RSA-PSS in X.509 is truly horrible, and OpenSSL does not expose very good APIs
to extract this, even though the library does handle it internally. Instead, we
must tediously unwrap RFC 4055's unnecessarily complicated encoding of
RFC 8017's unnecessarily flexible RSA-PSS definition.
This reverts commit 00baf58a71. That
change appears to have been incorrect. It's described as simplying
retrieving the "default signature digest", but it actually changed the
function's behavior entirely. The function wasn't retrieving defaults
previously.
A certificate contains, among other things, a public key and a
signature. The public key is the public key of the subject. However, the
signature was generated by the issuer. That is, if I get a certificate
from a CA, the public key will be my public key and the signature will
be my CA's signature over the certificate contents.
Now, the original code returned the digest used in the certificate's
signature. That is, it tells you which signature algorithm did my *CA*
use to sign my certificate.
The new code extracts the certificate's public key (my public key, not
the CA's). This doesn't necessarily tell you the signature algorithm, so
it then asks OpenSSL what the "default" signature algorithm would it use
with the key. This notion of "default" is ad-hoc and has changed over
time with OpenSSL releases. It doesn't correspond to any particular
protocol semantics. It's not necessarily the signature algorithm of the
certificate.
Now, looking at where this function is used, it's called by
freerdp_certificate_get_signature_alg, which is called by
tls_get_channel_binding to compute the tls-server-end-point channel
binding. That code cites RFC 5929, which discusses picking the hash
algorithm based on the certificate's signatureAlgorithm:
https://www.rfc-editor.org/rfc/rfc5929#section-4.1
That is, the old version of the code was correct and the
"simplification" broke it. Revert this and restore the original version.
I suspect this went unnoticed because, almost all the time, both the old
and new code picked SHA-256 and it was fine. But if the certificate was,
say, signed with SHA-384, the new code would compute the wrong channel
binding.
The RDS AAD Auth PDUs have no packet headers to indicate length.
Instead, these packets are zero-terminated strings. Somehow, Windows
accepts Authentication Request PDUs without a terminating null byte
during regular connections, but not through WVD websocket gateways.
* Add new option WITH_ABSOLUTE_PLUGIN_LOAD_PATHS to allow overriding
platform default option (load channel plugins with absolute paths or
from environment search paths)
* Fix freerdp_get_dynamic_addin_install_path: use native platform path
separators
* release all keyboard modifiers on pause
* release/sync keyboard modifier states on resume
* update modifier states on keyDown, keyUp and flagsChanged
the capture plugin was written for FreeRDP2 proxy, which used a
different approach that is no longer working with FreeRDP3.
Drop the module so that we don´t diffuse people into thinking that this
is working.
