask Z3 prover for instance if variable "x" can be 123 and
* the Z3 prover can tell us that.
*
* Overview
* ========
*
* The ExprEngine performs a "abstract execution" of each function.
* - ExprEngine performs "forward" analysis only. It starts at the top
* of the functions.
* - There is a abstract program state `Data::memory`.
* - The constraints are stored in the vector `Data::constraints`.
*
* Abstract program state
* ======================
*
* The map `Data::memory` contains the abstract values of all variables
* that are used in the current function scope.
*
* Use `--debug-bug-hunting --verbose` to dump out `Data::memory`.
* Example output:
* 2:5: { x=$1 y=$2}
* Explanation:
* At line 2, column 5: The memory has two variables. Variable x has the
* value $1. Variable y has the value $2.
*
* Different value names:
* - Typical abstract value has name that starts with "$". The number is
* just a incremented value.
* - If a variable has a known value then the concrete value is written.
* Example: `{ x=1 }`.
* - For an uninitialized value the output says "?". For example: `{ a=? }`
* - For buffers the output is something like `{ buf=($3,size=10,[:]=?,[$1]=$2) }`
* The first item "$3" is the name of the buffer value.
* The second item says that the size of this buffer is 10.
* After that comes `[index]=value` items that show what values buffer items have:
* `[:]=?` means that all items are uninitialized.
* `[$1]=$2` means that the buffer item at index "$1" has value "$2".
*
* Abstract execution
* ==================
*
* The function:
* static void execute(const Token *start, const Token *end, Data &data)
*
* Perform abstract execution of the code from `start` to `end`. The
* `data` is modified during the abstract execution.
*
* Each astTop token is executed. From that, operands are executed
* recursively in the "execute.." functions. The result of an operand is
* a abstract value.
*
* Branches
* --------
*
* Imagine:
* code1
* if (x > 0)
* code2
* else
* code3
* code4
*
* When "if" is reached.. the current `data` is branched into `thenData`
* and `elseData`.
* For "thenData" a constraint is added: x>0
* For "elseData" a constraint is added: !(x>0)
*
* Then analysis of `thenData` and `elseData` will continue separately,
* by recursive execution. The "code4" block will be analysed both with
* `thenData` and `elseData`.
*
* Z3
* ==
*
* The ExprEngine will not execute Z3 unless a check wants it to.
*
* The abstract values and all their constraints is added to a Z3 solver
* object and after that Z3 can tell us if some condition can be true.
*
* Z3 is a SMT solver:
* https://en.wikipedia.org/wiki/Satisfiability_modulo_theories
*
* In SMT:
* - all variables are "constant". A variable can not be changed or assigned.
* - There is no "execution". The solver considers all equations simultaneously.
*
* Simple example (TestExpr::expr6):
*
* void f(unsigned char x)
* {
* unsigned char y = 8 - x;\n"
* y > 1000;
* }
*
* If a check wants to know if "y > 1000" can be true, ExprEngine will
* generate this Z3 input:
*
* (declare-fun $1 () Int)
* (assert (and (>= $1 0) (<= $1 255)))
* (assert (> (- 8 $1) 1000))
*
* A symbol "$1" is created.
* assert that "$1" is a value 0-255.
* assert that "8-$1" is greater than 1000.
*
* Z3 can now determine if these assertions are possible or not. In this
* case these assertions are not possible, there is no value for $1 between
* 0-255 that means that "8-$1" is greater than 1000.
*/
#include "exprengine.h"
#include "astutils.h"
#include "errorlogger.h"
#include "settings.h"
#include "symboldatabase.h"
#include "tokenize.h"
#include <cstdlib>
#include <cstring>
#include <limits>
#include <memory>
#include <iostream>
#ifdef USE_Z3
#include <z3++.h>
#include <z3_version.h>
#define GET_VERSION_INT(A,B,C) ((A) * 10000 + (B) * 100 + (C))
#define Z3_VERSION_INT GET_VERSION_INT(Z3_MAJOR_VERSION, Z3_MINOR_VERSION, Z3_BUILD_NUMBER)
#endif
namespace {
struct BugHuntingException {
BugHuntingException(const Token *tok, const std::string &what) : tok(tok), what(what) {}
const Token *tok;
const std::string what;
};
}
std::string ExprEngine::str(int128_t value)
{
std::ostringstream ostr;
#ifdef __GNUC__
if (value == (int)value) {
ostr << (int) value;
return ostr.str();
}
if (value < 0) {
ostr << "-";
value = -value;
}
uint64_t high = value >> 64;
uint64_t low = value;
if (high > 0)
ostr << "h" << std::hex << high << "l";
ostr << std::hex << low;
#else
ostr << value;
#endif
return ostr.str();
}
static ExprEngine::ValuePtr getValueRangeFromValueType(const std::string &name, const ValueType *vt, const cppcheck::Platform &platform);
namespace {
class TrackExecution {
public:
TrackExecution() : mDataIndex(0), mAbortLine(-1) {}
int getNewDataIndex() {
return mDataIndex++;
}
void symbolRange(const Token *tok, ExprEngine::ValuePtr value) {
if (!tok || !value)
return;
if (tok->index() == 0)
return;
const std::string &symbolicExpression = value->getSymbolicExpression();
if (symbolicExpression[0] != '$')
return;
if (mSymbols.find(symbolicExpression) != mSymbols.end())
return;
mSymbols.insert(symbolicExpression);
mMap[tok].push_back(symbolicExpression + "=" + value->getRange());
}
void state(const Token *tok, const std::string &s) {
mMap[tok].push_back(s);
}
void print(std::ostream &out) {
std::set<std::pair<int,int>> locations;
for (auto it : mMap) {
locations.insert(std::pair<int,int>(it.first->linenr(), it.first->column()));
}
for (const std::pair<int,int> &loc : locations) {
int lineNumber = loc.first;
int column = loc.second;
for (auto &it : mMap) {
const Token *tok = it.first;
if (lineNumber != tok->linenr())
continue;
if (column != tok->column())
continue;
const std::vector<std::string> &dumps = it.second;
for (const std::string &dump : dumps)
out << lineNumber << ":" << column << ": " << dump << "\n";
}
}
}
void report(std::ostream &out, const Scope *functionScope) {
int linenr = -1;
std::string code;
for (const Token *tok = functionScope->bodyStart->next(); tok != functionScope->bodyEnd; tok = tok->next()) {
if (tok->linenr() > linenr) {
if (!code.empty())
out << getStatus(linenr) << " " << code << std::endl;
linenr = tok->linenr();
code.clear();
}
code += " " + tok->str();
}
out << getStatus(linenr) << " " << code << std::endl;
}
void setAbortLine(int linenr) {
if (linenr > 0 && (mAbortLine == -1 || linenr < mAbortLine))
mAbortLine = linenr;
}
void addError(int linenr) {
mErrors.insert(linenr);
}
bool isAllOk() const {
return mErrors.empty();
}
void addMissingContract(const std::string &f) {
mMissingContracts.insert(f);
}
const std::set<std::string> getMissingContracts() const {
return mMissingContracts;
}
private:
const char *getStatus(int linenr) const {
if (mErrors.find(linenr) != mErrors.end())
return "ERROR";
if (mAbortLine > 0 && linenr >= mAbortLine)
return "--";
return "ok";
}
std::map<const Token *, std::vector<std::string>> mMap;
int mDataIndex;
int mAbortLine;
std::set<std::string> mSymbols;
std::set<int> mErrors;
std::set<std::string> mMissingContracts;
};
class Data : public ExprEngine::DataBase {
public:
Data(int *symbolValueIndex, ErrorLogger *errorLogger, const Tokenizer *tokenizer, const Settings *settings, const std::string &currentFunction, const std::vector<ExprEngine::Callback> &callbacks, TrackExecution *trackExecution)
: DataBase(currentFunction, settings)
, symbolValueIndex(symbolValueIndex)
, errorLogger(errorLogger)
, tokenizer(tokenizer)
, callbacks(callbacks)
, mTrackExecution(trackExecution)
, mDataIndex(trackExecution->getNewDataIndex()) {}
typedef std::map<nonneg int, ExprEngine::ValuePtr> Memory;
Memory memory;
int * const symbolValueIndex;
ErrorLogger *errorLogger;
const Tokenizer * const tokenizer;
const std::vector<ExprEngine::Callback> &callbacks;
std::vector<ExprEngine::ValuePtr> constraints;
ExprEngine::ValuePtr executeContract(const Function *function, ExprEngine::ValuePtr(*executeExpression)(const Token*, Data&)) {
const auto it = settings->functionContracts.find(function->fullName());
if (it == settings->functionContracts.end())
return ExprEngine::ValuePtr();
const std::string &expects = it->second;
TokenList tokenList(settings);
std::istringstream istr(expects);
tokenList.createTokens(istr);
tokenList.createAst();
SymbolDatabase *symbolDatabase = const_cast<SymbolDatabase*>(tokenizer->getSymbolDatabase());
for (Token *tok = tokenList.front(); tok; tok = tok->next()) {
for (const Variable &arg: function->argumentList) {
if (arg.name() == tok->str()) {
tok->variable(&arg);
tok->varId(arg.declarationId());
}
}
}
symbolDatabase->setValueTypeInTokenList(false, tokenList.front());
return executeExpression(tokenList.front()->astTop(), *this);
}
void contractConstraints(const Function *function, ExprEngine::ValuePtr(*executeExpression)(const Token*, Data&)) {
auto value = executeContract(function, executeExpression);
if (value)
constraints.push_back(value);
}
void addError(int linenr) OVERRIDE {
mTrackExecution->addError(linenr);
}
void assignValue(const Token *tok, unsigned int varId, ExprEngine::ValuePtr value) {
if (varId == 0)
return;
mTrackExecution->symbolRange(tok, value);
if (value) {
if (auto arr = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(value)) {
for (const auto &dim: arr->size)
mTrackExecution->symbolRange(tok, dim);
for (const auto &indexAndValue: arr->data)
mTrackExecution->symbolRange(tok, indexAndValue.value);
} else if (auto s = std::dynamic_pointer_cast<ExprEngine::StructValue>(value)) {
for (const auto &m: s->member)
mTrackExecution->symbolRange(tok, m.second);
}
}
memory[varId] = value;
}
void assignStructMember(const Token *tok, ExprEngine::StructValue *structVal, const std::string &memberName, ExprEngine::ValuePtr value) {
mTrackExecution->symbolRange(tok, value);
structVal->member[memberName] = value;
}
void functionCall() {
// Remove values for global variables
const SymbolDatabase *symbolDatabase = tokenizer->getSymbolDatabase();
for (std::map<nonneg int, ExprEngine::ValuePtr>::iterator it = memory.begin(); it != memory.end();) {
unsigned int varid = it->first;
const Variable *var = symbolDatabase->getVariableFromVarId(varid);
if (var && var->isGlobal())
it = memory.erase(it);
else
++it;
}
}
std::string getNewSymbolName() OVERRIDE {
return "$" + std::to_string(++(*symbolValueIndex));
}
std::shared_ptr<ExprEngine::ArrayValue> getArrayValue(const Token *tok) {
const Memory::iterator it = memory.find(tok->varId());
if (it != memory.end())
