forked from OSchip/llvm-project
96 lines
3.2 KiB
C++
96 lines
3.2 KiB
C++
//== ReturnPointerRangeChecker.cpp ------------------------------*- C++ -*--==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines ReturnPointerRangeChecker, which is a path-sensitive check
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// which looks for an out-of-bound pointer being returned to callers.
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//
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//===----------------------------------------------------------------------===//
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#include "GRExprEngineInternalChecks.h"
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#include "clang/Analysis/PathSensitive/GRExprEngine.h"
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#include "clang/Analysis/PathSensitive/BugReporter.h"
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#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
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using namespace clang;
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namespace {
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class VISIBILITY_HIDDEN ReturnPointerRangeChecker :
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public CheckerVisitor<ReturnPointerRangeChecker> {
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BuiltinBug *BT;
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public:
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ReturnPointerRangeChecker() : BT(0) {}
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static void *getTag();
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void PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *RS);
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};
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}
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void clang::RegisterReturnPointerRangeChecker(GRExprEngine &Eng) {
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Eng.registerCheck(new ReturnPointerRangeChecker());
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}
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void *ReturnPointerRangeChecker::getTag() {
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static int x = 0; return &x;
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}
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void ReturnPointerRangeChecker::PreVisitReturnStmt(CheckerContext &C,
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const ReturnStmt *RS) {
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const GRState *state = C.getState();
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const Expr *RetE = RS->getRetValue();
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if (!RetE)
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return;
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SVal V = state->getSVal(RetE);
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const MemRegion *R = V.getAsRegion();
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const ElementRegion *ER = dyn_cast_or_null<ElementRegion>(R);
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if (!ER)
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return;
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DefinedOrUnknownSVal &Idx = cast<DefinedOrUnknownSVal>(ER->getIndex());
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// FIXME: All of this out-of-bounds checking should eventually be refactored into a
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// common place.
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// Zero index is always in bound, this also passes ElementRegions created for
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// pointer casts.
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if (Idx.isZeroConstant())
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return;
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SVal NumVal = C.getStoreManager().getSizeInElements(state,
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ER->getSuperRegion());
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DefinedOrUnknownSVal &NumElements = cast<DefinedOrUnknownSVal>(NumVal);
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const GRState *StInBound = state->AssumeInBound(Idx, NumElements, true);
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const GRState *StOutBound = state->AssumeInBound(Idx, NumElements, false);
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if (StOutBound && !StInBound) {
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ExplodedNode *N = C.GenerateNode(RS, StOutBound, true);
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if (!N)
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return;
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// FIXME: This bug correspond to CWE-466. Eventually we should have bug types explicitly
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// reference such exploit categories (when applicable).
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if (!BT)
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BT = new BuiltinBug("Return of pointer value outside of expected range",
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"Returned pointer value points outside the original object (potential buffer overflow)");
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// FIXME: It would be nice to eventually make this diagnostic more clear, e.g., by referencing
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// the original declaration or by saying *why* this reference is outside the range.
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// Generate a report for this bug.
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RangedBugReport *report =
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new RangedBugReport(*BT, BT->getDescription().c_str(), N);
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report->addRange(RetE->getSourceRange());
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C.EmitReport(report);
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}
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}
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