This commit addresses the comments in #1205. If a server only supports TLS 1.3, then it is not considered an issue if the server does not enforce a cipher order. However, if the server does not support a cipher order for TLS 1.2 and below, then that is an issue, even if the server does support a cipher order for TLS 1.3.
This PR is an attempt to fix#1163 by running separate tests for a server cipher order preference to TLSv1.3 and for SSLv3 - TLSv1.2.
If the server supports TLSv1.3, then a test is performed to determine whether the server enforces a cipher order to TLSv1.3. A separate test is performed for SSLv3 - TLSv1.2 unless it is known that the server does not support any of these protocols.
If the server enforces a cipher order for SSLv3 - TLSv1.2, but not for TLSv1.3, then cipher_pref_check() is not called for TLSv1.3, since cipher_pref_check() is intended to show the cipher order that the server enforces. As TLSv1.3 will be the negotiated protocol if it is supported, the negotiated cipher for TLSv1.3 will already be presented.
This PR still has one major flaw, which may create a problem when testing a TLSv1.3-only server. If run_protocols() is run before run_server_preference(), then everything will be okay, as run_server_preference() will be able to determine that SSLv3 - TLSv1.2 are not supported. However, if run_server_preference() is run by itself, run_server_preference() will not know that SSLv3 - TLSv1.2 are not supported and so it will try to determine whether the server enforces a cipher preference order for these protocols. The attempt to connect to the server will fail, but at the moment run_server_preference() doesn't know whether the failure is because the server does not support SSLv3 - TLSv1.2 or because the server supports at least one of these protocols, but does not support any ciphers in $list_fwd. At the moment, run_server_preference() incorrectly flags an error.
One option would be to perform additional tests against the server in this case to determine the reason for the connection failure. Another option would be to have some code that is always run earlier, such as determine_optimal_proto(), test whether a server that supports TLSv1.3 supports any earlier protocols (SSLv3 - TLSv1.2).
In run_drown(), $jsonID is set to "DROWN" and most calls to fileout() are of the form
fileout "$jsonID" ...
However, one call is written as
fileout "DROWN" ...
This PR changes this one call to be consistent with the others. This does not change the functionality of the program.
At the moment, $do_starttls is initialized to true in initialize_globals() and then it is set to true again in parse_cmd_line() if the --starttls command line option is used. Presumably the intention was to set $do_starttls to false in initialize_globals().
This PR fixes a minor bug in parse_tls_serverhello(). In some cases the server's entire response is not retrieved. In these cases, it is possible that the response from the server ends with a portion of a handshake message.
The loop at the beginning of parse_tls_serverhello() extracts the various handshake and alert messages from the server's response. If it gets to the end of the response, and what is at the end is not a complete message, it should just ignore that fragment and break out of the loop. At the moment, however, parse_tls_serverhello() just continues in the loop rather than breaking out. This has not been a problem up to now, since $msg_len is usually set to a positive value from a previous iteration of the loop, which causes the loop to end.
In the case of the server identified in #1353, however, $msg_len is 0 and so the continue rather than break results in an endless loop.
Add another pattern because the SEDs tested so far do not seem to be fine with header containing x0d x0a (CRLF) -- which is the usual case. So we also trigger on any sign on a single line which is not alphanumeric (plus _)
See #1351
This PR fixes a bug in modify_clienthello() that occurs when client simulation is being performed, the ClientHello contain an SNI extension, and $SNI is empty. In the case, modify_clienthello() should just skip over the SNI extension and not include one in the modified ClientHello. However, the code currently only skips over the 2-byte extension type. The result being that the remainder of the extension is included in the modified ClientHello. This PR fixes the problem by ensuring the $offset is advanced whether or not $SNI is empty.
PR #1336 included logic to pre-test the server side with sockets
and/or with openssl. However when the user supplied --ssl-native
sockets were never tested before. As a result ALL_FAILED_SOCKETS
was still true, so that the final eif statement complaint erroneously
that sockets didn't work but openssl does.
Also Travis complaint.
This PR fixes it by checking SSL_NATIVE to the final part of the
if statement.
One could also test sockets before and then set ALL_FAILED_SOCKETS
appropriately but that would only make sense if the socket methods
like run_robot() or run_heartbleed() would check ALL_FAILED_SOCKETS
first.
At the moment I went for this as it is easier and the case that sockets
aren't working but openssl does seems not very likely.
There are a few places where testssl.sh sends a TLS 1.2 (or TLS 1.3) ClientHello and expects the server to respond with a ServerHello as long as it supports TLS 1.2 (or TLS 1.3) or earlier.
run_protocols() performs a fairly thorough check for a server's ability to handle version negotiation, but the problem may also be caught by determine_optimal_sockets_params(), if the server rejects a TLS 1.2 ClientHello even though it supports some earlier protocol version.
In the future, we could try to make use of $OPTIMAL_SOCKETS_PROTO in order to make testssl.sh work a bit better with servers (if any still exist) that don't handle version negotiation correctly. At the moment, though, this PR just prints a warning to the user that the server is buggy, and that this may lead to problems in the scan. It doesn't call fileout() to add anything to the JSON/CSV output, since run_protocols() should already be doing that.
