Merge bitcoin/bitcoin#32581: allocators: Apply manual ASan poisoning to PoolResource

ad132761fc [allocators] Apply manual ASan poisoning to PoolResource (dergoegge)

Pull request description:

  Currently ASan will not detect use-after-free issues for memory allocated by a `PoolResource`. This is because ASan is only aware of the memory chunks allocated by `PoolResource` but not the individual "sub-chunks" within.

  E.g. this test will not produce an ASan error even though the referenced coin has been deallocated:

  ```c++
  diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
  index c46144b34b..aa6ca15ce1 100644
  --- a/src/test/coins_tests.cpp
  +++ b/src/test/coins_tests.cpp
  @@ -508,6 +508,17 @@ BOOST_FIXTURE_TEST_CASE(updatecoins_simulation_test, UpdateTest)
       BOOST_CHECK(spent_a_duplicate_coinbase);
   }

  +BOOST_AUTO_TEST_CASE(asan_uaf)
  +{
  +    CCoinsMapMemoryResource cache_coins_memory_resource{};
  +    CCoinsMap map(0, SaltedOutpointHasher(/*deterministic=*/true), CCoinsMap::key_equal{}, &cache_coins_memory_resource);
  +    COutPoint outpoint{};
  +    map.emplace(outpoint, Coin{});
  +    auto& coin = map.at(outpoint);
  +    map.erase(outpoint);
  +    coin.coin.nHeight = 1;
  +}
  +
   BOOST_AUTO_TEST_CASE(ccoins_serialization)
   {
       // Good example
  ```

  Fix this by applying [manual ASan poisoning](https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning) for memory allocated by `PoolResource`:

  * Newly allocated chunks are poisoned as a whole
  * "Sub-chunks" are unpoisoned/re-poisoned during allocation/deallocation

  With the poisoning applied, ASan catches the issue in the test above:
  ```
  $ ./build_unit/bin/test_bitcoin --run_test="coins_tests/asan_uaf"
  Running 1 test case...
  =================================================================
  ==366064==ERROR: AddressSanitizer: use-after-poison on address 0x7f99c3204870 at pc 0x55569dab6f8a bp 0x7ffe0210e4d0 sp 0x7ffe0210e4c8
  READ of size 4 at 0x7f99c3204870 thread T0 (b-test)
  ```

ACKs for top commit:
  achow101:
    ACK ad132761fc
  marcofleon:
    code review ACK ad132761fc

Tree-SHA512: eb5e80bfa9509225e784151807bd8aa21fb0826ca1781dfe81b1d60bd3766019384ea3f9cb8e53398fde2f4e994a9c201b5a9962b4d279d7e52bb60e8961be11

src/support/allocators/pool.h

@@ -14,6 +14,8 @@
 #include <type_traits>
 #include <utility>
 
+#include <util/check.h>
+
 /**
  * A memory resource similar to std::pmr::unsynchronized_pool_resource, but
  * optimized for node-based containers. It has the following properties:
@@ -155,12 +157,15 @@ class PoolResource final
         // if there is still any available memory left, put it into the freelist.
         size_t remaining_available_bytes = std::distance(m_available_memory_it, m_available_memory_end);
         if (0 != remaining_available_bytes) {
+            ASAN_UNPOISON_MEMORY_REGION(m_available_memory_it, sizeof(ListNode));
             PlacementAddToList(m_available_memory_it, m_free_lists[remaining_available_bytes / ELEM_ALIGN_BYTES]);
+            ASAN_POISON_MEMORY_REGION(m_available_memory_it, sizeof(ListNode));
         }
 
         void* storage = ::operator new (m_chunk_size_bytes, std::align_val_t{ELEM_ALIGN_BYTES});
         m_available_memory_it = new (storage) std::byte[m_chunk_size_bytes];
         m_available_memory_end = m_available_memory_it + m_chunk_size_bytes;
+        ASAN_POISON_MEMORY_REGION(m_available_memory_it, m_chunk_size_bytes);
         m_allocated_chunks.emplace_back(m_available_memory_it);
     }
 
@@ -202,6 +207,7 @@ public:
         for (std::byte* chunk : m_allocated_chunks) {
             std::destroy(chunk, chunk + m_chunk_size_bytes);
             ::operator delete ((void*)chunk, std::align_val_t{ELEM_ALIGN_BYTES});
+            ASAN_UNPOISON_MEMORY_REGION(chunk, m_chunk_size_bytes);
         }
     }
 
