Fix out-of-bounds read in GCP core_vertex_ids

.github/workflows/coverage.yml

@@ -79,7 +79,7 @@ jobs:
           cd build
           ctest --verbose -j ${{ steps.cpu-cores.outputs.count }}
           lcov --directory . --capture --output-file coverage.info --ignore-errors inconsistent,format,gcov,mismatch
-          lcov --remove coverage.info --ignore-errors unused '/usr/*' "$HOME/.cache/*" "*tests/*" --output-file coverage.info
+          lcov --remove coverage.info --ignore-errors unused,inconsistent '/usr/*' "$HOME/.cache/*" "*tests/*" --output-file coverage.info
 
       - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v7

cmake/recipes/finite_diff.cmake

@@ -9,5 +9,16 @@ message(STATUS "Third-party: creating target 'finitediff::finitediff'")
 include(CPM)
 CPMAddPackage("gh:zfergus/finite-diff@1.0.4")
 
+# ipc_toolkit compiles with EIGEN_DONT_VECTORIZE=1 when SIMD is enabled, which
+# changes how Eigen aligns and allocates matrices. finite-diff takes matrices
+# that our lambdas allocate and then reshapes and frees them inside its own
+# library code. If the two sides disagree about alignment, the library either
+# trips Eigen's "data is not aligned" assert (Debug) or frees a pointer that
+# was never allocated with Eigen's aligned allocator (Release). We make the
+# define PUBLIC so both sides always agree, the same way we do for MeshFEMSparse.
+if(IPC_TOOLKIT_WITH_SIMD)
+    target_compile_definitions(finitediff_finitediff PUBLIC EIGEN_DONT_VECTORIZE=1)
+endif()
+
 # Folder name for IDE
 set_target_properties(finitediff_finitediff PROPERTIES FOLDER "ThirdParty")

cmake/recipes/scalable_ccd.cmake

@@ -8,7 +8,7 @@ message(STATUS "Third-party: creating target 'scalable_ccd::scalable_ccd'")
 
 include(CPM)
 CPMAddPackage(
-    URI "gh:continuous-collision-detection/scalable-ccd#ccf4bc19aba432b9d5abdd41ae55d15ea166a0a5"
+    URI "gh:continuous-collision-detection/scalable-ccd#049d8af986c9cc115e013df7c8af791c2a513dcc"
     OPTIONS "SCALABLE_CCD_WITH_CUDA ${IPC_TOOLKIT_WITH_CUDA}"
 )
 

src/ipc/gcp/collisions/gcp_collision.cpp

@@ -486,12 +486,19 @@ double GCPCollisionTemplate<PrimitiveA, PrimitiveB>::compute_distance(
 
 template <typename PrimitiveA, typename PrimitiveB>
 auto GCPCollisionTemplate<PrimitiveA, PrimitiveB>::core_vertex_ids() const
-    -> std::array<index_t, N_CORE_DOFS>
+    -> std::array<index_t, N_CORE_POINTS>
 {
-    std::array<index_t, N_CORE_DOFS> vids {};
-    auto ids = get_core_indices();
-    for (int i = 0; i < N_CORE_DOFS; i++) {
-        vids[i] = m_vertex_ids[ids[i]];
+    // m_vertex_ids has one entry per vertex, so we cannot index it with the
+    // DOF indices from get_core_indices(). Those run up to ELEMENT_SIZE and
+    // read past the end of the vector. Instead, we map each core point to its
+    // vertex slot: the core points are the first vertices of each primitive.
+    std::array<index_t, N_CORE_POINTS> vids {};
+    for (int i = 0; i < PrimitiveA::N_CORE_POINTS; i++) {
+        vids[i] = m_vertex_ids[i];
+    }
+    for (int i = 0; i < PrimitiveB::N_CORE_POINTS; i++) {
+        vids[PrimitiveA::N_CORE_POINTS + i] =
+            m_vertex_ids[primitive_a->n_vertices() + i];
     }
     return vids;
 }

src/ipc/gcp/collisions/gcp_collision.hpp

@@ -171,7 +171,10 @@ class GCPCollisionTemplate : public GCPCollision {
     CollisionType type() const override;
 
     Eigen::Vector<int, N_CORE_DOFS> get_core_indices() const;
-    std::array<index_t, N_CORE_DOFS> core_vertex_ids() const;
+    /// @brief Get the mesh vertex ids of the core points.
+    /// @return One vertex id per core point: the core points of primitive A
+    /// followed by those of primitive B.
+    std::array<index_t, N_CORE_POINTS> core_vertex_ids() const;
 
     int num_vertices() const override
     {