return std::dynamic_pointer_cast<ExprEngine::ArrayValue>(it->second);
if (tok->varId() == 0 || !tok->variable())
return std::shared_ptr<ExprEngine::ArrayValue>();
auto val = std::make_shared<ExprEngine::ArrayValue>(this, tok->variable());
assignValue(tok, tok->varId(), val);
return val;
}
ExprEngine::ValuePtr getValue(unsigned int varId, const ValueType *valueType, const Token *tok) {
const Memory::const_iterator it = memory.find(varId);
if (it != memory.end())
return it->second;
if (!valueType)
return ExprEngine::ValuePtr();
ExprEngine::ValuePtr value = getValueRangeFromValueType(getNewSymbolName(), valueType, *settings);
if (value) {
if (tok->variable() && tok->variable()->nameToken())
addConstraints(value, tok->variable()->nameToken());
assignValue(tok, varId, value);
}
return value;
}
void trackCheckContract(const Token *tok, const std::string &solverOutput) {
std::ostringstream os;
os << "checkContract:{\n";
std::string line;
std::istringstream istr(solverOutput);
while (std::getline(istr, line))
os << " " << line << "\n";
os << "}";
mTrackExecution->state(tok, os.str());
}
void trackProgramState(const Token *tok) {
if (memory.empty())
return;
const SymbolDatabase * const symbolDatabase = tokenizer->getSymbolDatabase();
std::ostringstream s;
s << "{"; // << mDataIndex << ":";
for (auto mem : memory) {
ExprEngine::ValuePtr value = mem.second;
const Variable *var = symbolDatabase->getVariableFromVarId(mem.first);
if (!var)
continue;
s << " " << var->name() << "=";
if (!value)
s << "(null)";
else if (value->name[0] == '$' && value->getSymbolicExpression() != value->name)
s << "(" << value->name << "," << value->getSymbolicExpression() << ")";
else
s << value->name;
}
s << "}";
mTrackExecution->state(tok, s.str());
}
void addMissingContract(const std::string &f) {
mTrackExecution->addMissingContract(f);
}
const std::set<std::string> getMissingContracts() const {
return mTrackExecution->getMissingContracts();
}
ExprEngine::ValuePtr notValue(ExprEngine::ValuePtr v) {
auto b = std::dynamic_pointer_cast<ExprEngine::BinOpResult>(v);
if (b) {
std::string binop;
if (b->binop == "==")
binop = "!=";
else if (b->binop == "!=")
binop = "==";
else if (b->binop == ">=")
binop = "<";
else if (b->binop == "<=")
binop = ">";
else if (b->binop == ">")
binop = "<=";
else if (b->binop == "<")
binop = ">=";
if (!binop.empty())
return std::make_shared<ExprEngine::BinOpResult>(binop, b->op1, b->op2);
}
auto zero = std::make_shared<ExprEngine::IntRange>("0", 0, 0);
return std::make_shared<ExprEngine::BinOpResult>("==", v, zero);
}
void addConstraint(ExprEngine::ValuePtr condValue, bool trueCond) {
if (!condValue)
return;
if (trueCond)
constraints.push_back(condValue);
else
constraints.push_back(notValue(condValue));
}
void addConstraint(ExprEngine::ValuePtr lhsValue, ExprEngine::ValuePtr rhsValue, bool equals) {
if (!lhsValue || !rhsValue)
return;
constraints.push_back(std::make_shared<ExprEngine::BinOpResult>(equals?"==":"!=", lhsValue, rhsValue));
}
void addConstraints(ExprEngine::ValuePtr value, const Token *tok) {
MathLib::bigint low;
if (tok->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::LOW, &low))
addConstraint(std::make_shared<ExprEngine::BinOpResult>(">=", value, std::make_shared<ExprEngine::IntRange>(std::to_string(low), low, low)), true);
MathLib::bigint high;
if (tok->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::HIGH, &high))
addConstraint(std::make_shared<ExprEngine::BinOpResult>("<=", value, std::make_shared<ExprEngine::IntRange>(std::to_string(high), high, high)), true);
}
private:
TrackExecution * const mTrackExecution;
const int mDataIndex;
};
}
#ifdef __clang__
// work around "undefined reference to `__muloti4'" linker error - see https://bugs.llvm.org/show_bug.cgi?id=16404
__attribute__((no_sanitize("undefined")))
#endif
static ExprEngine::ValuePtr simplifyValue(ExprEngine::ValuePtr origValue)
{
auto b = std::dynamic_pointer_cast<ExprEngine::BinOpResult>(origValue);
if (!b)
return origValue;
if (!b->op1 || !b->op2)
return origValue;
auto intRange1 = std::dynamic_pointer_cast<ExprEngine::IntRange>(b->op1);
auto intRange2 = std::dynamic_pointer_cast<ExprEngine::IntRange>(b->op2);
if (intRange1 && intRange2 && intRange1->minValue == intRange1->maxValue && intRange2->minValue == intRange2->maxValue) {
const std::string &binop = b->binop;
int128_t v;
if (binop == "+")
v = intRange1->minValue + intRange2->minValue;
else if (binop == "-")
v = intRange1->minValue - intRange2->minValue;
else if (binop == "*")
v = intRange1->minValue * intRange2->minValue;
else if (binop == "/" && intRange2->minValue != 0)
v = intRange1->minValue / intRange2->minValue;
else if (binop == "%" && intRange2->minValue != 0)
v = intRange1->minValue % intRange2->minValue;
else
return origValue;
return std::make_shared<ExprEngine::IntRange>(ExprEngine::str(v), v, v);
}
return origValue;
}
static ExprEngine::ValuePtr translateUninitValueToRange(ExprEngine::ValuePtr value, const ::ValueType *valueType, Data &data)
{
if (!value)
return value;
if (value->type == ExprEngine::ValueType::UninitValue) {
auto rangeValue = getValueRangeFromValueType(data.getNewSymbolName(), valueType, *data.settings);
if (rangeValue)
return rangeValue;
}
if (auto conditionalValue = std::dynamic_pointer_cast<ExprEngine::ConditionalValue>(value)) {
if (conditionalValue->values.size() == 1 && conditionalValue->values[0].second && conditionalValue->values[0].second->type == ExprEngine::ValueType::UninitValue) {
auto rangeValue = getValueRangeFromValueType(data.getNewSymbolName(), valueType, *data.settings);
if (rangeValue)
return rangeValue;
}
}
return value;
}
static int128_t truncateInt(int128_t value, int bits, char sign)
{
value = value & (((int128_t)1 << bits) - 1);
// Sign extension
if (sign == 's' && value & (1ULL << (bits - 1)))
value |= ~(((int128_t)1 << bits) - 1);
return value;
}
ExprEngine::ArrayValue::ArrayValue(const std::string &name, ExprEngine::ValuePtr size, ExprEngine::ValuePtr value, bool pointer, bool nullPointer, bool uninitPointer)
: Value(name, ExprEngine::ValueType::ArrayValue)
, pointer(pointer), nullPointer(nullPointer), uninitPointer(uninitPointer)
{
this->size.push_back(size);
assign(ExprEngine::ValuePtr(), value);
}
ExprEngine::ArrayValue::ArrayValue(DataBase *data, const Variable *var)
: Value(data->getNewSymbolName(), ExprEngine::ValueType::ArrayValue)
, pointer(var->isPointer()), nullPointer(var->isPointer()), uninitPointer(var->isPointer())
{
if (var) {
for (const auto &dim : var->dimensions()) {
if (dim.known)
size.push_back(std::make_shared<ExprEngine::IntRange>(std::to_string(dim.num), dim.num, dim.num));
else
size.push_back(std::make_shared<ExprEngine::IntRange>(data->getNewSymbolName(), 1, ExprEngine::ArrayValue::MAXSIZE));
}
} else {
size.push_back(std::make_shared<ExprEngine::IntRange>(data->getNewSymbolName(), 1, ExprEngine::ArrayValue::MAXSIZE));
}
ValuePtr val;
if (var && !var->isGlobal() && !var->isStatic())
val = std::make_shared<ExprEngine::UninitValue>();
else if (var && var->valueType()) {
::ValueType vt(*var->valueType());
vt.pointer = 0;
val = getValueRangeFromValueType(data->getNewSymbolName(), &vt, *data->settings);
}
assign(ExprEngine::ValuePtr(), val);
}
std::string ExprEngine::ArrayValue::getRange() const
{
std::string r = getSymbolicExpression();
if (nullPointer)
r += std::string(r.empty() ? "" : ",") + "null";
if (uninitPointer)
r += std::string(r.empty() ? "" : ",") + "->?";
return r;
}
void ExprEngine::ArrayValue::assign(ExprEngine::ValuePtr index, ExprEngine::ValuePtr value)
{
if (!index)
data.clear();
if (value) {
ExprEngine::ArrayValue::IndexAndValue indexAndValue = {index, value};
data.push_back(indexAndValue);
}
}
void ExprEngine::ArrayValue::clear()
{
data.clear();
ExprEngine::ArrayValue::IndexAndValue indexAndValue = {
ExprEngine::ValuePtr(), std::make_shared<ExprEngine::IntRange>("0", 0, 0)
};
data.push_back(indexAndValue);
}
static bool isEqual(ExprEngine::ValuePtr v1, ExprEngine::ValuePtr v2)
{
if (!v1 || !v2)
return !v1 && !v2;
return v1->name == v2->name;
}
static bool isNonOverlapping(ExprEngine::ValuePtr v1, ExprEngine::ValuePtr v2)
{
if (!v1 || !v2)
return false; // Don't know!
auto intRange1 = std::dynamic_pointer_cast<ExprEngine::IntRange>(v1);
auto intRange2 = std::dynamic_pointer_cast<ExprEngine::IntRange>(v2);
if (intRange1 && intRange2 && (intRange1->minValue > intRange2->maxValue || intRange1->maxValue < intRange2->maxValue))
return true;
return false;
}
ExprEngine::ConditionalValue::Vector ExprEngine::ArrayValue::read(ExprEngine::ValuePtr index) const
{
ExprEngine::ConditionalValue::Vector ret;
if (!index)
return ret;
for (const auto &indexAndValue : data) {
if (::isEqual(index, indexAndValue.index))
ret.clear();
if (isNonOverlapping(index, indexAndValue.index))
continue;
// Array contains string literal data...
if (!indexAndValue.index && indexAndValue.value->type == ExprEngine::ValueType::StringLiteralValue) {
auto stringLiteral = std::dynamic_pointer_cast<ExprEngine::StringLiteralValue>(indexAndValue.value);
if (!stringLiteral) {
ret.push_back(std::pair<ValuePtr,ValuePtr>(indexAndValue.index, std::make_shared<ExprEngine::IntRange>("", -128, 128)));
continue;
}
if (auto i = std::dynamic_pointer_cast<ExprEngine::IntRange>(index)) {
if (i->minValue >= 0 && i->minValue == i->maxValue) {
int c = 0;
if (i->minValue < stringLiteral->size())
c = stringLiteral->string[i->minValue];
ret.push_back(std::pair<ValuePtr,ValuePtr>(indexAndValue.index, std::make_shared<ExprEngine::IntRange>(std::to_string(c), c, c)));
continue;
}
}
int cmin = 0, cmax = 0;
for (char c : stringLiteral->string) {
if (c < cmin)
cmin = c;
else if (c > cmax)
cmax = c;
}
ret.push_back(std::pair<ValuePtr,ValuePtr>(indexAndValue.index, std::make_shared<ExprEngine::IntRange>("", cmin, cmax)));
continue;
}
// Rename IntRange
if (auto i = std::dynamic_pointer_cast<ExprEngine::IntRange>(indexAndValue.value)) {
ret.push_back(std::pair<ValuePtr,ValuePtr>(indexAndValue.index, std::make_shared<ExprEngine::IntRange>(indexAndValue.value->name + ":" + index->name, i->minValue, i->maxValue)));
continue;
}
ret.push_back(std::pair<ValuePtr,ValuePtr>(indexAndValue.index, indexAndValue.value));
}
if (ret.size() == 1)
ret[0].first = ExprEngine::ValuePtr();
else if (ret.size() == 2 && !ret[0].first) {
ret[0].first = std::make_shared<ExprEngine::BinOpResult>("!=", index, ret[1].first);
ret[1].first = std::make_shared<ExprEngine::BinOpResult>("==", index, ret[1].first);
} else {
// FIXME!!
