Fix an out-of-bounds read in the OPTIONAL JOIN implementation (#1710)

ad-freiburg · Jan 23, 2025 · 6f6e0c4 · 6f6e0c4
1 parent 2cf878c
commit 6f6e0c4
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diff --git a/src/util/JoinAlgorithms/JoinAlgorithms.h b/src/util/JoinAlgorithms/JoinAlgorithms.h
@@ -491,6 +491,9 @@ void specialOptionalJoin(
       elFromFirstNotFoundAction(it);
     }
     it1 = next1;
+    if (it1 == end1) {
+      break;
+    }
 
     checkCancellation();
 

diff --git a/test/EngineTest.cpp b/test/EngineTest.cpp
@@ -278,6 +278,18 @@ TEST(OptionalJoin, specialOptionalJoinTwoColumns) {
     IdTable expectedResult = makeIdTableFromVector(
         {{4, 1, 2, U}, {2, 1, 3, 3}, {1, 1, 4, U}, {2, 2, 2, 4}, {1, 3, 1, 1}});
 
+    testOptionalJoin(a, b, jcls, expectedResult);
+  }
+  {
+    // Test a corner case that previously contained a bug.
+    IdTable a{makeIdTableFromVector({{4, U, 2}})};
+    IdTable b{makeIdTableFromVector({{3, 3, 1}})};
+    // Join a and b on the column pairs 1,2 and 2,1 (entries from columns 1 of
+    // a have to equal those of column 2 of b and vice versa).
+    JoinColumns jcls{{1, 2}, {2, 1}};
+
+    IdTable expectedResult = makeIdTableFromVector({{4, U, 2, U}});
+
     testOptionalJoin(a, b, jcls, expectedResult);
   }
 }