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reidrankin/wg-lla.sh

Created Jun 27, 2020
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Calculates cryptographically-bound IPv6 Link-Local Addresses from WireGuard public keys.
#!/bin/bash -e
blake2s_mix() {
local A_NAME="$1"
local A="$2"
local B_NAME="$3"
local B="$4"
local C_NAME="$5"
local C="$6"
local D_NAME="$7"
local D="$7"
local X="$9"
local Y="${10}"
A=$(((A + B + X) & 0xffffffff))
D=$((((D ^ A) << (32 - 16) | (D ^ A) >> 16) & 0xffffffff))
C=$(((C + D) & 0xffffffff))
B=$((((B ^ C) << (32 - 12) | (B ^ C) >> 12) & 0xffffffff))
A=$(((A + B + Y) & 0xffffffff))
D=$((((D ^ A) << (32 - 8) | (D ^ A) >> 8) & 0xffffffff))
C=$(((C + D) & 0xffffffff))
B=$((((B ^ C) << (32 - 7) | (B ^ C) >> 7) & 0xffffffff))
echo "$A_NAME=$A; $B_NAME=$B; $C_NAME=$C; $D_NAME=$D"
}
blake2s() {
dd bs=64 iflag=fullblock status=none | hexdump -ve '1 1 "%02x\n"' | {
local IV=(0x6a09e667 0xbb67ae85 0x3c6ef372 0xa54ff53a 0x510e527f 0x9b05688c 0x1f83d9ab 0x5be0cd19)
local S=(
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
14 10 4 8 9 15 13 6 1 12 0 2 11 7 5 3
11 8 12 0 5 2 15 13 10 14 3 6 7 1 9 4
7 9 3 1 13 12 11 14 2 6 5 10 4 0 15 8
9 0 5 7 2 4 10 15 14 1 11 12 6 8 3 13
2 12 6 10 0 11 8 3 4 13 7 5 15 14 1 9
12 5 1 15 14 13 4 10 0 7 6 3 9 2 8 11
13 11 7 14 12 1 3 9 5 0 15 4 8 6 2 10
6 15 14 9 11 3 0 8 12 2 13 7 1 4 10 5
10 2 8 4 7 6 1 5 15 11 9 14 3 12 13 0
)
local MLEN=0
local DLEN="$1"
# shellcheck disable=SC2155
local P="$(printf '0x010100%02x' "$DLEN")"
local H=($((IV[0] ^ P)) $((IV[1])) $((IV[2])) $((IV[3])) $((IV[4])) $((IV[5])) $((IV[6])) $((IV[7])))
local NEXT
IFS= read -r NEXT || :
while :; do
readarray -tn 63 INPUT
# shellcheck disable=SC2206
INPUT=($NEXT "${INPUT[@]}")
MLEN=$((MLEN + ${#INPUT[@]}))
local M=(0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)
for I in $(seq 0 15); do M[$I]="0x${INPUT[$(((I * 4) + 3))]}${INPUT[$(((I * 4) + 2))]}${INPUT[$(((I * 4) + 1))]}${INPUT[$(((I * 4) + 0))]}"; done
local F=(0 0)
IFS= read -r NEXT || F[0]=0xffffffff
local T=(
$(((MLEN >> 0) & 0xffffffff))
$(((MLEN >> 32) & 0xffffffff))
)
local V=(
$((H[0])) $((H[1])) $((H[2])) $((H[3]))
$((H[4])) $((H[5])) $((H[6])) $((H[7]))
$((IV[0])) $((IV[1])) $((IV[2])) $((IV[3]))
$((T[0] ^ IV[4])) $((T[1] ^ IV[5])) $((F[0] ^ IV[6])) $((F[1] ^ IV[7]))
)
for I in $(seq 0 16 $((9 * 16))); do
eval "$({
blake2s_mix "V[0]" "${V[0]}" "V[4]" "${V[4]}" "V[8]" "${V[8]}" "V[12]" "${V[12]}" "${M[S[$((I + 0))]]}" "${M[S[$((I + 1))]]}" &
blake2s_mix "V[1]" "${V[1]}" "V[5]" "${V[5]}" "V[9]" "${V[9]}" "V[13]" "${V[13]}" "${M[S[$((I + 2))]]}" "${M[S[$((I + 3))]]}" &
blake2s_mix "V[2]" "${V[2]}" "V[6]" "${V[6]}" "V[10]" "${V[10]}" "V[14]" "${V[14]}" "${M[S[$((I + 4))]]}" "${M[S[$((I + 5))]]}" &
blake2s_mix "V[3]" "${V[3]}" "V[7]" "${V[7]}" "V[11]" "${V[11]}" "V[15]" "${V[15]}" "${M[S[$((I + 6))]]}" "${M[S[$((I + 7))]]}" &
} & wait "$!")"
