================
@@ -2515,6 +2518,57 @@ void CStringChecker::evalSprintfCommon(CheckerContext
&C, const CallEvent &Call,
C.addTransition(State);
}
+void CStringChecker::evalGetentropy(CheckerContext &C,
+ const CallEvent &Call, CharKind CK) const {
+ DestinationArgExpr Buffer = {{Call.getArgExpr(0), 0}};
+ SizeArgExpr Size = {{Call.getArgExpr(1), 1}};
+ ProgramStateRef State = C.getState();
+ const LocationContext *LCtx = C.getLocationContext();
+ SValBuilder &Builder = C.getSValBuilder();
+ SVal MaxLength = Builder.makeIntVal(256, C.getASTContext().IntTy);
+
+ SVal SizeVal = C.getSVal(Size.Expression);
+ QualType SizeTy = Size.Expression->getType();
+
+ ProgramStateRef StateZeroSize, StateNonZeroSize;
+ std::tie(StateZeroSize, StateNonZeroSize) =
+ assumeZero(C, State, SizeVal, SizeTy);
+
+ if (StateZeroSize) {
+ StateZeroSize = State->BindExpr(Call.getOriginExpr(), LCtx,
+ Builder.makeZeroVal(C.getASTContext().IntTy));
+ C.addTransition(StateZeroSize);
+ return;
+ }
+
+ SVal Buff = C.getSVal(Buffer.Expression);
+ State = checkNonNull(C, StateNonZeroSize, Buffer, Buff);
+ if (!State)
+ return;
+
+ QualType cmpTy = C.getSValBuilder().getConditionType();
+ ProgramStateRef bufferTooLong, bufferNotTooLong;
+ std::tie(bufferTooLong, bufferNotTooLong) = State->assume(
+ Builder
+ .evalBinOpNN(State, BO_GT, *SizeVal.getAs<NonLoc>(),
*MaxLength.getAs<NonLoc>(), cmpTy)
+ .castAs<DefinedOrUnknownSVal>());
+ if (bufferTooLong) {
+ ErrorMessage Message;
+ llvm::raw_svector_ostream Os(Message);
+ Os << "size is greater than 256";
+ emitOutOfBoundsBug(C, bufferTooLong, Buffer.Expression, Message);
----------------
steakhal wrote:
```suggestion
emitOutOfBoundsBug(C, bufferTooLong, Buffer.Expression, "size is greater
than 256");
```
But actually, I don't think an "out of bounds" error is appropriate here; and
the provided message could be rephrased to "the 'length' argument to
'getentropy' must be smaller than or equal to 256". This hints the user how to
fix this. @haoNoQ WDYT of reporting this as an out-of-bounds access?
https://github.com/llvm/llvm-project/pull/83675
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