Fix interconnection udpifc UAF in ipc teardown

contrib/interconnect/ic_internal.h

@@ -165,7 +165,15 @@ typedef struct ChunkTransportStateEntry
 	int			motNodeId;
 	bool		valid;
 
-	/* Connection array */
+	/* Connection array
+	 *
+	 * MUST pay attention: use getMotionConn to get MotionConn.
+	 * must not use `->conns[index]` to get MotionConn. Because the struct
+	 * MotionConn is a base structure for MotionConnTCP and
+	 * MotionConnUDP. After connection setup, the `conns` will be fill
+	 * with MotionConnUDP/MotionConnTCP, but the pointer still is
+	 * MotionConn which should use `CONTAINER_OF` to get the real object.
+	 */
 	MotionConn *conns;
 	int			numConns;
 

contrib/interconnect/udp/ic_udpifc.c

@@ -3413,10 +3413,13 @@ static bool
 chunkTransportStateEntryInitialized(ChunkTransportState *transportStates,
 									int16 motNodeID)
 {
-	if (motNodeID > transportStates->size || !transportStates->states[motNodeID - 1].valid)
+	ChunkTransportStateEntry *pEntry = NULL;
+	if (motNodeID > transportStates->size) {
 		return false;
+	}
 
-	return true;
+	getChunkTransportStateNoValid(transportStates, motNodeID, &pEntry);
+	return pEntry->valid;
 }
 
 /*

src/include/cdb/cdbinterconnect.h

@@ -192,7 +192,16 @@ typedef struct MotionConnSentRecordTypmodEnt
 
 typedef struct ChunkTransportState
 {
-	/* array of per-motion-node chunk transport state */
+	/* array of per-motion-node chunk transport state
+	 *
+	 * MUST pay attention: use getChunkTransportStateNoValid/getChunkTransportState
+	 * to get ChunkTransportStateEntry.
+	 * must not use `->states[index]` to get ChunkTransportStateEntry. Because the struct
+	 * ChunkTransportStateEntry is a base structure for ChunkTransportStateEntryTCP and
+	 * ChunkTransportStateEntryUDP. After interconnect setup, the `states` will be fill
+	 * with EntryUDP/EntryTCP, but the pointer still is ChunkTransportStateEntry which
+	 * should use `CONTAINER_OF` to get the real object.
+	 */
 	int size;
 	struct ChunkTransportStateEntry *states;