Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -840,13 +840,13 @@
def OSReturnsRetained : InheritableAttr {
let Spellings = [Clang<"os_returns_retained">];
- let Subjects = SubjectList<[Function, ObjCMethod, ObjCProperty]>;
+ let Subjects = SubjectList<[Function, ObjCMethod, ObjCProperty, ParmVar]>;
let Documentation = [RetainBehaviorDocs];
}
def OSReturnsNotRetained : InheritableAttr {
let Spellings = [Clang<"os_returns_not_retained">];
- let Subjects = SubjectList<[Function, ObjCMethod, ObjCProperty]>;
+ let Subjects = SubjectList<[Function, ObjCMethod, ObjCProperty, ParmVar]>;
let Documentation = [RetainBehaviorDocs];
}
Index: clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h
+++ clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h
@@ -77,13 +77,21 @@
IncRef,
/// The argument is a pointer to a retain-counted object; on exit, the new
- /// value of the pointer is a +0 value or NULL.
+ /// value of the pointer is a +0 value.
UnretainedOutParameter,
/// The argument is a pointer to a retain-counted object; on exit, the new
- /// value of the pointer is a +1 value or NULL.
+ /// value of the pointer is a +1 value.
RetainedOutParameter,
+ /// The argument is a pointer to a retain-counted object; on exit, the new
+ /// value of the pointer is a +1 value iff the return code is zero.
+ RetainedOutParameterOnZero,
+
+ /// The argument is a pointer to a retain-counted object; on exit, the new
+ /// value of the pointer is a +1 value iff the return code is non-zero.
+ RetainedOutParameterOnNonZero,
+
/// The argument is treated as potentially escaping, meaning that
/// even when its reference count hits 0 it should be treated as still
/// possibly being alive as someone else *may* be holding onto the object.
Index: clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp
@@ -529,38 +529,81 @@
C.addTransition(state);
}
-static ProgramStateRef updateOutParameter(ProgramStateRef State,
- SVal ArgVal,
- ArgEffectKind Effect) {
- auto *ArgRegion = dyn_cast_or_null<TypedValueRegion>(ArgVal.getAsRegion());
- if (!ArgRegion)
- return State;
-
- QualType PointeeTy = ArgRegion->getValueType();
- if (!coreFoundation::isCFObjectRef(PointeeTy))
- return State;
-
- SVal PointeeVal = State->getSVal(ArgRegion);
- SymbolRef Pointee = PointeeVal.getAsLocSymbol();
- if (!Pointee)
- return State;
-
- switch (Effect) {
- case UnretainedOutParameter:
- State = setRefBinding(State, Pointee,
- RefVal::makeNotOwned(ObjKind::CF, PointeeTy));
- break;
- case RetainedOutParameter:
- // Do nothing. Retained out parameters will either point to a +1 reference
- // or NULL, but the way you check for failure differs depending on the API.
- // Consequently, we don't have a good way to track them yet.
- break;
+static SmallVector<ProgramStateRef, 2>
+updateOutParameter(ProgramStateRef State,
+ const RetainSummary &Summ,
+ const CallEvent &CE) {
+ SVal L = CE.getReturnValue();
+
+ // Splitting is required to support out parameters,
+ // as out parameters might be created only on the "success" branch.
+ // We want to avoid eagerly splitting unless out parameters are actually
+ // needed.
