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GenericTaintChecker now uses CallDescriptionMap to describe the possible
operation in code which trigger the introduction (sources), the removal
(filters), the passing along (propagations) and detection (sinks) of
tainted values.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D116025
Files:
clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
Index: clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
@@ -22,15 +22,14 @@
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include "llvm/Support/YAMLTraits.h"
-#include <algorithm>
#include <limits>
#include <memory>
-#include <unordered_map>
#include <utility>
using namespace clang;
@@ -38,577 +37,685 @@
using namespace taint;
namespace {
-class GenericTaintChecker : public Checker<check::PreCall, check::PostCall> {
-public:
- static void *getTag() {
- static int Tag;
- return &Tag;
+
+/// Check for CWE-134: Uncontrolled Format String.
+constexpr llvm::StringLiteral MsgUncontrolledFormatString =
+ "Untrusted data is used as a format string "
+ "(CWE-134: Uncontrolled Format String)";
+
+/// Check for:
+/// CERT/STR02-C. "Sanitize data passed to complex subsystems"
+/// CWE-78, "Failure to Sanitize Data into an OS Command"
+constexpr llvm::StringLiteral MsgSanitizeSystemArgs =
+ "Untrusted data is passed to a system call "
+ "(CERT/STR02-C. Sanitize data passed to complex subsystems)";
+
+/// Check if tainted data is used as a buffer size ins strn.. functions,
+/// and allocators.
+constexpr llvm::StringLiteral MsgTaintedBufferSize =
+ "Untrusted data is used to specify the buffer size "
+ "(CERT/STR31-C. Guarantee that storage for strings has sufficient space "
+ "for character data and the null terminator)";
+
+/// Check if tainted data is used as a custom sink's parameter.
+constexpr llvm::StringLiteral MsgCustomSink =
+ "Untrusted data is passed to a user-defined sink";
+
+using ArgIdxTy = int;
+using ArgVecTy = llvm::SmallVector<int, 2>;
+
+constexpr int InvalidArgIndex{-2};
+/// Denotes the return value.
+constexpr int ReturnValueIndex{-1};
+
+/// Check if the region the expression evaluates to is the standard input,
+/// and thus, is tainted.
+bool isStdin(const Expr *E, CheckerContext &C) {
+ ProgramStateRef State = C.getState();
+ SVal Val = C.getSVal(E);
+
+ // stdin is a pointer, so it would be a region.
+ const MemRegion *MemReg = Val.getAsRegion();
+
+ // The region should be symbolic, we do not know it's value.
+ const auto *SymReg = dyn_cast_or_null<SymbolicRegion>(MemReg);
+ if (!SymReg)
+ return false;
+
+ // Get it's symbol and find the declaration region it's pointing to.
+ const auto *Sm = dyn_cast<SymbolRegionValue>(SymReg->getSymbol());
+ if (!Sm)
+ return false;
+ const auto *DeclReg = dyn_cast_or_null<DeclRegion>(Sm->getRegion());
+ if (!DeclReg)
+ return false;
+
+ // This region corresponds to a declaration, find out if it's a global/extern
+ // variable named stdin with the proper type.
+ if (const auto *D = dyn_cast_or_null<VarDecl>(DeclReg->getDecl())) {
+ D = D->getCanonicalDecl();
+ if (D->getName().contains("stdin") && D->isExternC()) {
+ const auto *PtrTy = dyn_cast<PointerType>(D->getType().getTypePtr());
+ if (PtrTy && PtrTy->getPointeeType().getCanonicalType() ==
+ C.getASTContext().getFILEType().getCanonicalType())
+ return true;
+ }
}
+ return false;
+}
- void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
- void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
+/// Given a pointer argument, return the value it points to.
+Optional<SVal> getPointeeOf(CheckerContext &C, const Expr *Arg) {
+ ProgramStateRef State = C.getState();
+ SVal AddrVal = C.getSVal(Arg->IgnoreParens());
+ if (AddrVal.isUnknownOrUndef())
+ return None;
- void printState(raw_ostream &Out, ProgramStateRef State, const char *NL,
- const char *Sep) const override;
+ Optional<Loc> AddrLoc = AddrVal.getAs<Loc>();
+ if (!AddrLoc)
+ return None;
- using ArgVector = SmallVector<unsigned, 2>;
- using SignedArgVector = SmallVector<int, 2>;
+ QualType ArgTy = Arg->getType().getCanonicalType();
+ if (!ArgTy->isPointerType())
+ return State->getSVal(*AddrLoc);
- enum class VariadicType { None, Src, Dst };
+ QualType ValTy = ArgTy->getPointeeType();
- /// Used to parse the configuration file.
- struct TaintConfiguration {
- using NameScopeArgs = std::tuple<std::string, std::string, ArgVector>;
-
- struct Propagation {
- std::string Name;
- std::string Scope;
- ArgVector SrcArgs;
- SignedArgVector DstArgs;
- VariadicType VarType;
- unsigned VarIndex;
- };
-
- std::vector<Propagation> Propagations;
- std::vector<NameScopeArgs> Filters;
- std::vector<NameScopeArgs> Sinks;
-
- TaintConfiguration() = default;
- TaintConfiguration(const TaintConfiguration &) = default;
- TaintConfiguration(TaintConfiguration &&) = default;
- TaintConfiguration &operator=(const TaintConfiguration &) = default;
- TaintConfiguration &operator=(TaintConfiguration &&) = default;
- };
+ // Do not dereference void pointers. Treat them as byte pointers instead.
+ // FIXME: we might want to consider more than just the first byte.
+ if (ValTy->isVoidType())
+ ValTy = C.getASTContext().CharTy;
- /// Convert SignedArgVector to ArgVector.
- ArgVector convertToArgVector(CheckerManager &Mgr, const std::string &Option,
- const SignedArgVector &Args);
+ return State->getSVal(*AddrLoc, ValTy);
+}
- /// Parse the config.
- void parseConfiguration(CheckerManager &Mgr, const std::string &Option,
- TaintConfiguration &&Config);
+/// Given a pointer, return the SVal of its pointee or if it is tainted,
+/// otherwise return the pointer's SVal if tainted.
+Optional<SVal> getTaintedPointeeOrPointer(CheckerContext &C, const Expr *Arg) {
+ assert(Arg);
+ // Check for taint.
+ ProgramStateRef State = C.getState();
+ Optional<SVal> PointedToSVal = getPointeeOf(C, Arg);
- static const unsigned InvalidArgIndex{std::numeric_limits<unsigned>::max()};
- /// Denotes the return vale.
- static const unsigned ReturnValueIndex{std::numeric_limits<unsigned>::max() -
- 1};
+ if (PointedToSVal && isTainted(State, *PointedToSVal))
+ return PointedToSVal;
-private:
- mutable std::unique_ptr<BugType> BT;
- void initBugType() const {
- if (!BT)
- BT = std::make_unique<BugType>(this, "Use of Untrusted Data",
- "Untrusted Data");
+ if (isTainted(State, Arg, C.getLocationContext()))
+ return {C.getSVal(Arg)};
+
+ return {};
+}
+
+bool isTaintedOrPointsToTainted(const Expr *E, const ProgramStateRef &State,
+ CheckerContext &C) {
+ if (isTainted(State, E, C.getLocationContext()) || isStdin(E, C))
+ return true;
+
+ if (!E->getType().getTypePtr()->isPointerType())
+ return false;
+
+ Optional<SVal> V = getPointeeOf(C, E);
+ return (V && isTainted(State, *V));
+}
+
+/// ArgSet is used to describe arguments relevant for taint detection or
+/// taint application. A discrete set of argument indexes and a variadic
+/// argument list signified by a starting index are supported.
