From f555312151f716b54558776bce53bef9edb69d3a Mon Sep 17 00:00:00 2001
From: guiyao <guiyao@huawei.com>
Date: Mon, 14 Oct 2019 05:23:59 -0400
Subject: [PATCH] fix CVE-2019-16168

---
 src/analyze.c      |  4 +++-
 src/where.c        |  1 +
 test/analyzeC.test | 13 +++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/analyze.c b/src/analyze.c
index 48fd495..552330b 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -1497,7 +1497,9 @@ static void decodeIntArray(
       if( sqlite3_strglob("unordered*", z)==0 ){
         pIndex->bUnordered = 1;
       }else if( sqlite3_strglob("sz=[0-9]*", z)==0 ){
-        pIndex->szIdxRow = sqlite3LogEst(sqlite3Atoi(z+3));
+        int sz = sqlite3Atoi(z+3);
+        if( sz<2 ) sz = 2;
+        pIndex->szIdxRow = sqlite3LogEst(sz);
       }else if( sqlite3_strglob("noskipscan*", z)==0 ){
         pIndex->noSkipScan = 1;
       }
diff --git a/src/where.c b/src/where.c
index b83915e..1df9b46 100644
--- a/src/where.c
+++ b/src/where.c
@@ -2585,6 +2585,7 @@ static int whereLoopAddBtreeIndex(
     ** it to pNew->rRun, which is currently set to the cost of the index
     ** seek only. Then, if this is a non-covering index, add the cost of
     ** visiting the rows in the main table.  */
+    assert( pSrc->pTab->szTabRow>0 );
     rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow;
     pNew->rRun = sqlite3LogEstAdd(rLogSize, rCostIdx);
     if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
diff --git a/test/analyzeC.test b/test/analyzeC.test
index 02faa9c..246da89 100644
--- a/test/analyzeC.test
+++ b/test/analyzeC.test
@@ -132,6 +132,19 @@ do_execsql_test 4.3 {
   SELECT count(a) FROM t1;
 } {/.*INDEX t1ca.*/}
 
+# 2019-08-15.
+# Ticket https://www.sqlite.org/src/tktview/e4598ecbdd18bd82945f602901
+# The sz=N parameter in the sqlite_stat1 table needs to have a value of
+# 2 or more to avoid a division by zero in the query planner.
+#
+do_execsql_test 4.4 {
+  DROP TABLE IF EXISTS t44;
+  CREATE TABLE t44(a PRIMARY KEY);
+  INSERT INTO sqlite_stat1 VALUES('t44',null,'sz=0');
+  ANALYZE sqlite_master;
+  SELECT 0 FROM t44 WHERE a IN(1,2,3);
+} {}
+
 
 # The sz=NNN parameter works even if there is other extraneous text
 # in the sqlite_stat1.stat column.
-- 
1.8.3.1

