Re: [RFC 1/2] vpn-security-policies: add new feature vpn security-policies

Hi,

On Thu, 2017-07-13 at 20:33 +0200, Jonatan Schlag wrote:

For further explanation see: http://wiki.ipfire.org/devel/network/security-policies

Signed-off-by: Jonatan Schlag jonatan.schlag@ipfire.org

src/functions/functions.vpn-security-policies | 437 ++++++++++++++++++++++++++  1 file changed, 437 insertions(+)  create mode 100644 src/functions/functions.vpn-security-policies

diff --git a/src/functions/functions.vpn-security-policies b/src/functions/functions.vpn-security-policies new file mode 100644 index 0000000..9e24e4f --- /dev/null +++ b/src/functions/functions.vpn-security-policies @@ -0,0 +1,437 @@ +#!/bin/bash +#################################################################### ########### +#                                                                              # +# IPFire.org - A linux based firewall                                         # +# Copyright (C) 2013  IPFire Network Development Team                         # +#                                                                              #

It's 2017 :)

+# 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 3 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, see http://www.gnu.org/licenses /.       # +#                                                                              # +#################################################################### ###########

+VPN_SECURITY_POLICIES_CONFIG_SETTINGS="CIPHER COMPRESSION GROUP_TYPE INTEGRITY KEY_EXCHANGE LIFETIME PFS" +VPN_SECURITY_POLICIES_READONLY="system"

+VPN_SUPPORTED_CIPHERS="AES192 AES256 AES128" +VPN_SUPPORTED_INTEGRITY="SHA512 SHA256 SHA128" +VPN_SUPPORTED_GROUP_TYPES="MODP4096 MODP8192"

Obviously these need to be extended. But this will suit as a proof-of- concept. Just please order stuff alphabetically. In this case it is best to do it descending.

+vpn_security_policies_check_readonly() {

• # This functions checks if a policy is readonly
• # returns true when yes and false when no
• if isoneof name ${VPN_SECURITY_POLICIES_READONLY}; then

• return ${EXIT_TRUE}
  

• else

• return ${EXIT_FALSE}
  

• fi

+}

Ok.

+vpn_security_policies_write_config() {

• # This function writes all values to a via ${name}

specificated vpn security policy configuration file

• assert [ $# -ge 1 ]
• local name="${1}"
• if ! vpn_security_policy_exists ${name}; then

• log ERROR "No such policy: ${name}"
  

• return ${EXIT_ERROR}
  

• fi

I think you need to improve some of the error messages. A sentence is usually good. The shorter the sweeter. Not sure if "no such policy" is helpful when they are actually called security policies. So, don't go too short.

• if vpn_security_policies_check_readonly ${name}; then

• log ERROR "${name} is a readable only vpn security
  

policy"

• return ${EXIT_ERROR}
  

• fi

Here I would suggest: "The system security policy cannot be changed"

• local args
• list_append args ${VPN_SECURITY_POLICIES_CONFIG_SETTINGS}

No need to call list_append here. Settings args to VPN_SECURITY_POLICIES_CONFIG_SETTINGS is enough. You just just pass it to settings_write without using $args.

• local path="$(vpn_security_policies_path ${name})"
• if [ ! -w ${path} ]; then

• log ERROR "${path} is not writeable"
  

• return ${EXIT_ERROR}
  

• fi
• settings_write "${path}" ${args}
• # TODO everytime we successfully write a config we should

call some trigger to take the changes into effect +}

Space between the settings_write and comments, please.

What happens when the settings could not be written?

+vpn_security_policies_write_config_key() {

• # This funtion writes the value for one key to a via ${name}

specificated vpn security policy configuration file

• assert [ $# -ge 3 ]
• local name=${1}
• if ! vpn_security_policy_exists ${name}; then

• log ERROR "No such policy: ${name}"
  

• return ${EXIT_ERROR}
  

• fi
• local key=${2}
• shift 2
• local value="$@"
• log DEBUG "Set '${key}' to new value '${value}'"

Please group the argument parsing together at the top and then test if the policy exists. This is hard to read.

Also the logging message is a bit random since it doesn't mention the security policy here.

• # Read the config settings
• if ! vpn_security_policies_read_config ${name}; then

• return ${EXIT_ERROR}
  

• fi

This will overwrite any global variables. So you will need to call

local VPN_SECURITY_POLICIES_CONFIG_SETTINGS

before you read the settings from file.

• # Set the key to a new value
• eval "${key}="${value}""

Never ever use eval. This will allow someone to pass shell commands that may get executed. At no time ever we would want that.

There is a function called assign() that takes care of assigning a variable.

