From 4c87010981f3a9a41751e5550f6eb889ab5667e8 Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Mon, 20 Jan 2020 10:36:35 +0200
Subject: [PATCH] Fix crash in BRIN inclusion op functions, due to missing
datum copy.
The BRIN add_value() and union() functions need to make a longer-lived
copy of the argument, if they want to store it in the BrinValues struct
also passed as argument. The functions for the "inclusion operator
classes" used with box, range and inet types didn't take into account
that the union helper function might return its argument as is, without
making a copy. Check for that case, and make a copy if necessary. That
case arises at least with the range_union() function, when one of the
arguments is an 'empty' range:
CREATE TABLE brintest (n numrange);
CREATE INDEX brinidx ON brintest USING brin (n);
INSERT INTO brintest VALUES ('empty');
INSERT INTO brintest VALUES (numrange(0, 2^1000::numeric));
INSERT INTO brintest VALUES ('(-1, 0)');
SELECT brin_desummarize_range('brinidx', 0);
SELECT brin_summarize_range('brinidx', 0);
Backpatch down to 9.5, where BRIN was introduced.
Discussion: https://www.postgresql.org/message-id/e6e1d6eb-0a67-36aa-e779-bcca59167c14%40iki.fi
Reviewed-by: Emre Hasegeli, Tom Lane, Alvaro Herrera
---
src/backend/access/brin/brin_inclusion.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/src/backend/access/brin/brin_inclusion.c b/src/backend/access/brin/brin_inclusion.c
index fb7cbdb5fc5..7e380d66ed5 100644
--- a/src/backend/access/brin/brin_inclusion.c
+++ b/src/backend/access/brin/brin_inclusion.c
@@ -235,8 +235,14 @@ brin_inclusion_add_value(PG_FUNCTION_ARGS)
Assert(finfo != NULL);
result = FunctionCall2Coll(finfo, colloid,
column->bv_values[INCLUSION_UNION], newval);
- if (!attr->attbyval)
+ if (!attr->attbyval &&
+ DatumGetPointer(result) != DatumGetPointer(column->bv_values[INCLUSION_UNION]))
+ {
pfree(DatumGetPointer(column->bv_values[INCLUSION_UNION]));
+
+ if (result == newval)
+ result = datumCopy(result, attr->attbyval, attr->attlen);
+ }
column->bv_values[INCLUSION_UNION] = result;
PG_RETURN_BOOL(true);
@@ -574,8 +580,14 @@ brin_inclusion_union(PG_FUNCTION_ARGS)
result = FunctionCall2Coll(finfo, colloid,
col_a->bv_values[INCLUSION_UNION],
col_b->bv_values[INCLUSION_UNION]);
- if (!attr->attbyval)
+ if (!attr->attbyval &&
+ DatumGetPointer(result) != DatumGetPointer(col_a->bv_values[INCLUSION_UNION]))
+ {
pfree(DatumGetPointer(col_a->bv_values[INCLUSION_UNION]));
+
+ if (result == col_b->bv_values[INCLUSION_UNION])
+ result = datumCopy(result, attr->attbyval, attr->attlen);
+ }
col_a->bv_values[INCLUSION_UNION] = result;
PG_RETURN_VOID();
--
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