Empty search_path in Autovacuum and non-psql/pgbench clients.

This makes the client programs behave as documented regardless of the
connect-time search_path and regardless of user-created objects.  Today,
a malicious user with CREATE permission on a search_path schema can take
control of certain of these clients' queries and invoke arbitrary SQL
functions under the client identity, often a superuser.  This is
exploitable in the default configuration, where all users have CREATE
privilege on schema "public".

This changes behavior of user-defined code stored in the database, like
pg_index.indexprs and pg_extension_config_dump().  If they reach code
bearing unqualified names, "does not exist" or "no schema has been
selected to create in" errors might appear.  Users may fix such errors
by schema-qualifying affected names.  After upgrading, consider watching
server logs for these errors.

The --table arguments of src/bin/scripts clients have been lax; for
example, "vacuumdb -Zt pg_am\;CHECKPOINT" performed a checkpoint.  That
now fails, but for now, "vacuumdb -Zt 'pg_am(amname);CHECKPOINT'" still
performs a checkpoint.

Back-patch to 9.3 (all supported versions).

Reviewed by Tom Lane, though this fix strategy was not his first choice.
Reported by Arseniy Sharoglazov.

Security: CVE-2018-1058

3 files changed, 26 insertions, 4 deletions

diff --git a/src/bin/scripts/t/010_clusterdb.pl b/src/bin/scripts/t/010_clusterdb.pl
index dc0d78a27d3..bdb32734510 100644
--- a/src/bin/scripts/t/010_clusterdb.pl
+++ b/src/bin/scripts/t/010_clusterdb.pl
@@ -22,5 +22,5 @@ psql 'postgres',
 'CREATE TABLE test1 (a int); CREATE INDEX test1x ON test1 (a); CLUSTER test1 USING test1x';
 issues_sql_like(
 	[ 'clusterdb', '-t', 'test1', 'postgres' ],
-	qr/statement: CLUSTER test1;/,
+	qr/statement: CLUSTER public\.test1;/,
 	'cluster specific table');
diff --git a/src/bin/scripts/t/090_reindexdb.pl b/src/bin/scripts/t/090_reindexdb.pl
index bba1667b56f..54864b2209e 100644
--- a/src/bin/scripts/t/090_reindexdb.pl
+++ b/src/bin/scripts/t/090_reindexdb.pl
@@ -21,11 +21,11 @@ psql 'postgres',
   'CREATE TABLE test1 (a int); CREATE INDEX test1x ON test1 (a);';
 issues_sql_like(
 	[ 'reindexdb', '-t', 'test1', 'postgres' ],
-	qr/statement: REINDEX TABLE test1;/,
+	qr/statement: REINDEX TABLE public\.test1;/,
 	'reindex specific table');
 issues_sql_like(
 	[ 'reindexdb', '-i', 'test1x', 'postgres' ],
-	qr/statement: REINDEX INDEX test1x;/,
+	qr/statement: REINDEX INDEX public\.test1x;/,
 	'reindex specific index');
 issues_sql_like(
 	[ 'reindexdb', '-s', 'postgres' ],
diff --git a/src/bin/scripts/t/100_vacuumdb.pl b/src/bin/scripts/t/100_vacuumdb.pl
index ac160ba8374..bdd03bc2449 100644
--- a/src/bin/scripts/t/100_vacuumdb.pl
+++ b/src/bin/scripts/t/100_vacuumdb.pl
@@ -1,7 +1,7 @@
 use strict;
 use warnings;
 use TestLib;
-use Test::More tests => 18;
+use Test::More tests => 23;
 
 program_help_ok('vacuumdb');
 program_version_ok('vacuumdb');
@@ -30,3 +30,25 @@ issues_sql_like(
 	[ 'vacuumdb', '-Z', 'postgres' ],
 	qr/statement: ANALYZE;/,
 	'vacuumdb -Z');
+command_ok([qw(vacuumdb -Z --table=pg_am dbname=template1)],
+	'vacuumdb with connection string');
+
+command_fails([qw(vacuumdb -Zt pg_am;ABORT postgres)],
+	'trailing command in "-t", without COLUMNS');
+# Unwanted; better if it failed.
+command_ok([qw(vacuumdb -Zt pg_am(amname);ABORT postgres)],
+	'trailing command in "-t", with COLUMNS');
+
+psql('postgres', q|
+  CREATE TABLE "need""q(uot" (")x" text);
+
+  CREATE FUNCTION f0(int) RETURNS int LANGUAGE SQL AS 'SELECT $1 * $1';
+  CREATE FUNCTION f1(int) RETURNS int LANGUAGE SQL AS 'SELECT f0($1)';
+  CREATE TABLE funcidx (x int);
+  INSERT INTO funcidx VALUES (0),(1),(2),(3);
+  CREATE INDEX i0 ON funcidx ((f1(x)));
+|);
+command_ok([qw|vacuumdb -Z --table="need""q(uot"(")x") postgres|],
+	'column list');
+command_fails([qw|vacuumdb -Zt funcidx postgres|],
+	'unqualifed name via functional index');