dropbear: better handle interfaces

- introduce 'DirectInterface' option to bind exactly to specified interface;
  fixes #9666 and late IPv4/IPv6 address assignment
- option 'DirectInterface' takes precedence over 'Interface'
- improve interface/address handling,
  e.g. verify count of listening endpoints due to dropbear limit (10 for now)

Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>
This commit is contained in:
Konstantin Demin 2024-01-15 10:38:59 +03:00 committed by Rui Salvaterra
parent 865ae1c10c
commit 3f96246e97

View File

@ -146,19 +146,18 @@ hk_generate_as_needed()
done
}
append_ports()
# $1 - list with whitespace-separated elements
normalize_list()
{
local ipaddrs="$1"
local port="$2"
printf '%s' "$1" | tr -s ' \r\n\t' ' ' | sed -E 's/^ //;s/ $//'
}
[ -z "$ipaddrs" ] && {
procd_append_param command -p "$port"
return
}
for addr in $ipaddrs; do
procd_append_param command -p "$addr:$port"
done
warn_multiple_interfaces()
{
logger -t "${NAME}" -p daemon.warn \
"Option '$1' should specify SINGLE interface but instead it lists interfaces: $2"
logger -t "${NAME}" -p daemon.warn \
"Consider creating per-interface instances instead!"
}
validate_section_dropbear()
@ -166,6 +165,7 @@ validate_section_dropbear()
uci_load_validate dropbear dropbear "$1" "$2" \
'PasswordAuth:bool:1' \
'enable:bool:1' \
'DirectInterface:string' \
'Interface:string' \
'GatewayPorts:bool:0' \
'ForceCommand:string' \
@ -184,28 +184,139 @@ validate_section_dropbear()
dropbear_instance()
{
local ipaddrs
[ "$2" = 0 ] || {
echo "validation failed"
return 1
}
[ -n "${Interface}" ] && {
[ -n "${BOOT}" ] && return 0
[ "${enable}" = "1" ] || return 1
network_get_ipaddrs_all ipaddrs "${Interface}" || {
echo "interface ${Interface} has no physdev or physdev has no suitable ip"
return 1
}
}
local iface ndev ipaddrs
# 'DirectInterface' should specify single interface
# but end users may misinterpret this setting
DirectInterface=$(normalize_list "${DirectInterface}")
# 'Interface' should specify single interface
# but end users are often misinterpret this setting
Interface=$(normalize_list "${Interface}")
if [ -n "${Interface}" ] ; then
if [ -n "${DirectInterface}" ] ; then
logger -t "${NAME}" -p daemon.warn \
"Option 'DirectInterface' takes precedence over 'Interface'"
else
logger -t "${NAME}" -p daemon.info \
"Option 'Interface' binds to address(es) but not to interface"
logger -t "${NAME}" -p daemon.info \
"Consider using option 'DirectInterface' to bind directly to interface"
fi
fi
# handle 'DirectInterface'
iface=$(echo "${DirectInterface}" | awk '{print $1}')
case "${DirectInterface}" in
*\ *)
warn_multiple_interfaces DirectInterface "${DirectInterface}"
logger -t "${NAME}" -p daemon.warn \
"Using network interface '${iface}' for direct binding"
;;
esac
while [ -n "${iface}" ] ; do
# if network is available (even during boot) - proceed
if network_is_up "${iface}" ; then break ; fi
# skip during boot
[ -z "${BOOT}" ] || return 0
logger -t "${NAME}" -p daemon.crit \
"Network interface '${iface}' is not available!"
return 1
done
while [ -n "${iface}" ] ; do
# ${iface} is logical (higher level) interface name
# ${ndev} is 'real' interface name
# e.g.: if ${iface} is 'lan' (default LAN interface) then ${ndev} is 'br-lan'
network_get_device ndev "${iface}"
[ -z "${ndev}" ] || break
logger -t "${NAME}" -p daemon.crit \
"Missing network device for network interface '${iface}'!"