+class ArgSet {
+public:
+ ArgSet() = default;
+ ArgSet(ArgVecTy &&DiscreteArgs)
+ : DiscreteArgs(DiscreteArgs), VariadicIndex(None) {}
+ ArgSet(ArgVecTy &&DiscreteArgs, ArgIdxTy VariadicIndex)
+ : DiscreteArgs(DiscreteArgs), VariadicIndex(VariadicIndex) {}
+
+ bool contains(ArgIdxTy ArgIdx) const {
+ if (llvm::is_contained(DiscreteArgs, ArgIdx))
+ return true;
+
+ return VariadicIndex && ArgIdx >= *VariadicIndex;
}
- struct FunctionData {
- FunctionData() = delete;
- FunctionData(const FunctionDecl *FDecl, StringRef Name,
- std::string FullName)
- : FDecl(FDecl), Name(Name), FullName(std::move(FullName)) {}
- FunctionData(const FunctionData &) = default;
- FunctionData(FunctionData &&) = default;
- FunctionData &operator=(const FunctionData &) = delete;
- FunctionData &operator=(FunctionData &&) = delete;
-
- static Optional<FunctionData> create(const CallEvent &Call,
- const CheckerContext &C) {
- if (!Call.getDecl())
- return None;
-
- const FunctionDecl *FDecl = Call.getDecl()->getAsFunction();
- if (!FDecl || (FDecl->getKind() != Decl::Function &&
- FDecl->getKind() != Decl::CXXMethod))
- return None;
-
- StringRef Name = C.getCalleeName(FDecl);
- std::string FullName = FDecl->getQualifiedNameAsString();
- if (Name.empty() || FullName.empty())
- return None;
-
- return FunctionData{FDecl, Name, std::move(FullName)};
- }
+ bool isEmpty() const { return DiscreteArgs.empty() && !VariadicIndex; }
- bool isInScope(StringRef Scope) const {
- return StringRef(FullName).startswith(Scope);
+ ArgVecTy ArgsUpTo(ArgIdxTy LastArgIdx) const {
+ ArgVecTy Args;
+ for (ArgIdxTy I = ReturnValueIndex; I <= LastArgIdx; ++I) {
+ if (contains(I))
+ Args.push_back(I);
}
+ return Args;
+ }
- const FunctionDecl *const FDecl;
- const StringRef Name;
- const std::string FullName;
- };
-
- /// Catch taint related bugs. Check if tainted data is passed to a
- /// system call etc. Returns true on matching.
- bool checkPre(const CallEvent &Call, const FunctionData &FData,
- CheckerContext &C) const;
+private:
+ ArgVecTy DiscreteArgs;
+ Optional<ArgIdxTy> VariadicIndex;
+};
- /// Add taint sources on a pre-visit. Returns true on matching.
- bool addSourcesPre(const CallEvent &Call, const FunctionData &FData,
- CheckerContext &C) const;
+/// A struct used to specify taint propagation rules for a function.
+///
+/// If any of the possible taint source arguments is tainted, all of the
+/// destination arguments should also be tainted. If ReturnValueIndex is added
+/// to the dst list, the return value will be tainted.
+class GenericTaintRule {
+ /// Arguments which are taints sinks and should be checked, and a report
+ /// should be emitted if taint reaches these.
+ ArgSet SinkArgs;
+ /// Arguments which should be sanitized on function return.
+ ArgSet FilterArgs;
+ /// Arguments which can participate in taint propagationa. If any of the
+ /// arguments in PropSrcArgs is tainted, all arguments in PropDstArgs should
+ /// be tainted.
+ ArgSet PropSrcArgs;
+ ArgSet PropDstArgs;
+
+ /// A message that explains why the call is sensitive to taint.
+ Optional<StringRef> SinkMsg;
+
+ GenericTaintRule() = default;
+
+ GenericTaintRule(ArgSet &&Sink, ArgSet &&Filter, ArgSet &&Src, ArgSet &&Dst,
+ Optional<StringRef> SinkMsg = None)
+ : SinkArgs(std::move(Sink)), FilterArgs(std::move(Filter)),
+ PropSrcArgs(std::move(Src)), PropDstArgs(std::move(Dst)),
+ SinkMsg(SinkMsg) {}
- /// Mark filter's arguments not tainted on a pre-visit. Returns true on
- /// matching.
- bool addFiltersPre(const CallEvent &Call, const FunctionData &FData,
- CheckerContext &C) const;
+public:
+ /// Make a rule that reports a warning if taint reaches any of \p FilterArgs
+ /// arguments.
+ static GenericTaintRule Sink(ArgSet &&SinkArgs,
+ Optional<StringRef> Msg = None) {
+ return {std::move(SinkArgs), {}, {}, {}, Msg};
+ }
- /// Propagate taint generated at pre-visit. Returns true on matching.
- static bool propagateFromPre(const CallEvent &Call, CheckerContext &C);
+ /// Make a rule that sanitizes all FilterArgs arguments.
+ static GenericTaintRule Filter(ArgSet &&FilterArgs) {
+ return {{}, std::move(FilterArgs), {}, {}};
+ }
- /// Check if the region the expression evaluates to is the standard input,
- /// and thus, is tainted.
- static bool isStdin(const Expr *E, CheckerContext &C);
+ /// Make a rule that unconditionally taints all Args.
+ /// If Func is provided, it must also return true for taint to propagate.
+ static GenericTaintRule Source(ArgSet &&SourceArgs) {
+ return {{}, {}, {}, std::move(SourceArgs)};
+ }
- /// Given a pointer argument, return the value it points to.
- static Optional<SVal> getPointeeOf(CheckerContext &C, const Expr *Arg);
+ /// Make a rule that taints all PropDstArgs if any of PropSrcArgs is tainted.
+ static GenericTaintRule Prop(ArgSet &&SrcArgs, ArgSet &&DstArgs) {
+ return {{}, {}, std::move(SrcArgs), std::move(DstArgs)};
+ }
- /// Check for CWE-134: Uncontrolled Format String.
- static constexpr llvm::StringLiteral MsgUncontrolledFormatString =
- "Untrusted data is used as a format string "
- "(CWE-134: Uncontrolled Format String)";
- bool checkUncontrolledFormatString(const CallEvent &Call,
- CheckerContext &C) const;
+ /// Make a rule that taints all PropDstArgs if any of PropSrcArgs is tainted.
+ static GenericTaintRule SinkProp(ArgSet &&SinkArgs, ArgSet &&SrcArgs,
+ ArgSet &&DstArgs,
+ Optional<StringRef> Msg = None) {
+ return {
+ std::move(SinkArgs), {}, std::move(SrcArgs), std::move(DstArgs), Msg};
+ }
- /// Check for:
- /// CERT/STR02-C. "Sanitize data passed to complex subsystems"
- /// CWE-78, "Failure to Sanitize Data into an OS Command"
- static constexpr llvm::StringLiteral MsgSanitizeSystemArgs =
- "Untrusted data is passed to a system call "
- "(CERT/STR02-C. Sanitize data passed to complex subsystems)";
- bool checkSystemCall(const CallEvent &Call, StringRef Name,
- CheckerContext &C) const;
-
- /// Check if tainted data is used as a buffer size ins strn.. functions,
- /// and allocators.
- static constexpr llvm::StringLiteral MsgTaintedBufferSize =
- "Untrusted data is used to specify the buffer size "
- "(CERT/STR31-C. Guarantee that storage for strings has sufficient space "
- "for character data and the null terminator)";
- bool checkTaintedBufferSize(const CallEvent &Call, CheckerContext &C) const;
-
- /// Check if tainted data is used as a custom sink's parameter.
- static constexpr llvm::StringLiteral MsgCustomSink =
- "Untrusted data is passed to a user-defined sink";
- bool checkCustomSinks(const CallEvent &Call, const FunctionData &FData,
- CheckerContext &C) const;
+ /// Process a function which could either be a taint source, a taint sink, a
+ /// taint filter or a taint propagator.
+ void process(const CallEvent &Call, CheckerContext &C) const;
- /// Generate a report if the expression is tainted or points to tainted data.
- bool generateReportIfTainted(const Expr *E, StringRef Msg,
- CheckerContext &C) const;
+ /// Handles the resolution of indexes of type ArgIdxTy to Expr*-s.
+ static const Expr *GetArgExpr(ArgIdxTy ArgIdx, const CallEvent &Call) {
+ return ArgIdx == ReturnValueIndex ? Call.getOriginExpr()
+ : Call.getArgExpr(ArgIdx);
+ };
- struct TaintPropagationRule;
- template <typename T>
- using ConfigDataMap =
- std::unordered_multimap<std::string, std::pair<std::string, T>>;
- using NameRuleMap = ConfigDataMap<TaintPropagationRule>;
- using NameArgMap = ConfigDataMap<ArgVector>;
-
- /// Find a function with the given name and scope. Returns the first match
- /// or the end of the map.
- template <typename T>
- static auto findFunctionInConfig(const ConfigDataMap<T> &Map,
- const FunctionData &FData);
-
- /// A struct used to specify taint propagation rules for a function.
- ///
- /// If any of the possible taint source arguments is tainted, all of the
- /// destination arguments should also be tainted. Use InvalidArgIndex in the
- /// src list to specify that all of the arguments can introduce taint. Use
- /// InvalidArgIndex in the dst arguments to signify that all the non-const
- /// pointer and reference arguments might be tainted on return. If
- /// ReturnValueIndex is added to the dst list, the return value will be
- /// tainted.
- struct TaintPropagationRule {
- using PropagationFuncType = bool (*)(bool IsTainted, const CallEvent &Call,
- CheckerContext &C);
-
- /// List of arguments which can be taint sources and should be checked.
- ArgVector SrcArgs;
- /// List of arguments which should be tainted on function return.
- ArgVector DstArgs;
- /// Index for the first variadic parameter if exist.
- unsigned VariadicIndex;
- /// Show when a function has variadic parameters. If it has, it marks all
- /// of them as source or destination.
