boga95 updated this revision to Diff 178368.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D55734/new/
https://reviews.llvm.org/D55734
Files:
lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
Index: lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
+++ lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp
@@ -23,6 +23,8 @@
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include <climits>
+#include <initializer_list>
+#include <utility>
using namespace clang;
using namespace ento;
@@ -69,8 +71,8 @@
static Optional<SVal> getPointedToSVal(CheckerContext &C, const Expr *Arg);
/// Functions defining the attack surface.
- typedef ProgramStateRef (GenericTaintChecker::*FnCheck)(const CallExpr *,
- CheckerContext &C) const;
+ using FnCheck = ProgramStateRef (GenericTaintChecker::*)(
+ const CallExpr *, CheckerContext &C) const;
ProgramStateRef postScanf(const CallExpr *CE, CheckerContext &C) const;
ProgramStateRef postSocket(const CallExpr *CE, CheckerContext &C) const;
ProgramStateRef postRetTaint(const CallExpr *CE, CheckerContext &C) const;
@@ -100,7 +102,7 @@
bool generateReportIfTainted(const Expr *E, const char Msg[],
CheckerContext &C) const;
- typedef SmallVector<unsigned, 2> ArgVector;
+ using ArgVector = SmallVector<unsigned, 2>;
/// A struct used to specify taint propagation rules for a function.
///
@@ -112,30 +114,27 @@
/// ReturnValueIndex is added to the dst list, the return value will be
/// tainted.
struct TaintPropagationRule {
+ enum class VariadicType { None, Src, Dst };
+
/// 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;
- // TODO: Check if using other data structures would be more optimal.
-
- TaintPropagationRule() {}
-
- TaintPropagationRule(unsigned SArg,
- unsigned DArg, bool TaintRet = false) {
- SrcArgs.push_back(SArg);
- DstArgs.push_back(DArg);
- if (TaintRet)
- DstArgs.push_back(ReturnValueIndex);
- }
-
- TaintPropagationRule(unsigned SArg1, unsigned SArg2,
- unsigned DArg, bool TaintRet = false) {
- SrcArgs.push_back(SArg1);
- SrcArgs.push_back(SArg2);
- DstArgs.push_back(DArg);
- if (TaintRet)
- DstArgs.push_back(ReturnValueIndex);
- }
+ /// Index for the first variadic parameter if exist.
+ unsigned VariadicIndex;
+ /// Show when a function has variadic parameters. If it has, it mark all
+ /// of them as source or destination.
+ VariadicType VarType;
+
+ TaintPropagationRule()
+ : VariadicIndex(InvalidArgIndex), VarType(VariadicType::None) {}
+
+ TaintPropagationRule(std::initializer_list<unsigned> &&Src,
+ std::initializer_list<unsigned> &&Dst,
+ VariadicType Var = VariadicType::None,
+ unsigned VarIndex = InvalidArgIndex)
+ : SrcArgs(std::move(Src)), DstArgs(std::move(Dst)),
+ VariadicIndex(VarIndex), VarType(Var) {}
/// Get the propagation rule for a given function.
static TaintPropagationRule
@@ -144,9 +143,12 @@
CheckerContext &C);
inline void addSrcArg(unsigned A) { SrcArgs.push_back(A); }
- inline void addDstArg(unsigned A) { DstArgs.push_back(A); }
+ inline void addDstArg(unsigned A) { DstArgs.push_back(A); }
- inline bool isNull() const { return SrcArgs.empty(); }
+ inline bool isNull() const {
+ return SrcArgs.empty() && DstArgs.empty() &&
+ VariadicType::None == VarType;
+ }
inline bool isDestinationArgument(unsigned ArgNum) const {
return (std::find(DstArgs.begin(),
@@ -169,7 +171,6 @@
/// Pre-process a function which propagates taint according to the
/// taint rule.
ProgramStateRef process(const CallExpr *CE, CheckerContext &C) const;
-
};
};
@@ -206,26 +207,27 @@
// value as tainted even if it's just a pointer, pointing to tainted data.
// Check for exact name match for functions without builtin substitutes.