return 1
done
if [ -n "${iface}" ] ; then
logger -t "${NAME}" -p daemon.info \
"Using network interface '${iface}' (network device '${ndev}') for direct binding"
fi
# handle 'Interface'
while [ -z "${iface}" ] ; do
[ -n "${Interface}" ] || break
# skip during boot
[ -z "${BOOT}" ] || return 0
case "${Interface}" in
*\ *)
warn_multiple_interfaces Interface "${Interface}"
;;
esac
local c=0
# sysoptions.h
local DROPBEAR_MAX_PORTS=10
local a n if_ipaddrs
for n in ${Interface} ; do
[ -n "$n" ] || continue
if_ipaddrs=
network_get_ipaddrs_all if_ipaddrs "$n"
[ -n "${if_ipaddrs}" ] || {
logger -s -t "${NAME}" -p daemon.err \
"Network interface '$n' has no suitable IP address(es)!"
continue
}
[ $c -le ${DROPBEAR_MAX_PORTS} ] || {
logger -s -t "${NAME}" -p daemon.err \
"Network interface '$n' is NOT listened due to option limit exceed!"
continue
}
for a in ${if_ipaddrs} ; do
[ -n "$a" ] || continue
c=$((c+1))
if [ $c -le ${DROPBEAR_MAX_PORTS} ] ; then
ipaddrs="${ipaddrs} $a"
continue
fi
logger -t "${NAME}" -p daemon.err \
"Endpoint '$a:${Port}' on network interface '$n' is NOT listened due to option limit exceed!"
done
done
break
done
[ "${enable}" = "0" ] && return 1
PIDCOUNT="$(( ${PIDCOUNT} + 1))"
local pid_file="/var/run/${NAME}.${PIDCOUNT}.pid"
procd_open_instance
procd_set_param command "$PROG" -F -P "$pid_file"
if [ -n "${iface}" ] ; then
# if ${iface} is non-empty then ${ndev} is non-empty too
procd_append_param command -l "${ndev}" -p "${Port}"
else
if [ -z "${ipaddrs}" ] ; then
procd_append_param command -p "${Port}"
else
local a
for a in ${ipaddrs} ; do
[ -n "$a" ] || continue
procd_append_param command -p "$a:${Port}"
done
fi
fi
[ "${PasswordAuth}" -eq 0 ] && procd_append_param command -s
[ "${GatewayPorts}" -eq 1 ] && procd_append_param command -a
[ -n "${ForceCommand}" ] && procd_append_param command -c "${ForceCommand}"
@ -222,7 +333,6 @@ dropbear_instance()
hk_config 'rsakeyfile' "${rsakeyfile}"
fi
[ -n "${BannerFile}" ] && procd_append_param command -b "${BannerFile}"
append_ports "${ipaddrs}" "${Port}"
[ "${IdleTimeout}" -ne 0 ] && procd_append_param command -I "${IdleTimeout}"
[ "${SSHKeepAlive}" -ne 0 ] && procd_append_param command -K "${SSHKeepAlive}"
[ "${MaxAuthTries}" -ne 0 ] && procd_append_param command -T "${MaxAuthTries}"
@ -250,10 +360,21 @@ dropbear_instance()
load_interfaces()
{
config_get interface "$1" Interface
local enable
config_get enable "$1" enable 1
[ "${enable}" = "1" ] || return 0
[ "${enable}" = "1" ] && interfaces=" ${interface} ${interfaces}"
local direct_iface iface
config_get direct_iface "$1" DirectInterface
direct_iface=$(normalize_list "${direct_iface}")
# 'DirectInterface' takes precedence over 'Interface'
if [ -n "${direct_iface}" ] ; then
iface=$(echo "${direct_iface}" | awk '{print $1}')
else
config_get iface "$1" Interface
iface=$(normalize_list "${iface}")
fi
interfaces="${interfaces} ${iface}"
}
boot()
@ -278,13 +399,14 @@ service_triggers()
{
local interfaces
procd_add_config_trigger "config.change" "dropbear" /etc/init.d/dropbear reload
procd_add_config_trigger "config.change" "${NAME}" /etc/init.d/dropbear reload
config_load "${NAME}"
config_foreach load_interfaces dropbear
config_foreach load_interfaces "${NAME}"
[ -n "${interfaces}" ] && {
for n in $interfaces ; do
local n
for n in $(printf '%s\n' ${interfaces} | sort -u) ; do
procd_add_interface_trigger "interface.*" $n /etc/init.d/dropbear reload
done
}