ret.clear();
}
return ret;
}
std::string ExprEngine::ConditionalValue::getSymbolicExpression() const
{
std::ostringstream ostr;
ostr << "{";
bool first = true;
for (auto condvalue : values) {
ValuePtr cond = condvalue.first;
ValuePtr value = condvalue.second;
if (!first)
ostr << ",";
first = false;
ostr << "{"
<< (cond ? cond->getSymbolicExpression() : std::string("(null)"))
<< ","
<< value->getSymbolicExpression()
<< "}";
}
ostr << "}";
return ostr.str();
}
std::string ExprEngine::ArrayValue::getSymbolicExpression() const
{
std::ostringstream ostr;
if (size.empty())
ostr << "(null)";
else {
for (const auto &dim: size)
ostr << "[" << (dim ? dim->name : std::string("(null)")) << "]";
}
for (const auto &indexAndValue : data) {
ostr << ",["
<< (!indexAndValue.index ? std::string(":") : indexAndValue.index->name)
<< "]="
<< indexAndValue.value->name;
}
return ostr.str();
}
std::string ExprEngine::StructValue::getSymbolicExpression() const
{
std::ostringstream ostr;
ostr << "{";
bool first = true;
for (const auto& m: member) {
const std::string &memberName = m.first;
auto memberValue = m.second;
if (!first)
ostr << ",";
first = false;
ostr << memberName << "=" << (memberValue ? memberValue->getSymbolicExpression() : std::string("(null)"));
}
ostr << "}";
return ostr.str();
}
std::string ExprEngine::IntegerTruncation::getSymbolicExpression() const
{
return sign + std::to_string(bits) + "(" + inputValue->getSymbolicExpression() + ")";
}
#ifdef USE_Z3
struct ExprData {
typedef std::map<std::string, z3::expr> ValueExpr;
typedef std::vector<z3::expr> AssertionList;
z3::context context;
ValueExpr valueExpr;
AssertionList assertionList;
void addAssertions(z3::solver &solver) const {
for (auto assertExpr : assertionList)
solver.add(assertExpr);
}
z3::expr addInt(const std::string &name, int128_t minValue, int128_t maxValue) {
z3::expr e = context.int_const(name.c_str());
valueExpr.emplace(name, e);
if (minValue >= INT_MIN && maxValue <= INT_MAX)
assertionList.push_back(e >= int(minValue) && e <= int(maxValue));
else if (maxValue <= INT_MAX)
assertionList.push_back(e <= int(maxValue));
else if (minValue >= INT_MIN)
assertionList.push_back(e >= int(minValue));
return e;
}
z3::expr addFloat(const std::string &name) {
#if Z3_VERSION_INT >= GET_VERSION_INT(4,8,0)
z3::expr e = context.fpa_const(name.c_str(), 11, 53);
#else
z3::expr e = context.real_const(name.c_str());
#endif
valueExpr.emplace(name, e);
return e;
}
z3::expr getExpr(const ExprEngine::BinOpResult *b) {
auto op1 = getExpr(b->op1);
auto op2 = getExpr(b->op2);
if (b->binop == "+")
return op1 + op2;
if (b->binop == "-")
return op1 - op2;
if (b->binop == "*")
return op1 * op2;
if (b->binop == "/")
return op1 / op2;
if (b->binop == "%")
#if Z3_VERSION_INT >= GET_VERSION_INT(4,8,5)
return op1 % op2;
#else
return op1 - (op1 / op2) * op2;
#endif
if (b->binop == "==")
return int_expr(op1) == int_expr(op2);
if (b->binop == "!=")
return op1 != op2;
if (b->binop == ">=")
return op1 >= op2;
if (b->binop == "<=")
return op1 <= op2;
if (b->binop == ">")
return op1 > op2;
if (b->binop == "<")
return op1 < op2;
if (b->binop == "&&")
return bool_expr(op1) && bool_expr(op2);
if (b->binop == "||")
return bool_expr(op1) || bool_expr(op2);
if (b->binop == "<<")
return op1 * z3::pw(context.int_val(2), op2);
if (b->binop == ">>")
return op1 / z3::pw(context.int_val(2), op2);
throw BugHuntingException(nullptr, "Internal error: Unhandled operator " + b->binop);
}
z3::expr getExpr(ExprEngine::ValuePtr v) {
if (!v)
throw BugHuntingException(nullptr, "Can not solve expressions, operand value is null");
if (auto intRange = std::dynamic_pointer_cast<ExprEngine::IntRange>(v)) {
if (intRange->name[0] != '$')
#if Z3_VERSION_INT >= GET_VERSION_INT(4,7,1)
return context.int_val(int64_t(intRange->minValue));
#else
return context.int_val((long long)(intRange->minValue));
#endif
auto it = valueExpr.find(v->name);
if (it != valueExpr.end())
return it->second;
return addInt(v->name, intRange->minValue, intRange->maxValue);
}
if (auto floatRange = std::dynamic_pointer_cast<ExprEngine::FloatRange>(v)) {
auto it = valueExpr.find(v->name);
if (it != valueExpr.end())
return it->second;
return addFloat(v->name);
}
if (auto b = std::dynamic_pointer_cast<ExprEngine::BinOpResult>(v)) {
return getExpr(b.get());
}
if (auto c = std::dynamic_pointer_cast<ExprEngine::ConditionalValue>(v)) {
if (c->values.empty())
throw BugHuntingException(nullptr, "ConditionalValue is empty");
if (c->values.size() == 1)
return getExpr(c->values[0].second);
return z3::ite(getExpr(c->values[1].first),
getExpr(c->values[1].second),
getExpr(c->values[0].second));
}
if (auto integerTruncation = std::dynamic_pointer_cast<ExprEngine::IntegerTruncation>(v)) {
return getExpr(integerTruncation->inputValue);
//return getExpr(integerTruncation->inputValue) & ((1 << integerTruncation->bits) - 1);
}
if (v->type == ExprEngine::ValueType::UninitValue)
return context.int_val(0);
throw BugHuntingException(nullptr, "Internal error: Unhandled value type");
}
z3::expr getConstraintExpr(ExprEngine::ValuePtr v) {
if (v->type == ExprEngine::ValueType::IntRange)
return (getExpr(v) != 0);
return bool_expr(getExpr(v));
}
private:
z3::expr bool_expr(z3::expr e) {
if (e.is_bool())
return e;
return e != 0;
}
z3::expr int_expr(z3::expr e) {
if (e.is_bool())
return z3::ite(e, context.int_val(1), context.int_val(0));
return e;
}
};
#endif
bool ExprEngine::IntRange::isEqual(DataBase *dataBase, int value) const
{
if (value < minValue || value > maxValue)
return false;
const Data *data = dynamic_cast<Data *>(dataBase);
if (data->constraints.empty())
return true;
#ifdef USE_Z3
// Check the value against the constraints
ExprData exprData;
z3::solver solver(exprData.context);
try {
z3::expr e = exprData.addInt(name, minValue, maxValue);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e == value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
return true; // Safe option is to return true
}
#else
// The value may or may not be in range
return false;
#endif
}
bool ExprEngine::IntRange::isGreaterThan(DataBase *dataBase, int value) const
{
if (maxValue <= value)
return false;
const Data *data = dynamic_cast<Data *>(dataBase);
if (data->constraints.empty())
return true;
#ifdef USE_Z3
// Check the value against the constraints
ExprData exprData;
z3::solver solver(exprData.context);
try {
z3::expr e = exprData.addInt(name, minValue, maxValue);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e > value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
return true; // Safe option is to return true
}
#else
// The value may or may not be in range
return false;
#endif
}
bool ExprEngine::IntRange::isLessThan(DataBase *dataBase, int value) const
{
if (minValue >= value)
return false;
const Data *data = dynamic_cast<Data *>(dataBase);
if (data->constraints.empty())
return true;
#ifdef USE_Z3
// Check the value against the constraints
ExprData exprData;
z3::solver solver(exprData.context);
try {
z3::expr e = exprData.addInt(name, minValue, maxValue);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e < value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
return true; // Safe option is to return true
}
#else
// The value may or may not be in range
return false;
#endif
}
bool ExprEngine::FloatRange::isEqual(DataBase *dataBase, int value) const
{
const Data *data = dynamic_cast<Data *>(dataBase);
if (data->constraints.empty())
return true;
if (MathLib::isFloat(name)) {
float f = MathLib::toDoubleNumber(name);
return value >= f - 0.00001 && value <= f + 0.00001;
}
#ifdef USE_Z3
// Check the value against the constraints
ExprData exprData;
z3::solver solver(exprData.context);
try {
z3::expr e = exprData.addFloat(name);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e >= value && e <= value);
return solver.check() != z3::unsat;
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
return true; // Safe option is to return true
}
#else
// The value may or may not be in range
return false;
#endif
}
bool ExprEngine::FloatRange::isGreaterThan(DataBase *dataBase, int value) const
{
if (value < minValue || value > maxValue)
return false;
const Data *data = dynamic_cast<Data *>(dataBase);
if (data->constraints.empty())
return true;
if (MathLib::isFloat(name))
return value > MathLib::toDoubleNumber(name);
#ifdef USE_Z3
// Check the value against the constraints
ExprData exprData;
z3::solver solver(exprData.context);
try {
z3::expr e = exprData.addFloat(name);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e > value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
return true; // Safe option is to return true
}
#else
// The value may or may not be in range
return false;
#endif
}
bool ExprEngine::FloatRange::isLessThan(DataBase *dataBase, int value) const
{
if (value < minValue || value > maxValue)
return false;
const Data *data = dynamic_cast<Data *>(dataBase);
if (data->constraints.empty())
return true;
if (MathLib::isFloat(name))
return value < MathLib::toDoubleNumber(name);
#ifdef USE_Z3
// Check the value against the constraints
ExprData exprData;
z3::solver solver(exprData.context);
try {
z3::expr e = exprData.addFloat(name);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e < value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
return true; // Safe option is to return true
}
#else
// The value may or may not be in range
return false;
#endif
}
bool ExprEngine::BinOpResult::isEqual(ExprEngine::DataBase *dataBase, int value) const
{
#ifdef USE_Z3
ExprData exprData;
z3::solver solver(exprData.context);
z3::expr e = exprData.getExpr(this);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e == value);
return solver.check() == z3::sat;
#else
(void)dataBase;
(void)value;
return false;
#endif
}
bool ExprEngine::BinOpResult::isGreaterThan(ExprEngine::DataBase *dataBase, int value) const
{
#ifdef USE_Z3
try {
ExprData exprData;
z3::solver solver(exprData.context);
z3::expr e = exprData.getExpr(this);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e > value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3:" << exception << std::endl;
return true; // Safe option is to return true
}
#else
(void)dataBase;
(void)value;
return false;
#endif
}
bool ExprEngine::BinOpResult::isLessThan(ExprEngine::DataBase *dataBase, int value) const
{
#ifdef USE_Z3
try {
ExprData exprData;
z3::solver solver(exprData.context);
z3::expr e = exprData.getExpr(this);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e < value);
return solver.check() == z3::sat;
} catch (const z3::exception &exception) {
std::cerr << "z3:" << exception << std::endl;
return true; // Safe option is to return true
}
#else
(void)dataBase;
(void)value;
return false;
#endif
}
std::string ExprEngine::BinOpResult::getExpr(ExprEngine::DataBase *dataBase) const