• if ! vpn_security_policies_write_config ${name}; then

• return ${EXIT_ERROR}
  

• fi
• return ${EXIT_TRUE}

+}

+vpn_security_policies_read_config() {

• # Reads one or more keys out of a settings file or all if no

key is provided.

• assert [ $# -ge 1 ]
• local name="${1}"
• shift 1
• if ! vpn_security_policy_exists ${name}; then

• log ERROR "No such policy: ${name}"
  

• return ${EXIT_ERROR}
  

• fi
• local args
• if [ $# -eq 0 ] && [ -n

"${VPN_SECURITY_POLICIES_CONFIG_SETTINGS}" ]; then

• list_append args
  

${VPN_SECURITY_POLICIES_CONFIG_SETTINGS}

• else

• list_append args $@
  

• fi
• local path="$(vpn_security_policies_path ${name})"
• if [ ! -r ${path} ]; then

• log ERROR "${path} is not readable"
  

• return ${EXIT_ERROR}
  

• fi

Why do you need to do this every time? Doesn't settings_read do this?

• settings_read "${path}" ${args}

+}

+vpn_security_policies_path() {

• # Returns the path to a the configuration fora given name
• assert [ $# -eq 1 ]
• local name=${1}
• if vpn_security_policies_check_readonly ${name}; then

• echo "/usr/share/network/vpn/security-
  

policies/${name}"

• else

• echo "/etc/network/vpn/security-policies/${name}"
  

• fi

+}

Hard-coded paths :(

+vpn_security_policies_show() {

• # Print the content of a vpn security policy configuration

file in a nice way

• assert [ $# -eq 1 ]
• local name=${1}

Here you will need to do the local variable initialization before you red this in - as above.

• # Break if read fails
• if ! vpn_security_policies_read_config ${name}; then

• return ${EXIT_ERROR}
  

• fi
• cli_print_fmt1 0 "Security Policy: ${name}"
• cli_space
• # This could be done in a loop but a loop is much more

complicated

• # because we print 'Group Types' but the variable is named

'GROUP_TYPES'

• cli_print_fmt1 1 "Ciphers:"
• cli_print_fmt1 2 "${CIPHER}"
• cli_space

This does not show any broken ciphers as broken. But we could add this later as well. This patch is quite huge already.

• cli_print_fmt1 1 "Integrity:"
• cli_print_fmt1 2 "${INTEGRITY}"
• cli_space
• cli_print_fmt1 1 "Group Types:"
• cli_print_fmt1 2 "${GROUP_TYPE}"
• cli_space
• cli_print_fmt1 1 "Key exchange:" "${KEY_EXCHANGE}"

Capital E in Exchange

• cli_print_fmt1 1 "Key Lifetime in seconds:" "${LIFETIME}"

The lifetime should be formatted nicely because seconds are hard to understand. There is a function that formats these nicely.

• if enabled PFS; then

• cli_print_fmt1 1 "Perfect Forward Secrecy:"
  

"enabled"

• else

• cli_print_fmt1 1 "Perfect Forward Secrecy:"
  

"disabled"

• fi
• cli_space
• if enabled COMPRESSION; then

• cli_print_fmt1 1 "Compression:" "enabled"
  

• else

• cli_print_fmt1 1 "Compression:" "disabled"
  

• fi
• cli_space

+}

+vpn_security_policy_exists() {

• # This function checks if a vpn security policy exists
• # Returns True when yes and false when not
• assert [ $# -eq 1 ]
• local name=${1}
• local path=$(vpn_security_policies_path ${name})
• [ -f ${path} ]

+}

+vpn_security_policies_cipher(){

• # This function parses the parameters for the 'cipher'

command

• local name=${1}
• shift
• if [ $# -eq 0 ]; then

• log ERROR "You must pass at least one value after
  

cipher"

• return ${EXIT_ERROR}
  

• fi

local CIPHER

• if ! vpn_security_policies_read_config ${name} "CIPHER";

then

• return ${EXIT_ERROR}
  

• fi
• # Remove duplicated entries to proceed the list safely
• CIPHER="$(list_unique ${CIPHER})"
• while [ $# -gt 0 ]; do

• case "${1}" in
  

• 	-*)
  

• 		value=${1#-}
  

• 		# Check if the cipher is in the list
  

of ciphers and

• 		# check if the list has after
  

removing this cipher at least one valid value

• 		if list_match ${value} ${CIPHER} &&
  

[ $(list_length ${CIPHER}) -gt 1 ]; then

• 			list_remove CIPHER ${value}
  

• 		else
  

• 			log ERROR "Can not remove
  

${value} from the list of Ciphers because ${value} is not in the list or the list would be empty after removing this cipher"

• 		fi
  

There is no return here which ends the function on this error.

