[scudo] Skip special quarantine blocks in iterateOverChunks

If a quarantine block is allocated, it will be passed through to a
user who calls iterateOverChunks. Make these special block allocations
state Quarantined so they are not passed to iterateOverChunks.

Remove the FIXME in the combined tests for quarantine since this
fixes those tests too.

Also add a specific new test that fails without this fix.

Author: cferris1000

compiler-rt/lib/scudo/standalone/combined.h

@@ -101,7 +101,8 @@ class Allocator {
       Chunk::UnpackedHeader Header = {};
       Header.ClassId = QuarantineClassId & Chunk::ClassIdMask;
       Header.SizeOrUnusedBytes = sizeof(QuarantineBatch);
-      Header.State = Chunk::State::Allocated;
+      // Do not use Allocated or this block will show up in iterateOverChunks.
+      Header.State = Chunk::State::Quarantined;
       Chunk::storeHeader(Allocator.Cookie, Ptr, &Header);
 
       // Reset tag to 0 as this chunk may have been previously used for a tagged
@@ -120,7 +121,7 @@ class Allocator {
       Chunk::UnpackedHeader Header;
       Chunk::loadHeader(Allocator.Cookie, Ptr, &Header);
 
-      if (UNLIKELY(Header.State != Chunk::State::Allocated))
+      if (UNLIKELY(Header.State != Chunk::State::Quarantined))
         reportInvalidChunkState(AllocatorAction::Deallocating, Ptr);
       DCHECK_EQ(Header.ClassId, QuarantineClassId);
       DCHECK_EQ(Header.Offset, 0);

compiler-rt/lib/scudo/standalone/tests/combined_test.cpp

@@ -24,6 +24,7 @@
 #include <set>
 #include <stdlib.h>
 #include <thread>
+#include <unordered_map>
 #include <vector>
 
 static constexpr scudo::Chunk::Origin Origin = scudo::Chunk::Origin::Malloc;
@@ -151,12 +152,10 @@ void TestAllocator<Config>::operator delete(void *ptr) {
 
 template <class TypeParam> struct ScudoCombinedTest : public Test {
   ScudoCombinedTest() {
-    UseQuarantine = std::is_same<TypeParam, scudo::AndroidConfig>::value;
     Allocator = std::make_unique<AllocatorT>();
   }
   ~ScudoCombinedTest() {
     Allocator->releaseToOS(scudo::ReleaseToOS::Force);
-    UseQuarantine = true;
   }
 
   void RunTest();
@@ -525,30 +524,25 @@ SCUDO_TYPED_TEST(ScudoCombinedTest, IterateOverChunks) {
   auto *Allocator = this->Allocator.get();
   // Allocates a bunch of chunks, then iterate over all the chunks, ensuring
   // they are the ones we allocated. This requires the allocator to not have any
-  // other allocated chunk at this point (eg: won't work with the Quarantine).
-  // FIXME: Make it work with UseQuarantine and tagging enabled. Internals of
-  // iterateOverChunks reads header by tagged and non-tagger pointers so one of
-  // them will fail.
-  if (!UseQuarantine) {
-    std::vector<void *> V;
-    for (scudo::uptr I = 0; I < 64U; I++)
-      V.push_back(Allocator->allocate(
-          static_cast<scudo::uptr>(std::rand()) %
-              (TypeParam::Primary::SizeClassMap::MaxSize / 2U),
-          Origin));
-    Allocator->disable();
-    Allocator->iterateOverChunks(
-        0U, static_cast<scudo::uptr>(SCUDO_MMAP_RANGE_SIZE - 1),
-        [](uintptr_t Base, UNUSED size_t Size, void *Arg) {
-          std::vector<void *> *V = reinterpret_cast<std::vector<void *> *>(Arg);
-          void *P = reinterpret_cast<void *>(Base);
-          EXPECT_NE(std::find(V->begin(), V->end(), P), V->end());
-        },
-        reinterpret_cast<void *>(&V));
-    Allocator->enable();
-    for (auto P : V)
-      Allocator->deallocate(P, Origin);
-  }
+  // other allocated chunk at this point.
+  std::vector<void *> V;
+  for (scudo::uptr I = 0; I < 64U; I++)
+    V.push_back(Allocator->allocate(
+        static_cast<scudo::uptr>(std::rand()) %
+            (TypeParam::Primary::SizeClassMap::MaxSize / 2U),
+        Origin));
+  Allocator->disable();
+  Allocator->iterateOverChunks(
+      0U, static_cast<scudo::uptr>(SCUDO_MMAP_RANGE_SIZE - 1),
+      [](uintptr_t Base, UNUSED size_t Size, void *Arg) {
+        std::vector<void *> *V = reinterpret_cast<std::vector<void *> *>(Arg);
+        void *P = reinterpret_cast<void *>(Base);
+        EXPECT_NE(std::find(V->begin(), V->end(), P), V->end());
+      },
+      reinterpret_cast<void *>(&V));
+  Allocator->enable();
+  for (auto P : V)
+    Allocator->deallocate(P, Origin);
 }
 
 SCUDO_TYPED_TEST(ScudoCombinedDeathTest, UseAfterFree) {
@@ -1161,3 +1155,34 @@ TEST(ScudoCombinedTest, QuarantineDisabled) {
   // No quarantine stats should not be present.
   EXPECT_EQ(Stats.find("Stats: Quarantine"), std::string::npos);
 }
+
+// Verify that no special quarantine blocks appear in iterateOverChunks.
+TEST(ScudoCombinedTest, QuarantineIterateOverChunks) {
+  using AllocatorT = scudo::Allocator<TestQuarantineConfig>;
+  auto Allocator = std::unique_ptr<AllocatorT>(new AllocatorT());
+
+  // Do a bunch of allocations and deallocations. At the end there should
+  // be no special quarantine blocks in our callbacks, and no blocks at all.
+  std::vector<scudo::uptr> Sizes = {128, 128, 256, 256};
+  for (auto const Size : Sizes) {
+    void *Ptr = Allocator->allocate(Size, Origin);
+    EXPECT_NE(Ptr, nullptr);
+    Allocator->deallocate(Ptr, Origin);
+  }
+  std::unordered_map<uintptr_t, size_t> Pointers;
+  Allocator->disable();
+  Allocator->iterateOverChunks(
+      0, static_cast<scudo::uptr>(SCUDO_MMAP_RANGE_SIZE - 1),
+      [](uintptr_t Base, size_t Size, void *Arg) {
+        std::unordered_map<uintptr_t, size_t> *Pointers =
+            reinterpret_cast<std::unordered_map<uintptr_t, size_t> *>(Arg);
+        (*Pointers)[Base] = Size;
+      },
+      reinterpret_cast<void *>(&Pointers));
+  Allocator->enable();
+
+  for (const auto [Base, Size] : Pointers) {
+    EXPECT_TRUE(false) << "Unexpected pointer found in iterateOverChunks "
+                       << std::hex << Base << " Size " << std::dec << Size;
+  }
+}