{
#ifdef USE_Z3
try {
ExprData exprData;
z3::solver solver(exprData.context);
z3::expr e = exprData.getExpr(this);
for (auto constraint : dynamic_cast<const Data *>(dataBase)->constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
solver.add(e);
std::ostringstream os;
os << solver;
switch (solver.check()) {
case z3::sat:
os << "\nz3::sat\n";
break;
case z3::unsat:
os << "\nz3::unsat\n";
break;
case z3::unknown:
os << "\nz3::unknown\n";
break;
}
return os.str();
} catch (const z3::exception &exception) {
std::ostringstream os;
os << "\nz3:" << exception << "\n";
return os.str();
}
#else
(void)dataBase;
return "";
#endif
}
// Todo: This is taken from ValueFlow and modified.. we should reuse it
static int getIntBitsFromValueType(const ValueType *vt, const cppcheck::Platform &platform)
{
if (!vt)
return 0;
switch (vt->type) {
case ValueType::Type::BOOL:
return 1;
case ValueType::Type::CHAR:
return platform.char_bit;
case ValueType::Type::SHORT:
return platform.short_bit;
case ValueType::Type::INT:
return platform.int_bit;
case ValueType::Type::LONG:
return platform.long_bit;
case ValueType::Type::LONGLONG:
return platform.long_long_bit;
default:
return 0;
}
}
static ExprEngine::ValuePtr getValueRangeFromValueType(const std::string &name, const ValueType *vt, const cppcheck::Platform &platform)
{
if (!vt || !(vt->isIntegral() || vt->isFloat()) || vt->pointer)
return ExprEngine::ValuePtr();
int bits = getIntBitsFromValueType(vt, platform);
if (bits == 1) {
return std::make_shared<ExprEngine::IntRange>(name, 0, 1);
} else if (bits > 1) {
if (vt->sign == ValueType::Sign::UNSIGNED) {
return std::make_shared<ExprEngine::IntRange>(name, 0, ((int128_t)1 << bits) - 1);
} else {
return std::make_shared<ExprEngine::IntRange>(name, -((int128_t)1 << (bits - 1)), ((int128_t)1 << (bits - 1)) - 1);
}
}
if (vt->isFloat())
return std::make_shared<ExprEngine::FloatRange>(name, -std::numeric_limits<float>::infinity(), std::numeric_limits<float>::infinity());
return ExprEngine::ValuePtr();
}
static void call(const std::vector<ExprEngine::Callback> &callbacks, const Token *tok, ExprEngine::ValuePtr value, Data *dataBase)
{
if (value) {
for (ExprEngine::Callback f : callbacks) {
try {
f(tok, *value, dataBase);
} catch (const BugHuntingException &e) {
throw BugHuntingException(tok, e.what);
}
}
}
}
static ExprEngine::ValuePtr executeExpression(const Token *tok, Data &data);
static ExprEngine::ValuePtr executeExpression1(const Token *tok, Data &data);
static ExprEngine::ValuePtr calculateArrayIndex(const Token *tok, Data &data, const ExprEngine::ArrayValue &arrayValue)
{
int nr = 1;
const Token *tok2 = tok;
while (Token::simpleMatch(tok2->astOperand1(), "[")) {
tok2 = tok2->astOperand1();
nr++;
}
ExprEngine::ValuePtr totalIndex;
ExprEngine::ValuePtr dim;
while (Token::simpleMatch(tok, "[")) {
auto rawIndex = executeExpression(tok->astOperand2(), data);
ExprEngine::ValuePtr index;
if (dim)
index = simplifyValue(std::make_shared<ExprEngine::BinOpResult>("*", dim, rawIndex));
else
index = rawIndex;
if (!totalIndex)
totalIndex = index;
else
totalIndex = simplifyValue(std::make_shared<ExprEngine::BinOpResult>("+", index, totalIndex));
if (arrayValue.size.size() >= nr) {
if (arrayValue.size[nr-1]) {
if (!dim)
dim = arrayValue.size[nr-1];
else
dim = simplifyValue(std::make_shared<ExprEngine::BinOpResult>("*", dim, arrayValue.size[nr-1]));
}
}
nr--;
tok = tok->astOperand1();
}
return totalIndex;
}
static ExprEngine::ValuePtr executeReturn(const Token *tok, Data &data)
{
ExprEngine::ValuePtr retval = executeExpression(tok->astOperand1(), data);
call(data.callbacks, tok, retval, &data);
return retval;
}
static ExprEngine::ValuePtr truncateValue(ExprEngine::ValuePtr val, const ValueType *valueType, Data &data)
{
if (!valueType)
return val;
if (valueType->pointer != 0)
return val;
if (!valueType->isIntegral())
return val; // TODO
int bits = getIntBitsFromValueType(valueType, *data.settings);
if (bits == 0)
// TODO
return val;
if (auto range = std::dynamic_pointer_cast<ExprEngine::IntRange>(val)) {
if (range->minValue == range->maxValue) {
int128_t newValue = truncateInt(range->minValue, bits, valueType->sign == ValueType::Sign::SIGNED ? 's' : 'u');
if (newValue == range->minValue)
return val;
return std::make_shared<ExprEngine::IntRange>(ExprEngine::str(newValue), newValue, newValue);
}
if (auto typeRange = getValueRangeFromValueType("", valueType, *data.settings)) {
auto typeIntRange = std::dynamic_pointer_cast<ExprEngine::IntRange>(typeRange);
if (typeIntRange) {
if (range->minValue >= typeIntRange->minValue && range->maxValue <= typeIntRange->maxValue)
return val;
}
}
return std::make_shared<ExprEngine::IntegerTruncation>(data.getNewSymbolName(), val, bits, valueType->sign == ValueType::Sign::SIGNED ? 's' : 'u');
}
// TODO
return val;
}
static ExprEngine::ValuePtr executeAssign(const Token *tok, Data &data)
{
ExprEngine::ValuePtr rhsValue = executeExpression(tok->astOperand2(), data);
if (!rhsValue) {
const ValueType * const vt1 = tok->astOperand1() ? tok->astOperand1()->valueType() : nullptr;
const ValueType * const vt2 = tok->astOperand2() ? tok->astOperand2()->valueType() : nullptr;
if (vt1 && vt1->pointer == 0 && vt1->isIntegral())
rhsValue = getValueRangeFromValueType(data.getNewSymbolName(), vt1, *data.settings);
else if (vt2 && vt2->container && vt2->container->stdStringLike) {
auto size = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 0, ~0ULL);
auto value = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), -128, 127);
rhsValue = std::make_shared<ExprEngine::ArrayValue>(data.getNewSymbolName(), size, value, false, false, false);
call(data.callbacks, tok->astOperand2(), rhsValue, &data);
}
}
if (!rhsValue)
throw BugHuntingException(tok, "Expression '" + tok->expressionString() + "'; Failed to evaluate RHS");
ExprEngine::ValuePtr assignValue;
if (tok->str() == "=")
assignValue = rhsValue;
else {
// "+=" => "+"
std::string binop(tok->str());
binop = binop.substr(0, binop.size() - 1);
ExprEngine::ValuePtr lhsValue = executeExpression(tok->astOperand1(), data);
assignValue = simplifyValue(std::make_shared<ExprEngine::BinOpResult>(binop, lhsValue, rhsValue));
}
const Token *lhsToken = tok->astOperand1();
assignValue = truncateValue(assignValue, lhsToken->valueType(), data);
call(data.callbacks, tok, assignValue, &data);
if (lhsToken->varId() > 0) {
data.assignValue(lhsToken, lhsToken->varId(), assignValue);
} else if (lhsToken->str() == "[") {
const Token *tok2 = lhsToken;
while (Token::simpleMatch(tok2->astOperand1(), "["))
tok2 = tok2->astOperand1();
auto arrayValue = data.getArrayValue(tok2->astOperand1());
if (arrayValue) {
// Is it array initialization?
const Token *arrayInit = tok2->astOperand1();
if (arrayInit && arrayInit->variable() && arrayInit->variable()->nameToken() == arrayInit) {
if (assignValue->type == ExprEngine::ValueType::StringLiteralValue)
arrayValue->assign(ExprEngine::ValuePtr(), assignValue);
} else {
auto indexValue = calculateArrayIndex(lhsToken, data, *arrayValue);
arrayValue->assign(indexValue, assignValue);
}
}
} else if (lhsToken->isUnaryOp("*")) {
auto pval = executeExpression(lhsToken->astOperand1(), data);
if (pval && pval->type == ExprEngine::ValueType::AddressOfValue) {
auto val = std::dynamic_pointer_cast<ExprEngine::AddressOfValue>(pval);
if (val)
data.assignValue(lhsToken, val->varId, assignValue);
} else if (pval && pval->type == ExprEngine::ValueType::BinOpResult) {
auto b = std::dynamic_pointer_cast<ExprEngine::BinOpResult>(pval);
if (b && b->binop == "+") {
std::shared_ptr<ExprEngine::ArrayValue> arr;
ExprEngine::ValuePtr offset;
if (b->op1->type == ExprEngine::ValueType::ArrayValue) {
arr = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(b->op1);
offset = b->op2;
} else {
arr = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(b->op2);
offset = b->op1;
}
if (arr && offset) {
arr->assign(offset, assignValue);
}
}
}
} else if (Token::Match(lhsToken, ". %name%")) {
auto structVal = executeExpression(lhsToken->astOperand1(), data);
if (structVal && structVal->type == ExprEngine::ValueType::StructValue)
data.assignStructMember(tok, &*std::static_pointer_cast<ExprEngine::StructValue>(structVal), lhsToken->strAt(1), assignValue);
}
return assignValue;
}
#ifdef USE_Z3
static void checkContract(Data &data, const Token *tok, const Function *function, const std::vector<ExprEngine::ValuePtr> &argValues)
{
ExprData exprData;
z3::solver solver(exprData.context);
try {
// Invert contract, we want to know if the contract might not be met
solver.add(z3::ite(exprData.getConstraintExpr(data.executeContract(function, executeExpression1)), exprData.context.bool_val(false), exprData.context.bool_val(true)));
bool bailoutValue = false;
for (nonneg int i = 0; i < argValues.size(); ++i) {
const Variable *argvar = function->getArgumentVar(i);
if (!argvar || !argvar->nameToken())
continue;
ExprEngine::ValuePtr argValue = argValues[i];
if (!argValue || argValue->type == ExprEngine::ValueType::BailoutValue) {
bailoutValue = true;
break;
}
if (argValue && argValue->type == ExprEngine::ValueType::IntRange) {
solver.add(exprData.getExpr(data.getValue(argvar->declarationId(), nullptr, nullptr)) == exprData.getExpr(argValue));
}
}
if (!bailoutValue) {
for (auto constraint : data.constraints)
solver.add(exprData.getConstraintExpr(constraint));
exprData.addAssertions(solver);
// Log solver expressions for debugging/testing purposes
std::ostringstream os;
os << solver;
data.trackCheckContract(tok, os.str());
}
if (bailoutValue || solver.check() == z3::sat) {
data.addError(tok->linenr());
std::list<const Token*> callstack{tok};
const char * const id = "bughuntingFunctionCall";
const auto contractIt = data.settings->functionContracts.find(function->fullName());
const std::string functionName = contractIt->first;
const std::string functionExpects = contractIt->second;
ErrorMessage errmsg(callstack,
&data.tokenizer->list,
Severity::SeverityType::error,
id,
"Function '" + function->name() + "' is called, can not determine that its contract '" + functionExpects + "' is always met.",
CWE(0),
false);
errmsg.incomplete = bailoutValue;
errmsg.function = functionName;
data.errorLogger->reportErr(errmsg);
}
} catch (const z3::exception &exception) {
std::cerr << "z3: " << exception << std::endl;
} catch (const BugHuntingException &e) {
std::list<const Token*> callstack{tok};
const char * const id = "internalErrorInExprEngine";
const auto contractIt = data.settings->functionContracts.find(function->fullName());
const std::string functionExpects = contractIt->second;
ErrorMessage errmsg(callstack,
&data.tokenizer->list,
Severity::SeverityType::error,
id,
"Function '" + function->name() + "' is called, can not determine that its contract is always met.",
CWE(0),