- TaintPropagationRule Rule = llvm::StringSwitch<TaintPropagationRule>(Name)
- .Case("atoi", TaintPropagationRule(0, ReturnValueIndex))
- .Case("atol", TaintPropagationRule(0, ReturnValueIndex))
- .Case("atoll", TaintPropagationRule(0, ReturnValueIndex))
- .Case("getc", TaintPropagationRule(0, ReturnValueIndex))
- .Case("fgetc", TaintPropagationRule(0, ReturnValueIndex))
- .Case("getc_unlocked", TaintPropagationRule(0, ReturnValueIndex))
- .Case("getw", TaintPropagationRule(0, ReturnValueIndex))
- .Case("toupper", TaintPropagationRule(0, ReturnValueIndex))
- .Case("tolower", TaintPropagationRule(0, ReturnValueIndex))
- .Case("strchr", TaintPropagationRule(0, ReturnValueIndex))
- .Case("strrchr", TaintPropagationRule(0, ReturnValueIndex))
- .Case("read", TaintPropagationRule(0, 2, 1, true))
- .Case("pread", TaintPropagationRule(InvalidArgIndex, 1, true))
- .Case("gets", TaintPropagationRule(InvalidArgIndex, 0, true))
- .Case("fgets", TaintPropagationRule(2, 0, true))
- .Case("getline", TaintPropagationRule(2, 0))
- .Case("getdelim", TaintPropagationRule(3, 0))
- .Case("fgetln", TaintPropagationRule(0, ReturnValueIndex))
- .Default(TaintPropagationRule());
+ TaintPropagationRule Rule =
+ llvm::StringSwitch<TaintPropagationRule>(Name)
+ .Case("atoi", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("atol", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("atoll", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("getc", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("fgetc", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("getc_unlocked", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("getw", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("toupper", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("tolower", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("strchr", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("strrchr", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Case("read", TaintPropagationRule({0, 2}, {1, ReturnValueIndex}))
+ .Case("pread", TaintPropagationRule({0, 2, 3}, {1, ReturnValueIndex}))
+ .Case("gets", TaintPropagationRule({}, {0, ReturnValueIndex}))
+ .Case("fgets", TaintPropagationRule({2}, {0, ReturnValueIndex}))
+ .Case("getline", TaintPropagationRule({2}, {0}))
+ .Case("getdelim", TaintPropagationRule({3}, {0}))
+ .Case("fgetln", TaintPropagationRule({0}, {ReturnValueIndex}))
+ .Default(TaintPropagationRule());
if (!Rule.isNull())
return Rule;
@@ -233,18 +235,18 @@
// Check if it's one of the memory setting/copying functions.
// This check is specialized but faster then calling isCLibraryFunction.
unsigned BId = 0;
- if ( (BId = FDecl->getMemoryFunctionKind()) )
- switch(BId) {
+ if ((BId = FDecl->getMemoryFunctionKind()))
+ switch (BId) {
case Builtin::BImemcpy:
case Builtin::BImemmove:
case Builtin::BIstrncpy:
case Builtin::BIstrncat:
- return TaintPropagationRule(1, 2, 0, true);
+ return TaintPropagationRule({1, 2}, {0, ReturnValueIndex});
case Builtin::BIstrlcpy:
case Builtin::BIstrlcat:
- return TaintPropagationRule(1, 2, 0, false);
+ return TaintPropagationRule({1, 2}, {0});
case Builtin::BIstrndup:
- return TaintPropagationRule(0, 1, ReturnValueIndex);
+ return TaintPropagationRule({0, 1}, {ReturnValueIndex});
default:
break;
@@ -252,20 +254,23 @@
// Process all other functions which could be defined as builtins.