- VariadicType VarType;
- /// Special function for tainted source determination. If defined, it can
- /// override the default behavior.
- PropagationFuncType PropagationFunc;
-
- TaintPropagationRule()
- : VariadicIndex(InvalidArgIndex), VarType(VariadicType::None),
- PropagationFunc(nullptr) {}
-
- TaintPropagationRule(ArgVector &&Src, ArgVector &&Dst,
- VariadicType Var = VariadicType::None,
- unsigned VarIndex = InvalidArgIndex,
- PropagationFuncType Func = nullptr)
- : SrcArgs(std::move(Src)), DstArgs(std::move(Dst)),
- VariadicIndex(VarIndex), VarType(Var), PropagationFunc(Func) {}
-
- /// Get the propagation rule for a given function.
- static TaintPropagationRule
- getTaintPropagationRule(const NameRuleMap &CustomPropagations,
- const FunctionData &FData, CheckerContext &C);
-
- void addSrcArg(unsigned A) { SrcArgs.push_back(A); }
- void addDstArg(unsigned A) { DstArgs.push_back(A); }
-
- bool isNull() const {
- return SrcArgs.empty() && DstArgs.empty() &&
- VariadicType::None == VarType;
- }
+ /// Functions for custom taintedness propagation.
+ static bool UntrustedEnv(CheckerContext &C);
+};
- bool isDestinationArgument(unsigned ArgNum) const {
- return llvm::is_contained(DstArgs, ArgNum);
- }
+using RuleLookupTy = CallDescriptionMap<GenericTaintRule>;
- static bool isTaintedOrPointsToTainted(const Expr *E,
- const ProgramStateRef &State,
- CheckerContext &C) {
- if (isTainted(State, E, C.getLocationContext()) || isStdin(E, C))
- return true;
+/// Used to parse the configuration file.
+struct TaintConfiguration {
+ using NameScopeArgs = std::tuple<std::string, std::string, ArgVecTy>;
+ enum class VariadicType { None, Src, Dst };
- if (!E->getType().getTypePtr()->isPointerType())
- return false;
+ struct Common {
+ std::string Name;
+ std::string Scope;
+ };
- Optional<SVal> V = getPointeeOf(C, E);
- return (V && isTainted(State, *V));
- }
+ struct Sink : Common {
+ ArgVecTy SinkArgs;
+ };
- /// Pre-process a function which propagates taint according to the
- /// taint rule.
- ProgramStateRef process(const CallEvent &Call, CheckerContext &C) const;
+ struct Filter : Common {
+ ArgVecTy FilterArgs;
+ };
- // Functions for custom taintedness propagation.
- static bool postSocket(bool IsTainted, const CallEvent &Call,
- CheckerContext &C);
+ struct Propagation : Common {
+ ArgVecTy SrcArgs;
+ ArgVecTy DstArgs;
+ VariadicType VarType;
+ int VarIndex;
};
- /// Defines a map between the propagation function's name, scope
- /// and TaintPropagationRule.
- NameRuleMap CustomPropagations;
+ std::vector<Propagation> Propagations;
+ std::vector<Filter> Filters;
+ std::vector<Sink> Sinks;
+
+ TaintConfiguration() = default;
+ TaintConfiguration(const TaintConfiguration &) = default;
+ TaintConfiguration(TaintConfiguration &&) = default;
+ TaintConfiguration &operator=(const TaintConfiguration &) = default;
+ TaintConfiguration &operator=(TaintConfiguration &&) = default;
+};
+
+struct GenericTaintRuleParser {
+ GenericTaintRuleParser(CheckerManager &Mgr) : Mgr(Mgr) {}
+ /// Container type used to gather call identification objects grouped into
+ /// pairs with their corresponding taint rules. It is temporary as it is used
+ /// to finally initialize RuleLookupTy, which is considered to be immutable.
+ using RulesContTy = std::vector<std::pair<CallDescription, GenericTaintRule>>;
+ RulesContTy parseConfiguration(const std::string &Option,
+ TaintConfiguration &&Config) const;
+
+private:
+ using NamePartTy = llvm::SmallVector<SmallString<32>, 2>;
+ using CallDescAPITy = llvm::SmallVector<const char *, 2>;
+
+ /// Validate part of the configuration, which contains a list of argument
+ /// indexes.
+ void validateArgVector(const std::string &Option, const ArgVecTy &Args) const;
- /// Defines a map between the filter function's name, scope and filtering
- /// args.
- NameArgMap CustomFilters;
+ template <typename Config>
+ auto parseNameParts(const Config &C) const -> NamePartTy;
- /// Defines a map between the sink function's name, scope and sinking args.
- NameArgMap CustomSinks;
+ void parseConfig(const std::string &Option, TaintConfiguration::Sink &&P,
+ RulesContTy &Rules) const;
+ void parseConfig(const std::string &Option, TaintConfiguration::Filter &&P,
+ RulesContTy &Rules) const;
+ void parseConfig(const std::string &Option,
+ TaintConfiguration::Propagation &&P,
+ RulesContTy &Rules) const;
+
+ CheckerManager &Mgr;
};
-const unsigned GenericTaintChecker::ReturnValueIndex;
-const unsigned GenericTaintChecker::InvalidArgIndex;
+class GenericTaintChecker : public Checker<check::PreCall, check::PostCall> {
+public:
+ static void *getTag() {
+ static int Tag;
+ return &Tag;
+ }
-// FIXME: these lines can be removed in C++17
-constexpr llvm::StringLiteral GenericTaintChecker::MsgUncontrolledFormatString;
-constexpr llvm::StringLiteral GenericTaintChecker::MsgSanitizeSystemArgs;
-constexpr llvm::StringLiteral GenericTaintChecker::MsgTaintedBufferSize;
-constexpr llvm::StringLiteral GenericTaintChecker::MsgCustomSink;
-} // end of anonymous namespace
+ void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
+ void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
-using TaintConfig = GenericTaintChecker::TaintConfiguration;
+ void printState(raw_ostream &Out, ProgramStateRef State, const char *NL,
+ const char *Sep) const override;
-LLVM_YAML_IS_SEQUENCE_VECTOR(TaintConfig::Propagation)
-LLVM_YAML_IS_SEQUENCE_VECTOR(TaintConfig::NameScopeArgs)
+ /// Generate a report if the expression is tainted or points to tainted data.
+ bool generateReportIfTainted(const Expr *E, StringRef Msg,
+ CheckerContext &C) const;
+
+private:
+ mutable std::unique_ptr<BugType> BT;
+ void initBugType() const {
+ if (!BT)
+ BT = std::make_unique<BugType>(this, "Use of Untrusted Data",
+ "Untrusted Data");
+ }
+
+ bool checkUncontrolledFormatString(const CallEvent &Call,
+ CheckerContext &C) const;
+
+ void taintUnsafeSocketProtocol(const CallEvent &Call,
+ CheckerContext &C) const;
+
+ /// Default taint rules are initilized with the help of a CheckerContext to
+ /// access the names of built-in functions like memcpy.
+ void initTaintRules(CheckerContext &C) const;
+
+ /// CallDescription currently cannot restrict matches to the global namespace
+ /// only, which is why multiple CallDescriptionMaps are used, as we want to
+ /// disambiguate global C functions from functions inside user-defined
+ /// namespaces.
+ // TODO: Remove separation to simplify matching logic once CallDescriptions
+ // are more expressive.
+
+ mutable Optional<RuleLookupTy> GlobalCTaintRules;
+ mutable Optional<RuleLookupTy> TaintRules;
+};
+} // end of anonymous namespace
+
+/// YAML serialization mapping.
