From e13ac5586c49c77f301329b79bd7e8f489d0e66f Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 17 May 2016 17:01:18 -0400
Subject: [PATCH] Avoid possible crash in contrib/bloom's blendscan().
It's possible to begin and end an indexscan without ever calling
amrescan. contrib/bloom, unlike every other index AM, allocated
its "scan->opaque" storage at amrescan time, and thus would crash
in amendscan if amrescan hadn't been called. We could fix this
by putting in a null-pointer check in blendscan, but I see no very
good reason why contrib/bloom should march to its own drummer in
this respect. Let's move that initialization to blbeginscan
instead. Per report from Jeff Janes.
---
contrib/bloom/blscan.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/contrib/bloom/blscan.c b/contrib/bloom/blscan.c
index fc82f543738..aebf32a8d2f 100644
--- a/contrib/bloom/blscan.c
+++ b/contrib/bloom/blscan.c
@@ -29,9 +29,16 @@ IndexScanDesc
blbeginscan(Relation r, int nkeys, int norderbys)
{
IndexScanDesc scan;
+ BloomScanOpaque so;
scan = RelationGetIndexScan(r, nkeys, norderbys);
+ so = (BloomScanOpaque) palloc(sizeof(BloomScanOpaqueData));
+ initBloomState(&so->state, scan->indexRelation);
+ so->sign = NULL;
+
+ scan->opaque = so;
+
return scan;
}
@@ -42,23 +49,10 @@ void
blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
ScanKey orderbys, int norderbys)
{
- BloomScanOpaque so;
-
- so = (BloomScanOpaque) scan->opaque;
-
- if (so == NULL)
- {
- /* if called from blbeginscan */
- so = (BloomScanOpaque) palloc(sizeof(BloomScanOpaqueData));
- initBloomState(&so->state, scan->indexRelation);
- scan->opaque = so;
+ BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
- }
- else
- {
- if (so->sign)
- pfree(so->sign);
- }
+ if (so->sign)
+ pfree(so->sign);
so->sign = NULL;
if (scankey && scan->numberOfKeys > 0)
--
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