CVE: CVE-2019-19923 Upstream-Status: Backport Signed-off-by: Ross Burton From b64463719dc53bde98b0ce3930b10a32560c3a02 Mon Sep 17 00:00:00 2001 From: "D. Richard Hipp" Date: Wed, 18 Dec 2019 20:51:58 +0000 Subject: [PATCH] Continue to back away from the LEFT JOIN optimization of check-in [41c27bc0ff1d3135] by disallowing query flattening if the outer query is DISTINCT. Without this fix, if an index scan is run on the table within the view on the right-hand side of the LEFT JOIN, stale result registers might be accessed yielding incorrect results, and/or an OP_IfNullRow opcode might be invoked on the un-opened table, resulting in a NULL-pointer dereference. This problem was found by the Yongheng and Rui fuzzer. FossilOrigin-Name: 862974312edf00e9d1068115d1a39b7235b7db68b6d86b81d38a12f025a4748e --- sqlite3.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/sqlite3.c b/sqlite3.c index d29da07..5bc06c8 100644 --- a/sqlite3.c +++ b/sqlite3.c @@ -129216,6 +129216,7 @@ static void substSelect( ** (3b) the FROM clause of the subquery may not contain a virtual ** table and ** (3c) the outer query may not be an aggregate. +** (3d) the outer query may not be DISTINCT. ** ** (4) The subquery can not be DISTINCT. ** @@ -129412,8 +129413,11 @@ static int flattenSubquery( */ if( (pSubitem->fg.jointype & JT_OUTER)!=0 ){ isLeftJoin = 1; - if( pSubSrc->nSrc>1 || isAgg || IsVirtual(pSubSrc->a[0].pTab) ){ - /* (3a) (3c) (3b) */ + if( pSubSrc->nSrc>1 /* (3a) */ + || isAgg /* (3b) */ + || IsVirtual(pSubSrc->a[0].pTab) /* (3c) */ + || (p->selFlags & SF_Distinct)!=0 /* (3d) */ + ){ return 0; } } -- 2.24.1