[clang-tools-extra] 7f5abb6 - [clangd] Fix a use-after-free

[Kadir Cetinkaya via cfe-commits]

Author: Kadir Cetinkaya
Date: 2021-03-25T18:26:17+01:00
New Revision: 7f5abb63733238b89cf5d47116b2af68cda2af4e

URL: https://github.com/llvm/llvm-project/commit/7f5abb63733238b89cf5d47116b2af68cda2af4e
DIFF: https://github.com/llvm/llvm-project/commit/7f5abb63733238b89cf5d47116b2af68cda2af4e.diff

LOG: [clangd] Fix a use-after-free

Clangd was storing reference to a possibly-dead string in compiled
config. This patch fixes the issue by copying suppression strings from
fragments into compiled Config.

Fixes https://github.com/clangd/clangd/issues/724.

Differential Revision: https://reviews.llvm.org/D99326

Added: 
    

Modified: 
    clang-tools-extra/clangd/ConfigCompile.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clangd/ConfigCompile.cpp b/clang-tools-extra/clangd/ConfigCompile.cpp
index 9aed3c4679f5e..8f402ae061535 100644
--- a/clang-tools-extra/clangd/ConfigCompile.cpp
+++ b/clang-tools-extra/clangd/ConfigCompile.cpp
@@ -371,7 +371,7 @@ struct FragmentCompiler {
   }
 
   void compile(Fragment::DiagnosticsBlock &&F) {
-    std::vector<llvm::StringRef> Normalized;
+    std::vector<std::string> Normalized;
     for (const auto &Suppressed : F.Suppress) {
       if (*Suppressed == "*") {
         Out.Apply.push_back([&](const Params &, Config &C) {
@@ -380,15 +380,16 @@ struct FragmentCompiler {
         });
         return;
       }
-      Normalized.push_back(normalizeSuppressedCode(*Suppressed));
+      Normalized.push_back(normalizeSuppressedCode(*Suppressed).str());
     }
     if (!Normalized.empty())
-      Out.Apply.push_back([Normalized](const Params &, Config &C) {
-        if (C.Diagnostics.SuppressAll)
-          return;
-        for (llvm::StringRef N : Normalized)
-          C.Diagnostics.Suppress.insert(N);
-      });
+      Out.Apply.push_back(
+          [Normalized(std::move(Normalized))](const Params &, Config &C) {
+            if (C.Diagnostics.SuppressAll)
+              return;
+            for (llvm::StringRef N : Normalized)
+              C.Diagnostics.Suppress.insert(N);
+          });
 
     compile(std::move(F.ClangTidy));
   }