false);
errmsg.incomplete = true;
data.errorLogger->reportErr(errmsg);
}
}
#endif
static ExprEngine::ValuePtr executeFunctionCall(const Token *tok, Data &data)
{
if (Token::simpleMatch(tok->previous(), "sizeof (")) {
ExprEngine::ValuePtr retVal;
if (tok->hasKnownIntValue()) {
const MathLib::bigint value = tok->getKnownIntValue();
retVal = std::make_shared<ExprEngine::IntRange>(std::to_string(value), value, value);
} else {
retVal = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 1, 0x7fffffff);
}
call(data.callbacks, tok, retVal, &data);
return retVal;
}
std::vector<ExprEngine::ValuePtr> argValues;
for (const Token *argtok : getArguments(tok)) {
auto val = executeExpression(argtok, data);
argValues.push_back(val);
if (!argtok->valueType() || (argtok->valueType()->constness & 1) == 1)
continue;
if (auto arrayValue = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(val)) {
ValueType vt(*argtok->valueType());
vt.pointer = 0;
auto anyVal = getValueRangeFromValueType(data.getNewSymbolName(), &vt, *data.settings);
arrayValue->assign(ExprEngine::ValuePtr(), anyVal);
} else if (auto addressOf = std::dynamic_pointer_cast<ExprEngine::AddressOfValue>(val)) {
ValueType vt(*argtok->valueType());
vt.pointer = 0;
if (vt.isIntegral() && argtok->valueType()->pointer == 1)
data.assignValue(argtok, addressOf->varId, getValueRangeFromValueType(data.getNewSymbolName(), &vt, *data.settings));
}
}
if (tok->astOperand1()->function()) {
const std::string &functionName = tok->astOperand1()->function()->fullName();
const auto contractIt = data.settings->functionContracts.find(functionName);
if (contractIt != data.settings->functionContracts.end()) {
#ifdef USE_Z3
checkContract(data, tok, tok->astOperand1()->function(), argValues);
#endif
} else if (!argValues.empty()) {
bool bailout = false;
for (const auto v: argValues)
bailout |= (v && v->type == ExprEngine::ValueType::BailoutValue);
if (!bailout)
data.addMissingContract(functionName);
}
}
auto val = getValueRangeFromValueType(data.getNewSymbolName(), tok->valueType(), *data.settings);
call(data.callbacks, tok, val, &data);
data.functionCall();
return val;
}
static ExprEngine::ValuePtr executeArrayIndex(const Token *tok, Data &data)
{
const Token *tok2 = tok;
while (Token::simpleMatch(tok2->astOperand1(), "["))
tok2 = tok2->astOperand1();
auto arrayValue = data.getArrayValue(tok2->astOperand1());
if (arrayValue) {
auto indexValue = calculateArrayIndex(tok, data, *arrayValue);
auto conditionalValues = arrayValue->read(indexValue);
for (auto value: conditionalValues)
call(data.callbacks, tok, value.second, &data);
if (conditionalValues.size() == 1 && !conditionalValues[0].first)
return conditionalValues[0].second;
return std::make_shared<ExprEngine::ConditionalValue>(data.getNewSymbolName(), conditionalValues);
}
// TODO: Pointer value..
executeExpression(tok->astOperand1(), data);
executeExpression(tok->astOperand2(), data);
return ExprEngine::ValuePtr();
}
static ExprEngine::ValuePtr executeCast(const Token *tok, Data &data)
{
const Token *expr = tok->astOperand2() ? tok->astOperand2() : tok->astOperand1();
auto val = executeExpression(expr, data);
if (expr->valueType() && expr->valueType()->type == ::ValueType::Type::VOID && expr->valueType()->pointer > 0) {
if (!tok->valueType() || expr->valueType()->pointer < tok->valueType()->pointer)
return std::make_shared<ExprEngine::UninitValue>();
::ValueType vt(*tok->valueType());
vt.pointer = 0;
auto range = getValueRangeFromValueType(data.getNewSymbolName(), &vt, *data.settings);
if (tok->valueType()->pointer == 0)
return range;
bool uninitPointer = false, nullPointer = false;
if (val && val->type == ExprEngine::ValueType::ArrayValue) {
nullPointer = std::static_pointer_cast<ExprEngine::ArrayValue>(val)->nullPointer;
uninitPointer = std::static_pointer_cast<ExprEngine::ArrayValue>(val)->uninitPointer;
}
auto bufferSize = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 1, ~0UL);
return std::make_shared<ExprEngine::ArrayValue>(data.getNewSymbolName(), bufferSize, range, true, nullPointer, uninitPointer);
}
if (val) {
// TODO: Cast this..
call(data.callbacks, tok, val, &data);
return val;
}
val = getValueRangeFromValueType(data.getNewSymbolName(), tok->valueType(), *data.settings);
call(data.callbacks, tok, val, &data);
return val;
}
static ExprEngine::ValuePtr executeDot(const Token *tok, Data &data)
{
if (!tok->astOperand1() || !tok->astOperand1()->varId()) {
auto v = getValueRangeFromValueType(data.getNewSymbolName(), tok->valueType(), *data.settings);
call(data.callbacks, tok, v, &data);
return v;
}
std::shared_ptr<ExprEngine::StructValue> structValue = std::dynamic_pointer_cast<ExprEngine::StructValue>(data.getValue(tok->astOperand1()->varId(), nullptr, nullptr));
if (!structValue) {
if (tok->originalName() == "->") {
std::shared_ptr<ExprEngine::ArrayValue> pointerValue = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(data.getValue(tok->astOperand1()->varId(), nullptr, nullptr));
if (pointerValue && pointerValue->pointer && !pointerValue->data.empty()) {
call(data.callbacks, tok->astOperand1(), pointerValue, &data);
auto indexValue = std::make_shared<ExprEngine::IntRange>("0", 0, 0);
ExprEngine::ValuePtr ret;
for (auto val: pointerValue->read(indexValue)) {
structValue = std::dynamic_pointer_cast<ExprEngine::StructValue>(val.second);
if (structValue) {
auto memberValue = structValue->getValueOfMember(tok->astOperand2()->str());
call(data.callbacks, tok, memberValue, &data);
if (!ret)
ret = memberValue;
}
}
return ret;
} else {
call(data.callbacks, tok->astOperand1(), data.getValue(tok->astOperand1()->varId(), nullptr, nullptr), &data);
}
}
if (!structValue) {
auto v = getValueRangeFromValueType(data.getNewSymbolName(), tok->valueType(), *data.settings);
if (!v)
v = std::make_shared<ExprEngine::BailoutValue>();
call(data.callbacks, tok, v, &data);
return v;
}
}
call(data.callbacks, tok->astOperand1(), structValue, &data);
ExprEngine::ValuePtr memberValue = structValue->getValueOfMember(tok->astOperand2()->str());
call(data.callbacks, tok, memberValue, &data);
return memberValue;
}
static ExprEngine::ValuePtr executeBinaryOp(const Token *tok, Data &data)
{
ExprEngine::ValuePtr v1 = executeExpression(tok->astOperand1(), data);
ExprEngine::ValuePtr v2;
if (tok->str() == "?") {
if (tok->astOperand1()->hasKnownIntValue()) {
if (tok->astOperand1()->getKnownIntValue())
v2 = executeExpression(tok->astOperand2()->astOperand1(), data);
else
v2 = executeExpression(tok->astOperand2()->astOperand2(), data);
call(data.callbacks, tok, v2, &data);
return v2;
}
Data trueData(data);
trueData.addConstraint(v1, true);
auto trueValue = simplifyValue(executeExpression(tok->astOperand2()->astOperand1(), trueData));
Data falseData(data);
falseData.addConstraint(v1, false);
auto falseValue = simplifyValue(executeExpression(tok->astOperand2()->astOperand2(), falseData));
auto result = simplifyValue(std::make_shared<ExprEngine::BinOpResult>("?", v1, std::make_shared<ExprEngine::BinOpResult>(":", trueValue, falseValue)));
call(data.callbacks, tok, result, &data);
return result;
} else if (tok->str() == "&&" || tok->str() == "||") {
Data data2(data);
data2.addConstraint(v1, tok->str() == "&&");
v2 = executeExpression(tok->astOperand2(), data2);
} else {
v2 = executeExpression(tok->astOperand2(), data);
}
if (v1 && v2) {
auto result = simplifyValue(std::make_shared<ExprEngine::BinOpResult>(tok->str(), v1, v2));
call(data.callbacks, tok, result, &data);
return result;
}
if (tok->str() == "&&" && (v1 || v2)) {
auto result = v1 ? v1 : v2;
call(data.callbacks, tok, result, &data);
return result;
}
return ExprEngine::ValuePtr();
}
static ExprEngine::ValuePtr executeAddressOf(const Token *tok, Data &data)
{
auto addr = std::make_shared<ExprEngine::AddressOfValue>(data.getNewSymbolName(), tok->astOperand1()->varId());
call(data.callbacks, tok, addr, &data);
return addr;
}
static ExprEngine::ValuePtr executeDeref(const Token *tok, Data &data)
{
ExprEngine::ValuePtr pval = executeExpression(tok->astOperand1(), data);
if (!pval) {
auto v = getValueRangeFromValueType(data.getNewSymbolName(), tok->valueType(), *data.settings);
if (tok->astOperand1()->varId()) {
pval = std::make_shared<ExprEngine::ArrayValue>(data.getNewSymbolName(), ExprEngine::ValuePtr(), v, true, false, false);
data.assignValue(tok->astOperand1(), tok->astOperand1()->varId(), pval);
}
call(data.callbacks, tok, v, &data);
return v;
}
auto addressOf = std::dynamic_pointer_cast<ExprEngine::AddressOfValue>(pval);
if (addressOf) {
auto val = data.getValue(addressOf->varId, tok->valueType(), tok);
call(data.callbacks, tok, val, &data);
return val;
}
auto pointer = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(pval);
if (pointer) {
auto indexValue = std::make_shared<ExprEngine::IntRange>("0", 0, 0);
auto conditionalValues = pointer->read(indexValue);
for (auto value: conditionalValues)
call(data.callbacks, tok, value.second, &data);
if (conditionalValues.size() == 1 && !conditionalValues[0].first)
return conditionalValues[0].second;
return std::make_shared<ExprEngine::ConditionalValue>(data.getNewSymbolName(), conditionalValues);
}
return ExprEngine::ValuePtr();
}
static ExprEngine::ValuePtr executeVariable(const Token *tok, Data &data)
{
auto val = data.getValue(tok->varId(), tok->valueType(), tok);
call(data.callbacks, tok, val, &data);
return val;
}
static ExprEngine::ValuePtr executeKnownMacro(const Token *tok, Data &data)
{
auto val = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), tok->getKnownIntValue(), tok->getKnownIntValue());
call(data.callbacks, tok, val, &data);
return val;
}
static ExprEngine::ValuePtr executeNumber(const Token *tok, Data &data)
{
if (tok->valueType()->isFloat()) {
long double value = MathLib::toDoubleNumber(tok->str());
auto v = std::make_shared<ExprEngine::FloatRange>(tok->str(), value, value);
call(data.callbacks, tok, v, &data);
return v;
}
int128_t value = MathLib::toLongNumber(tok->str());
auto v = std::make_shared<ExprEngine::IntRange>(tok->str(), value, value);
call(data.callbacks, tok, v, &data);
return v;
}
static ExprEngine::ValuePtr executeStringLiteral(const Token *tok, Data &data)
{
std::string s = tok->str();
return std::make_shared<ExprEngine::StringLiteralValue>(data.getNewSymbolName(), s.substr(1, s.size()-2));
}
static ExprEngine::ValuePtr executeExpression1(const Token *tok, Data &data)
{
if (tok->str() == "return")
return executeReturn(tok, data);
if (tok->isAssignmentOp())
// TODO: Handle more operators
return executeAssign(tok, data);
if (tok->astOperand1() && tok->astOperand2() && tok->str() == "[")
return executeArrayIndex(tok, data);
if (tok->str() == "(") {
if (!tok->isCast())
return executeFunctionCall(tok, data);
return executeCast(tok, data);
}
if (tok->str() == ".")