+LLVM_YAML_IS_SEQUENCE_VECTOR(TaintConfiguration::Sink)
+LLVM_YAML_IS_SEQUENCE_VECTOR(TaintConfiguration::Filter)
+LLVM_YAML_IS_SEQUENCE_VECTOR(TaintConfiguration::Propagation)
namespace llvm {
namespace yaml {
-template <> struct MappingTraits<TaintConfig> {
- static void mapping(IO &IO, TaintConfig &Config) {
+template <> struct MappingTraits<TaintConfiguration> {
+ static void mapping(IO &IO, TaintConfiguration &Config) {
IO.mapOptional("Propagations", Config.Propagations);
IO.mapOptional("Filters", Config.Filters);
IO.mapOptional("Sinks", Config.Sinks);
}
};
-template <> struct MappingTraits<TaintConfig::Propagation> {
- static void mapping(IO &IO, TaintConfig::Propagation &Propagation) {
+template <> struct MappingTraits<TaintConfiguration::Sink> {
+ static void mapping(IO &IO, TaintConfiguration::Sink &Sink) {
+ IO.mapRequired("Name", Sink.Name);
+ IO.mapOptional("Scope", Sink.Scope);
+ IO.mapRequired("Args", Sink.SinkArgs);
+ }
+};
+
+template <> struct MappingTraits<TaintConfiguration::Filter> {
+ static void mapping(IO &IO, TaintConfiguration::Filter &Filter) {
+ IO.mapRequired("Name", Filter.Name);
+ IO.mapOptional("Scope", Filter.Scope);
+ IO.mapRequired("Args", Filter.FilterArgs);
+ }
+};
+
+template <> struct MappingTraits<TaintConfiguration::Propagation> {
+ static void mapping(IO &IO, TaintConfiguration::Propagation &Propagation) {
IO.mapRequired("Name", Propagation.Name);
IO.mapOptional("Scope", Propagation.Scope);
IO.mapOptional("SrcArgs", Propagation.SrcArgs);
IO.mapOptional("DstArgs", Propagation.DstArgs);
IO.mapOptional("VariadicType", Propagation.VarType,
- GenericTaintChecker::VariadicType::None);
- IO.mapOptional("VariadicIndex", Propagation.VarIndex,
- GenericTaintChecker::InvalidArgIndex);
+ TaintConfiguration::VariadicType::None);
+ IO.mapOptional("VariadicIndex", Propagation.VarIndex, InvalidArgIndex);
}
};
-template <> struct ScalarEnumerationTraits<GenericTaintChecker::VariadicType> {
- static void enumeration(IO &IO, GenericTaintChecker::VariadicType &Value) {
- IO.enumCase(Value, "None", GenericTaintChecker::VariadicType::None);
- IO.enumCase(Value, "Src", GenericTaintChecker::VariadicType::Src);
- IO.enumCase(Value, "Dst", GenericTaintChecker::VariadicType::Dst);
- }
-};
-
-template <> struct MappingTraits<TaintConfig::NameScopeArgs> {
- static void mapping(IO &IO, TaintConfig::NameScopeArgs &NSA) {
- IO.mapRequired("Name", std::get<0>(NSA));
- IO.mapOptional("Scope", std::get<1>(NSA));
- IO.mapRequired("Args", std::get<2>(NSA));
+template <> struct ScalarEnumerationTraits<TaintConfiguration::VariadicType> {
+ static void enumeration(IO &IO, TaintConfiguration::VariadicType &Value) {
+ IO.enumCase(Value, "None", TaintConfiguration::VariadicType::None);
+ IO.enumCase(Value, "Src", TaintConfiguration::VariadicType::Src);
+ IO.enumCase(Value, "Dst", TaintConfiguration::VariadicType::Dst);
}
};
} // namespace yaml
} // namespace llvm
/// A set which is used to pass information from call pre-visit instruction
-/// to the call post-visit. The values are unsigned integers, which are either
+/// to the call post-visit. The values are signed integers, which are either
/// ReturnValueIndex, or indexes of the pointer/reference argument, which
/// points to data, which should be tainted on return.
-REGISTER_SET_WITH_PROGRAMSTATE(TaintArgsOnPostVisit, unsigned)
+REGISTER_SET_WITH_PROGRAMSTATE(TaintArgsOnPostVisit, ArgIdxTy)
-GenericTaintChecker::ArgVector
-GenericTaintChecker::convertToArgVector(CheckerManager &Mgr,
- const std::string &Option,
- const SignedArgVector &Args) {
- ArgVector Result;
+void GenericTaintRuleParser::validateArgVector(const std::string &Option,
+ const ArgVecTy &Args) const {
for (int Arg : Args) {
- if (Arg == -1)
- Result.push_back(ReturnValueIndex);
- else if (Arg < -1) {
- Result.push_back(InvalidArgIndex);
+ if (Arg < ReturnValueIndex) {
Mgr.reportInvalidCheckerOptionValue(
- this, Option,
+ Mgr.getChecker<GenericTaintChecker>(), Option,
"an argument number for propagation rules greater or equal to -1");
- } else
- Result.push_back(static_cast<unsigned>(Arg));
+ }
}
- return Result;
}
-void GenericTaintChecker::parseConfiguration(CheckerManager &Mgr,
- const std::string &Option,
- TaintConfiguration &&Config) {
- for (auto &P : Config.Propagations) {
- GenericTaintChecker::CustomPropagations.emplace(
- P.Name,
- std::make_pair(P.Scope, TaintPropagationRule{
- std::move(P.SrcArgs),
- convertToArgVector(Mgr, Option, P.DstArgs),
- P.VarType, P.VarIndex}));
+template <typename Config>
+auto GenericTaintRuleParser::parseNameParts(const Config &C) const
+ -> NamePartTy {
+ NamePartTy NameParts;
+ if (!C.Scope.empty()) {
+ // If the Scope argument contains multiple "::" parts, those are considered
+ // namespace identifiers.
+ llvm::SmallVector<StringRef, 2> NSParts;
+ StringRef{C.Scope}.split(NSParts, "::", /*MaxSplit*/ -1,
+ /*KeepEmpty*/ false);
+ NameParts.append(NSParts.begin(), NSParts.end());
}
+ NameParts.emplace_back(C.Name);
+ return NameParts;
+}
- for (auto &F : Config.Filters) {
- GenericTaintChecker::CustomFilters.emplace(
- std::get<0>(F),
- std::make_pair(std::move(std::get<1>(F)), std::move(std::get<2>(F))));
- }
+void GenericTaintRuleParser::parseConfig(const std::string &Option,
+ TaintConfiguration::Sink &&S,
+ RulesContTy &Rules) const {
+ validateArgVector(Option, S.SinkArgs);
+
+ // The ArrayRef<const char*> API of CallDescription makes it necessary to
+ // first get an owning string representation, and then get the underlying
+ // C-string representation.
+ // FIXME: Once CallDescription supports the (possibly move) construction via
+ // ArrayRef<SmallString>, ArrayRef<std::string> or from a range, this can be
+ // simplified.
+ NamePartTy NameParts{parseNameParts(S)};
+ CallDescAPITy CallDescParts{NameParts.size()};
+ llvm::transform(NameParts, CallDescParts.begin(),
+ [](auto &&P) { return P.c_str(); });
+ Rules.template emplace_back(CallDescParts,
+ GenericTaintRule::Sink(std::move(S.SinkArgs)));
+}
- for (auto &S : Config.Sinks) {
- GenericTaintChecker::CustomSinks.emplace(
- std::get<0>(S),
- std::make_pair(std::move(std::get<1>(S)), std::move(std::get<2>(S))));
- }
+void GenericTaintRuleParser::parseConfig(const std::string &Option,
+ TaintConfiguration::Filter &&S,
+ RulesContTy &Rules) const {
+ validateArgVector(Option, S.FilterArgs);
+
+ // The ArrayRef<const char*> API of CallDescription makes it necessary to
+ // first get an owning string representation, and then get the underlying
+ // C-string representation.
+ // FIXME: Once CallDescription supports the (possibly move) construction via
+ // ArrayRef<SmallString>, ArrayRef<std::string> or from a range, this can be
+ // simplified.
+ NamePartTy NameParts{parseNameParts(S)};
+ CallDescAPITy CallDescParts{NameParts.size()};
+ llvm::transform(NameParts, CallDescParts.begin(),
+ [](auto &&P) { return P.c_str(); });
+ Rules.template emplace_back(
+ CallDescParts, GenericTaintRule::Filter(std::move(S.FilterArgs)));
}
-template <typename T>
-auto GenericTaintChecker::findFunctionInConfig(const ConfigDataMap<T> &Map,
- const FunctionData &FData) {
- auto Range = Map.equal_range(std::string(FData.Name));
- auto It =
- std::find_if(Range.first, Range.second, [&FData](const auto &Entry) {
- const auto &Value = Entry.second;
- StringRef Scope = Value.first;
- return Scope.empty() || FData.isInScope(Scope);
- });
- return It != Range.second ? It : Map.end();
+void GenericTaintRuleParser::parseConfig(const std::string &Option,
+ TaintConfiguration::Propagation &&P,
+ RulesContTy &Rules) const {
+ validateArgVector(Option, P.SrcArgs);
+ validateArgVector(Option, P.DstArgs);
+ bool IsSrcVariadic = P.VarType == TaintConfiguration::VariadicType::Src;
+ bool IsDstVariadic = P.VarType == TaintConfiguration::VariadicType::Dst;
+
+ ArgSet SrcDesc = IsSrcVariadic ? ArgSet(std::move(P.SrcArgs), P.VarIndex)
+ : ArgSet(std::move(P.SrcArgs));
+ ArgSet DstDesc = IsDstVariadic ? ArgSet(std::move(P.DstArgs), P.VarIndex)
+ : ArgSet(std::move(P.DstArgs));
+
+ // The ArrayRef<const char*> API of CallDescription makes it necessary to
+ // first get an owning string representation, and then get the underlying
+ // C-string representation.