This PR modifies run_protocols() to use the information collected by determine_optimal_sockets_params(). If it has already been determined that a protocol is supported, then no test is run. run_protocols() will still run a test for a protocol even if it has been determined that the server does not support that protocol. The reason for running the test is to verify that the server handles version negotiation correctly. This could be a TLSv1 server that rejects a TLSv1.2 or TLSv1.3 ClientHello, or it could happen in the opposite direction. At one point there was a server that would respond to an SSLv3 ClientHello with a TLSv1.2 ServerHello.
This PR required a couple of changes to determine_optimal_sockets_params() so that additional information could be passed to run_protocols(). If the server supports TLS 1.3, then run_protocols() needs to know which version (RFC 8446, draft 28, draft 27, etc.) rather than just that TLS 1.3 is supported. If the server supports TLS 1.2, but not TLS 1.3, then run_protocols() needs to know about at least one TLS 1.2 cipher that the server supports so that it can form a TLS 1.3 ClientHello that has no more than 128 ciphers and that should result in the server returning a TLS 1.2 ServerHello.
In a PR that I'm developing to to use the results of determine_optimal_sockets_params() in run_protocols() I add specific versions of TLS 1.3 to PROTOS_OFFERED (e.g., tls1_3_rfc8446, tsl1_3_draft28). If that PR is accepted, then the current check for TLS 1.3-only will no longer work. So, this commit changes the way that the check for TLS 1.3-only is performed in order to avoid problems if the other PR is merged.
This PR takes advantage of the testing done by determine_optimal_sockets_params() in order to simplify determine_sizelimitbug().
By the time that determine_sizelimitbug() is called, determine_optimal_sockets_params() has already determined whether TLSv1.2 ClientHello with 128 ciphers (including 00FF) sent by tls_sockets() works, and it has set TLS12_CIPHER to a list of exactly 128 ciphers (including 00FF) that works with the server. So, determine_sizelimitbug() doesn't have to check whether the server supports TLSv1.2 and no longer needs to send tests using 127 or 128 ciphers. determine_sizelimitbug() can just perform one test with 129 ciphers, if the server supports TLSv1.2, and use the results to set $SERVER_SIZE_LIMIT_BUG.
This PR reverts determine_optimal_proto() to use OpenSSL again rather than tls_sockets().
The primary reason for this is that the primary purpose of determine_optimal_proto() is to set OPTIMAL_PROTO, which is only used with $OPENSSL s_client. So, the best way to determine what works best on the $OPENSSL s_client command line is to use $OPENSSL s_client.
In most cases, determine_optimal_proto_sockets_helper() would set OPTIMAL_PROTO to an acceptable value, but it might not always do so. For example, suppose that a server
* supports different cipher suites with different protocols,
* supports TLSv1.2, but only with cipher suites not supported by $OPENSSL, but
* supports TLSv1.1 with at least one cipher suite supported by $OPENSSL.
In the above case, determine_optimal_proto_sockets_helper() would set OPTIMAL_PROTO to "-tls1_2", but testing using $OPENSSL would result in OPTIMAL_PROTO being set to "-tls1_1".
Using $OPENSSL for determine_optimal_proto() also allows for edge cases to be detected earlier:
* If the server only supports TLSv1.3, and $OPENSSL does not support TLSv1.3, then the code in this PR will detect that (rather than waiting until run_protocols() is executed).
* The code in this PR can also detect if the server only supports SSLv3 (and possibly also SSLv2), but $OPENSSL does not support SSLv3.
* This code can also detect the (rare) case in which connections using $OPENSSL succeed, but connections using tls_sockets() fail.
[Note also that in the current code, if $all_failed is true, then a message may be printed that $OPENSSL is not IPv6 aware, even if testing was performed using tls_sockets() rather than $OPENSSL.]
This PR fixes an issue with sub_session_resumption() when using OpenSSL 1.1.1.
As noted in #1335, some servers will return a session ticket for TLSv1.2, but not for TLSv1.3.
OpenSSL 1.1.1 does not support the "-no_ssl2" option, and so when using OpenSSL 1.1.1 sub_session_resumption() adds $OPTIMAL_PROTO to the $OPENSSL s_client command line. When determine_optimal_proto_sockets_helper() is called, $OPTIMAL_PROTO will generally be set to "-tls1_2" (or "-tls1_1" or "-tls1") unless the server is a TLSv1.3-only server. As a result sub_session_resumption() will specify that same protocol on the command line if OpenSSL 1.1.1 is being used.
If "--ssl-native" is used, however, then determine_optimal_proto() will set $OPTIMAL_PROTO to "-tls1_3" if the server supports TLSv1.3 (and doesn't use STARTTLS). Similarly, if the version of determine_optimal_proto() in #1336 is used, then $OPTIMAL_PROTO will usually be empty. In either case, sub_session_resumption() will send a TLSv1.3 ClientHello, even if the server only supports session tickets for TLSv1.2 and below.
This PR appears to fix the problem. This PR makes no changes when using a version of OpenSSL that supports "-no_ssl2". When using a version of OpenSSL that does not support "-no_ssl2", however, rather than using $OPTIMAL_PROTO, this PR has sub_session_resumption() use whatever protocol version the server connected with when $sessticket_lifetime_hint was set.
David Cooper
Dirk Wetter
Thomas Kähn
Christoph Settgast
Gonçalo Ribeiro