Chris Lattner has strong opinions about directory
layout. :)
Rename the 'EntoSA' directories to 'StaticAnalyzer'.
Internally we will still use the 'ento' namespace
for the analyzer engine (unless there are further
sabre rattlings...).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122514 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp b/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp
new file mode 100644
index 0000000..9092f93
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp
@@ -0,0 +1,277 @@
+//= UnixAPIChecker.h - Checks preconditions for various Unix APIs --*- C++ -*-//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines UnixAPIChecker, which is an assortment of checks on calls
+// to various, widely used UNIX/Posix functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ExprEngineInternalChecks.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/StaticAnalyzer/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/PathSensitive/CheckerVisitor.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/StringSwitch.h"
+#include <fcntl.h>
+
+using namespace clang;
+using namespace ento;
+using llvm::Optional;
+
+namespace {
+class UnixAPIChecker : public CheckerVisitor<UnixAPIChecker> {
+ enum SubChecks {
+ OpenFn = 0,
+ PthreadOnceFn = 1,
+ MallocZero = 2,
+ NumChecks
+ };
+
+ BugType *BTypes[NumChecks];
+
+public:
+ Optional<uint64_t> Val_O_CREAT;
+
+public:
+ UnixAPIChecker() { memset(BTypes, 0, sizeof(*BTypes) * NumChecks); }
+ static void *getTag() { static unsigned tag = 0; return &tag; }
+
+ void PreVisitCallExpr(CheckerContext &C, const CallExpr *CE);
+};
+} //end anonymous namespace
+
+void ento::RegisterUnixAPIChecker(ExprEngine &Eng) {
+ Eng.registerCheck(new UnixAPIChecker());
+}
+
+//===----------------------------------------------------------------------===//
+// Utility functions.
+//===----------------------------------------------------------------------===//
+
+static inline void LazyInitialize(BugType *&BT, const char *name) {
+ if (BT)
+ return;
+ BT = new BugType(name, "Unix API");
+}
+
+//===----------------------------------------------------------------------===//
+// "open" (man 2 open)
+//===----------------------------------------------------------------------===//
+
+static void CheckOpen(CheckerContext &C, UnixAPIChecker &UC,
+ const CallExpr *CE, BugType *&BT) {
+ // The definition of O_CREAT is platform specific. We need a better way
+ // of querying this information from the checking environment.
+ if (!UC.Val_O_CREAT.hasValue()) {
+ if (C.getASTContext().Target.getTriple().getVendor() == llvm::Triple::Apple)
+ UC.Val_O_CREAT = 0x0200;
+ else {
+ // FIXME: We need a more general way of getting the O_CREAT value.
+ // We could possibly grovel through the preprocessor state, but
+ // that would require passing the Preprocessor object to the ExprEngine.
+ return;
+ }
+ }
+
+ LazyInitialize(BT, "Improper use of 'open'");
+
+ // Look at the 'oflags' argument for the O_CREAT flag.
+ const GRState *state = C.getState();
+
+ if (CE->getNumArgs() < 2) {
+ // The frontend should issue a warning for this case, so this is a sanity
+ // check.
+ return;
+ }
+
+ // Now check if oflags has O_CREAT set.
+ const Expr *oflagsEx = CE->getArg(1);
+ const SVal V = state->getSVal(oflagsEx);
+ if (!isa<NonLoc>(V)) {
+ // The case where 'V' can be a location can only be due to a bad header,
+ // so in this case bail out.
+ return;
+ }
+ NonLoc oflags = cast<NonLoc>(V);
+ NonLoc ocreateFlag =
+ cast<NonLoc>(C.getSValBuilder().makeIntVal(UC.Val_O_CREAT.getValue(),
+ oflagsEx->getType()));
+ SVal maskedFlagsUC = C.getSValBuilder().evalBinOpNN(state, BO_And,
+ oflags, ocreateFlag,
+ oflagsEx->getType());
+ if (maskedFlagsUC.isUnknownOrUndef())
+ return;
+ DefinedSVal maskedFlags = cast<DefinedSVal>(maskedFlagsUC);
+
+ // Check if maskedFlags is non-zero.
+ const GRState *trueState, *falseState;
+ llvm::tie(trueState, falseState) = state->assume(maskedFlags);
+
+ // Only emit an error if the value of 'maskedFlags' is properly
+ // constrained;
+ if (!(trueState && !falseState))
+ return;
+
+ if (CE->getNumArgs() < 3) {
+ ExplodedNode *N = C.generateSink(trueState);
+ if (!N)
+ return;
+
+ EnhancedBugReport *report =
+ new EnhancedBugReport(*BT,
+ "Call to 'open' requires a third argument when "
+ "the 'O_CREAT' flag is set", N);
+ report->addRange(oflagsEx->getSourceRange());
+ C.EmitReport(report);
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// pthread_once
+//===----------------------------------------------------------------------===//
+
+static void CheckPthreadOnce(CheckerContext &C, UnixAPIChecker &,
+ const CallExpr *CE, BugType *&BT) {
+
+ // This is similar to 'CheckDispatchOnce' in the MacOSXAPIChecker.