if (Rule.isNull()) {
- if (C.isCLibraryFunction(FDecl, "snprintf") ||
- C.isCLibraryFunction(FDecl, "sprintf"))
- return TaintPropagationRule(InvalidArgIndex, 0, true);
+ if (C.isCLibraryFunction(FDecl, "snprintf"))
+ return TaintPropagationRule({1}, {0, ReturnValueIndex}, VariadicType::Src,
+ 3);
+ else if (C.isCLibraryFunction(FDecl, "sprintf"))
+ return TaintPropagationRule({}, {0, ReturnValueIndex}, VariadicType::Src,
+ 2);
else if (C.isCLibraryFunction(FDecl, "strcpy") ||
C.isCLibraryFunction(FDecl, "stpcpy") ||
C.isCLibraryFunction(FDecl, "strcat"))
- return TaintPropagationRule(1, 0, true);
+ return TaintPropagationRule({1}, {0, ReturnValueIndex});
else if (C.isCLibraryFunction(FDecl, "bcopy"))
- return TaintPropagationRule(0, 2, 1, false);
+ return TaintPropagationRule({0, 2}, {1});
else if (C.isCLibraryFunction(FDecl, "strdup") ||
C.isCLibraryFunction(FDecl, "strdupa"))
- return TaintPropagationRule(0, ReturnValueIndex);
+ return TaintPropagationRule({0}, {ReturnValueIndex});
else if (C.isCLibraryFunction(FDecl, "wcsdup"))
- return TaintPropagationRule(0, ReturnValueIndex);
+ return TaintPropagationRule({0}, {ReturnValueIndex});
}
// Skipping the following functions, since they might be used for cleansing
@@ -324,7 +329,6 @@
if (!State)
return;
C.addTransition(State);
-
}
bool GenericTaintChecker::propagateFromPre(const CallExpr *CE,
@@ -338,9 +342,8 @@
if (TaintArgs.isEmpty())
return false;
- for (llvm::ImmutableSet<unsigned>::iterator
- I = TaintArgs.begin(), E = TaintArgs.end(); I != E; ++I) {
- unsigned ArgNum = *I;
+ for (auto I = TaintArgs.begin(), E = TaintArgs.end(); I != E; ++I) {
+ unsigned ArgNum = *I;
// Special handling for the tainted return value.
if (ArgNum == ReturnValueIndex) {
@@ -352,7 +355,7 @@
// tainted after the call.
if (CE->getNumArgs() < (ArgNum + 1))
return false;
- const Expr* Arg = CE->getArg(ArgNum);
+ const Expr *Arg = CE->getArg(ArgNum);
Optional<SVal> V = getPointedToSVal(C, Arg);
if (V)
State = State->addTaint(*V);
@@ -404,7 +407,8 @@
C.addTransition(State);
}
-bool GenericTaintChecker::checkPre(const CallExpr *CE, CheckerContext &C) const{
+bool GenericTaintChecker::checkPre(const CallExpr *CE,
+ CheckerContext &C) const {
if (checkUncontrolledFormatString(CE, C))
return true;
@@ -458,53 +462,31 @@
// Check for taint in arguments.
bool IsTainted = false;
- for (ArgVector::const_iterator I = SrcArgs.begin(),
- E = SrcArgs.end(); I != E; ++I) {
+ for (ArgVector::const_iterator I = SrcArgs.begin(), E = SrcArgs.end(); I != E;
+ ++I) {
unsigned ArgNum = *I;
-
- if (ArgNum == InvalidArgIndex) {
- // Check if any of the arguments is tainted, but skip the
- // destination arguments.
- for (unsigned int i = 0; i < CE->getNumArgs(); ++i) {
- if (isDestinationArgument(i))
- continue;
- if ((IsTainted = isTaintedOrPointsToTainted(CE->getArg(i), State, C)))
- break;
- }
- break;
- }
-
if (CE->getNumArgs() < (ArgNum + 1))
return State;
if ((IsTainted = isTaintedOrPointsToTainted(CE->getArg(ArgNum), State, C)))
break;
}
+
+ // Check for taint in variadic arguments.
+ if (!IsTainted && VariadicType::Src == VarType) {
+ // Check if any of the arguments is tainted
+ for (unsigned int i = VariadicIndex; i < CE->getNumArgs(); ++i) {
+ if ((IsTainted = isTaintedOrPointsToTainted(CE->getArg(i), State, C)))
+ break;
+ }
+ }
+
if (!IsTainted)
return State;
// Mark the arguments which should be tainted after the function returns.
