[PATCH] Fix hostaddr crash during non-blocking cancellation

From 78190176b20392fa2396731d4693ebe6286679c8 Mon Sep 17 00:00:00 2001
From: Jacob Champion <jacob.champion@enterprisedb.com>
Date: Mon, 5 May 2025 14:19:10 -0700
Subject: [PATCH v1 1/2] Fix connhost type during non-blocking cancellation

PQcancelCreate() creates a deep copy of the connection's pg_conn_host,
but it missed the type field, which ended up initialized to
CHT_HOST_NAME. The type communicates which pointers in the struct are
valid, so if a connection used hostaddr without a host name (which would
normally result in a type of CHT_HOST_ADDRESS), the client would later
segfault in emitHostIdentityInfo().

Backpatch to 17, where the new API was introduced.

Reviewed-by: TODO
Backpatch-through: 17
---
 src/interfaces/libpq/fe-cancel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/interfaces/libpq/fe-cancel.c b/src/interfaces/libpq/fe-cancel.c
index 25de2a337c9..9674d0a156b 100644
--- a/src/interfaces/libpq/fe-cancel.c
+++ b/src/interfaces/libpq/fe-cancel.c
@@ -137,6 +137,8 @@ PQcancelCreate(PGconn *conn)
 		goto oom_error;
 
 	originalHost = conn->connhost[conn->whichhost];
+	cancelConn->connhost[0].type = originalHost.type;
+
 	if (originalHost.host)
 	{
 		cancelConn->connhost[0].host = strdup(originalHost.host);
-- 
2.34.1

From e13d6f97cdd9b2806b4c8fe9db78766d7e7fe1e6 Mon Sep 17 00:00:00 2001
From: Jacob Champion <jacob.champion@enterprisedb.com>
Date: Mon, 5 May 2025 14:09:54 -0700
Subject: [PATCH v1 2/2] WIP: add TCP tests

Regression test for the previous patch. Needs discussion on-list.
---
 .cirrus.tasks.yml                            |  2 +-
 src/test/modules/libpq_pipeline/meson.build  |  1 +
 src/test/modules/libpq_pipeline/t/002_tcp.pl | 45 ++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 src/test/modules/libpq_pipeline/t/002_tcp.pl

diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml
index 92057006c93..dc7786fff42 100644
--- a/.cirrus.tasks.yml
+++ b/.cirrus.tasks.yml
@@ -29,7 +29,7 @@ env:
   MTEST_ARGS: --print-errorlogs --no-rebuild -C build
   PGCTLTIMEOUT: 120 # avoids spurious failures during parallel tests
   TEMP_CONFIG: ${CIRRUS_WORKING_DIR}/src/tools/ci/pg_ci_base.conf
-  PG_TEST_EXTRA: kerberos ldap ssl libpq_encryption load_balance oauth
+  PG_TEST_EXTRA: kerberos ldap ssl libpq_encryption load_balance oauth tcp
 
 
 # What files to preserve in case tests fail
diff --git a/src/test/modules/libpq_pipeline/meson.build b/src/test/modules/libpq_pipeline/meson.build
index 3fd70a04a38..9edf6c0a22b 100644
--- a/src/test/modules/libpq_pipeline/meson.build
+++ b/src/test/modules/libpq_pipeline/meson.build
@@ -26,6 +26,7 @@ tests += {
   'tap': {
     'tests': [
       't/001_libpq_pipeline.pl',
+      't/002_tcp.pl',
     ],
     'deps': [libpq_pipeline],
   },
diff --git a/src/test/modules/libpq_pipeline/t/002_tcp.pl b/src/test/modules/libpq_pipeline/t/002_tcp.pl
new file mode 100644
index 00000000000..64902a1a9c2
--- /dev/null
+++ b/src/test/modules/libpq_pipeline/t/002_tcp.pl
@@ -0,0 +1,45 @@
+
+# Copyright (c) 2021-2025, PostgreSQL Global Development Group
+
+use strict;
+use warnings FATAL => 'all';
+
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Force test nodes to begin in TCP mode.
+# Use an INIT block so it runs after the BEGIN block in Utils.pm.
+
+INIT { $PostgreSQL::Test::Utils::use_unix_sockets = 0; }
+
+use PostgreSQL::Test::Cluster;
+
+if (!$ENV{PG_TEST_EXTRA} || $ENV{PG_TEST_EXTRA} !~ /\btcp\b/)
+{
+	plan skip_all =>
+	  'Potentially unsafe test TCP not enabled in PG_TEST_EXTRA';
+}
+
+my $node = PostgreSQL::Test::Cluster->new('main');
+$node->init;
+$node->start;
+
+# Don't let PGHOST interfere with these tests.
+delete $ENV{PGHOST};
+
+my @cases = (
+	$node->connstr('postgres') . " max_protocol_version=latest",
+	$node->connstr('postgres') . " max_protocol_version=3.0",
+	"hostaddr=127.0.0.1 port=" . $node->port);
+
+foreach my $c (@cases)
+{
+	# Don't use $node->command_ok(); it overrides PGHOST too.
+	command_ok(
+		[ 'libpq_pipeline', 'cancel', $c ],
+		"libpq_pipeline cancel, connstr: " . $c);
+}
+
+$node->stop('fast');
+
+done_testing();
-- 
2.34.1