+ // They can possibly be refactored.
+
+ LazyInitialize(BT, "Improper use of 'pthread_once'");
+
+ if (CE->getNumArgs() < 1)
+ return;
+
+ // Check if the first argument is stack allocated. If so, issue a warning
+ // because that's likely to be bad news.
+ const GRState *state = C.getState();
+ const MemRegion *R = state->getSVal(CE->getArg(0)).getAsRegion();
+ if (!R || !isa<StackSpaceRegion>(R->getMemorySpace()))
+ return;
+
+ ExplodedNode *N = C.generateSink(state);
+ if (!N)
+ return;
+
+ llvm::SmallString<256> S;
+ llvm::raw_svector_ostream os(S);
+ os << "Call to 'pthread_once' uses";
+ if (const VarRegion *VR = dyn_cast<VarRegion>(R))
+ os << " the local variable '" << VR->getDecl()->getName() << '\'';
+ else
+ os << " stack allocated memory";
+ os << " for the \"control\" value. Using such transient memory for "
+ "the control value is potentially dangerous.";
+ if (isa<VarRegion>(R) && isa<StackLocalsSpaceRegion>(R->getMemorySpace()))
+ os << " Perhaps you intended to declare the variable as 'static'?";
+
+ EnhancedBugReport *report = new EnhancedBugReport(*BT, os.str(), N);
+ report->addRange(CE->getArg(0)->getSourceRange());
+ C.EmitReport(report);
+}
+
+//===----------------------------------------------------------------------===//
+// "malloc" with allocation size 0
+//===----------------------------------------------------------------------===//
+
+// FIXME: Eventually this should be rolled into the MallocChecker, but this
+// check is more basic and is valuable for widespread use.
+static void CheckMallocZero(CheckerContext &C, UnixAPIChecker &UC,
+ const CallExpr *CE, BugType *&BT) {
+
+ // Sanity check that malloc takes one argument.
+ if (CE->getNumArgs() != 1)
+ return;
+
+ // Check if the allocation size is 0.
+ const GRState *state = C.getState();
+ SVal argVal = state->getSVal(CE->getArg(0));
+
+ if (argVal.isUnknownOrUndef())
+ return;
+
+ const GRState *trueState, *falseState;
+ llvm::tie(trueState, falseState) = state->assume(cast<DefinedSVal>(argVal));
+
+ // Is the value perfectly constrained to zero?
+ if (falseState && !trueState) {
+ ExplodedNode *N = C.generateSink(falseState);
+ if (!N)
+ return;
+
+ // FIXME: Add reference to CERT advisory, and/or C99 standard in bug
+ // output.
+
+ LazyInitialize(BT, "Undefined allocation of 0 bytes");
+
+ EnhancedBugReport *report =
+ new EnhancedBugReport(*BT, "Call to 'malloc' has an allocation size"
+ " of 0 bytes", N);
+ report->addRange(CE->getArg(0)->getSourceRange());
+ report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
+ CE->getArg(0));
+ C.EmitReport(report);
+ return;
+ }
+ // Assume the the value is non-zero going forward.
+ assert(trueState);
+ if (trueState != state) {
+ C.addTransition(trueState);
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// Central dispatch function.
+//===----------------------------------------------------------------------===//
+
+typedef void (*SubChecker)(CheckerContext &C, UnixAPIChecker &UC,
+ const CallExpr *CE, BugType *&BT);
+namespace {
+ class SubCheck {
+ SubChecker SC;
+ UnixAPIChecker *UC;
+ BugType **BT;
+ public:
+ SubCheck(SubChecker sc, UnixAPIChecker *uc, BugType *& bt) : SC(sc), UC(uc),
+ BT(&bt) {}
+ SubCheck() : SC(NULL), UC(NULL), BT(NULL) {}
+
+ void run(CheckerContext &C, const CallExpr *CE) const {
+ if (SC)
+ SC(C, *UC, CE, *BT);
+ }
+ };
+} // end anonymous namespace
+
+void UnixAPIChecker::PreVisitCallExpr(CheckerContext &C, const CallExpr *CE) {
+ // Get the callee. All the functions we care about are C functions
+ // with simple identifiers.
+ const GRState *state = C.getState();
+ const Expr *Callee = CE->getCallee();
+ const FunctionTextRegion *Fn =
+ dyn_cast_or_null<FunctionTextRegion>(state->getSVal(Callee).getAsRegion());
+
+ if (!Fn)
+ return;
+
+ const IdentifierInfo *FI = Fn->getDecl()->getIdentifier();
+ if (!FI)
+ return;
+
+ const SubCheck &SC =
+ llvm::StringSwitch<SubCheck>(FI->getName())
+ .Case("open",
+ SubCheck(CheckOpen, this, BTypes[OpenFn]))
+ .Case("pthread_once",
+ SubCheck(CheckPthreadOnce, this, BTypes[PthreadOnceFn]))
+ .Case("malloc",
+ SubCheck(CheckMallocZero, this, BTypes[MallocZero]))
+ .Default(SubCheck());
+
+ SC.run(C, CE);
+}