+ // FIXME: Once CallDescription supports the (possibly move) construction via
+ // ArrayRef<SmallString>, ArrayRef<std::string> or from a range, this can be
+ // simplified.
+ NamePartTy NameParts{parseNameParts(P)};
+ CallDescAPITy CallDescParts{NameParts.size()};
+ llvm::transform(NameParts, CallDescParts.begin(),
+ [](auto &&P) { return P.c_str(); });
+ Rules.template emplace_back(
+ CallDescParts,
+ GenericTaintRule::Prop(std::move(SrcDesc), std::move(DstDesc)));
}
-GenericTaintChecker::TaintPropagationRule
-GenericTaintChecker::TaintPropagationRule::getTaintPropagationRule(
- const NameRuleMap &CustomPropagations, const FunctionData &FData,
- CheckerContext &C) {
- // TODO: Currently, we might lose precision here: we always mark a return
- // value as tainted even if it's just a pointer, pointing to tainted data.
+GenericTaintRuleParser::RulesContTy
+GenericTaintRuleParser::parseConfiguration(const std::string &Option,
+ TaintConfiguration &&Config) const {
+
+ RulesContTy Rules;
+
+ for (auto &F : Config.Filters)
+ parseConfig(Option, std::move(F), Rules);
+ for (auto &S : Config.Sinks)
+ parseConfig(Option, std::move(S), Rules);
+
+ for (auto &P : Config.Propagations)
+ parseConfig(Option, std::move(P), Rules);
+
+ return Rules;
+}
+
+void GenericTaintChecker::initTaintRules(CheckerContext &C) const {
// Check for exact name match for functions without builtin substitutes.
// Use qualified name, because these are C functions without namespace.
- TaintPropagationRule Rule =
- llvm::StringSwitch<TaintPropagationRule>(FData.FullName)
- // Source functions
- // TODO: Add support for vfscanf & family.
- .Case("fdopen", {{}, {ReturnValueIndex}})
- .Case("fopen", {{}, {ReturnValueIndex}})
- .Case("freopen", {{}, {ReturnValueIndex}})
- .Case("getch", {{}, {ReturnValueIndex}})
- .Case("getchar", {{}, {ReturnValueIndex}})
- .Case("getchar_unlocked", {{}, {ReturnValueIndex}})
- .Case("gets", {{}, {0, ReturnValueIndex}})
- .Case("scanf", {{}, {}, VariadicType::Dst, 1})
- .Case("socket", {{},
- {ReturnValueIndex},
- VariadicType::None,
- InvalidArgIndex,
- &TaintPropagationRule::postSocket})
- .Case("wgetch", {{}, {ReturnValueIndex}})
- // Propagating functions
- .Case("atoi", {{0}, {ReturnValueIndex}})
- .Case("atol", {{0}, {ReturnValueIndex}})
- .Case("atoll", {{0}, {ReturnValueIndex}})
- .Case("fgetc", {{0}, {ReturnValueIndex}})
- .Case("fgetln", {{0}, {ReturnValueIndex}})
- .Case("fgets", {{2}, {0, ReturnValueIndex}})
- .Case("fscanf", {{0}, {}, VariadicType::Dst, 2})
- .Case("sscanf", {{0}, {}, VariadicType::Dst, 2})
- .Case("getc", {{0}, {ReturnValueIndex}})
- .Case("getc_unlocked", {{0}, {ReturnValueIndex}})
- .Case("getdelim", {{3}, {0}})
- .Case("getline", {{2}, {0}})
- .Case("getw", {{0}, {ReturnValueIndex}})
- .Case("pread", {{0, 1, 2, 3}, {1, ReturnValueIndex}})
- .Case("read", {{0, 2}, {1, ReturnValueIndex}})
- .Case("strchr", {{0}, {ReturnValueIndex}})
- .Case("strrchr", {{0}, {ReturnValueIndex}})
- .Case("tolower", {{0}, {ReturnValueIndex}})
- .Case("toupper", {{0}, {ReturnValueIndex}})
- .Default({});
-
- if (!Rule.isNull())
- return Rule;
+
+ if (GlobalCTaintRules || TaintRules)
+ return;
+
+ using RulesConstructionTy =
+ std::vector<std::pair<CallDescription, GenericTaintRule>>;
+ using TR = GenericTaintRule;
+
+ const auto &BI = C.getASTContext().BuiltinInfo;
+
+ RulesConstructionTy GlobalCRules{
+ // Sources
+ {{"fdopen"}, TR::Source(ArgSet{{ReturnValueIndex}})},
+ {{"fopen"}, TR::Source({{ReturnValueIndex}})},
+ {{"freopen"}, TR::Source({{ReturnValueIndex}})},
+ {{"getch"}, TR::Source({{ReturnValueIndex}})},
+ {{"getchar"}, TR::Source({{ReturnValueIndex}})},
+ {{"getchar_unlocked"}, TR::Source({{ReturnValueIndex}})},
+ {{"gets"}, TR::Source({{0}, ReturnValueIndex})},
+ {{"scanf"}, TR::Source({{}, 1})},
+ {{"wgetch"}, TR::Source({{}, ReturnValueIndex})},
+
+ // Props
+ {{"atoi"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"atol"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"atoll"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"fgetc"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"fgetln"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"fgets"}, TR::Prop({{2}}, {{0}, ReturnValueIndex})},
+ {{"fscanf"}, TR::Prop({{0}}, {{}, 2})},
+ {{"sscanf"}, TR::Prop({{0}}, {{}, 2})},
+ {{"getc"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"getc_unlocked"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"getdelim"}, TR::Prop({{3}}, {{0}})},
+ {{"getline"}, TR::Prop({{2}}, {{0}})},
+ {{"getw"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"pread"}, TR::Prop({{0, 1, 2, 3}}, {{1, ReturnValueIndex}})},
+ {{"read"}, TR::Prop({{0, 2}}, {{1, ReturnValueIndex}})},
+ {{"strchr"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"strrchr"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"tolower"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{"toupper"}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {BI.getName(Builtin::BIstrncat)}},
+ TR::Prop({{1, 2}}, {{0, ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {BI.getName(Builtin::BIstrlcpy)}},
+ TR::Prop({{1, 2}}, {{0}})},
+ {{CDF_MaybeBuiltin, {BI.getName(Builtin::BIstrlcat)}},
+ TR::Prop({{1, 2}}, {{0}})},
+ {{CDF_MaybeBuiltin, {"snprintf"}},
+ TR::Prop({{1}, 3}, {{0, ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"sprintf"}},
+ TR::Prop({{1}, 2}, {{0, ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"strcpy"}},
+ TR::Prop({{1}}, {{0, ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"stpcpy"}},
+ TR::Prop({{1}}, {{0, ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"strcat"}},
+ TR::Prop({{1}}, {{0, ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"strdup"}}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"strdupa"}}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+ {{CDF_MaybeBuiltin, {"wcsdup"}}, TR::Prop({{0}}, {{ReturnValueIndex}})},
+
+ // Sinks
+ {{"system"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"popen"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"execl"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"execle"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"execlp"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"execvp"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"execvP"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"execve"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{"dlopen"}, TR::Sink({{0}}, MsgSanitizeSystemArgs)},
+ {{CDF_MaybeBuiltin, {"malloc"}}, TR::Sink({{0}}, MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {"calloc"}}, TR::Sink({{0}}, MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {"alloca"}}, TR::Sink({{0}}, MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {"memccpy"}}, TR::Sink({{3}}, MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {"realloc"}}, TR::Sink({{1}}, MsgTaintedBufferSize)},
+ {{{"setproctitle"}}, TR::Sink({{0}, 1}, MsgUncontrolledFormatString)},
+ {{{"setproctitle_fast"}},
+ TR::Sink({{0}, 1}, MsgUncontrolledFormatString)},
+
+ // SinkProps
+ {{CDF_MaybeBuiltin, BI.getName(Builtin::BImemcpy)},
+ TR::SinkProp({{2}}, {{1, 2}}, {{0, ReturnValueIndex}},
+ MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {BI.getName(Builtin::BImemmove)}},
+ TR::SinkProp({{2}}, {{1, 2}}, {{0, ReturnValueIndex}},
+ MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {BI.getName(Builtin::BIstrncpy)}},
+ TR::SinkProp({{2}}, {{1, 2}}, {{0, ReturnValueIndex}},
+ MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {BI.getName(Builtin::BIstrndup)}},
+ TR::SinkProp({{1}}, {{0, 1}}, {{ReturnValueIndex}},
+ MsgTaintedBufferSize)},
+ {{CDF_MaybeBuiltin, {"bcopy"}},
+ TR::SinkProp({{2}}, {{0, 2}}, {{1}}, MsgTaintedBufferSize)}};
// `getenv` returns taint only in untrusted environments.