- for (ArgVector::const_iterator I = DstArgs.begin(),
- E = DstArgs.end(); I != E; ++I) {
+ for (ArgVector::const_iterator I = DstArgs.begin(), E = DstArgs.end(); I != E;
+ ++I) {
unsigned ArgNum = *I;
-
- // Should we mark all arguments as tainted?
- if (ArgNum == InvalidArgIndex) {
- // 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 int i = 0; i < CE->getNumArgs(); ++i) {
- const Expr *Arg = CE->getArg(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);
- }
- continue;
- }
-
// Should mark the return value?
if (ArgNum == ReturnValueIndex) {
State = State->add<TaintArgsOnPostVisit>(ReturnValueIndex);
@@ -516,10 +498,26 @@
State = State->add<TaintArgsOnPostVisit>(ArgNum);
}
+ // 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 int i = VariadicIndex; i < CE->getNumArgs(); ++i) {
+ const Expr *Arg = CE->getArg(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);
+ }
+ }
+
return State;
}
-
// If argument 0 (file descriptor) is tainted, all arguments except for arg 0
// and arg 1 should get taint.
ProgramStateRef GenericTaintChecker::preFscanf(const CallExpr *CE,
@@ -539,7 +537,6 @@
return nullptr;
}
-
// If argument 0(protocol domain) is network, the return value should get taint.
ProgramStateRef GenericTaintChecker::postSocket(const CallExpr *CE,
CheckerContext &C) const {
@@ -558,7 +555,7 @@
}
ProgramStateRef GenericTaintChecker::postScanf(const CallExpr *CE,
- CheckerContext &C) const {
+ CheckerContext &C) const {
ProgramStateRef State = C.getState();
if (CE->getNumArgs() < 2)
return State;
@@ -602,14 +599,14 @@
// This region corresponds to a declaration, find out if it's a global/extern
// variable named stdin with the proper type.
- if (const VarDecl *D = dyn_cast_or_null<VarDecl>(DeclReg->getDecl())) {
+ if (const auto *D = dyn_cast_or_null<VarDecl>(DeclReg->getDecl())) {
D = D->getCanonicalDecl();
if ((D->getName().find("stdin") != StringRef::npos) && D->isExternC())
- if (const PointerType * PtrTy =
- dyn_cast<PointerType>(D->getType().getTypePtr()))
- if (PtrTy->getPointeeType().getCanonicalType() ==
- C.getASTContext().getFILEType().getCanonicalType())
- return true;
+ if (const auto *PtrTy =
+ dyn_cast<PointerType>(D->getType().getTypePtr()) &&
+ PtrTy->getPointeeType().getCanonicalType() ==
+ C.getASTContext().getFILEType().getCanonicalType())
+ return true;
}
return false;
}
@@ -667,8 +664,8 @@
return false;
}
-bool GenericTaintChecker::checkUncontrolledFormatString(const CallExpr *CE,
- CheckerContext &C) const{
+bool GenericTaintChecker::checkUncontrolledFormatString(
+ const CallExpr *CE, CheckerContext &C) const {
// Check if the function contains a format string argument.
unsigned int ArgNum = 0;
if (!getPrintfFormatArgumentNum(CE, C, ArgNum))
@@ -679,8 +676,7 @@
MsgUncontrolledFormatString, C);
}
-bool GenericTaintChecker::checkSystemCall(const CallExpr *CE,
- StringRef Name,
+bool GenericTaintChecker::checkSystemCall(const CallExpr *CE, 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
@@ -712,8 +708,8 @@
// If the function has a buffer size argument, set ArgNum.
unsigned ArgNum = InvalidArgIndex;
unsigned BId = 0;
- if ( (BId = FDecl->getMemoryFunctionKind()) )
- switch(BId) {
+ if ((BId = FDecl->getMemoryFunctionKind()))
+ switch (BId) {
case Builtin::BImemcpy:
case Builtin::BImemmove:
case Builtin::BIstrncpy:
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