Add support for testing postgres protocol over TLS/SSL

The Postgres protocol uses STARTTLS with a custom start packet. This
functionality is supported by openssl s_client in the current openssl
master branch but not yet in any released version.

This patch detects whether the given openssl binary supports postgres
and runs the default tests against a postgres server.

Example of no openssl support:

    ~/bin/testssl$ ./testssl.sh --quiet
    --openssl=/opt/openssl/openssl-1.1.0c/bin/openssl --starttls=postgres
    test.postgres.server.com:5432

     Start 2016-12-07 18:03:24    -->> ip.add.re.ss:5432
    (test.postgres.server.com:5432) <<--

    Fatal error: Your /opt/openssl/openssl-1.1.0c/bin/openssl does not
    support the "-starttls postgres" option

Example of openssl support:

    ~/bin/testssl$ ./testssl.sh --quiet
    --openssl=/opt/openssl/openssl-2016-12-07/bin/openssl --startt ls=postgres
    test.postgres.server.com:5432

     Start 2016-12-07 18:06:03    -->> ip.add.re.ss:5432
    (test.postgres.server.com:5432) <<--

     Service set:            STARTTLS via POSTGRES

     Testing protocols (via openssl, SSLv2 via sockets)

     SSLv2               not offered (OK)
     SSLv3               offered (NOT ok)
     TLS 1               offered
     TLS 1.1             offered
     TLS 1.2             offered (OK)
     SPDY/NPN            (SPDY is an HTTP protocol and thus not tested here)
     HTTP2/ALPN          (HTTP/2 is a HTTP protocol and thus not tested
    here)
    ...

testssl.sh

@@ -226,6 +226,7 @@ HAS_SPDY=false
 HAS_FALLBACK_SCSV=false
 HAS_PROXY=false
 HAS_XMPP=false
+HAS_POSTGRES=false
 ADD_RFC_STR="rfc"                       # display RFC ciphernames
 PORT=443                                # unless otherwise auto-determined, see below
 NODE=""
@@ -6227,6 +6228,16 @@ starttls_nntp_dialog() {
      return $ret
 }
 
+starttls_postgres_dialog() {
+     debugme echo "=== starting postgres STARTTLS dialog ==="
+     local reINITTLS="\x00\x00\x00\x08\x04\xD2\x16\x2F"
+     starttls_just_send "${reINITTLS}"                     && debugme echo "initiated STARTTLS" &&
+     starttls_full_read '' '' 'S'                          && debugme echo "received ack for STARTTLS"
+     local ret=$?
+     debugme echo "=== finished postgres STARTTLS dialog with ${ret} ==="
+     return $ret
+}
+
 # arg for a fd doesn't work here
 fd_socket() {
      local jabber=""
@@ -6301,6 +6312,9 @@ EOF
                     starttls_line "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>" "proceed"
                     # BTW: https://xmpp.net !
                     ;;
+               postgres|postgress) # Postgres SQL, see http://www.postgresql.org/docs/devel/static/protocol-message-formats.html
+                    starttls_postgres_dialog
+                    ;;
                *) # we need to throw an error here -- otherwise testssl.sh treats the STARTTLS protocol as plain SSL/TLS which leads to FP
                     fatal "FIXME: STARTTLS protocol $STARTTLS_PROTOCOL is not yet supported" -4
           esac
@@ -9155,6 +9169,7 @@ test_openssl_suffix() {
 
 find_openssl_binary() {
      local s_client_has=$TEMPDIR/s_client_has.txt
+     local s_client_starttls_has=$TEMPDIR/s_client_starttls_has.txt
 
      # 0. check environment variable whether it's executable
      if [[ -n "$OPENSSL" ]] && [[ ! -x "$OPENSSL" ]]; then
@@ -9211,6 +9226,8 @@ find_openssl_binary() {
 
      $OPENSSL s_client -help 2>$s_client_has
 
+     $OPENSSL s_client -starttls foo 2>$s_client_starttls_has
+
      grep -qw '\-alpn' $s_client_has && \
           HAS_ALPN=true
 
@@ -9226,6 +9243,9 @@ find_openssl_binary() {
      grep -q '\-xmpp' $s_client_has && \
           HAS_XMPP=true
 
