openssh/regress/integrity.sh

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# $OpenBSD: integrity.sh,v 1.19 2016/11/25 02:56:49 dtucker Exp $
# Placed in the Public Domain.
tid="integrity"
cp $OBJ/sshd_proxy $OBJ/sshd_proxy_bak
# start at byte 2900 (i.e. after kex) and corrupt at different offsets
# XXX the test hangs if we modify the low bytes of the packet length
# XXX and ssh tries to read...
tries=10
startoffset=2900
macs=`${SSH} -Q mac`
# The following are not MACs, but ciphers with integrated integrity. They are
# handled specially below.
macs="$macs `${SSH} -Q cipher-auth`"
# avoid DH group exchange as the extra traffic makes it harder to get the
# offset into the stream right.
echo "KexAlgorithms diffie-hellman-group14-sha1,diffie-hellman-group1-sha1" \
>> $OBJ/ssh_proxy
# sshd-command for proxy (see test-exec.sh)
cmd="$SUDO sh ${SRC}/sshd-log-wrapper.sh ${TEST_SSHD_LOGFILE} ${SSHD} -i -f $OBJ/sshd_proxy"
for m in $macs; do
trace "test $tid: mac $m"
elen=0
epad=0
emac=0
ecnt=0
skip=0
for off in `jot $tries $startoffset`; do
skip=`expr $skip - 1`
if [ $skip -gt 0 ]; then
# avoid modifying the high bytes of the length
continue
fi
cp $OBJ/sshd_proxy_bak $OBJ/sshd_proxy
# modify output from sshd at offset $off
pxy="proxycommand=$cmd | $OBJ/modpipe -wm xor:$off:1"
if ${SSH} -Q cipher-auth | grep "^${m}\$" >/dev/null 2>&1 ; then
echo "Ciphers=$m" >> $OBJ/sshd_proxy
macopt="-c $m"
else
echo "Ciphers=aes128-ctr" >> $OBJ/sshd_proxy
echo "MACs=$m" >> $OBJ/sshd_proxy
macopt="-m $m -c aes128-ctr"
fi
verbose "test $tid: $m @$off"
${SSH} $macopt -2F $OBJ/ssh_proxy -o "$pxy" \
-oServerAliveInterval=1 -oServerAliveCountMax=30 \
999.999.999.999 'printf "%4096s" " "' >/dev/null
if [ $? -eq 0 ]; then
fail "ssh -m $m succeeds with bit-flip at $off"
fi
ecnt=`expr $ecnt + 1`
out=$(egrep -v "^debug" $TEST_SSH_LOGFILE | tail -2 | \
tr -s '\r\n' '.')
case "$out" in
Bad?packet*) elen=`expr $elen + 1`; skip=3;;
Corrupted?MAC* | *message?authentication?code?incorrect*)
emac=`expr $emac + 1`; skip=0;;
padding*) epad=`expr $epad + 1`; skip=0;;
*) fail "unexpected error mac $m at $off: $out";;
esac
done
verbose "test $tid: $ecnt errors: mac $emac padding $epad length $elen"
if [ $emac -eq 0 ]; then
fail "$m: no mac errors"
fi
expect=`expr $ecnt - $epad - $elen`
if [ $emac -ne $expect ]; then
fail "$m: expected $expect mac errors, got $emac"
fi
done