[PATCH] D64883: Add new warning -Walloca for use of builtin alloca function

[Elaina Guan via Phabricator via cfe-commits]

ziyig updated this revision to Diff 211816.
ziyig marked an inline comment as done.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64883/new/

https://reviews.llvm.org/D64883

Files:
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Sema/warn-alloca.c


Index: clang/test/Sema/warn-alloca.c
===
--- /dev/null
+++ clang/test/Sema/warn-alloca.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -DSILENCE -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Walloca %s
+
+#ifdef SILENCE
+  // expected-no-diagnostics
+#endif
+
+void test1(int a) {
+  __builtin_alloca(a);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function '__builtin_alloca' is discouraged; 
there is no way to check for failure but failure may still occur, resulting in 
a possibly exploitable security vulnerability}}
+#endif
+}
+
+void test2(int a) {
+  __builtin_alloca_with_align(a, 32);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function '__builtin_alloca_with_align' is 
discouraged; there is no way to check for failure but failure may still occur, 
resulting in a possibly exploitable security vulnerability}}
+#endif
+}
Index: clang/lib/Sema/SemaChecking.cpp
===
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1169,6 +1169,10 @@
   case Builtin::BI__builtin_alloca_with_align:
 if (SemaBuiltinAllocaWithAlign(TheCall))
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
+Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+<< TheCall->getDirectCallee();
 break;
   case Builtin::BI__assume:
   case Builtin::BI__builtin_assume:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2772,6 +2772,11 @@
 def err_cannot_find_suitable_accessor : Error<
   "cannot find suitable %select{getter|setter}0 for property %1">;
 
+def warn_alloca : Warning<
+  "use of function %0 is discouraged; there is no way to check for failure but 
"
+  "failure may still occur, resulting in a possibly exploitable security 
vulnerability">,
+  InGroup>, DefaultIgnore;
+
 def warn_alloca_align_alignof : Warning<
   "second argument to __builtin_alloca_with_align is supposed to be in bits">,
   InGroup>;


Index: clang/test/Sema/warn-alloca.c
===
--- /dev/null
+++ clang/test/Sema/warn-alloca.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -DSILENCE -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Walloca %s
+
+#ifdef SILENCE
+  // expected-no-diagnostics
+#endif
+
+void test1(int a) {
+  __builtin_alloca(a);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function '__builtin_alloca' is discouraged; there is no way to check for failure but failure may still occur, resulting in a possibly exploitable security vulnerability}}
+#endif
+}
+
+void test2(int a) {
+  __builtin_alloca_with_align(a, 32);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function '__builtin_alloca_with_align' is discouraged; there is no way to check for failure but failure may still occur, resulting in a possibly exploitable security vulnerability}}
+#endif
+}
Index: clang/lib/Sema/SemaChecking.cpp
===
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1169,6 +1169,10 @@
   case Builtin::BI__builtin_alloca_with_align:
 if (SemaBuiltinAllocaWithAlign(TheCall))
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
+Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+<< TheCall->getDirectCallee();
 break;
   case Builtin::BI__assume:
   case Builtin::BI__builtin_assume:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2772,6 +2772,11 @@
 def err_cannot_find_suitable_accessor : Error<
   "cannot find suitable %select{getter|setter}0 for property %1">;
 
+def warn_alloca : Warning<
+  "use of function %0 is discouraged; there is no way to check for failure but "
+  "failure may still occur, resulting in a possibly exploitable security vulnerability">,
+  InGroup>, DefaultIgnore;
+
 def warn_alloca_align_alignof : Warning<
   "second argument to __builtin_alloca_with_align is supposed to be in bits">,
   InGroup>;
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[PATCH] D64883: Add new warning -Walloca for use of builtin alloca function

[Elaina Guan via Phabricator via cfe-commits]

ziyig added inline comments.



Comment at: clang/lib/Sema/SemaChecking.cpp:1172
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:

aaron.ballman wrote:
> Do we want to warn on all uses of alloca(), or just the ones that get past 
> the call to `SemaBuiltinAllocaWithAlign()`?
I don't have strong opinion about this. Which one do you think is better?


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[PATCH] D64883: Add new warning -Walloca for use of builtin alloca function

[Elaina Guan via Phabricator via cfe-commits]

ziyig updated this revision to Diff 211785.
ziyig marked 9 inline comments as done.
ziyig added a comment.

Updated the warning message and the test cases.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64883/new/

https://reviews.llvm.org/D64883

Files:
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Sema/warn-alloca.c


Index: clang/test/Sema/warn-alloca.c
===
--- /dev/null
+++ clang/test/Sema/warn-alloca.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -DSILENCE -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Walloca %s
+
+#ifdef SILENCE
+  // expected-no-diagnostics
+#endif
+
+void test1(int a) {
+  __builtin_alloca(a);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function __builtin_alloca is discouraged; 
there is no way to check for failure but failure may still occur, resulting in 
a possibly exploitable security vulnerability}}
+#endif
+}
+
+void test2(int a) {
+  __builtin_alloca_with_align(a, 32);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function __builtin_alloca_with_align is 
discouraged; there is no way to check for failure but failure may still occur, 
resulting in a possibly exploitable security vulnerability}}
+#endif
+}
Index: clang/lib/Sema/SemaChecking.cpp
===
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1169,6 +1169,10 @@
   case Builtin::BI__builtin_alloca_with_align:
 if (SemaBuiltinAllocaWithAlign(TheCall))
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
+Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+<< TheCall->getDirectCallee()->getNameInfo().getAsString();
 break;
   case Builtin::BI__assume:
   case Builtin::BI__builtin_assume:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2772,6 +2772,11 @@
 def err_cannot_find_suitable_accessor : Error<
   "cannot find suitable %select{getter|setter}0 for property %1">;
 