+ bool SplitNecessary = false;
+ for (auto &P : Summ.getArgEffects())
+ if (P.second.getKind() == RetainedOutParameterOnNonZero ||
+ P.second.getKind() == RetainedOutParameterOnZero)
+ SplitNecessary = true;
+
+ ProgramStateRef AssumeNonZero = State;
+ ProgramStateRef AssumeZero = State;
+
+ if (SplitNecessary) {
+ if (auto DL = L.getAs<DefinedOrUnknownSVal>()) {
+ AssumeNonZero = AssumeNonZero->assume(*DL, true);
+ AssumeZero = AssumeZero->assume(*DL, false);
+ }
+ }
+
+ for (unsigned idx = 0, e = CE.getNumArgs(); idx != e; ++idx) {
+ SVal ArgVal = CE.getArgSVal(idx);
+ ArgEffect AE = Summ.getArg(idx);
+
+ auto *ArgRegion = dyn_cast_or_null<TypedValueRegion>(ArgVal.getAsRegion());
+ if (!ArgRegion)
+ continue;
- default:
- llvm_unreachable("only for out parameters");
+ QualType PointeeTy = ArgRegion->getValueType();
+ SVal PointeeVal = State->getSVal(ArgRegion);
+ SymbolRef Pointee = PointeeVal.getAsLocSymbol();
+ if (!Pointee)
+ continue;
+
+ auto makeNotOwned = [&](ProgramStateRef St) {
+ return setRefBinding(St, Pointee,
+ RefVal::makeNotOwned(AE.getObjKind(), PointeeTy));
+ };
+ auto makeOwned = [&](ProgramStateRef St) {
+ return setRefBinding(St, Pointee,
+ RefVal::makeOwned(ObjKind::OS, PointeeTy));
+ };
+
+ switch (AE.getKind()) {
+ case UnretainedOutParameter:
+ AssumeNonZero = makeNotOwned(AssumeNonZero);
+ AssumeZero = makeNotOwned(AssumeZero);
+ break;
+ case RetainedOutParameter:
+ AssumeNonZero = makeOwned(AssumeNonZero);
+ AssumeZero = makeOwned(AssumeZero);
+ break;
+ case RetainedOutParameterOnNonZero:
+ AssumeNonZero = makeOwned(AssumeNonZero);
+ break;
+ case RetainedOutParameterOnZero:
+ AssumeZero = makeOwned(AssumeZero);
+ break;
+ default:
+ break;
+ }
}
- return State;
+ if (SplitNecessary) {
+ return {AssumeNonZero, AssumeZero};
+ } else {
+ assert(AssumeZero == AssumeNonZero);
+ return {AssumeZero};
+ }
}
void RetainCountChecker::checkSummary(const RetainSummary &Summ,
@@ -582,10 +625,7 @@
SVal V = CallOrMsg.getArgSVal(idx);
ArgEffect Effect = Summ.getArg(idx);
- if (Effect.getKind() == RetainedOutParameter ||
- Effect.getKind() == UnretainedOutParameter) {
- state = updateOutParameter(state, V, Effect.getKind());
- } else if (SymbolRef Sym = V.getAsLocSymbol()) {
+ if (SymbolRef Sym = V.getAsLocSymbol()) {
if (const RefVal *T = getRefBinding(state, Sym)) {
if (shouldEscapeOSArgumentOnCall(CallOrMsg, idx, T))
@@ -661,10 +701,15 @@
state = setRefBinding(state, Sym, *updatedRefVal);
}
- if (DeallocSent) {
- C.addTransition(state, C.getPredecessor(), &DeallocSentTag);
- } else {
- C.addTransition(state);
+ SmallVector<ProgramStateRef, 2> Out =
+ updateOutParameter(state, Summ, CallOrMsg);
+
+ for (ProgramStateRef St : Out) {
+ if (DeallocSent) {
+ C.addTransition(St, C.getPredecessor(), &DeallocSentTag);
+ } else {
+ C.addTransition(St);
+ }
}
}
@@ -700,6 +745,8 @@
switch (AE.getKind()) {
case UnretainedOutParameter:
case RetainedOutParameter:
+ case RetainedOutParameterOnZero:
+ case RetainedOutParameterOnNonZero:
llvm_unreachable("Applies to pointer-to-pointer parameters, which should "
"not have ref state.");
Index: clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
+++ clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
@@ -522,6 +522,8 @@
case IncRef:
case UnretainedOutParameter:
case RetainedOutParameter:
+ case RetainedOutParameterOnZero:
+ case RetainedOutParameterOnNonZero:
case MayEscape:
case StopTracking:
case StopTrackingHard:
@@ -811,6 +813,29 @@
return None;
}
+/// \return Whether the chain of typedefs starting from {@code QT}
+/// has a typedef with a given name {@code Name}.
+static bool hasTypedefNamed(QualType QT,
+ StringRef Name) {
+ while (auto *T = dyn_cast<TypedefType>(QT)) {
+ const auto &Context = T->getDecl()->getASTContext();
+ if (T->getDecl()->getIdentifier() == &Context.Idents.get(Name))
+ return true;
+ QT = T->getDecl()->getUnderlyingType();
+ }
+ return false;
+}
+
+static QualType getCallableReturnType(const NamedDecl *ND) {
+ if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
+ return FD->getReturnType();
+ } else if (const auto *MD = dyn_cast<ObjCMethodDecl>(ND)) {
+ return MD->getReturnType();
+ } else {
+ llvm_unreachable("Unexpected decl");
+ }
+}
+
bool RetainSummaryManager::applyParamAnnotationEffect(
const ParmVarDecl *pd, unsigned parm_idx, const NamedDecl *FD,
RetainSummaryTemplate &Template) {
@@ -822,19 +847,46 @@
return true;
} else if (auto K =
hasAnyEnabledAttrOf<CFReturnsRetainedAttr,
+ OSReturnsRetainedAttr,
GeneralizedReturnsRetainedAttr>(pd, QT)) {
- Template->addArg(AF, parm_idx, ArgEffect(RetainedOutParameter, *K));
+
+ // For OSObjects, we try to guess whether the object is created based
+ // on the return value.
