https://github.com/ojhunt created
https://github.com/llvm/llvm-project/pull/138376
When parsing a function pointer typed field we use
Parser::ParseTypeQualifierListOpt, but then drops subsequent type attributes
and qualifiers unless explicitly handled.
There is an existing solution for the _Atomic qualifier, and this PR simply
extends that to __ptrauth for now. In future we may want to investigate a more
robust mechanism to ensure type qualifiers are not silently dropped so that
future type qualifiers do not suffer the same problem.
>From 8fefeb81c38ad2f196a117103e40290171db51b6 Mon Sep 17 00:00:00 2001
From: Oliver Hunt <oli...@apple.com>
Date: Fri, 2 May 2025 20:59:19 -0700
Subject: [PATCH] [clang][ptrauth] reject incorrectly placed ptrauth qualifier
When parsing a function pointer typed field we use
Parser::ParseTypeQualifierListOpt, but then drops subsequent
type attributes and qualifiers unless explicitly handled.
There is an existing solution for the _Atomic qualifier, and
this PR simply extends that to __ptrauth for now. In future
we may want to investigate a more robust mechanism to ensure
type qualifiers are not silently dropped so that future type
qualifiers do not suffer the same problem.
---
clang/include/clang/Parse/Parser.h | 2 +-
clang/lib/Parse/ParseDecl.cpp | 11 +++++++----
clang/lib/Parse/ParseDeclCXX.cpp | 2 +-
clang/test/Sema/ptrauth-struct-function-ptr-field.c | 7 +++++++
4 files changed, 16 insertions(+), 6 deletions(-)
create mode 100644 clang/test/Sema/ptrauth-struct-function-ptr-field.c
diff --git a/clang/include/clang/Parse/Parser.h
b/clang/include/clang/Parse/Parser.h
index 00e4b980bf44a..46a2d26beb7f9 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -3253,7 +3253,7 @@ class Parser : public CodeCompletionHandler {
void ParseTypeQualifierListOpt(
DeclSpec &DS, unsigned AttrReqs = AR_AllAttributesParsed,
- bool AtomicAllowed = true, bool IdentifierRequired = false,
+ bool AtomicOrPtrauthAllowed = true, bool IdentifierRequired = false,
std::optional<llvm::function_ref<void()>> CodeCompletionHandler =
std::nullopt);
void ParseDirectDeclarator(Declarator &D);
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 4cfb8de615f05..4fe3565687905 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -6511,7 +6511,7 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified,
bool DeductionGuide,
/// Note: vendor can be GNU, MS, etc and can be explicitly controlled via
/// AttrRequirements bitmask values.
void Parser::ParseTypeQualifierListOpt(
- DeclSpec &DS, unsigned AttrReqs, bool AtomicAllowed,
+ DeclSpec &DS, unsigned AttrReqs, bool AtomicOrPtrauthAllowed,
bool IdentifierRequired,
std::optional<llvm::function_ref<void()>> CodeCompletionHandler) {
if ((AttrReqs & AR_CXX11AttributesParsed) &&
@@ -6551,7 +6551,7 @@ void Parser::ParseTypeQualifierListOpt(
getLangOpts());
break;
case tok::kw__Atomic:
- if (!AtomicAllowed)
+ if (!AtomicOrPtrauthAllowed)
goto DoneWithTypeQuals;
diagnoseUseOfC11Keyword(Tok);
isInvalid = DS.SetTypeQual(DeclSpec::TQ_atomic, Loc, PrevSpec, DiagID,
@@ -6584,6 +6584,8 @@ void Parser::ParseTypeQualifierListOpt(
// __ptrauth qualifier.
case tok::kw___ptrauth:
+ if (!AtomicOrPtrauthAllowed)
+ goto DoneWithTypeQuals;
ParsePtrauthQualifier(DS.getAttributes());
EndLoc = PrevTokLocation;
continue;
@@ -6860,7 +6862,8 @@ void Parser::ParseDeclaratorInternal(Declarator &D,
((D.getContext() != DeclaratorContext::CXXNew)
? AR_GNUAttributesParsed
: AR_GNUAttributesParsedAndRejected);
- ParseTypeQualifierListOpt(DS, Reqs, true, !D.mayOmitIdentifier());
+ ParseTypeQualifierListOpt(DS, Reqs, /*AtomicOrPtrauthAllowed=*/true,
+ !D.mayOmitIdentifier());
D.ExtendWithDeclSpec(DS);
// Recursively parse the declarator.
@@ -7725,7 +7728,7 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
// Parse cv-qualifier-seq[opt].
ParseTypeQualifierListOpt(
DS, AR_NoAttributesParsed,
- /*AtomicAllowed*/ false,
+ /*AtomicOrPtrauthAllowed=*/false,
/*IdentifierRequired=*/false, llvm::function_ref<void()>([&]() {
Actions.CodeCompletion().CodeCompleteFunctionQualifiers(DS, D);
}));
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 7e0a8af07a3be..6ee2cd31311ef 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -2802,7 +2802,7 @@ void
Parser::MaybeParseAndDiagnoseDeclSpecAfterCXX11VirtSpecifierSeq(
// GNU-style and C++11 attributes are not allowed here, but they will be
// handled by the caller. Diagnose everything else.
ParseTypeQualifierListOpt(
- DS, AR_NoAttributesParsed, false,
+ DS, AR_NoAttributesParsed, /*AtomicOrPtrauthAllowed=*/false,
/*IdentifierRequired=*/false, llvm::function_ref<void()>([&]() {
Actions.CodeCompletion().CodeCompleteFunctionQualifiers(DS, D, &VS);
}));
diff --git a/clang/test/Sema/ptrauth-struct-function-ptr-field.c
b/clang/test/Sema/ptrauth-struct-function-ptr-field.c
new file mode 100644
index 0000000000000..f9eccd559c37d
--- /dev/null
+++ b/clang/test/Sema/ptrauth-struct-function-ptr-field.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple arm64-apple-ios -x c -fsyntax-only -verify
-fptrauth-intrinsics %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -triple arm64-apple-ios -x c++ -fsyntax-only -verify
-fptrauth-intrinsics %s -fexperimental-new-constant-interpreter
+
+struct Foo {
+ void (*f)(int) __ptrauth(1,1,1);
+ // expected-error@-1 {{expected ';' at end of declaration list}}
+};
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