eval "$({
blake2s_mix "V[0]" "${V[0]}" "V[5]" "${V[5]}" "V[10]" "${V[10]}" "V[15]" "${V[15]}" "${M[S[$((I + 8))]]}" "${M[S[$((I + 9))]]}" &
blake2s_mix "V[1]" "${V[1]}" "V[6]" "${V[6]}" "V[11]" "${V[11]}" "V[12]" "${V[12]}" "${M[S[$((I + 10))]]}" "${M[S[$((I + 11))]]}" &
blake2s_mix "V[2]" "${V[2]}" "V[7]" "${V[7]}" "V[8]" "${V[8]}" "V[13]" "${V[13]}" "${M[S[$((I + 12))]]}" "${M[S[$((I + 13))]]}" &
blake2s_mix "V[3]" "${V[3]}" "V[4]" "${V[4]}" "V[9]" "${V[9]}" "V[14]" "${V[14]}" "${M[S[$((I + 14))]]}" "${M[S[$((I + 15))]]}" &
} & wait "$!")"
done
H=(
$((H[0] ^ V[0] ^ V[8]))
$((H[1] ^ V[1] ^ V[9]))
$((H[2] ^ V[2] ^ V[10]))
$((H[3] ^ V[3] ^ V[11]))
$((H[4] ^ V[4] ^ V[12]))
$((H[5] ^ V[5] ^ V[13]))
$((H[6] ^ V[6] ^ V[14]))
$((H[7] ^ V[7] ^ V[15]))
)
if [ $((F[0])) -ne 0 ]; then break; fi
done
for WORD in "${H[@]}"; do
printf '%02x%02x%02x%02x' "$(((WORD >> 0) & 0xff))" "$(((WORD >> 8) & 0xff))" "$(((WORD >> 16) & 0xff))" "$(((WORD >> 24) & 0xff))"
done | head -c "$((DLEN * 2))"
}
printf '\n'
}
wg_lla() {
local WORDS
eval "WORDS=($(base64 -d | blake2s 32 | sed -r 's/[0-9a-f]{4}/0x\0 /g'))"
printf '%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n' "$((0xfe80 | (WORDS[0] & 0x003f)))" "${WORDS[1]}" "${WORDS[2]}" "${WORDS[3]}" "${WORDS[4]}" "${WORDS[5]}" "${WORDS[6]}" "${WORDS[7]}"
}
IFACES=("$@")
DRY_RUN=1
if [ $# -gt 1 ] && [ "${IFACES[${#IFACES[@]} - 1]}" == "assign" ]; then
unset 'IFACES[${#IFACES[@]} - 1]'
DRY_RUN=0
fi
if [ ${#IFACES[@]} -eq 0 ]; then
printf 'Usage: %s { <interface> | all | interfaces } [assign]\n\n' "$(basename "$0")" 1>&2
printf 'Calculates cryptographically-bound IPv6 Link-Local Addresses for the specified\n' 1>&2
printf 'WireGuard interface(s) and its peers.\n' 1>&2
exit 1
fi
if [ ${#IFACES[@]} -eq 1 ] && [ "${IFACES[0]}" == "all" ]; then
read -ra IFACES <<EOF
$(wg show interfaces)
EOF
fi
for IFACE in "${IFACES[@]}"; do
IFACE_KEY="$(wg show "$IFACE" public-key)"
IFACE_LLA="$(printf '%s' "$IFACE_KEY" | wg_lla)"
printf '%s\t%s/10\n' "$IFACE_KEY" "$IFACE_LLA"
if [ "$DRY_RUN" -eq 0 ]; then
ip address add "$IFACE_LLA/10" dev "$IFACE" 2>/dev/null || :
fi
wg show "$IFACE" allowed-ips | while read -r LINE; do
PEER="$(printf '%s' "$LINE" | cut -f 1)"
ALLOWED_IPS="$(printf '%s' "$LINE" | cut -f 2)"
LLA="$(printf '%s' "$PEER" | wg_lla)"
printf '%s\t%s/128\n' "$PEER" "$LLA"
if [ "$DRY_RUN" -eq 0 ]; then
wg set "$IFACE" peer "$PEER" allowed-ips "$(printf '%s' "$ALLOWED_IPS" | sed -r 's/\s+/,/g'),$LLA/128"
fi
done
done
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