GaussDB Kernel: Configuring the Backslash Quote Usage

# Copyright (C) 2020 Greenbone Networks GmbH
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.150444");
  script_version("2020-11-20T12:35:19+0000");
  script_tag(name:"last_modification", value:"2020-11-20 12:35:19 +0000 (Fri, 20 Nov 2020)");
  script_tag(name:"creation_date", value:"2020-11-20 10:52:10 +0000 (Fri, 20 Nov 2020)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:H/Au:S/C:N/I:N/A:N");
  script_tag(name:"qod", value:"97");

  script_name("GaussDB Kernel: Configuring the Backslash Quote Usage");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2020 Greenbone Networks GmbH");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "gb_huawei_gaussdb_kernel_ssh_login_detect.nasl", "gaussdbkernel_authentication_information.nasl");
  script_mandatory_keys("huawei/gaussdb_kernel/detected", "Compliance/Launch");

  script_tag(name:"summary", value:"backslash_quote specifies whether a single quotation mark (') in a string can be
replaced by a backslash quote (\'). The backslash-quote (\') is accepted in
PostgreSQL due to historical reasons. However, this may bring security risks, such
as SQL injection attacks. To prevent such risks, you are advised to set
backslash_quote to deny queries containing the backslash-quote. In addition, you
are advised to use SQL standard method in which a single quotation mark (') is
Repeated ('').");

  exit(0);
}

include( "policy_functions.inc" );
include( "ssh_func.inc" );

cmd = "SELECT name,setting FROM pg_settings WHERE name='backslash_quote';";
title = "Configuring the Backslash Quote Usage";
solution = "Set backslash_quote to safe_encoding in the postgresql.conf file and then
restart the database.";
default = "safe_encoding or off";
test_type = "SQL_Query";

if( ! get_kb_item( "login/SSH/success" ) || ! sock = ssh_login_or_reuse_connection() ) {
  compliant = "incomplete";
  value = "error";
  comment = "No SSH connection to host";
}else if ( ! value = policy_gsql_cmd( socket:sock, query:cmd, db_type:"gaussdbkernel" ) ) {
  compliant = "incomplete";
  value = "error";
  comment = "SQL command did not return anything";
}else if ( value =~ "failed to connect" ) {
  compliant = "incomplete";
  value = "error";
  comment = "No connection to database";
}else{
  value = ereg_replace( string:chomp(value), pattern:"^\s+", replace:"" );
  setting = eregmatch( string:value, pattern:"backslash_quote\s+\|\s+(.+)" );
  if( ! setting[1] ){
    compliant = "incomplete";
    comment = "Can not determine setting.";
  }else if( setting[1] =~ "(safe_encoding|off)" ) {
    compliant = "yes";
  }else{
    compliant = "no";
  }
}

policy_reporting( result:value, default:default, compliant:compliant, fixtext:solution,
  type:test_type, test:cmd, info:comment );

policy_set_kbs( type:test_type, cmd:cmd, default:default, solution:solution, title:title,
  value:value, compliant:compliant );

exit( 0 );