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recognise TLS alert as a sign that SSLv2 is not supported

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Revert the exception from previous commit 20b38d5aa6
that TLS alerts on SSLv2 client hello won't be a proper reply -- due to a reality check,
see #908.

In order to have better debugging info the TLS alert message is printed
in clear. Messages code and text assignements was moveed to a separate
function.
This commit is contained in:
Dirk 2017-11-29 11:43:35 +01:00
parent ece1d868c4
commit f61b701f5a
1 changed files with 74 additions and 49 deletions
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123
testssl.sh
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@ -4235,11 +4235,6 @@ run_protocols() {
[[ $DEBUG -ge 3 ]] && hexdump -C "$TEMPDIR/$NODEIP.sslv2_sockets.dd" | head -1
fileout "sslv2" "WARN" "SSLv2: received a strange SSLv2 reply (rerun with DEBUG>=2)"
;;
8) # no correct server hello
prln_cyan "no valid SSLv2 server hello"
fileout "sslv2" "WARN" "server sent no valid reply"
add_tls_offered ssl2 no
;;
1) # no sslv2 server hello returned, like in openlitespeed which returns HTTP!
prln_done_best "not offered (OK)"
fileout "sslv2" "OK" "SSLv2 is not offered"
@ -8299,12 +8294,21 @@ get_dh_ephemeralkey() {
# arg1: name of file with socket reply
# arg2: true if entire server hello should be parsed
# return values: 0=no SSLv2 (reset)
# 1=no SSLv2 (plaintext reply like it happens with OLS webservers)
# 3=SSLv2 supported (in $TEMPDIR/$NODEIP.sslv2_sockets.dd is reply for further processing
# --> there could be checked whether ciphers e.g have been returned at all (or anything else)
# 4=looks like an STARTTLS 5xx message
# 6=socket coudln't be opened
# 7=strange reply we can't deal with
parse_sslv2_serverhello() {
local ret v2_hello_ascii v2_hello_initbyte v2_hello_length
local v2_hello_handshake v2_cert_type v2_hello_cert_length
local v2_hello_cipherspec_length tmp_der_certfile
local -i certificate_len nr_ciphers_detected offset i
# server hello: in hex representation, see below
local ret=3
local parse_complete="false"
# SSLv2 server hello: in hex representation, see below
# byte 1+2: length of server hello 0123
# 3: 04=Handshake message, server hello 45
# 4: session id hit or not (boolean: 00=false, this 67
@ -8317,8 +8321,8 @@ parse_sslv2_serverhello() {
# [certificate length] ==> certificate
# [cipher spec length] ==> ciphers GOOD: HERE ARE ALL CIPHERS ALREADY!
local ret=3
local parse_complete="false"
# Note: recent SSL/TLS stacks reply with a TLS alert on a SSLv2 client hello.
# The TLS error message is different and could be used for fingerprinting.
if [[ "$2" == "true" ]]; then
parse_complete=true
@ -8347,8 +8351,18 @@ parse_sslv2_serverhello() {
# this could be a 500/5xx for some weird reason where the STARTTLS handshake failed
debugme echo "$(hex2ascii "$v2_hello_ascii")"
ret=4
elif [[ "${v2_hello_ascii:0:4}" == "1503" ]]; then
# Cloudflare does this, OpenSSL 1.1.1 and picoTLS. With different alert messages
# Just in case somebody's interested in the exact error, we deliver it ;-)
debugme echo -n ">TLS< alert message discovered: ${v2_hello_ascii} "
case "${v2_hello_ascii:10:2}" in
01) debugme echo "(01/warning: 0x"${v2_hello_ascii:12:2}"/$(tls_alert "${v2_hello_ascii:12:2}"))" ;;
02) debugme echo "(02/fatal: 0x"${v2_hello_ascii:12:2}"/$(tls_alert "${v2_hello_ascii:12:2}"))" ;;
*) debugme echo "("${v2_hello_ascii:10:2}" : "${v2_hello_ascii:12:2}"))" ;;
esac
ret=0
elif [[ $v2_hello_initbyte != "8" ]] || [[ $v2_hello_handshake != "04" ]]; then
ret=8
ret=1
if [[ $DEBUG -ge 2 ]]; then
echo "no correct server hello"
echo "SSLv2 server init byte: 0x0$v2_hello_initbyte"
@ -8501,6 +8515,52 @@ check_tls_serverhellodone() {
return 1
}
# arg1: tls alert error/warning code
# returns: description
tls_alert() {
local tls_alert_text=""
case "$1" in
00) tls_alert_text="close notify" ;;
0A) tls_alert_text="unexpected message" ;;
14) tls_alert_text="bad record mac" ;;
15) tls_alert_text="decryption failed" ;;
16) tls_alert_text="record overflow" ;;
1E) tls_alert_text="decompression failure" ;;
28) tls_alert_text="handshake failure" ;;
29) tls_alert_text="no certificate RESERVED" ;;
2A) tls_alert_text="bad certificate" ;;
2B) tls_alert_text="unsupported certificate" ;;
2C) tls_alert_text="certificate revoked" ;;
2D) tls_alert_text="certificate expired" ;;