- if (FData.FullName == "getenv") {
- if (C.getAnalysisManager()
- .getAnalyzerOptions()
- .ShouldAssumeControlledEnvironment)
- return {};
- return {{}, {ReturnValueIndex}};
+ if (TR::UntrustedEnv(C)) {
+ // void setproctitle_init(int argc, char *argv[], char *envp[])
+ GlobalCRules.push_back(
+ {{{"setproctitle_init"}}, TR::Sink({{2}}, MsgCustomSink)});
+ GlobalCRules.push_back({{"getenv"}, TR::Source({{ReturnValueIndex}})});
}
- assert(FData.FDecl);
-
- // Check if it's one of the memory setting/copying functions.
- // This check is specialized but faster then calling isCLibraryFunction.
- const FunctionDecl *FDecl = FData.FDecl;
- unsigned BId = 0;
- if ((BId = FDecl->getMemoryFunctionKind())) {
- switch (BId) {
- case Builtin::BImemcpy:
- case Builtin::BImemmove:
- case Builtin::BIstrncpy:
- case Builtin::BIstrncat:
- return {{1, 2}, {0, ReturnValueIndex}};
- case Builtin::BIstrlcpy:
- case Builtin::BIstrlcat:
- return {{1, 2}, {0}};
- case Builtin::BIstrndup:
- return {{0, 1}, {ReturnValueIndex}};
-
- default:
- break;
- }
- }
+ GlobalCTaintRules.emplace(std::make_move_iterator(GlobalCRules.begin()),
+ std::make_move_iterator(GlobalCRules.end()));
- // Process all other functions which could be defined as builtins.
- if (Rule.isNull()) {
- const auto OneOf = [FDecl](const auto &... Name) {
- // FIXME: use fold expression in C++17
- using unused = int[];
- bool ret = false;
- static_cast<void>(unused{
- 0, (ret |= CheckerContext::isCLibraryFunction(FDecl, Name), 0)...});
- return ret;
- };
- if (OneOf("snprintf"))
- return {{1}, {0, ReturnValueIndex}, VariadicType::Src, 3};
- if (OneOf("sprintf"))
- return {{1}, {0, ReturnValueIndex}, VariadicType::Src, 2};
- if (OneOf("strcpy", "stpcpy", "strcat"))
- return {{1}, {0, ReturnValueIndex}};
- if (OneOf("bcopy"))
- return {{0, 2}, {1}};
- if (OneOf("strdup", "strdupa", "wcsdup"))
- return {{0}, {ReturnValueIndex}};
+ // User-provided taint configuration.
+ CheckerManager *Mgr = C.getAnalysisManager().getCheckerManager();
+ assert(Mgr);
+ GenericTaintRuleParser ConfigParser{*Mgr};
+ std::string Option{"Config"};
+ StringRef ConfigFile =
+ Mgr->getAnalyzerOptions().getCheckerStringOption(this, Option);
+ llvm::Optional<TaintConfiguration> Config =
+ getConfiguration<TaintConfiguration>(*Mgr, this, Option, ConfigFile);
+ if (!Config) {
+ TaintRules = RuleLookupTy{};
+ return;
}
- // Skipping the following functions, since they might be used for cleansing or
- // smart memory copy:
- // - memccpy - copying until hitting a special character.
+ GenericTaintRuleParser::RulesContTy Rules{
+ ConfigParser.parseConfiguration(Option, std::move(Config.getValue()))};
- auto It = findFunctionInConfig(CustomPropagations, FData);
- if (It != CustomPropagations.end())
- return It->second.second;
- return {};
+ TaintRules.emplace(std::make_move_iterator(Rules.begin()),
+ std::make_move_iterator(Rules.end()));
}
void GenericTaintChecker::checkPreCall(const CallEvent &Call,
CheckerContext &C) const {
- Optional<FunctionData> FData = FunctionData::create(Call, C);
- if (!FData)
- return;
- // Check for taintedness related errors first: system call, uncontrolled
- // format string, tainted buffer size.
- if (checkPre(Call, *FData, C))
- return;
+ initTaintRules(C);
- // Marks the function's arguments and/or return value tainted if it present in
- // the list.
- if (addSourcesPre(Call, *FData, C))
- return;
+ const GenericTaintRule *MaybeGlobalCMatch = GlobalCTaintRules->lookup(Call);
+ const GenericTaintRule *MaybeMatch =
+ TaintRules ? TaintRules->lookup(Call) : nullptr;
+ bool ConsiderGlobalCMatch = MaybeGlobalCMatch && Call.isGlobalCFunction();
- addFiltersPre(Call, *FData, C);
-}
+ if (ConsiderGlobalCMatch)
+ MaybeGlobalCMatch->process(Call, C);
-void GenericTaintChecker::checkPostCall(const CallEvent &Call,
- CheckerContext &C) const {
- // Set the marked values as tainted. The return value only accessible from
- // checkPostStmt.
- propagateFromPre(Call, C);
-}
+ if (!ConsiderGlobalCMatch && MaybeMatch)
+ MaybeMatch->process(Call, C);
-void GenericTaintChecker::printState(raw_ostream &Out, ProgramStateRef State,
- const char *NL, const char *Sep) const {
- printTaint(State, Out, NL, Sep);
-}
+ // FIXME: These edge cases are to be eliminated from here eventually.
+ //
+ // Additional check that is not supported by CallDescription.
+ // TODO: Make CallDescription be able to match attributes such as printf-like
+ // arguments.
+ checkUncontrolledFormatString(Call, C);
-bool GenericTaintChecker::addSourcesPre(const CallEvent &Call,
- const FunctionData &FData,
- CheckerContext &C) const {
- // First, try generating a propagation rule for this function.
- TaintPropagationRule Rule = TaintPropagationRule::getTaintPropagationRule(
- this->CustomPropagations, FData, C);
- if (!Rule.isNull()) {
- ProgramStateRef State = Rule.process(Call, C);
- if (State) {
- C.addTransition(State);
- return true;
- }
- }
- return false;
+ // TODO: Modeling sockets should be done in a specific checker.
+ // Socket is a source, which taints the return value.
+ taintUnsafeSocketProtocol(Call, C);
}
-bool GenericTaintChecker::addFiltersPre(const CallEvent &Call,
- const FunctionData &FData,
+void GenericTaintChecker::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
- auto It = findFunctionInConfig(CustomFilters, FData);
- if (It == CustomFilters.end())
- return false;
-
- ProgramStateRef State = C.getState();
- const auto &Value = It->second;
- const ArgVector &Args = Value.second;
- for (unsigned ArgNum : Args) {
- if (ArgNum >= Call.getNumArgs())
- continue;
-
- const Expr *Arg = Call.getArgExpr(ArgNum);
- Optional<SVal> V = getPointeeOf(C, Arg);
- if (V)
- State = removeTaint(State, *V);
- }
-
- if (State != C.getState()) {
- C.addTransition(State);
- return true;
- }
- return false;
-}
-
-bool GenericTaintChecker::propagateFromPre(const CallEvent &Call,
- CheckerContext &C) {
+ // Set the marked values as tainted. The return value only accessible from
+ // checkPostStmt.
ProgramStateRef State = C.getState();
// Depending on what was tainted at pre-visit, we determined a set of
@@ -616,9 +723,14 @@
// stored in the state as TaintArgsOnPostVisit set.
TaintArgsOnPostVisitTy TaintArgs = State->get<TaintArgsOnPostVisit>();
if (TaintArgs.isEmpty())
- return false;
+ return;
+
+ assert(Call.getNumArgs() <=
+ static_cast<std::size_t>(std::numeric_limits<ArgIdxTy>::max()) &&
+ "ArgIdxTy is not large enough to represent the number of arguments.");
+ ArgIdxTy CallNumArgs = Call.getNumArgs();
- for (unsigned ArgNum : TaintArgs) {
+ for (ArgIdxTy ArgNum : TaintArgs) {
// Special handling for the tainted return value.
if (ArgNum == ReturnValueIndex) {
State = addTaint(State, Call.getReturnValue());
@@ -627,8 +739,8 @@
// The arguments are pointer arguments. The data they are pointing at is
// tainted after the call.
