From 6b6c64a96dea5492448aa98cf24eca9325e80371 Mon Sep 17 00:00:00 2001
From: Thomas Munro <tmunro@postgresql.org>
Date: Tue, 13 Nov 2018 17:39:36 +1300
Subject: Fix handling of HBA ldapserver with multiple hostnames.

Commit 35c0754f failed to handle space-separated lists of alternative
hostnames in ldapserver, when building a URI for ldap_initialize()
(OpenLDAP).  Such lists need to be expanded to space-separated URIs.

Repair.  Back-patch to 11, to fix bug report #15495.

Author: Thomas Munro
Reported-by: Renaud Navarro
Discussion: https://postgr.es/m/15495-2c39fc196c95cd72%40postgresql.org
---
 src/backend/libpq/auth.c | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

(limited to 'src/backend/libpq/auth.c')

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 85175655359..bbf102ed7de 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -2352,12 +2352,44 @@ InitializeLDAPConnection(Port *port, LDAP **ldap)
 #else
 #ifdef HAVE_LDAP_INITIALIZE
 	{
-		char	   *uri;
+		const char *hostnames = port->hba->ldapserver;
+		char	   *uris = NULL;
 
-		uri = psprintf("%s://%s:%d", scheme, port->hba->ldapserver,
-					   port->hba->ldapport);
-		r = ldap_initialize(ldap, uri);
-		pfree(uri);
+		/*
+		 * We have a space-separated list of hostnames.  Convert it
+		 * to a space-separated list of URIs.
+		 */
+		do
+		{
+			const char *hostname;
+			size_t		hostname_size;
+			char	   *new_uris;
+
+			/* Find the leading hostname. */
+			hostname_size = strcspn(hostnames, " ");
+			hostname = pnstrdup(hostnames, hostname_size);
+
+			/* Append a URI for this hostname. */
+			new_uris = psprintf("%s%s%s://%s:%d",
+								uris ? uris : "",
+								uris ? " " : "",
+								scheme,
+								hostname,
+								port->hba->ldapport);
+
+			pfree(hostname);
+			if (uris)
+				pfree(uris);
+			uris = new_uris;
+
+			/* Step over this hostname and any spaces. */
+			hostnames += hostname_size;
+			while (*hostnames == ' ')
+				++hostnames;
+		} while (*hostnames);
+
+		r = ldap_initialize(ldap, uris);
+		pfree(uris);
 		if (r != LDAP_SUCCESS)
 		{
 			ereport(LOG,
-- 
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