"node check": check role membership when trying to read pg_settings

From PostgreSQL 10, a member of the default roles "pg_monitor" and/or
"pg_read_all_settings" can read pg_settings without requiring superuser
privileges.

Previously, a hint was being emitted about making the repmgr user a
member of one of those groups, but no check for membership was being
made, meaning the check could only be run by a superuser.
This commit is contained in:
Ian Barwick
2019-08-07 14:23:50 +09:00
parent 10870503d1
commit 38b373e6df
4 changed files with 53 additions and 6 deletions

View File

@@ -336,12 +336,10 @@ establish_db_connection_by_params(t_conninfo_param_list *param_list,
bool
is_superuser_connection(PGconn *conn, t_connection_user *userinfo)
{
char *current_user = NULL;
const char *superuser_status = NULL;
bool is_superuser = false;
const char *current_user = PQuser(conn);
const char *superuser_status = PQparameterStatus(conn, "is_superuser");
current_user = PQuser(conn);
superuser_status = PQparameterStatus(conn, "is_superuser");
is_superuser = (strcmp(superuser_status, "on") == 0) ? true : false;
if (userinfo != NULL)
@@ -356,6 +354,51 @@ is_superuser_connection(PGconn *conn, t_connection_user *userinfo)
}
bool
connection_has_pg_settings(PGconn *conn)
{
bool has_pg_settings = false;
/* superusers can always read pg_settings */
if (is_superuser_connection(conn, NULL) == true)
{
has_pg_settings = true;
}
/* from PostgreSQL 10, a non-superuser may have been granted access */
else if(PQserverVersion(conn) >= 100000)
{
PQExpBufferData query;
PGresult *res;
initPQExpBuffer(&query);
appendPQExpBufferStr(&query,
" SELECT CASE "
" WHEN pg_catalog.pg_has_role(CURRENT_USER, 'pg_monitor','MEMBER') "
" THEN TRUE "
" WHEN pg_catalog.pg_has_role(CURRENT_USER, 'pg_read_all_settings','MEMBER') "
" THEN TRUE "
" ELSE FALSE "
" END AS has_pg_settings");
res = PQexec(conn, query.data);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
log_db_error(conn, query.data,
_("connection_has_pg_settings(): unable to query user roles"));
}
else
{
has_pg_settings = atobool(PQgetvalue(res, 0, 0));
}
termPQExpBuffer(&query);
PQclear(res);
}
return has_pg_settings;
}
void
close_connection(PGconn **conn)
{