+     grep -q 'postgres' $s_client_starttls_has && \
+          HAS_POSTGRES=true
+
      if [[ "$OPENSSL_TIMEOUT" != "" ]]; then
           if which timeout >&2 2>/dev/null ; then
                # there are different "timeout". Check whether --preserve-status is supported
@@ -9307,7 +9327,7 @@ help() {
 "$PROG_NAME <options> URI", where <options> is:
 
      -t, --starttls <protocol>     does a default run against a STARTTLS enabled <protocol, 
-                                   protocol is <ftp|smtp|pop3|imap|xmpp|telnet|ldap> (latter two require supplied openssl)
+                                   protocol is <ftp|smtp|pop3|imap|xmpp|telnet|ldap|postgres> (latter three require supplied openssl)
      --xmpphost <to_domain>        for STARTTLS enabled XMPP it supplies the XML stream to-'' domain -- sometimes needed
      --mx <domain/host>            tests MX records from high to low priority (STARTTLS, port 25)
      --file <fname>                mass testing option: Reads command lines from <fname>, one line per instance.
@@ -9440,6 +9460,7 @@ HAS_ALPN: $HAS_ALPN
 HAS_FALLBACK_SCSV: $HAS_FALLBACK_SCSV
 HAS_PROXY: $HAS_PROXY
 HAS_XMPP: $HAS_XMPP
+HAS_POSTGRES: $HAS_POSTGRES
 
 PATH: $PATH
 PROG_NAME: $PROG_NAME
@@ -10070,7 +10091,7 @@ determine_optimal_proto() {
 }
 
 
-# arg1: ftp smtp, pop3, imap, xmpp, telnet, ldap (maybe with trailing s)
+# arg1: ftp smtp, pop3, imap, xmpp, telnet, ldap, postgres (maybe with trailing s)
 determine_service() {
      local ua
      local protocol
@@ -10097,9 +10118,13 @@ determine_service() {
           service_detection $OPTIMAL_PROTO
      else
           # STARTTLS
-          protocol=${1%s}    # strip trailing 's' in ftp(s), smtp(s), pop3(s), etc
+          if [[ "$1" == postgres ]]; then
+               protocol="postgres"
+          else
+               protocol=${1%s}    # strip trailing 's' in ftp(s), smtp(s), pop3(s), etc
+          fi
           case "$protocol" in
-               ftp|smtp|pop3|imap|xmpp|telnet|ldap)
+               ftp|smtp|pop3|imap|xmpp|telnet|ldap|postgres)
                     STARTTLS="-starttls $protocol"
                     SNI=""
                     if [[ "$protocol" == xmpp ]]; then
@@ -10113,6 +10138,12 @@ determine_service() {
                               # see http://xmpp.org/rfcs/rfc3920.html
                          fi
                     fi
+                    if [[ "$protocol" == postgres ]]; then
+                         # Check if openssl version supports postgres.
+                         if ! "$HAS_POSTGRES"; then
+                              fatal "Your $OPENSSL does not support the \"-starttls postgres\" option" -5
+                         fi
+                    fi
                     $OPENSSL s_client -connect $NODEIP:$PORT $PROXY $BUGS $STARTTLS 2>$ERRFILE >$TMPFILE </dev/null
                     if [[ $? -ne 0 ]]; then
                          debugme cat $TMPFILE
@@ -10126,7 +10157,7 @@ determine_service() {
                     outln
                     ;;
                *)   outln
-                    fatal "momentarily only ftp, smtp, pop3, imap, xmpp, telnet and ldap allowed" -4
+                    fatal "momentarily only ftp, smtp, pop3, imap, xmpp, telnet, ldap and postgres allowed" -4
                     ;;
           esac
      fi
@@ -10438,8 +10469,8 @@ parse_cmd_line() {
                     STARTTLS_PROTOCOL=$(parse_opt_equal_sign "$1" "$2")
                     [[ $? -eq 0 ]] && shift
                     case $STARTTLS_PROTOCOL in
-                         ftp|smtp|pop3|imap|xmpp|telnet|ldap|nntp) ;;
+                         ftp|smtp|pop3|imap|xmpp|telnet|ldap|nntp|postgres) ;;
-                         ftps|smtps|pop3s|imaps|xmpps|telnets|ldaps|nntps) ;;
+                         ftps|smtps|pop3s|imaps|xmpps|telnets|ldaps|nntps|postgress) ;;
                          *)   pr_magentaln "\nunrecognized STARTTLS protocol \"$1\", see help" 1>&2
                               help 1 ;;
                     esac