I think you should check this after the loop to support things like:

-3DES +AES256

This would crash if 3DES is the last cipher but the user does not intend to remove all ciphers.

• 		;;
  

• 	+*)
  

• 		value=${1#+}
  

• 		# Check if the Ciphers is in the
  

list of supported ciphers.

• 		if ! isoneof value
  

${VPN_SUPPORTED_CIPHERS}; then

• 			log ERROR "${value} is not a
  

supported cipher and can thats why not added to the list of ciphers"

• 		else
  

• 			if list_match ${value}
  

${CIPHER}; then

• 				log WARNING
  

"${value} is already in the list of ciphers of this policy"

• 			else
  

• 				list_append CIPHER
  

${value}

• 			fi
  

• 		fi
  

• 		;;
  

• esac
  

• shift
  

• done
• vpn_security_policies_write_config_key ${name} "CIPHER"

${CIPHER}

Are there no errors to catch here?

+}

+vpn_security_policies_compression(){

• # This function parses the parameters for the 'compression'

command

• local name=${1}
• local value=${2}
• # Check if we get only one argument after compression <name>
• if [ ! $# -eq 2 ] || ! isbool value; then

• log ERROR "You can pass only one parameter after
  

compression and this one must be 'on' or 'off'"

• return ${EXIT_ERROR}
  

• fi

Probably not the nicest handling in case of no argument or so. This also suggests two values but actually more would be accepted as well.

• vpn_security_policies_write_config_key "${name}"

"COMPRESSION" "${value}" +}

+vpn_security_policies_group_type(){

• # This function parses the parameters for the 'group-type'

command.

• local name=${1}
• shift
• if [ $# -eq 0 ]; then

• log ERROR "You must pass at least one value after
  

group-type"

• return ${EXIT_ERROR}
  

• fi
• if ! vpn_security_policies_read_config ${name} "GROUP_TYPE";

then

• return ${EXIT_ERROR}
  

• fi
• # Remove duplicated entries to proceed the list safely
• GROUP_TYPE="$(list_unique ${GROUP_TYPE})"
• while [ $# -gt 0 ]; do

• case "${1}" in
  

• 	-*)
  

• 		value=${1#-}
  

• 		# Check if the group type is in the
  

list of group types and

• 		# check if the list has after
  

removing this group type at leatst one valid value

• 		if list_match ${value} ${GROUP_TYPE}
  

&& [ $(list_length ${GROUP_TYPE}) -gt 1 ]; then

• 			list_remove GROUP_TYPE
  

${value}

• 		else
  

• 			log ERROR "Can not remove
  

${value} from the list of group types because ${value} is not in the list or the list would be empty after removing this group type"

• 		fi
  

• 		;;
  

• 	+*)
  

• 		value=${1#+}
  

• 		# Check if the group type is in the
  

list of supported group types.

• 		if ! isoneof value
  

${VPN_SUPPORTED_GROUP_TYPES}; then

• 			log ERROR "${value} is not a
  

supported group type and can thats why not added to the list of group types"

• 		else
  

• 			if list_match ${value}
  

${GROUP_TYPE}; then

• 				log WARNING
  

"${value} is already in the list of group-types of this policy"

• 			else
  

• 				list_append
  

GROUP_TYPES ${value}

• 			fi
  

• 		fi
  

• 		;;
  

• esac
  

• shift
  

• done
• vpn_security_policies_write_config_key ${name} "GROUP_TYPE"

${GROUP_TYPE} +}

Same as above.

+vpn_security_policies_integrity(){

• # This function parses the parameters for the 'integrity'

command

• local name=${1}
• shift
• if [ $# -eq 0 ]; then

• log ERROR "You must pass at least one value after
  

integrity"

• return ${EXIT_ERROR}
  

• fi
• if ! vpn_security_policies_read_config ${name} "INTEGRITY";

then

• return ${EXIT_ERROR}
  

• fi
• # Remove duplicated entries to proceed the list safely
• INTEGRITY="$(list_unique ${INTEGRITY})"
• while [ $# -gt 0 ]; do

• case "${1}" in
  

• 	-*)
  

• 		value=${1#-}
  

• 		# Check if the integrity hash is in
  

the list of integrity hashes and

• 		# check if the list has after
  

removing this  integrity hash at least one valid value

• 		if list_match ${value} ${INTEGRITY}
  

&& [ $(list_length ${INTEGRITY}) -gt 1 ]; then

• 			list_remove INTEGRITY
  

${value}

• 		else
  

• 			log ERROR "Can not remove
  

${value} from the list of integrity hashes because ${value} is not in the list or the list would be empty after removing this integrity hash"

• 		fi
  

• 		;;
  

• 	+*)
  

• 		value=${1#+}
  

• 		# Check if the Ciphers is in the
  

list of supported integrity hashes.