return executeDot(tok, data);
if (tok->str() == "::" && tok->hasKnownIntValue()) { // TODO handle :: better
auto v = tok->getKnownIntValue();
return std::make_shared<ExprEngine::IntRange>(std::to_string(v), v, v);
}
if (tok->astOperand1() && tok->astOperand2())
return executeBinaryOp(tok, data);
if (tok->isUnaryOp("&") && Token::Match(tok->astOperand1(), "%var%"))
return executeAddressOf(tok, data);
if (tok->isUnaryOp("*"))
return executeDeref(tok, data);
if (tok->varId())
return executeVariable(tok, data);
if (tok->isName() && tok->hasKnownIntValue())
return executeKnownMacro(tok, data);
if (tok->isNumber() || tok->tokType() == Token::Type::eChar)
return executeNumber(tok, data);
if (tok->tokType() == Token::Type::eString)
return executeStringLiteral(tok, data);
return ExprEngine::ValuePtr();
}
static ExprEngine::ValuePtr executeExpression(const Token *tok, Data &data)
{
return translateUninitValueToRange(executeExpression1(tok, data), tok->valueType(), data);
}
static ExprEngine::ValuePtr createVariableValue(const Variable &var, Data &data);
static void execute(const Token *start, const Token *end, Data &data, int recursion=0)
{
if (++recursion > 20)
// FIXME
return;
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (Token::Match(tok, "[;{}]"))
data.trackProgramState(tok);
if (Token::simpleMatch(tok, "while (") && (tok->linkAt(1), ") ;") && tok->next()->astOperand1()->hasKnownIntValue() && tok->next()->astOperand1()->getKnownIntValue() == 0) {
tok = tok->tokAt(4);
continue;
}
if (tok->str() == "break") {
const Scope *scope = tok->scope();
while (scope->type == Scope::eIf || scope->type == Scope::eElse)
scope = scope->nestedIn;
tok = scope->bodyEnd;
if (!precedes(tok,end))
return;
}
if (Token::simpleMatch(tok, "try"))
// TODO this is a bailout
throw BugHuntingException(tok, "Unhandled:" + tok->str());
// Variable declaration..
if (tok->variable() && tok->variable()->nameToken() == tok) {
if (Token::Match(tok, "%varid% ; %varid% =", tok->varId())) {
// if variable is not used in assignment rhs then we do not need to create a "confusing" variable value..
bool foundInRhs = false;
visitAstNodes(tok->tokAt(3)->astOperand2(), [&](const Token *rhs) {
if (rhs->varId()==tok->varId()) {
foundInRhs = true;
return ChildrenToVisit::done;
}
return ChildrenToVisit::op1_and_op2;
});
if (!foundInRhs) {
tok = tok->tokAt(2);
continue;
}
} else if (tok->variable()->isArray()) {
data.assignValue(tok, tok->varId(), std::make_shared<ExprEngine::ArrayValue>(&data, tok->variable()));
if (Token::Match(tok, "%name% ["))
tok = tok->linkAt(1);
} else if (Token::Match(tok, "%var% ;"))
data.assignValue(tok, tok->varId(), createVariableValue(*tok->variable(), data));
} else if (!tok->astParent() && (tok->astOperand1() || tok->astOperand2())) {
executeExpression(tok, data);
if (Token::Match(tok, "throw|return"))
return;
}
else if (Token::simpleMatch(tok, "if (")) {
const Token *cond = tok->next()->astOperand2(); // TODO: C++17 condition
const ExprEngine::ValuePtr condValue = executeExpression(cond, data);
Data thenData(data);
Data elseData(data);
thenData.addConstraint(condValue, true);
elseData.addConstraint(condValue, false);
const Token *thenStart = tok->linkAt(1)->next();
const Token *thenEnd = thenStart->link();
const Token *exceptionToken = nullptr;
std::string exceptionMessage;
auto exec = [&](const Token *tok1, const Token *tok2, Data& data) {
try {
execute(tok1, tok2, data, recursion);
} catch (BugHuntingException &e) {
if (!exceptionToken || (e.tok && precedes(e.tok, exceptionToken))) {
exceptionToken = e.tok;
exceptionMessage = e.what;
}
}
};
exec(thenStart->next(), end, thenData);
if (Token::simpleMatch(thenEnd, "} else {")) {
const Token *elseStart = thenEnd->tokAt(2);
exec(elseStart->next(), end, elseData);
} else {
exec(thenEnd, end, elseData);
}
if (exceptionToken)
throw BugHuntingException(exceptionToken, exceptionMessage);
return;
}
else if (Token::simpleMatch(tok, "switch (")) {
auto condValue = executeExpression(tok->next()->astOperand2(), data); // TODO: C++17 condition
const Token *bodyStart = tok->linkAt(1)->next();
const Token *bodyEnd = bodyStart->link();
const Token *defaultStart = nullptr;
Data defaultData(data);
const Token *exceptionToken = nullptr;
std::string exceptionMessage;
auto exec = [&](const Token *tok1, const Token *tok2, Data& data) {
try {
execute(tok1, tok2, data, recursion);
} catch (BugHuntingException &e) {
if (!exceptionToken || (e.tok && precedes(e.tok, exceptionToken))) {
exceptionToken = e.tok;
exceptionMessage = e.what;
}
}
};
for (const Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) {
if (tok2->str() == "{")
tok2 = tok2->link();
else if (Token::Match(tok2, "case %char%|%num% :")) {
const MathLib::bigint caseValue1 = tok2->next()->getKnownIntValue();
auto caseValue = std::make_shared<ExprEngine::IntRange>(MathLib::toString(caseValue1), caseValue1, caseValue1);
Data caseData(data);
caseData.addConstraint(condValue, caseValue, true);
defaultData.addConstraint(condValue, caseValue, false);
exec(tok2->tokAt(2), end, caseData);
} else if (Token::Match(tok2, "case %name% :") && !Token::Match(tok2->tokAt(3), ";| case")) {
Data caseData(data);
exec(tok2->tokAt(2), end, caseData);
} else if (Token::simpleMatch(tok2, "default :"))
defaultStart = tok2;
}
exec(defaultStart ? defaultStart : bodyEnd, end, defaultData);
if (exceptionToken)
throw BugHuntingException(exceptionToken, exceptionMessage);
return;
}
if (Token::Match(tok, "for|while (") && Token::simpleMatch(tok->linkAt(1), ") {")) {
const Token *bodyStart = tok->linkAt(1)->next();
const Token *bodyEnd = bodyStart->link();
// TODO this is very rough code
std::set<int> changedVariables;
for (const Token *tok2 = tok; tok2 != bodyEnd; tok2 = tok2->next()) {
if (Token::Match(tok2, "%assign%")) {
const Token *lhs = tok2->astOperand1();
while (Token::simpleMatch(lhs, "["))
lhs = lhs->astOperand1();
if (!lhs)
throw BugHuntingException(tok2, "Unhandled assignment in loop");
if (Token::Match(lhs, ". %name% =|[") && lhs->astOperand1() && lhs->astOperand1()->valueType()) {
const Token *structToken = lhs->astOperand1();
if (!structToken->valueType() || !structToken->varId())
throw BugHuntingException(tok2, "Unhandled assignment in loop");
const Scope *structScope = structToken->valueType()->typeScope;
if (!structScope)
throw BugHuntingException(tok2, "Unhandled assignment in loop");
const std::string &memberName = tok2->previous()->str();
ExprEngine::ValuePtr memberValue;
for (const Variable &member : structScope->varlist) {
if (memberName == member.name() && member.valueType()) {
memberValue = createVariableValue(member, data);
break;
}
}
if (!memberValue)
throw BugHuntingException(tok2, "Unhandled assignment in loop");
ExprEngine::ValuePtr structVal1 = data.getValue(structToken->varId(), structToken->valueType(), structToken);
if (!structVal1)
structVal1 = createVariableValue(*structToken->variable(), data);
auto structVal = std::dynamic_pointer_cast<ExprEngine::StructValue>(structVal1);
if (!structVal)
throw BugHuntingException(tok2, "Unhandled assignment in loop");
data.assignStructMember(tok2, &*structVal, memberName, memberValue);
continue;
}
if (lhs->isUnaryOp("*") && lhs->astOperand1()->varId()) {
const Token *varToken = tok2->astOperand1()->astOperand1();
ExprEngine::ValuePtr val = data.getValue(varToken->varId(), varToken->valueType(), varToken);
if (val && val->type == ExprEngine::ValueType::ArrayValue) {
// Try to assign "any" value
auto arrayValue = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(val);
arrayValue->assign(std::make_shared<ExprEngine::IntRange>("0", 0, 0), std::make_shared<ExprEngine::BailoutValue>());
continue;
}
}
if (!lhs->variable())
throw BugHuntingException(tok2, "Unhandled assignment in loop");
// give variable "any" value
int varid = lhs->varId();
if (changedVariables.find(varid) != changedVariables.end())
continue;
changedVariables.insert(varid);
auto oldValue = data.getValue(varid, nullptr, nullptr);
if (oldValue && oldValue->isUninit())
call(data.callbacks, lhs, oldValue, &data);
if (oldValue && oldValue->type == ExprEngine::ValueType::ArrayValue) {
// Try to assign "any" value
auto arrayValue = std::dynamic_pointer_cast<ExprEngine::ArrayValue>(oldValue);
arrayValue->assign(std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 0, ~0ULL), std::make_shared<ExprEngine::BailoutValue>());
continue;
}
data.assignValue(tok2, varid, getValueRangeFromValueType(data.getNewSymbolName(), lhs->valueType(), *data.settings));
continue;
} else if (Token::Match(tok2, "++|--") && tok2->astOperand1() && tok2->astOperand1()->variable()) {
// give variable "any" value
const Token *vartok = tok2->astOperand1();
int varid = vartok->varId();
if (changedVariables.find(varid) != changedVariables.end())
continue;
changedVariables.insert(varid);
auto oldValue = data.getValue(varid, nullptr, nullptr);
if (oldValue && oldValue->type == ExprEngine::ValueType::UninitValue)
call(data.callbacks, tok2, oldValue, &data);
data.assignValue(tok2, varid, getValueRangeFromValueType(data.getNewSymbolName(), vartok->valueType(), *data.settings));
}
}
}
if (Token::simpleMatch(tok, "} else {"))
tok = tok->linkAt(2);
}
}
void ExprEngine::executeAllFunctions(ErrorLogger *errorLogger, const Tokenizer *tokenizer, const Settings *settings, const std::vector<ExprEngine::Callback> &callbacks, std::ostream &report)
{
const SymbolDatabase *symbolDatabase = tokenizer->getSymbolDatabase();
for (const Scope *functionScope : symbolDatabase->functionScopes) {
try {
executeFunction(functionScope, errorLogger, tokenizer, settings, callbacks, report);
} catch (const BugHuntingException &e) {
// FIXME.. there should not be exceptions
std::string functionName = functionScope->function->name();
std::cout << "Verify: Aborted analysis of function '" << functionName << "':" << e.tok->linenr() << ": " << e.what << std::endl;
} catch (const std::exception &e) {
// FIXME.. there should not be exceptions
std::string functionName = functionScope->function->name();
std::cout << "Verify: Aborted analysis of function '" << functionName << "': " << e.what() << std::endl;
}
}
}
static ExprEngine::ValuePtr createStructVal(const Scope *structScope, bool uninitData, Data &data)
{
if (!structScope)
return ExprEngine::ValuePtr();
std::shared_ptr<ExprEngine::StructValue> structValue = std::make_shared<ExprEngine::StructValue>(data.getNewSymbolName());
auto uninitValue = std::make_shared<ExprEngine::UninitValue>();