- if (Call.getNumArgs() < (ArgNum + 1))
- return false;
+ if (CallNumArgs < (ArgNum + 1))
+ return;
const Expr *Arg = Call.getArgExpr(ArgNum);
Optional<SVal> V = getPointeeOf(C, Arg);
if (V)
@@ -640,221 +752,160 @@
if (State != C.getState()) {
C.addTransition(State);
- return true;
+ return;
}
- return false;
}
-bool GenericTaintChecker::checkPre(const CallEvent &Call,
- const FunctionData &FData,
- CheckerContext &C) const {
- if (checkUncontrolledFormatString(Call, C))
- return true;
-
- if (checkSystemCall(Call, FData.Name, C))
- return true;
-
- if (checkTaintedBufferSize(Call, C))
- return true;
-
- return checkCustomSinks(Call, FData, C);
-}
-
-Optional<SVal> GenericTaintChecker::getPointeeOf(CheckerContext &C,
- const Expr *Arg) {
- ProgramStateRef State = C.getState();
- SVal AddrVal = C.getSVal(Arg->IgnoreParens());
- if (AddrVal.isUnknownOrUndef())
- return None;
-
- Optional<Loc> AddrLoc = AddrVal.getAs<Loc>();
- if (!AddrLoc)
- return None;
-
- QualType ArgTy = Arg->getType().getCanonicalType();
- if (!ArgTy->isPointerType())
- return State->getSVal(*AddrLoc);
-
- QualType ValTy = ArgTy->getPointeeType();
-
- // Do not dereference void pointers. Treat them as byte pointers instead.
- // FIXME: we might want to consider more than just the first byte.
- if (ValTy->isVoidType())
- ValTy = C.getASTContext().CharTy;
-
- return State->getSVal(*AddrLoc, ValTy);
+void GenericTaintChecker::printState(raw_ostream &Out, ProgramStateRef State,
+ const char *NL, const char *Sep) const {
+ printTaint(State, Out, NL, Sep);
}
-ProgramStateRef
-GenericTaintChecker::TaintPropagationRule::process(const CallEvent &Call,
- CheckerContext &C) const {
+void GenericTaintRule::process(const CallEvent &Call, CheckerContext &C) const {
ProgramStateRef State = C.getState();
- // Check for taint in arguments.
- bool IsTainted = true;
- for (unsigned ArgNum : SrcArgs) {
- if (ArgNum >= Call.getNumArgs())
- continue;
-
- if ((IsTainted =
- isTaintedOrPointsToTainted(Call.getArgExpr(ArgNum), State, C)))
- break;
- }
+ assert(Call.getNumArgs() <=
+ static_cast<std::size_t>(std::numeric_limits<ArgIdxTy>::max()) &&
+ "ArgIdxTy is not large enough to represent the number of arguments.");
+
+ /// Iterate every call argument, and get their corresponding Expr and SVal.
+ const auto ForEachCallArg = [&C, &Call](auto &&F) {
+ for (ArgIdxTy I = ReturnValueIndex, N = Call.getNumArgs(); I < N; ++I) {
+ const Expr *E = GetArgExpr(I, Call);
+ assert(E);
+ SVal S = C.getSVal(E);
+ F(I, E, S);
+ }
+ };
- // Check for taint in variadic arguments.
- if (!IsTainted && VariadicType::Src == VarType) {
- // Check if any of the arguments is tainted
- for (unsigned i = VariadicIndex; i < Call.getNumArgs(); ++i) {
- if ((IsTainted =
- isTaintedOrPointsToTainted(Call.getArgExpr(i), State, C)))
- break;
+ /// Check for taint sinks.
+ ForEachCallArg([this, &C, &State](ArgIdxTy I, const Expr *E, SVal) {
+ if (SinkArgs.contains(I) && isTaintedOrPointsToTainted(E, State, C))
+ C.getAnalysisManager()
+ .getCheckerManager()
+ ->getChecker<GenericTaintChecker>()
+ ->generateReportIfTainted(E, SinkMsg ? *SinkMsg : MsgCustomSink, C);
+ });
+
+ /// Check for taint filters.
+ ForEachCallArg([this, &C, &State](ArgIdxTy I, const Expr *E, SVal S) {
+ if (FilterArgs.contains(I)) {
+ State = removeTaint(State, S);
+ Optional<SVal> P = getPointeeOf(C, E);
+ if (P)
+ State = removeTaint(State, *P);
}
- }
+ });
+
+ /// Check for taint propagation sources.
+ /// A rule is relevant if PropSrcArgs is empty, or if any of its signified
+ /// args are tainted in context of the current CallEvent.
+ bool IsMatching = PropSrcArgs.isEmpty();
+ ForEachCallArg(
+ [this, &C, &IsMatching, &State](ArgIdxTy I, const Expr *E, SVal) {
+ IsMatching |=
+ PropSrcArgs.contains(I) && isTaintedOrPointsToTainted(E, State, C);
+ });
- if (PropagationFunc)
- IsTainted = PropagationFunc(IsTainted, Call, C);
+ if (!IsMatching)
+ return;
- if (!IsTainted)
- return State;
+ /// Propagate taint where it is necessary.
+ // TODO: Currently, we might lose precision here: we always mark a return
+ // value as tainted even if it's just a pointer, pointing to tainted data.
+ ForEachCallArg([this, &C, &State](ArgIdxTy I, const Expr *E, SVal S) {
+ if (PropDstArgs.contains(I))
+ State = State->add<TaintArgsOnPostVisit>(I);
- // Mark the arguments which should be tainted after the function returns.
- for (unsigned ArgNum : DstArgs) {
- // Should mark the return value?
- if (ArgNum == ReturnValueIndex) {
- State = State->add<TaintArgsOnPostVisit>(ReturnValueIndex);
- continue;
- }
+ Optional<SVal> MaybeValueToTaint = [E, &C, S]() -> Optional<SVal> {
+ if (!E)
+ return {};
- if (ArgNum >= Call.getNumArgs())
- continue;
+ const QualType ArgTy = E->getType();
- // Mark the given argument.
- State = State->add<TaintArgsOnPostVisit>(ArgNum);
- }
+ const bool IsNonConstRef =
+ ArgTy->isReferenceType() && !ArgTy.isConstQualified();
+ const bool IsNonConstPtr =
+ ArgTy->isPointerType() && !ArgTy->getPointeeType().isConstQualified();
- // Mark all variadic arguments tainted if present.
- if (VariadicType::Dst == VarType) {
- // For all pointer and references that were passed in:
- // If they are not pointing to const data, mark data as tainted.
- // TODO: So far we are just going one level down; ideally we'd need to
- // recurse here.
- for (unsigned i = VariadicIndex; i < Call.getNumArgs(); ++i) {
- const Expr *Arg = Call.getArgExpr(i);
- // Process pointer argument.
- const Type *ArgTy = Arg->getType().getTypePtr();
- QualType PType = ArgTy->getPointeeType();
- if ((!PType.isNull() && !PType.isConstQualified()) ||
- (ArgTy->isReferenceType() && !Arg->getType().isConstQualified())) {
- State = State->add<TaintArgsOnPostVisit>(i);
- }
- }
- }
+ if (IsNonConstRef)
+ return S;
+ if (IsNonConstPtr)
+ return getPointeeOf(C, E);
+ return {};
+ }();
- return State;
-}
+ if (MaybeValueToTaint.hasValue())
+ State = State->add<TaintArgsOnPostVisit>(I);
+ });
-// If argument 0(protocol domain) is network, the return value should get taint.
-bool GenericTaintChecker::TaintPropagationRule::postSocket(
- bool /*IsTainted*/, const CallEvent &Call, CheckerContext &C) {
- SourceLocation DomLoc = Call.getArgExpr(0)->getExprLoc();
- StringRef DomName = C.getMacroNameOrSpelling(DomLoc);
- // White list the internal communication protocols.
- if (DomName.equals("AF_SYSTEM") || DomName.equals("AF_LOCAL") ||
- DomName.equals("AF_UNIX") || DomName.equals("AF_RESERVED_36"))
- return false;
- return true;
+ if (State != C.getState())
+ C.addTransition(State);
}
-bool GenericTaintChecker::isStdin(const Expr *E, CheckerContext &C) {
- ProgramStateRef State = C.getState();
- SVal Val = C.getSVal(E);
-
- // stdin is a pointer, so it would be a region.
- const MemRegion *MemReg = Val.getAsRegion();
+bool GenericTaintRule::UntrustedEnv(CheckerContext &C) {
+ return !C.getAnalysisManager()
+ .getAnalyzerOptions()
+ .ShouldAssumeControlledEnvironment;
+}
- // The region should be symbolic, we do not know it's value.
- const auto *SymReg = dyn_cast_or_null<SymbolicRegion>(MemReg);
- if (!SymReg)
- return false;
+bool GenericTaintChecker::generateReportIfTainted(const Expr *E, StringRef Msg,
+ CheckerContext &C) const {
+ assert(E);
+ Optional<SVal> TaintedSVal{getTaintedPointeeOrPointer(C, E)};
- // Get it's symbol and find the declaration region it's pointing to.
- const auto *Sm = dyn_cast<SymbolRegionValue>(SymReg->getSymbol());
- if (!Sm)
- return false;
- const auto *DeclReg = dyn_cast_or_null<DeclRegion>(Sm->getRegion());
- if (!DeclReg)
+ if (!TaintedSVal)
return false;
- // This region corresponds to a declaration, find out if it's a global/extern
- // variable named stdin with the proper type.
