From ec3481ed13254ecdec32acf7a0fafd536ec77aff Mon Sep 17 00:00:00 2001
From: Marios Trivyzas <matriv@gmail.com>
Date: Mon, 16 Mar 2020 13:49:48 +0100
Subject: [PATCH] SQL: Fix NPE for parameterized LIKE/RLIKE (#53573)

Fix NPE when `null` is passed as a parameter for a parameterized
pattern of LIKE/RLIKE. e.g.: `field LIKE ?` params=[null]`
Check for null pattern in LIKE/RLIKE as for RLIKE (RegexpQuery) we
get an IllegalArgumentExpression from Lucence but for LIKE
(WildcardQuery) we get an NPE.

Fixes: #53557
---
 .../xpack/sql/parser/ExpressionBuilder.java            |  3 +++
 .../xpack/sql/parser/ExpressionTests.java              | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/parser/ExpressionBuilder.java b/x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/parser/ExpressionBuilder.java
index bf8b22d8a39d5..671d90fbd54f6 100644
--- a/x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/parser/ExpressionBuilder.java
+++ b/x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/parser/ExpressionBuilder.java
@@ -264,6 +264,9 @@ public LikePattern visitPattern(PatternContext ctx) {
         }
 
         String pattern = string(ctx.value);
+        if (pattern == null) {
+            throw new ParsingException(source(ctx.value), "Pattern must not be [null]");
+        }
         int pos = pattern.indexOf('*');
         if (pos >= 0) {
             throw new ParsingException(source(ctx.value),
diff --git a/x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/parser/ExpressionTests.java b/x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/parser/ExpressionTests.java
index ad2d3066e121f..6211f40e0f0e5 100644
--- a/x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/parser/ExpressionTests.java
+++ b/x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/parser/ExpressionTests.java
@@ -21,16 +21,19 @@
 import org.elasticsearch.xpack.sql.expression.predicate.operator.arithmetic.Add;
 import org.elasticsearch.xpack.sql.expression.predicate.operator.arithmetic.Mul;
 import org.elasticsearch.xpack.sql.expression.predicate.operator.arithmetic.Sub;
+import org.elasticsearch.xpack.sql.proto.SqlTypedParamValue;
 
 import java.time.Duration;
 import java.time.Period;
 import java.time.temporal.TemporalAmount;
+import java.util.Collections;
 import java.util.Locale;
 
 import static java.lang.String.format;
 import static org.elasticsearch.xpack.ql.type.DataTypes.BOOLEAN;
 import static org.elasticsearch.xpack.ql.type.DataTypes.DOUBLE;
 import static org.elasticsearch.xpack.ql.type.DataTypes.INTEGER;
+import static org.elasticsearch.xpack.ql.type.DataTypes.KEYWORD;
 import static org.elasticsearch.xpack.ql.type.DataTypes.LONG;
 import static org.hamcrest.Matchers.startsWith;
 
@@ -542,4 +545,11 @@ public void testCaseWithOperand() {
         assertEquals("WHEN 1 THEN 'one'", ifc.sourceText());
         assertEquals("many", c.elseResult().toString());
     }
+
+    public void testLikePatternWithNullParameterNotAllowed() {
+        ParsingException e = expectThrows(ParsingException.class,
+                () -> parser.createExpression("a LIKE ?",
+                    Collections.singletonList(new SqlTypedParamValue(KEYWORD.typeName(), null))));
+        assertEquals("line 1:9: Pattern must not be [null]", e.getMessage());
+    }
 }