for (const Variable &member : structScope->varlist) {
if (uninitData) {
if (member.isPointer()) {
structValue->member[member.name()] = uninitValue;
continue;
}
if (member.valueType() && member.valueType()->type >= ::ValueType::Type::CHAR) {
structValue->member[member.name()] = uninitValue;
continue;
}
}
if (member.valueType() && member.valueType()->isIntegral()) {
ExprEngine::ValuePtr memberValue = createVariableValue(member, data);
if (memberValue)
structValue->member[member.name()] = memberValue;
}
}
return structValue;
}
static ExprEngine::ValuePtr createVariableValue(const Variable &var, Data &data)
{
if (!var.nameToken())
return ExprEngine::ValuePtr();
const ValueType *valueType = var.valueType();
if (!valueType || valueType->type == ValueType::Type::UNKNOWN_TYPE)
valueType = var.nameToken()->valueType();
if (!valueType || valueType->type == ValueType::Type::UNKNOWN_TYPE) {
// variable with unknown type
if (var.isLocal() && var.isPointer() && !var.isArray())
return std::make_shared<ExprEngine::UninitValue>();
return ExprEngine::ValuePtr();
}
if (valueType->pointer > 0) {
if (var.isLocal())
return std::make_shared<ExprEngine::UninitValue>();
auto bufferSize = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 1, ~0UL);
ExprEngine::ValuePtr pointerValue;
if (valueType->type == ValueType::Type::RECORD)
pointerValue = createStructVal(valueType->typeScope, var.isLocal() && !var.isStatic(), data);
else {
ValueType vt(*valueType);
vt.pointer = 0;
if (vt.constness & 1)
pointerValue = getValueRangeFromValueType(data.getNewSymbolName(), &vt, *data.settings);
else
pointerValue = std::make_shared<ExprEngine::UninitValue>();
}
return std::make_shared<ExprEngine::ArrayValue>(data.getNewSymbolName(), bufferSize, pointerValue, true, true, var.isLocal() && !var.isStatic());
}
if (var.isArray())
return std::make_shared<ExprEngine::ArrayValue>(&data, &var);
if (valueType->isIntegral() || valueType->isFloat()) {
ExprEngine::ValuePtr value;
if (var.isLocal() && !var.isStatic())
value = std::make_shared<ExprEngine::UninitValue>();
else
value = getValueRangeFromValueType(data.getNewSymbolName(), valueType, *data.settings);
data.addConstraints(value, var.nameToken());
return value;
}
if (valueType->type == ValueType::Type::RECORD)
return createStructVal(valueType->typeScope, var.isLocal() && !var.isStatic(), data);
if (valueType->smartPointerType) {
auto structValue = createStructVal(valueType->smartPointerType->classScope, var.isLocal() && !var.isStatic(), data);
auto size = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 1, ~0UL);
return std::make_shared<ExprEngine::ArrayValue>(data.getNewSymbolName(), size, structValue, true, true, false);
}
if (valueType->container) {
ExprEngine::ValuePtr value;
if (valueType->container->stdStringLike)
value = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), -128, 127);
else if (valueType->containerTypeToken) {
ValueType vt = ValueType::parseDecl(valueType->containerTypeToken, data.settings);
value = getValueRangeFromValueType(data.getNewSymbolName(), &vt, *data.settings);
} else
return ExprEngine::ValuePtr();
auto bufferSize = std::make_shared<ExprEngine::IntRange>(data.getNewSymbolName(), 0, ~0U);
return std::make_shared<ExprEngine::ArrayValue>(data.getNewSymbolName(), bufferSize, value, false, false, false);
}
return ExprEngine::ValuePtr();
}
void ExprEngine::executeFunction(const Scope *functionScope, ErrorLogger *errorLogger, const Tokenizer *tokenizer, const Settings *settings, const std::vector<ExprEngine::Callback> &callbacks, std::ostream &report)
{
if (!functionScope->bodyStart)
return;
const Function *function = functionScope->function;
if (!function)
return;
if (functionScope->bodyStart->fileIndex() > 0)
// TODO.. what about functions in headers?
return;
const std::string currentFunction = function->fullName();
int symbolValueIndex = 0;
TrackExecution trackExecution;
Data data(&symbolValueIndex, errorLogger, tokenizer, settings, currentFunction, callbacks, &trackExecution);
for (const Variable &arg : function->argumentList)
data.assignValue(functionScope->bodyStart, arg.declarationId(), createVariableValue(arg, data));
data.contractConstraints(function, executeExpression1);
try {
execute(functionScope->bodyStart, functionScope->bodyEnd, data);
} catch (BugHuntingException &e) {
if (settings->debugBugHunting)
report << "BugHuntingException tok.line:" << e.tok->linenr() << " what:" << e.what << "\n";
trackExecution.setAbortLine(e.tok->linenr());
auto bailoutValue = std::make_shared<BailoutValue>();
for (const Token *tok = e.tok; tok != functionScope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "return|throw|while|if|for (")) {
tok = tok->next();
continue;
}
call(callbacks, tok, bailoutValue, &data);
}
}
const bool bugHuntingReport = !settings->bugHuntingReport.empty();
if (settings->debugBugHunting && (settings->verbose || callbacks.empty() || !trackExecution.isAllOk())) {
if (bugHuntingReport)
report << "[debug]" << std::endl;
trackExecution.print(report);
if (!callbacks.empty()) {
if (bugHuntingReport)
report << "[details]" << std::endl;
trackExecution.report(report, functionScope);
}
}
// Write a report
if (bugHuntingReport) {
for (const std::string &f: trackExecution.getMissingContracts())
report << "[missing contract] " << f << std::endl;
}
}
static float getKnownFloatValue(const Token *tok, float def)
{
for (const auto &value: tok->values()) {
if (value.isKnown() && value.valueType == ValueFlow::Value::ValueType::FLOAT)
return value.floatValue;
}
return def;
}
void ExprEngine::runChecks(ErrorLogger *errorLogger, const Tokenizer *tokenizer, const Settings *settings)
{
std::function<void(const Token *, const ExprEngine::Value &, ExprEngine::DataBase *)> bufferOverflow = [=](const Token *tok, const ExprEngine::Value &value, ExprEngine::DataBase *dataBase) {
if (!Token::simpleMatch(tok->astParent(), ","))
return;
if (!tok->valueType() || tok->valueType()->pointer != 1 || tok->valueType()->type != ::ValueType::Type::CHAR)
return;
int argnr = (tok == tok->astParent()->astOperand1()) ? 0 : 1;
const Token *ftok = tok->astParent();
while (Token::simpleMatch(ftok, ",")) {
++argnr;
ftok = ftok->astParent();
}
ftok = ftok ? ftok->previous() : nullptr;
if (!Token::Match(ftok, "%name% ("))
return;
int overflowArgument = 0;
if (const Library::Function *func = settings->library.getFunction(ftok)) {
for (auto argNrChecks: func->argumentChecks) {
int nr = argNrChecks.first;
const Library::ArgumentChecks &checks = argNrChecks.second;
for (const Library::ArgumentChecks::MinSize &minsize: checks.minsizes) {
if (minsize.type == Library::ArgumentChecks::MinSize::STRLEN && minsize.arg == argnr)
overflowArgument = nr;
}
}
}
if (!overflowArgument)
return;
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingBufferOverflow", "Buffer read/write, when calling '" + ftok->str() + "' it cannot be determined that " + std::to_string(overflowArgument) + getOrdinalText(overflowArgument) + " argument is not overflowed", CWE(120), false);
if (value.type == ExprEngine::ValueType::BailoutValue)
errmsg.incomplete = true;
else
errmsg.function = dataBase->currentFunction;
errorLogger->reportErr(errmsg);
};
std::function<void(const Token *, const ExprEngine::Value &, ExprEngine::DataBase *)> divByZero = [=](const Token *tok, const ExprEngine::Value &value, ExprEngine::DataBase *dataBase) {
if (!tok->astParent() || !std::strchr("/%", tok->astParent()->str()[0]))
return;
if (tok->hasKnownIntValue() && tok->getKnownIntValue() != 0)
return;
if (tok->isImpossibleIntValue(0))
return;
if (value.isUninit())
return;
float f = getKnownFloatValue(tok, 0.0f);
if (f > 0.0f || f < 0.0f)
return;
if (value.type == ExprEngine::ValueType::BailoutValue) {
if (Token::simpleMatch(tok->previous(), "sizeof ("))
return;
}
if (tok->astParent()->astOperand2() == tok && value.isEqual(dataBase, 0)) {
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{settings->clang ? tok : tok->astParent()};
const char * const id = (tok->valueType() && tok->valueType()->isFloat()) ? "bughuntingDivByZeroFloat" : "bughuntingDivByZero";
const bool bailout = (value.type == ExprEngine::ValueType::BailoutValue);
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, id, "There is division, cannot determine that there can't be a division by zero.", CWE(369), false);
if (!bailout)
errmsg.function = dataBase->currentFunction;
else
errmsg.incomplete = bailout;
errorLogger->reportErr(errmsg);
}
};
#ifdef BUG_HUNTING_INTEGEROVERFLOW
std::function<void(const Token *, const ExprEngine::Value &, ExprEngine::DataBase *)> integerOverflow = [&](const Token *tok, const ExprEngine::Value &value, ExprEngine::DataBase *dataBase) {
if (!tok->isArithmeticalOp() || !tok->valueType() || !tok->valueType()->isIntegral() || tok->valueType()->pointer > 0)
return;
const ExprEngine::BinOpResult *b = dynamic_cast<const ExprEngine::BinOpResult *>(&value);
if (!b)
return;
int bits = getIntBitsFromValueType(tok->valueType(), *settings);
if (bits == 0 || bits >= 60)
return;
std::string errorMessage;
if (tok->valueType()->sign == ::ValueType::Sign::SIGNED) {
MathLib::bigint v = 1LL << (bits - 1);
if (b->isGreaterThan(dataBase, v-1))
errorMessage = "greater than " + std::to_string(v - 1);
if (b->isLessThan(dataBase, -v)) {
if (!errorMessage.empty())
errorMessage += " or ";
errorMessage += "less than " + std::to_string(-v);
}
} else {
MathLib::bigint maxValue = (1LL << bits) - 1;
if (b->isGreaterThan(dataBase, maxValue))
errorMessage = "greater than " + std::to_string(maxValue);
if (b->isLessThan(dataBase, 0)) {
if (!errorMessage.empty())
errorMessage += " or ";
errorMessage += "less than 0";
}
}
if (errorMessage.empty())
return;
errorMessage = "There is integer arithmetic, cannot determine that there can't be overflow (if result is " + errorMessage + ").";
if (tok->valueType()->sign == ::ValueType::Sign::UNSIGNED)
errorMessage += " Note that unsigned integer overflow is defined and will wrap around.";
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingIntegerOverflow", errorMessage, false);
errorLogger->reportErr(errmsg);
};
#endif
std::function<void(const Token *, const ExprEngine::Value &, ExprEngine::DataBase *)> uninit = [=](const Token *tok, const ExprEngine::Value &value, ExprEngine::DataBase *dataBase) {
if (!tok->astParent())
return;
if (!value.isUninit())
return;
// lhs in assignment
if (tok->astParent()->str() == "=" && tok == tok->astParent()->astOperand1())
return;
// Avoid FP when there is bailout..