@@ -217,7 +223,11 @@ public:
                 // we've already got data in the pool's freelist, unlink one element and return the pointer
                 // to the unlinked memory. Since FreeList is trivially destructible we can just treat it as
                 // uninitialized memory.
-                return std::exchange(m_free_lists[num_alignments], m_free_lists[num_alignments]->m_next);
+                ASAN_UNPOISON_MEMORY_REGION(m_free_lists[num_alignments], sizeof(ListNode));
+                auto* next{m_free_lists[num_alignments]->m_next};
+                ASAN_POISON_MEMORY_REGION(m_free_lists[num_alignments], sizeof(ListNode));
+                ASAN_UNPOISON_MEMORY_REGION(m_free_lists[num_alignments], bytes);
+                return std::exchange(m_free_lists[num_alignments], next);
             }
 
             // freelist is empty: get one allocation from allocated chunk memory.
@@ -228,6 +238,7 @@ public:
             }
 
             // Make sure we use the right amount of bytes for that freelist (might be rounded up),
+            ASAN_UNPOISON_MEMORY_REGION(m_available_memory_it, round_bytes);
             return std::exchange(m_available_memory_it, m_available_memory_it + round_bytes);
         }
 
@@ -244,7 +255,9 @@ public:
             const std::size_t num_alignments = NumElemAlignBytes(bytes);
             // put the memory block into the linked list. We can placement construct the FreeList
             // into the memory since we can be sure the alignment is correct.
+            ASAN_UNPOISON_MEMORY_REGION(p, sizeof(ListNode));
             PlacementAddToList(p, m_free_lists[num_alignments]);
+            ASAN_POISON_MEMORY_REGION(p, std::max(bytes, sizeof(ListNode)));
         } else {
             // Can't use the pool => forward deallocation to ::operator delete().
             ::operator delete (p, std::align_val_t{alignment});

src/test/util/poolresourcetester.h

@@ -6,6 +6,7 @@
 #define BITCOIN_TEST_UTIL_POOLRESOURCETESTER_H
 
 #include <support/allocators/pool.h>
+#include <util/check.h>
 
 #include <algorithm>
 #include <cassert>
@@ -48,7 +49,10 @@ public:
             size_t size = 0;
             while (ptr != nullptr) {
                 ++size;
+                const auto* ptr_ = ptr;
+                ASAN_UNPOISON_MEMORY_REGION(ptr_, sizeof(typename PoolResource<MAX_BLOCK_SIZE_BYTES, ALIGN_BYTES>::ListNode));
                 ptr = ptr->m_next;
+                ASAN_POISON_MEMORY_REGION(ptr_, sizeof(typename PoolResource<MAX_BLOCK_SIZE_BYTES, ALIGN_BYTES>::ListNode));
             }
             sizes.push_back(size);
         }
@@ -81,7 +85,10 @@ public:
             auto* ptr = resource.m_free_lists[freelist_idx];
             while (ptr != nullptr) {
                 free_blocks.emplace_back(ptr, bytes);
+                const auto* ptr_ = ptr;
+                ASAN_UNPOISON_MEMORY_REGION(ptr_, sizeof(typename PoolResource<MAX_BLOCK_SIZE_BYTES, ALIGN_BYTES>::ListNode));
                 ptr = ptr->m_next;
+                ASAN_POISON_MEMORY_REGION(ptr_, sizeof(typename PoolResource<MAX_BLOCK_SIZE_BYTES, ALIGN_BYTES>::ListNode));
             }
         }
         // also add whatever has not yet been used for blocks

src/util/check.h

@@ -126,4 +126,15 @@ constexpr T&& inline_assertion_check(LIFETIMEBOUND T&& val, [[maybe_unused]] con
 
 // NOLINTEND(bugprone-lambda-function-name)
 
+#if defined(__has_feature)
+#    if __has_feature(address_sanitizer)
+#       include <sanitizer/asan_interface.h>
+#    endif
+#endif
+
+#ifndef ASAN_POISON_MEMORY_REGION
+#   define ASAN_POISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
+#   define ASAN_UNPOISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
+#endif
+
 #endif // BITCOIN_UTIL_CHECK_H