+def warn_alloca : Warning<
+  "use of function %0 is discouraged; there is no way to check for failure but 
"
+  "failure may still occur, resulting in a possibly exploitable security 
vulnerability">,
+  InGroup>, DefaultIgnore;
+
 def warn_alloca_align_alignof : Warning<
   "second argument to __builtin_alloca_with_align is supposed to be in bits">,
   InGroup>;


Index: clang/test/Sema/warn-alloca.c
===
--- /dev/null
+++ clang/test/Sema/warn-alloca.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -DSILENCE -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Walloca %s
+
+#ifdef SILENCE
+  // expected-no-diagnostics
+#endif
+
+void test1(int a) {
+  __builtin_alloca(a);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function __builtin_alloca is discouraged; there is no way to check for failure but failure may still occur, resulting in a possibly exploitable security vulnerability}}
+#endif
+}
+
+void test2(int a) {
+  __builtin_alloca_with_align(a, 32);
+#ifndef SILENCE
+  // expected-warning@-2 {{use of function __builtin_alloca_with_align is discouraged; there is no way to check for failure but failure may still occur, resulting in a possibly exploitable security vulnerability}}
+#endif
+}
Index: clang/lib/Sema/SemaChecking.cpp
===
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1169,6 +1169,10 @@
   case Builtin::BI__builtin_alloca_with_align:
 if (SemaBuiltinAllocaWithAlign(TheCall))
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
+Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+<< TheCall->getDirectCallee()->getNameInfo().getAsString();
 break;
   case Builtin::BI__assume:
   case Builtin::BI__builtin_assume:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2772,6 +2772,11 @@
 def err_cannot_find_suitable_accessor : Error<
   "cannot find suitable %select{getter|setter}0 for property %1">;
 
+def warn_alloca : Warning<
+  "use of function %0 is discouraged; there is no way to check for failure but "
+  "failure may still occur, resulting in a possibly exploitable security vulnerability">,
+  InGroup>, DefaultIgnore;
+
 def warn_alloca_align_alignof : Warning<
   "second argument to __builtin_alloca_with_align is supposed to be in bits">,
   InGroup>;
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[PATCH] D64883: Add new warning -Walloca for use of builtin alloca function

[Elaina Guan via Phabricator via cfe-commits]

ziyig created this revision.
ziyig added reviewers: gbiv, aaron.ballman.
Herald added a reviewer: george.burgess.iv.
Herald added subscribers: cfe-commits, kristina.
Herald added a project: clang.

Add new warning -Walloca for use of builtin alloca function.

Also warns the use of __builtin_alloca_with_align. GCC has this warning, and 
we'd like to have this for compatibility.


Repository:
  rC Clang

https://reviews.llvm.org/D64883

Files:
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Sema/warn-alloca.c


Index: clang/test/Sema/warn-alloca.c
===
--- /dev/null
+++ clang/test/Sema/warn-alloca.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Walloca %s
+
+void test1(int a) {
+  __builtin_alloca(a); // expected-warning {{use of builtin function 
__builtin_alloca}}
+}
+
+void test2(int a) {
+  __builtin_alloca_with_align(a, 32); // expected-warning {{use of builtin 
function __builtin_alloca_with_align}}
+}
+
Index: clang/lib/Sema/SemaChecking.cpp
===
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1169,6 +1169,10 @@
   case Builtin::BI__builtin_alloca_with_align:
 if (SemaBuiltinAllocaWithAlign(TheCall))
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
+Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+<< Context.BuiltinInfo.getName(BuiltinID);
 break;
   case Builtin::BI__assume:
   case Builtin::BI__builtin_assume:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2772,6 +2772,10 @@
 def err_cannot_find_suitable_accessor : Error<
   "cannot find suitable %select{getter|setter}0 for property %1">;
 
+def warn_alloca : Warning<
+  "use of builtin function %0">,
+  InGroup>, DefaultIgnore;
+
 def warn_alloca_align_alignof : Warning<
   "second argument to __builtin_alloca_with_align is supposed to be in bits">,
   InGroup>;


Index: clang/test/Sema/warn-alloca.c
===
--- /dev/null
+++ clang/test/Sema/warn-alloca.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Walloca %s
+
+void test1(int a) {
+  __builtin_alloca(a); // expected-warning {{use of builtin function __builtin_alloca}}
+}
+
+void test2(int a) {
+  __builtin_alloca_with_align(a, 32); // expected-warning {{use of builtin function __builtin_alloca_with_align}}
+}
+
Index: clang/lib/Sema/SemaChecking.cpp
===
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1169,6 +1169,10 @@
   case Builtin::BI__builtin_alloca_with_align:
 if (SemaBuiltinAllocaWithAlign(TheCall))
   return ExprError();
+LLVM_FALLTHROUGH;
+  case Builtin::BI__builtin_alloca:
+Diag(TheCall->getBeginLoc(), diag::warn_alloca)
+<< Context.BuiltinInfo.getName(BuiltinID);
 break;
   case Builtin::BI__assume:
   case Builtin::BI__builtin_assume:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2772,6 +2772,10 @@
 def err_cannot_find_suitable_accessor : Error<
   "cannot find suitable %select{getter|setter}0 for property %1">;
 
+def warn_alloca : Warning<
+  "use of builtin function %0">,
+  InGroup>, DefaultIgnore;
+
 def warn_alloca_align_alignof : Warning<
   "second argument to __builtin_alloca_with_align is supposed to be in bits">,
   InGroup>;
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