From 2489c38cdc58bdd2f181651e741440bb6b83e80b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 3 Nov 2022 12:01:57 -0400
Subject: [PATCH] Avoid crash after function syntax error in a replication
worker.
If a syntax error occurred in a SQL-language or PL/pgSQL-language
CREATE FUNCTION or DO command executed in a logical replication worker,
we'd suffer a null pointer dereference or assertion failure. That
seems like a rather contrived case, but nonetheless worth fixing.
The cause is that function_parse_error_transpose assumes it must be
executing within the context of a Portal, but logical/worker.c
doesn't create a Portal since it's not running the standard executor.
We can just back off the hard Assert check and make it fail gracefully
if there's not an ActivePortal. (I have a feeling that the aggressive
check here was my fault originally, probably because I wasn't sure if
the case would always hold and wanted to find out. Well, now we know.)
The hazard seems to exist in all branches that have logical replication,
so back-patch to v10.
Maxim Orlov, Anton Melnikov, Masahiko Sawada, Tom Lane
Discussion: https://postgr.es/m/b570c367-ba38-95f3-f62d-5f59b9808226@inbox.ru
Discussion: https://postgr.es/m/adf0452f-8c6b-7def-d35e-ab516c80088e@inbox.ru
---
src/backend/catalog/pg_proc.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index 25d35230d02..98c47a5db6b 100644
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -1012,7 +1012,6 @@ function_parse_error_transpose(const char *prosrc)
{
int origerrposition;
int newerrposition;
- const char *queryText;
/*
* Nothing to do unless we are dealing with a syntax error that has a
@@ -1030,11 +1029,22 @@ function_parse_error_transpose(const char *prosrc)
}
/* We can get the original query text from the active portal (hack...) */
- Assert(ActivePortal && ActivePortal->status == PORTAL_ACTIVE);
- queryText = ActivePortal->sourceText;
+ if (ActivePortal && ActivePortal->status == PORTAL_ACTIVE)
+ {
+ const char *queryText = ActivePortal->sourceText;
- /* Try to locate the prosrc in the original text */
- newerrposition = match_prosrc_to_query(prosrc, queryText, origerrposition);
+ /* Try to locate the prosrc in the original text */
+ newerrposition = match_prosrc_to_query(prosrc, queryText,
+ origerrposition);
+ }
+ else
+ {
+ /*
+ * Quietly give up if no ActivePortal. This is an unusual situation
+ * but it can happen in, e.g., logical replication workers.
+ */
+ newerrposition = -1;
+ }
if (newerrposition > 0)
{