+ if (K == ObjKind::OS) {
+ QualType QT = getCallableReturnType(FD);
+
+ // The usual convention is to create an object on non-zero return, but
+ // it's reverted if the typedef chain has a typedef kern_return_t,
+ // becauese kReturnSuccess constant is defined as zero.
+ bool SuccessOnZero = hasTypedefNamed(QT, "kern_return_t");
+ bool ShouldSplit = !QT.isNull() && !QT->isVoidType();
+ ArgEffectKind AK = RetainedOutParameter;
+ if (ShouldSplit && SuccessOnZero) {
+ AK = RetainedOutParameterOnZero;
+ } else if (ShouldSplit && !SuccessOnZero) {
+ AK = RetainedOutParameterOnNonZero;
+ }
+ Template->addArg(AF, parm_idx, ArgEffect(AK, *K));
+ }
+
+ // For others:
+ // Do nothing. Retained out parameters will either point to a +1 reference
+ // or NULL, but the way you check for failure differs depending on the
+ // API. Consequently, we don't have a good way to track them yet.
return true;
- } else if (auto K = hasAnyEnabledAttrOf<CFReturnsNotRetainedAttr>(pd, QT)) {
+ } else if (auto K = hasAnyEnabledAttrOf<CFReturnsNotRetainedAttr,
+ OSReturnsNotRetainedAttr,
+ GeneralizedReturnsNotRetainedAttr>(
+ pd, QT)) {
Template->addArg(AF, parm_idx, ArgEffect(UnretainedOutParameter, *K));
return true;
- } else {
- if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
- for (const auto *OD : MD->overridden_methods()) {
- const ParmVarDecl *OP = OD->parameters()[parm_idx];
- if (applyParamAnnotationEffect(OP, parm_idx, OD, Template))
- return true;
- }
+ }
+
+ if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
+ for (const auto *OD : MD->overridden_methods()) {
+ const ParmVarDecl *OP = OD->parameters()[parm_idx];
+ if (applyParamAnnotationEffect(OP, parm_idx, OD, Template))
+ return true;
}
}
Index: clang/test/Analysis/osobject-retain-release.cpp
===================================================================
--- clang/test/Analysis/osobject-retain-release.cpp
+++ clang/test/Analysis/osobject-retain-release.cpp
@@ -94,6 +94,134 @@
void escape_with_source(void *p) {}
bool coin();
+bool write_into_out_param_on_success(OS_RETURNS_RETAINED OSObject **obj);
+
+void use_out_param() {
+ OSObject *obj;
+ if (write_into_out_param_on_success(&obj)) {
+ obj->release();
+ }
+}
+
+void use_out_param_leak() {
+ OSObject *obj;
+ write_into_out_param_on_success(&obj); // expected-note{{Call to function 'write_into_out_param_on_success' returns an OSObject of type OSObject with a +1 retain count}}
+} // expected-warning{{Potential leak of an object stored into 'obj'}}
+ // expected-note@-1{{Object leaked: object allocated and stored into 'obj' is not referenced later in this execution path and has a retain count of +1}}
+
+typedef int kern_return_t;
+typedef kern_return_t IOReturn;
+typedef kern_return_t OSReturn;
+#define kOSReturnSuccess 0
+#define kIOReturnSuccess 0
+
+bool write_into_two_out_params(OS_RETURNS_RETAINED OSObject **a,
+ OS_RETURNS_RETAINED OSObject **b);
+
+void use_write_into_two_out_params() {
+ OSObject *obj1;
+ OSObject *obj2;
+ if (write_into_two_out_params(&obj1, &obj2)) {
+ obj1->release();
+ obj2->release();
+ }
+}
+
+void use_write_two_out_params_leak() {
+ OSObject *obj1;
+ OSObject *obj2;
+ write_into_two_out_params(&obj1, &obj2); // expected-note{{Call to function 'write_into_two_out_params' returns an OSObject of type OSObject with a +1 retain count}}
+ // expected-note@-1{{Call to function 'write_into_two_out_params' returns an OSObject of type OSObject with a +1 retain count}}
+} // expected-warning{{Potential leak of an object stored into 'obj1'}}
+ // expected-warning@-1{{Potential leak of an object stored into 'obj2'}}
+ // expected-note@-2{{Object leaked: object allocated and stored into 'obj1' is not referenced later in this execution path and has a retain count of +1}}
+ // expected-note@-3{{Object leaked: object allocated and stored into 'obj2' is not referenced later in this execution path and has a retain count of +1}}
+
+void always_write_into_two_out_params(OS_RETURNS_RETAINED OSObject **a,
+ OS_RETURNS_RETAINED OSObject **b);
+
+void use_always_write_into_two_out_params() {
+ OSObject *obj1;
+ OSObject *obj2;