- if (const auto *D = dyn_cast_or_null<VarDecl>(DeclReg->getDecl())) {
- D = D->getCanonicalDecl();
- if (D->getName().contains("stdin") && D->isExternC()) {
- const auto *PtrTy = dyn_cast<PointerType>(D->getType().getTypePtr());
- if (PtrTy && PtrTy->getPointeeType().getCanonicalType() ==
- C.getASTContext().getFILEType().getCanonicalType())
- return true;
- }
+ // Generate diagnostic.
+ if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
+ initBugType();
+ auto report = std::make_unique<PathSensitiveBugReport>(*BT, Msg, N);
+ report->addRange(E->getSourceRange());
+ report->addVisitor(std::make_unique<TaintBugVisitor>(*TaintedSVal));
+ C.emitReport(std::move(report));
+ return true;
}
return false;
}
+/// TODO: remove checking for printf format attributes and socket whitelisting
+/// from GenericTaintChecker, and that means the following functions:
+/// getPrintfFormatArgumentNum,
+/// GenericTaintChecker::checkUncontrolledFormatString,
+/// GenericTaintChecker::taintUnsafeSocketProtocol
+
static bool getPrintfFormatArgumentNum(const CallEvent &Call,
const CheckerContext &C,
- unsigned &ArgNum) {
+ ArgIdxTy &ArgNum) {
// Find if the function contains a format string argument.
// Handles: fprintf, printf, sprintf, snprintf, vfprintf, vprintf, vsprintf,
// vsnprintf, syslog, custom annotated functions.
- const FunctionDecl *FDecl = Call.getDecl()->getAsFunction();
+ const Decl *CallDecl = Call.getDecl();
+ if (!CallDecl)
+ return false;
+ const FunctionDecl *FDecl = CallDecl->getAsFunction();
if (!FDecl)
return false;
+
+ assert(Call.getNumArgs() <=
+ static_cast<std::size_t>(std::numeric_limits<ArgIdxTy>::max()) &&
+ "ArgIdxTy is not large enough to represent the number of arguments.");
+ ArgIdxTy CallNumArgs = Call.getNumArgs();
+
for (const auto *Format : FDecl->specific_attrs<FormatAttr>()) {
ArgNum = Format->getFormatIdx() - 1;
- if ((Format->getType()->getName() == "printf") &&
- Call.getNumArgs() > ArgNum)
+ if ((Format->getType()->getName() == "printf") && CallNumArgs > ArgNum)
return true;
}
- // Or if a function is named setproctitle (this is a heuristic).
- if (C.getCalleeName(FDecl).contains("setproctitle")) {
- ArgNum = 0;
- return true;
- }
-
- return false;
-}
-
-bool GenericTaintChecker::generateReportIfTainted(const Expr *E, StringRef Msg,
- CheckerContext &C) const {
- assert(E);
-
- // Check for taint.
- ProgramStateRef State = C.getState();
- Optional<SVal> PointedToSVal = getPointeeOf(C, E);
- SVal TaintedSVal;
- if (PointedToSVal && isTainted(State, *PointedToSVal))
- TaintedSVal = *PointedToSVal;
- else if (isTainted(State, E, C.getLocationContext()))
- TaintedSVal = C.getSVal(E);
- else
- return false;
-
- // Generate diagnostic.
- if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
- initBugType();
- auto report = std::make_unique<PathSensitiveBugReport>(*BT, Msg, N);
- report->addRange(E->getSourceRange());
- report->addVisitor(std::make_unique<TaintBugVisitor>(TaintedSVal));
- C.emitReport(std::move(report));
- return true;
- }
return false;
}
bool GenericTaintChecker::checkUncontrolledFormatString(
const CallEvent &Call, CheckerContext &C) const {
// Check if the function contains a format string argument.
- unsigned ArgNum = 0;
+ int ArgNum = 0;
if (!getPrintfFormatArgumentNum(Call, C, ArgNum))
return false;
@@ -864,102 +915,32 @@
MsgUncontrolledFormatString, C);
}
-bool GenericTaintChecker::checkSystemCall(const CallEvent &Call, StringRef Name,
- CheckerContext &C) const {
- // TODO: It might make sense to run this check on demand. In some cases,
- // we should check if the environment has been cleansed here. We also might
- // need to know if the user was reset before these calls(seteuid).
- unsigned ArgNum = llvm::StringSwitch<unsigned>(Name)
- .Case("system", 0)
- .Case("popen", 0)
- .Case("execl", 0)
- .Case("execle", 0)
- .Case("execlp", 0)
- .Case("execv", 0)
- .Case("execvp", 0)
- .Case("execvP", 0)
- .Case("execve", 0)
- .Case("dlopen", 0)
- .Default(InvalidArgIndex);
-
- if (ArgNum == InvalidArgIndex || Call.getNumArgs() < (ArgNum + 1))
- return false;
-
- return generateReportIfTainted(Call.getArgExpr(ArgNum), MsgSanitizeSystemArgs,
- C);
-}
-
-// TODO: Should this check be a part of the CString checker?
-// If yes, should taint be a global setting?
-bool GenericTaintChecker::checkTaintedBufferSize(const CallEvent &Call,
- CheckerContext &C) const {
- const auto *FDecl = Call.getDecl()->getAsFunction();
- // If the function has a buffer size argument, set ArgNum.
- unsigned ArgNum = InvalidArgIndex;
- unsigned BId = 0;
- if ((BId = FDecl->getMemoryFunctionKind())) {
- switch (BId) {
- case Builtin::BImemcpy:
- case Builtin::BImemmove:
- case Builtin::BIstrncpy:
- ArgNum = 2;
- break;
- case Builtin::BIstrndup:
- ArgNum = 1;
- break;
- default:
- break;
- }
- }
+void GenericTaintChecker::taintUnsafeSocketProtocol(const CallEvent &Call,
+ CheckerContext &C) const {
+ if (Call.getNumArgs() < 1)
+ return;
+ const IdentifierInfo *ID = Call.getCalleeIdentifier();
+ if (!ID)
+ return;
+ if (!ID->getName().equals("socket"))
+ return;
- if (ArgNum == InvalidArgIndex) {
- using CCtx = CheckerContext;
- if (CCtx::isCLibraryFunction(FDecl, "malloc") ||
- CCtx::isCLibraryFunction(FDecl, "calloc") ||
- CCtx::isCLibraryFunction(FDecl, "alloca"))
- ArgNum = 0;
- else if (CCtx::isCLibraryFunction(FDecl, "memccpy"))
- ArgNum = 3;
- else if (CCtx::isCLibraryFunction(FDecl, "realloc"))
- ArgNum = 1;
- else if (CCtx::isCLibraryFunction(FDecl, "bcopy"))
- ArgNum = 2;
- }
+ SourceLocation DomLoc = Call.getArgExpr(0)->getExprLoc();
+ StringRef DomName = C.getMacroNameOrSpelling(DomLoc);
+ // White list the internal communication protocols.
+ bool SafeProtocol = DomName.equals("AF_SYSTEM") ||
+ DomName.equals("AF_LOCAL") || DomName.equals("AF_UNIX") ||
+ DomName.equals("AF_RESERVED_36");
+ if (SafeProtocol)
+ return;
- return ArgNum != InvalidArgIndex && Call.getNumArgs() > ArgNum &&
- generateReportIfTainted(Call.getArgExpr(ArgNum), MsgTaintedBufferSize,
- C);
+ C.addTransition(C.getState()->add<TaintArgsOnPostVisit>(ReturnValueIndex));
}
-bool GenericTaintChecker::checkCustomSinks(const CallEvent &Call,
- const FunctionData &FData,
- CheckerContext &C) const {
- auto It = findFunctionInConfig(CustomSinks, FData);
- if (It == CustomSinks.end())
- return false;
-
- const auto &Value = It->second;
- const GenericTaintChecker::ArgVector &Args = Value.second;
- for (unsigned ArgNum : Args) {
- if (ArgNum >= Call.getNumArgs())
- continue;
-
- if (generateReportIfTainted(Call.getArgExpr(ArgNum), MsgCustomSink, C))
- return true;
- }
-
- return false;
-}
+/// Checker registration
void ento::registerGenericTaintChecker(CheckerManager &Mgr) {
- auto *Checker = Mgr.registerChecker<GenericTaintChecker>();
- std::string Option{"Config"};
- StringRef ConfigFile =
- Mgr.getAnalyzerOptions().getCheckerStringOption(Checker, Option);
- llvm::Optional<TaintConfig> Config =
- getConfiguration<TaintConfig>(Mgr, Checker, Option, ConfigFile);
- if (Config)
- Checker->parseConfiguration(Mgr, Option, std::move(Config.getValue()));
+ Mgr.registerChecker<GenericTaintChecker>();
}
bool ento::shouldRegisterGenericTaintChecker(const CheckerManager &mgr) {
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