From 599fd0f023181c0a484df2a18cf1d75a3553852e Mon Sep 17 00:00:00 2001
From: Roman Siromakha <elsid.mail@gmail.com>
Date: Sun, 28 Jan 2024 19:26:50 +0100
Subject: [PATCH 32/36] Fix out of bounds access in dtMergeCorridorStartMoved
 and add tests (#635)

size can become negative if req > maxPath. This may happen when visited buffer is larger than path buffer.

Add tests to cover different use cases of the function including Should add visited points not present in path up to the path capacity to cover the fix.

List tests files explicitly. When new file is added CMake does not add it to the already generated list if GLOB is used.
---
 DetourCrowd/Source/DetourPathCorridor.cpp     |  10 +-
 RecastDemo/premake5.lua                       |   3 +-
 Tests/CMakeLists.txt                          |  15 ++-
 .../DetourCrowd/Tests_DetourPathCorridor.cpp  | 119 ++++++++++++++++++
 4 files changed, 136 insertions(+), 11 deletions(-)
 create mode 100644 Tests/DetourCrowd/Tests_DetourPathCorridor.cpp

diff --git a/DetourCrowd/Source/DetourPathCorridor.cpp b/DetourCrowd/Source/DetourPathCorridor.cpp
index bddea5a..3835a38 100644
--- a/DetourCrowd/Source/DetourPathCorridor.cpp
+++ b/DetourCrowd/Source/DetourPathCorridor.cpp
@@ -59,13 +59,13 @@ int dtMergeCorridorStartMoved(dtPolyRef* path, const int npath, const int maxPat
 	int size = dtMax(0, npath-orig);
 	if (req+size > maxPath)
 		size = maxPath-req;
-	if (size)
+	if (size > 0)
 		memmove(path+req, path+orig, size*sizeof(dtPolyRef));
-	
+
 	// Store visited
-	for (int i = 0; i < req; ++i)
-		path[i] = visited[(nvisited-1)-i];				
-	
+	for (int i = 0, n = dtMin(req, maxPath); i < n; ++i)
+		path[i] = visited[(nvisited-1)-i];
+
 	return req+size;
 }
 
diff --git a/RecastDemo/premake5.lua b/RecastDemo/premake5.lua
index 7ede4d6..826859e 100644
--- a/RecastDemo/premake5.lua
+++ b/RecastDemo/premake5.lua
@@ -223,14 +223,15 @@ project "Tests"
 		"../Tests/Recast/*.cpp",
 		"../Tests/Detour/*.h",
 		"../Tests/Detour/*.cpp",
+		"../Tests/DetourCrowd/*.cpp",
 		"../Tests/Contrib/catch2/*.cpp"
 	}
 
 	-- project dependencies
 	links { 
 		"DebugUtils",
-		"Detour",
 		"DetourCrowd",
+		"Detour",
 		"DetourTileCache",
 		"Recast",
 	}
diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 9a87479..c37a6c9 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -1,14 +1,19 @@
-file(GLOB TESTS_SOURCES Detour/*.cpp Recast/*.cpp)
-
 include_directories(../Detour/Include)
 include_directories(../Recast/Include)
 
-add_executable(Tests ${TESTS_SOURCES})
+add_executable(Tests
+	Detour/Tests_Detour.cpp
+	Recast/Bench_rcVector.cpp
+	Recast/Tests_Alloc.cpp
+	Recast/Tests_Recast.cpp
+	Recast/Tests_RecastFilter.cpp
+	DetourCrowd/Tests_DetourPathCorridor.cpp
+)
 
 set_property(TARGET Tests PROPERTY CXX_STANDARD 17)
 
-add_dependencies(Tests Recast Detour)
-target_link_libraries(Tests Recast Detour)
+add_dependencies(Tests Recast Detour DetourCrowd)
+target_link_libraries(Tests Recast Detour DetourCrowd)
 
 find_package(Catch2 QUIET)
 if (Catch2_FOUND)
diff --git a/Tests/DetourCrowd/Tests_DetourPathCorridor.cpp b/Tests/DetourCrowd/Tests_DetourPathCorridor.cpp
new file mode 100644
index 0000000..1c199cb
--- /dev/null
+++ b/Tests/DetourCrowd/Tests_DetourPathCorridor.cpp
@@ -0,0 +1,119 @@
+#include "catch2/catch_all.hpp"
+
+#include "DetourPathCorridor.h"
+
+TEST_CASE("dtMergeCorridorStartMoved")
+{
+    SECTION("Should handle empty input")
+    {
+        dtPolyRef* const path = nullptr;
+        const int npath = 0;
+        const int maxPath = 0;
+        const dtPolyRef* const visited = nullptr;
+        const int nvisited = 0;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 0);
+    }
+
+    SECTION("Should handle empty visited")
+    {
+        dtPolyRef path[] = {1};
+        const int npath = 1;
+        const int maxPath = 1;
+        const dtPolyRef* const visited = nullptr;
+        const int nvisited = 0;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 1);
+        const dtPolyRef expectedPath[] = {1};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+
+    SECTION("Should handle empty path")
+    {
+        dtPolyRef* const path = nullptr;
+        const int npath = 0;
+        const int maxPath = 0;
+        const dtPolyRef visited[] = {1};
+        const int nvisited = 1;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 0);
+    }
+
+    SECTION("Should strip visited points from path except last")
+    {
+        dtPolyRef path[] = {1, 2};
+        const int npath = 2;
+        const int maxPath = 2;
+        const dtPolyRef visited[] = {1, 2};
+        const int nvisited = 2;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 1);
+        const dtPolyRef expectedPath[] = {2, 2};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+
+    SECTION("Should add visited points not present in path in reverse order")
+    {
+        dtPolyRef path[] = {1, 2, 0};
+        const int npath = 2;
+        const int maxPath = 3;
+        const dtPolyRef visited[] = {1, 2, 3, 4};
+        const int nvisited = 4;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 3);
+        const dtPolyRef expectedPath[] = {4, 3, 2};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+
+    SECTION("Should add visited points not present in path up to the path capacity")
+    {
+        dtPolyRef path[] = {1, 2, 0};
+        const int npath = 2;
+        const int maxPath = 3;
+        const dtPolyRef visited[] = {1, 2, 3, 4, 5};
+        const int nvisited = 5;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 3);
+        const dtPolyRef expectedPath[] = {5, 4, 3};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+
+    SECTION("Should not change path if there is no intersection with visited")
+    {
+        dtPolyRef path[] = {1, 2};
+        const int npath = 2;
+        const int maxPath = 2;
+        const dtPolyRef visited[] = {3, 4};
+        const int nvisited = 2;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 2);
+        const dtPolyRef expectedPath[] = {1, 2};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+
+    SECTION("Should save unvisited path points")
+    {
+        dtPolyRef path[] = {1, 2, 0};
+        const int npath = 2;
+        const int maxPath = 3;
+        const dtPolyRef visited[] = {1, 3};
+        const int nvisited = 2;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 3);
+        const dtPolyRef expectedPath[] = {3, 1, 2};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+
+    SECTION("Should save unvisited path points up to the path capacity")
+    {
+        dtPolyRef path[] = {1, 2};
+        const int npath = 2;
+        const int maxPath = 2;
+        const dtPolyRef visited[] = {1, 3};
+        const int nvisited = 2;
+        const int result = dtMergeCorridorStartMoved(path, npath, maxPath, visited, nvisited);
+        CHECK(result == 2);
+        const dtPolyRef expectedPath[] = {3, 1};
+        CHECK_THAT(path, Catch::Matchers::RangeEquals(expectedPath));
+    }
+}
-- 
2.43.0