+ always_write_into_two_out_params(&obj1, &obj2);
+ obj1->release();
+ obj2->release();
+}
+
+void use_always_write_into_two_out_params_leak() {
+ OSObject *obj1;
+ OSObject *obj2;
+ always_write_into_two_out_params(&obj1, &obj2); // expected-note{{Call to function 'always_write_into_two_out_params' returns an OSObject of type OSObject with a +1 retain count}}
+ // expected-note@-1{{Call to function 'always_write_into_two_out_params' returns an OSObject of type OSObject with a +1 retain count}}
+} // expected-warning{{Potential leak of an object stored into 'obj1'}}
+ // expected-warning@-1{{Potential leak of an object stored into 'obj2'}}
+ // expected-note@-2{{Object leaked: object allocated and stored into 'obj1' is not referenced later in this execution path and has a retain count of +1}}
+ // expected-note@-3{{Object leaked: object allocated and stored into 'obj2' is not referenced later in this execution path and has a retain count of +1}}
+
+char *write_into_out_param_on_nonnull(OS_RETURNS_RETAINED OSObject **obj);
+
+void use_out_param_osreturn_on_nonnull() {
+ OSObject *obj;
+ if (write_into_out_param_on_nonnull(&obj)) {
+ obj->release();
+ }
+}
+
+void use_out_param_leak_osreturn_on_nonnull() {
+ OSObject *obj;
+ write_into_out_param_on_nonnull(&obj); // expected-note{{Call to function 'write_into_out_param_on_nonnull' returns an OSObject of type OSObject with a +1 retain count}}
+} // expected-warning{{Potential leak of an object stored into 'obj'}}
+ // expected-note@-1{{Object leaked: object allocated and stored into 'obj' is not referenced later in this execution path and has a retain count of +1}}
+
+bool write_optional_out_param(OS_RETURNS_RETAINED OSObject **obj=nullptr);
+
+void use_optional_out_param() {
+ if (write_optional_out_param()) {};
+}
+
+OSReturn write_into_out_param_on_os_success(OS_RETURNS_RETAINED OSObject **obj);
+
+void write_into_non_retained_out_param(OS_RETURNS_NOT_RETAINED OSObject **obj);
+
+void use_write_into_non_retained_out_param() {
+ OSObject *obj;
+ write_into_non_retained_out_param(&obj);
+}
+
+void use_write_into_non_retained_out_param_uaf() {
+ OSObject *obj;
+ write_into_non_retained_out_param(&obj); // expected-note{{Call to function 'write_into_non_retained_out_param' returns an OSObject of type OSObject with a +0 retain count}}
+ obj->release(); // expected-warning{{Incorrect decrement of the reference count of an object that is not owned at this point by the caller}}
+ // expected-note@-1{{Incorrect decrement of the reference count of an object that is not owned at this point by the caller}}
+}
+
+void always_write_into_out_param(OS_RETURNS_RETAINED OSObject **obj);
+
+void use_void_out_param_osreturn() {
+ OSObject *obj;
+ always_write_into_out_param(&obj);
+ obj->release();
+}
+
+void use_void_out_param_osreturn_leak() {
+ OSObject *obj;
+ always_write_into_out_param(&obj); // expected-note{{Call to function 'always_write_into_out_param' returns an OSObject of type OSObject with a +1 retain count}}
+} // expected-warning{{Potential leak of an object stored into 'obj'}}
+ // expected-note@-1{{Object leaked: object allocated and stored into 'obj' is not referenced later in this execution path and has a retain count of +1}}
+
+void use_out_param_osreturn() {
+ OSObject *obj;
+ if (write_into_out_param_on_os_success(&obj) == kOSReturnSuccess) {
+ obj->release();
+ }
+}
+
+void use_out_param_leak_osreturn() {
+ OSObject *obj;
+ write_into_out_param_on_os_success(&obj); // expected-note{{Call to function 'write_into_out_param_on_os_success' returns an OSObject of type OSObject with a +1 retain count}}
+} // expected-warning{{Potential leak of an object stored into 'obj'}}
+ // expected-note@-1{{Object leaked: object allocated and stored into 'obj' is not referenced later in this execution path and has a retain count of +1}}
+
bool os_consume_violation_two_args(OS_CONSUME OSObject *obj, bool extra) {
if (coin()) { // expected-note{{Assuming the condition is false}}
// expected-note@-1{{Taking false branch}}
@@ -431,4 +559,3 @@
void test_escape_to_unknown_block(Blk blk) {
blk(getObject()); // no-crash
}
-