2E) tls_alert_text="certificate unknown" ;;
2F) tls_alert_text="illegal parameter" ;;
30) tls_alert_text="unknown ca" ;;
31) tls_alert_text="access denied" ;;
32) tls_alert_text="decode error" ;;
33) tls_alert_text="decrypt error" ;;
3C) tls_alert_text="export restriction RESERVED" ;;
46) tls_alert_text="protocol version" ;;
47) tls_alert_text="insufficient security" ;;
50) tls_alert_text="internal error" ;;
56) tls_alert_text="inappropriate fallback" ;;
5A) tls_alert_text="user canceled" ;;
64) tls_alert_text="no renegotiation" ;;
6D) tls_alert_text="missing extension" ;;
6E) tls_alert_text="unsupported extension" ;;
6F) tls_alert_text="certificate unobtainable" ;;
70) tls_alert_text="unrecognized name" ;;
71) tls_alert_text="bad certificate status response" ;;
72) tls_alert_text="bad certificate hash value" ;;
73) tls_alert_text="unknown psk identity" ;;
74) tls_alert_text="certificate required" ;;
78) tls_alert_text="no application protocol" ;;
*) tls_alert_text="$(hex2dec "$1")";;
esac
echo "$tls_alert_text"
return 0
}
# arg1: ASCII-HEX encoded reply
# arg2: (optional): "all" - process full response (including Certificate and certificate_status handshake messages)
# "ephemeralkey" - extract the server's ephemeral key (if any)
@ -8520,7 +8580,7 @@ parse_tls_serverhello() {
local tls_alert_descrip tls_sid_len_hex issuerDN subjectDN CAissuerDN CAsubjectDN
local -i tls_sid_len offset extns_offset nr_certs=0
local tls_msg_type tls_content_type tls_protocol tls_protocol2 tls_hello_time
local tls_err_level tls_err_descr tls_cipher_suite rfc_cipher_suite tls_compression_method
local tls_err_level tls_err_descr_no tls_cipher_suite rfc_cipher_suite tls_compression_method
local tls_extensions="" extension_type named_curve_str="" named_curve_oid
local -i i j extension_len tls_extensions_len ocsp_response_len ocsp_response_list_len
local -i certificate_list_len certificate_len cipherlist_len
@ -8616,50 +8676,15 @@ parse_tls_serverhello() {
debugme tmln_warning "Malformed message."
return 1
fi
#FIXME: can't we skip the tls alert handling if we have $DEBUG -ne 0?
if [[ $tls_alert_ascii_len -gt 0 ]]; then
debugme echo "TLS alert messages:"
for (( i=0; i+3 < tls_alert_ascii_len; i=i+4 )); do
tls_err_level=${tls_alert_ascii:i:2} # 1: warning, 2: fatal
j=$i+2
tls_err_descr=${tls_alert_ascii:j:2}
debugme tm_out " tls_err_descr: 0x${tls_err_descr} / = $(hex2dec ${tls_err_descr})"
case $tls_err_descr in
00) tls_alert_descrip="close notify" ;;
0A) tls_alert_descrip="unexpected message" ;;
14) tls_alert_descrip="bad record mac" ;;
15) tls_alert_descrip="decryption failed" ;;
16) tls_alert_descrip="record overflow" ;;
1E) tls_alert_descrip="decompression failure" ;;
28) tls_alert_descrip="handshake failure" ;;
29) tls_alert_descrip="no certificate RESERVED" ;;
2A) tls_alert_descrip="bad certificate" ;;
2B) tls_alert_descrip="unsupported certificate" ;;
2C) tls_alert_descrip="certificate revoked" ;;
2D) tls_alert_descrip="certificate expired" ;;
2E) tls_alert_descrip="certificate unknown" ;;
2F) tls_alert_descrip="illegal parameter" ;;
30) tls_alert_descrip="unknown ca" ;;
31) tls_alert_descrip="access denied" ;;
32) tls_alert_descrip="decode error" ;;
33) tls_alert_descrip="decrypt error" ;;
3C) tls_alert_descrip="export restriction RESERVED" ;;
46) tls_alert_descrip="protocol version" ;;
47) tls_alert_descrip="insufficient security" ;;
50) tls_alert_descrip="internal error" ;;
56) tls_alert_descrip="inappropriate fallback" ;;
5A) tls_alert_descrip="user canceled" ;;
64) tls_alert_descrip="no renegotiation" ;;
6D) tls_alert_descrip="missing extension" ;;
6E) tls_alert_descrip="unsupported extension" ;;
6F) tls_alert_descrip="certificate unobtainable" ;;
70) tls_alert_descrip="unrecognized name" ;;
71) tls_alert_descrip="bad certificate status response" ;;
72) tls_alert_descrip="bad certificate hash value" ;;
73) tls_alert_descrip="unknown psk identity" ;;
74) tls_alert_descrip="certificate required" ;;
78) tls_alert_descrip="no application protocol" ;;
*) tls_alert_descrip="$(hex2dec "$tls_err_descr")";;
esac
tls_err_descr_no=${tls_alert_ascii:j:2}
debugme tm_out " tls_err_descr_no: 0x${tls_err_descr_no} / = $(hex2dec ${tls_err_descr_no})"
tls_alert_descrip="$(tls_alert "$tls_err_descr_no")"
if [[ $DEBUG -ge 2 ]]; then
tmln_out " ($tls_alert_descrip)"
tm_out " tls_err_level: ${tls_err_level}"