if (value.type == ExprEngine::ValueType::BailoutValue) {
if (tok->hasKnownValue())
return;
if (tok->function())
return;
if (Token::Match(tok, "<<|>>|,"))
// Only warn about the operands
return;
// lhs for scope operator
if (Token::Match(tok, "%name% ::"))
return;
if (tok->astParent()->str() == "::" && tok == tok->astParent()->astOperand1())
return;
if (tok->str() == "(")
// cast: result is not uninitialized if expression is initialized
// function: does not return a uninitialized value
return;
// Containers are not uninitialized
std::vector<const Token *> tokens{tok, tok->astOperand1(), tok->astOperand2()};
if (Token::Match(tok->previous(), ". %name%"))
tokens.push_back(tok->previous()->astOperand1());
for (const Token *t: tokens) {
if (t && t->valueType() && t->valueType()->pointer == 0 && t->valueType()->container)
return;
}
const Variable *var = tok->variable();
if (var && !var->isPointer()) {
if (!var->isLocal() || var->isStatic())
return;
}
if (var && (Token::Match(var->nameToken(), "%name% =") || Token::Match(var->nameToken(), "%varid% ; %varid% =", var->declarationId())))
return;
if (var && var->nameToken() == tok)
return;
}
// Avoid FP for array declaration
const Token *parent = tok->astParent();
while (parent && parent->str() == "[")
parent = parent->astParent();
if (!parent)
return;
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingUninit", "Cannot determine that '" + tok->expressionString() + "' is initialized", CWE_USE_OF_UNINITIALIZED_VARIABLE, false);
errorLogger->reportErr(errmsg);
};
std::function<void(const Token *, const ExprEngine::Value &, ExprEngine::DataBase *)> checkFunctionCall = [=](const Token *tok, const ExprEngine::Value &value, ExprEngine::DataBase *dataBase) {
if (!Token::Match(tok->astParent(), "[(,]"))
return;
const Token *parent = tok->astParent();
while (Token::simpleMatch(parent, ","))
parent = parent->astParent();
if (!parent || parent->str() != "(")
return;
int num = 0;
for (const Token *argTok: getArguments(parent->astOperand1())) {
--num;
if (argTok == tok) {
num = -num;
break;
}
}
if (num <= 0)
return;
if (parent->astOperand1()->function()) {
const Variable *arg = parent->astOperand1()->function()->getArgumentVar(num - 1);
if (arg && arg->nameToken()) {
std::string bad;
MathLib::bigint low;
if (arg->nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::LOW, &low)) {
if (!(tok->hasKnownIntValue() && tok->getKnownIntValue() >= low) && value.isLessThan(dataBase, low))
bad = "__cppcheck_low__(" + std::to_string(low) + ")";
}
MathLib::bigint high;
if (arg->nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::HIGH, &high)) {
if (!(tok->hasKnownIntValue() && tok->getKnownIntValue() <= high) && value.isGreaterThan(dataBase, high))
bad = "__cppcheck_high__(" + std::to_string(high) + ")";
}
if (!bad.empty()) {
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack,
&tokenizer->list,
Severity::SeverityType::error,
"bughuntingInvalidArgValue",
"There is function call, cannot determine that " + std::to_string(num) + getOrdinalText(num) + " argument value meets the attribute " + bad, CWE(0), false);
errorLogger->reportErr(errmsg);
return;
}
}
}
// Check invalid function argument values..
for (const Library::InvalidArgValue &invalidArgValue : Library::getInvalidArgValues(settings->library.validarg(parent->astOperand1(), num))) {
bool err = false;
std::string bad;
switch (invalidArgValue.type) {
case Library::InvalidArgValue::eq:
if (!tok->hasKnownIntValue() || tok->getKnownIntValue() == MathLib::toLongNumber(invalidArgValue.op1))
err = value.isEqual(dataBase, MathLib::toLongNumber(invalidArgValue.op1));
bad = "equals " + invalidArgValue.op1;
break;
case Library::InvalidArgValue::le:
if (!tok->hasKnownIntValue() || tok->getKnownIntValue() <= MathLib::toLongNumber(invalidArgValue.op1))
err = value.isLessThan(dataBase, MathLib::toLongNumber(invalidArgValue.op1) + 1);
bad = "less equal " + invalidArgValue.op1;
break;
case Library::InvalidArgValue::lt:
if (!tok->hasKnownIntValue() || tok->getKnownIntValue() < MathLib::toLongNumber(invalidArgValue.op1))
err = value.isLessThan(dataBase, MathLib::toLongNumber(invalidArgValue.op1));
bad = "less than " + invalidArgValue.op1;
break;
case Library::InvalidArgValue::ge:
if (!tok->hasKnownIntValue() || tok->getKnownIntValue() >= MathLib::toLongNumber(invalidArgValue.op1))
err = value.isGreaterThan(dataBase, MathLib::toLongNumber(invalidArgValue.op1) - 1);
bad = "greater equal " + invalidArgValue.op1;
break;
case Library::InvalidArgValue::gt:
if (!tok->hasKnownIntValue() || tok->getKnownIntValue() > MathLib::toLongNumber(invalidArgValue.op1))
err = value.isGreaterThan(dataBase, MathLib::toLongNumber(invalidArgValue.op1));
bad = "greater than " + invalidArgValue.op1;
break;
case Library::InvalidArgValue::range:
// TODO
err = value.isEqual(dataBase, MathLib::toLongNumber(invalidArgValue.op1));
err |= value.isEqual(dataBase, MathLib::toLongNumber(invalidArgValue.op2));
bad = "range " + invalidArgValue.op1 + "-" + invalidArgValue.op2;
break;
}
if (err) {
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingInvalidArgValue", "There is function call, cannot determine that " + std::to_string(num) + getOrdinalText(num) + " argument value is valid. Bad value: " + bad, CWE(0), false);
errorLogger->reportErr(errmsg);
break;
}
}
// Uninitialized function argument..
if (settings->library.isuninitargbad(parent->astOperand1(), num) && settings->library.isnullargbad(parent->astOperand1(), num) && value.type == ExprEngine::ValueType::ArrayValue) {
const ExprEngine::ArrayValue &arrayValue = static_cast<const ExprEngine::ArrayValue &>(value);
auto index0 = std::make_shared<ExprEngine::IntRange>("0", 0, 0);
for (const auto &v: arrayValue.read(index0)) {
if (v.second->isUninit()) {
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingUninitArg", "There is function call, cannot determine that " + std::to_string(num) + getOrdinalText(num) + " argument is initialized.", CWE_USE_OF_UNINITIALIZED_VARIABLE, false);
errorLogger->reportErr(errmsg);
break;
}
}
}
};
std::function<void(const Token *, const ExprEngine::Value &, ExprEngine::DataBase *)> checkAssignment = [=](const Token *tok, const ExprEngine::Value &value, ExprEngine::DataBase *dataBase) {
if (!Token::simpleMatch(tok->astParent(), "="))
return;
const Token *lhs = tok->astParent()->astOperand1();
while (Token::simpleMatch(lhs, "."))
lhs = lhs->astOperand2();
if (!lhs || !lhs->variable() || !lhs->variable()->nameToken())
return;
const Token *vartok = lhs->variable()->nameToken();
MathLib::bigint low;
if (vartok->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::LOW, &low)) {
if (value.isLessThan(dataBase, low)) {
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingAssign", "There is assignment, cannot determine that value is greater or equal with " + std::to_string(low), CWE_INCORRECT_CALCULATION, false);
errorLogger->reportErr(errmsg);
}
}
MathLib::bigint high;
if (vartok->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::HIGH, &high)) {
if (value.isGreaterThan(dataBase, high)) {
dataBase->addError(tok->linenr());
std::list<const Token*> callstack{tok};
ErrorMessage errmsg(callstack, &tokenizer->list, Severity::SeverityType::error, "bughuntingAssign", "There is assignment, cannot determine that value is lower or equal with " + std::to_string(high), CWE_INCORRECT_CALCULATION, false);
errorLogger->reportErr(errmsg);
}
}
};
std::vector<ExprEngine::Callback> callbacks;
callbacks.push_back(bufferOverflow);
callbacks.push_back(divByZero);
callbacks.push_back(checkFunctionCall);
callbacks.push_back(checkAssignment);
#ifdef BUG_HUNTING_INTEGEROVERFLOW
callbacks.push_back(integerOverflow);
#endif
callbacks.push_back(uninit);
std::ostringstream report;
ExprEngine::executeAllFunctions(errorLogger, tokenizer, settings, callbacks, report);
if (settings->bugHuntingReport.empty())
std::cout << report.str();
else if (errorLogger)
errorLogger->bughuntingReport(report.str());
}
static void dumpRecursive(ExprEngine::ValuePtr val)
{
if (!val) {
std::cout << "NULL";
return;
}
switch (val->type) {
case ExprEngine::ValueType::AddressOfValue:
std::cout << "AddressOfValue(" << std::dynamic_pointer_cast<ExprEngine::AddressOfValue>(val)->varId << ")";
break;
case ExprEngine::ValueType::ArrayValue:
std::cout << "ArrayValue";
break;
case ExprEngine::ValueType::BailoutValue:
std::cout << "BailoutValue";
break;
case ExprEngine::ValueType::BinOpResult: {
auto b = std::dynamic_pointer_cast<ExprEngine::BinOpResult>(val);
std::cout << "(";
dumpRecursive(b->op1);
std::cout << " " << b->binop << " ";
dumpRecursive(b->op2);
std::cout << ")";
}
break;
case ExprEngine::ValueType::ConditionalValue:
std::cout << "ConditionalValue";
break;
case ExprEngine::ValueType::FloatRange:
std::cout << "FloatRange";
break;
case ExprEngine::ValueType::IntRange:
std::cout << "IntRange";
break;
case ExprEngine::ValueType::IntegerTruncation:
std::cout << "IntegerTruncation(";
dumpRecursive(std::dynamic_pointer_cast<ExprEngine::IntegerTruncation>(val)->inputValue);
std::cout << ")";
break;
case ExprEngine::ValueType::StringLiteralValue:
std::cout << "StringLiteralValue";
break;
case ExprEngine::ValueType::StructValue:
std::cout << "StructValue";
break;
case ExprEngine::ValueType::UninitValue:
std::cout << "UninitValue";
break;
}
}
void ExprEngine::dump(ExprEngine::ValuePtr val)
{
dumpRecursive(val);
std::cout << "\n";
}