Do not warn on correct use of the '%n' format specifier.

While '%n' can be used for evil in an attacker-controlled format string, there
isn't any acute danger in using it in a literal format string with an argument
of the appropriate type.

llvm-svn: 160984

1 files changed, 0 insertions, 9 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 200b9439a66..dce912c4771 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2561,15 +2561,6 @@ CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
     HandleNonStandardConversionSpecification(LM, CS, startSpecifier,
                                              specifierLen);
 
-  // Are we using '%n'?
-  if (CS.getKind() == ConversionSpecifier::nArg) {
-    // Issue a warning about this being a possible security issue.
-    EmitFormatDiagnostic(S.PDiag(diag::warn_printf_write_back),
-                         getLocationOfByte(CS.getStart()),
-                         /*IsStringLocation*/true,
-                         getSpecifierRange(startSpecifier, specifierLen));
-  }
-
   // The remaining checks depend on the data arguments.
   if (HasVAListArg)
     return true;