• 		if ! isoneof value
  

${VPN_SUPPORTED_INTEGRITY}; then

• 			log ERROR "${value} is not a
  

supported integrity hashes and can thats why not added to the list of integrity hashes"

• 		else
  

• 			if list_match ${value}
  

${INTEGRITY}; then

• 				log WARNING
  

"${value} is already in the list of integrety hashes of this policy"

• 			else
  

• 				list_append
  

INTEGRITY ${value}

• 			fi
  

• 		fi
  

• 		;;
  

• esac
  

• shift
  

• done
• vpn_security_policies_write_config_key ${name} "INTEGRITY"

${INTEGRITY} +}

Likewise.

+vpn_security_policies_key_exchange() {

• # This function parses the parameters for the 'key-exchange'

command

• local name=${1}
• local value=${2}
• # Check if we get only one argument after compression <name>
• if [ ! $# -eq 2 ] || ! isoneof value "ikev1" "ikev2"; then

• log ERROR "You can pass only one parameter after
  

key-exchange and this one must be 'ikev1' or 'ikev2'"

• return ${EXIT_ERROR}
  

• fi

Should we accept values like "IKEv2", too?

• vpn_security_policies_write_config_key "${name}"

"KEY_EXCHANGE" "${value}" +}

+vpn_security_policies_lifetime(){

• # This function parses the parameters for the 'lifetime'

command

• local name=${1}
• local value=${2}
• # Check if we get only one argument after compression <name>
• if [ ! $# -eq 2 ] || ! isinteger value || [ ${value} -le 0

]; then

• log ERROR "You can pass only one parameter after
  

liftime and this one must be an valid integer greater zero"

• return ${EXIT_ERROR}
  

• fi
• vpn_security_policies_write_config_key "${name}" "LIFETIME"

"${value}" +}

This one should accept values like "1h". There is a function for it.

+vpn_security_policies_pfs(){

• # This function parses the parameters for the 'pfs' command
• local name=${1}
• local value=${2}
• # Check if we get only one argument after compression <name>
• if [ ! $# -eq 2 ] || ! isbool value; then

• log ERROR "You can pass only one parameter after pfs
  

and this one must be 'on' or 'off'"

• return ${EXIT_ERROR}
  

• fi
• vpn_security_policies_write_config_key "${name}" "PFS"

"${value}" +}

See above.

+vpn_security_policies_check_name() {

• # This function checks if a vpn security policy name is

valid

• # Allowed are only A-Za-z0-9
• assert [ $# -eq 1 ]
• local name=${1}
• [[ ${name} =~ [[:alnum:]] ]]

This only checks if there is at least one alphanumerical character in the string. But it does not exclusively check for them I think.

+}

+vpn_security_policies_new() {

• # Function that creates based on the paramters one ore more

new vpn security policies

• local name
• for name in $@; do

• if vpn_security_policy_exists ${name}; then
  

• 	log ERROR "The vpn security policy ${name}
  

does already exist"

• 	continue
  

• fi
  

• if vpn_security_policies_check_name ${name}; then
  

• 	log ERROR "'${name}' contains illegal
  

characters. Allowed are only A-Za-z0-9 are allowed"

• 	continue
  

• fi
  

• log DEBUG "Creating vpn security policy ${name}"
  

• cp "$(vpn_security_policies_path "system")"
  

"$(vpn_security_policies_path ${name})"

Don't use cp.

• done

+}

What happens when I create a new policy called "system"?

+vpn_security_policies_destroy() {

• # Function that deletes based on the passed parameters one

ore more vpn security policies

• local name
• for name in $@; do

• if ! vpn_security_policy_exists ${name}; then
  

• 	log ERROR "The vpn security policy ${name}
  

does not exist"

• 	continue
  

• fi
  

• if vpn_security_policies_check_readonly ${name};
  

then

• 	log ERROR "The vpn security policy ${name}
  

is readonly and can thats why not deleted"

• 	continue
  

• fi
  

• log DEBUG "Deleting vpn security policy ${name}"
  

• rm -f $(vpn_security_policies_path ${name})
  

• done

+}

This is overall good work. See the comments above and go through them one by one and please send an updated version of the patch when ever you are ready.

Best, -Michael