pg_read_server_files doesn't let me use pg_ls_dir() or pg_read_file?

From: hubert depesz lubaczewski <depesz(at)depesz(dot)com>
To: PostgreSQL mailing lists <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: pg_read_server_files doesn't let me use pg_ls_dir() or pg_read_file?
Date: 2023-03-14 19:33:10
Message-ID: ZBDL9gMrc0/fjrLU@depesz.com
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Hi,
Tested it now on built today Pg 16devel, straight from repo.

In docs (https://www.postgresql.org/docs/current/functions-admin.html#FUNCTIONS-ADMIN-GENFILE) I found:
> The functions shown in Table 9.99 provide native access to files on
> the machine hosting the server. Only files within the database cluster
> directory and the log_directory can be accessed, unless the user is
> a superuser or is granted the role pg_read_server_files. Use
> a relative path for files in the cluster directory, and a path
> matching the log_directory configuration setting for log files.

which I understand that if I'll grant pg_read_server_files to some user,
then this user should be able to use the generic file access functions.

So I tried:

#v+
$ select current_user;
current_user
──────────────
test
(1 row)

$ \du+ test
List of roles
Role name │ Attributes │ Member of │ Description
───────────┼────────────┼───────────────────────────────────────────────────────────────┼─────────────
test │ │ {pg_read_all_settings,pg_read_all_stats,pg_read_server_files} │

$ select * from pg_ls_dir('.');
ERROR: permission denied for function pg_ls_dir

$ select * from pg_ls_dir('log');
ERROR: permission denied for function pg_ls_dir

$ select * from pg_ls_dir('/etc');
ERROR: permission denied for function pg_ls_dir

$ select * from pg_read_file('PG_VERSION');
ERROR: permission denied for function pg_read_file

$ select * from pg_read_file('/etc/passwd');
ERROR: permission denied for function pg_read_file
#v-

After I additionally granted EXECUTE on the functions, I was able to run them, even when I revoked pg_read_server_files.

Am I missing something in there, or is this a bug?

Best regards,

depesz

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