[MS-RDPBCGR] Section 5.3 describes the encryption level and method values for
standard RDP security.
Looking at the current usage of these values in the FreeRDP code gives me
reason to believe that there is a certain lack of understanding of how these
values should be handled.
The encryption level is only configured on the server side in the "Encryption
Level" setting found in the Remote Desktop Session Host Configuration RDP-Tcp
properties dialog and this value is never transferred from the client to the
server over the wire.
The possible options are "None", "Low", "Client Compatible", "High" and
"FIPS Compliant". The client receices this value in the Server Security Data
block (TS_UD_SC_SEC1), probably only for informational purposes and maybe to
give the client the possibility to verify if the server's decision for the
encryption method confirms to the server's encryption level.
The possible encryption methods are "NONE", "40BIT", "56BIT", "128BIT" and
"FIPS" and the RDP client advertises the ones it supports to the server in the
Client Security Data block (TS_UD_CS_SEC).
The server's configured encryption level value restricts the possible final
encryption method.
Something that I was not able to find in the documentation is the priority
level of the individual encryption methods based on which the server makes its
final method decision if there are several options.
My analysis with Windows Servers reveiled that the order is 128, 56, 40, FIPS.
The server only chooses FIPS if the level is "FIPS Comliant" or if it is the
only method advertised by the client.
Bottom line:
* FreeRDP's client side does not need to set settings->EncryptionLevel
(which was done quite frequently).
* FreeRDP's server side does not have to set the supported encryption methods
list in settings->EncryptionMethods
Changes in this commit:
Removed unnecessary/confusing changes of EncryptionLevel/Methods settings
Refactor settings->DisableEncryption
* This value actually means "Advanced RDP Encryption (NLA/TLS) is NOT used"
* The old name caused lots of confusion among developers
* Renamed it to "UseRdpSecurityLayer" (the compare logic stays untouched)
Any client's setting of settings->EncryptionMethods were annihilated
* All clients "want" to set all supported methods
* Some clients forgot 56bit because 56bit was not supported at the time the
code was written
* settings->EncryptionMethods was overwritten anyways in nego_connect()
* Removed all client side settings of settings->EncryptionMethods
The default is "None" (0)
* Changed nego_connect() to advertise all supported methods if
settings->EncryptionMethods is 0 (None)
* Added a commandline option /encryption-methods:comma separated list of the
values "40", "56", "128", "FIPS". E.g. /encryption-methods:56,128
* Print warning if server chooses non-advertised method
Verify received level and method in client's gcc_read_server_security_data
* Only accept valid/known encryption methods
* Verify encryption level/method combinations according to MS-RDPBCGR 5.3.2
Server implementations can now set settings->EncryptionLevel
* The default for settings->EncryptionLevel is 0 (None)
* nego_send_negotiation_response() changes it to ClientCompatible in that case
* default to ClientCompatible if the server implementation set an invalid level
Fix server's gcc_write_server_security_data
* Verify server encryption level value set by server implementations
* Choose rdp encryption method based on level and supported client methods
* Moved FIPS to the lowest priority (only used if other methods are possible)
Updated sample server
* Support RDP Security (RdpKeyFile was not set)
* Added commented sample code for setting the security level
When "detect" is used as gateway usage method (which is the default)
it is tried to by-pass gateway connection for local hosts.
The detection might take some time therefore print a message that people
are aware that a detection is tried.
Fixes#2171
Client side code always tells the server that it is capable of processing
encrypted licensing packages (SEC_LICENSE_ENCRYPT_SC) but didn't set
the recently added flag to indicate that.
Fixes#2196
rpc_send_enqueue_pdu returns -1 on error but the type of error isn't
distinguishable. Therefore make sure that the buffer gets always freed.
The only exception to this is when the pdu was already queued. Then the
dequeuing function should take care of freeing the buffer when
processing the pdu.
According to the Microsoft RDP specification, T.128 flow control PDUs
should be ignored when reading Share Control headers.
(http://msdn.microsoft.com/en-us/library/cc240576.aspx). This patch
checks if we got a flow control PDU (length = 0x8000) and advances the
stream to ignore the PDU.
The fOpRedundant field of the GlyphIndex primary drawing order
(MS-RDPEGDI, chapter 2.2.2.2.1.1.2.13) was neglected which resulted in some
severe text rendering errors.
* According to MS-RDPBCGR 2.2.7.1.5 the pointerCacheSize is optional
and its absence or a zero value indicates missing client support for
the New Pointer Update.
* Added and fixed some comments regarding the meaning of the KBDFLAGS_DOWN
keyboard flag and how it is currently used in the code.
"Fixed" the slow path keyboard input to generate the same keyboard flags
as the corresponding fast path code.
* Some arbitrary value was used for the ConnectPDULength in the GCC
Conference Create Response. According to MS-RDPBCGR 4.1.4 this value must
be ignored by the client so we encode a zero value instead.
"libfreerdp" consisted of multiple (small) single libraries. If the cmake
option MONOLITHIC was used only one library was build combining all of
the libfreerdp-* libraries.
The only exceptions to this are libfreerdp-server and libfreerdp-client these
are build as separate libraries.
This commit obsoltes non-monolithic builds and makes monolithic builds
the default. The cmake option MONOLITHIC is also removed.
* Zeroing xevent helped address some erratic behavior.
* valgrind complained about using xfBitmap uninitialized
during shutdown, traced it back to the initialization.
Bitmap_Prototype->size > sizeof(rdpBitmap).
* Early exit from recv_tpkt_pdu is necessary to address
a shutdown crash - the channelId value was being used
without being set in the disconnect case.
(freerdp_color_convert_drawing_order_color_to_gdi_color): Declare new
function.
* libfreerdp/codec/color.c:
(freerdp_color_convert_drawing_order_color_to_gdi_color): Implement.
(freerdp_image_convert_8bpp): Properly use the ARGB32/ABGR32/RGB32/BGR32
macros when converting 8bpp data to 32bpp.
(freerdp_image_convert_32bpp): Fix CLRCONV_ALPHA and CLRCONV_INVERT
processing for 32bpp destination.
(freerdp_mono_image_convert): Use ARGB32/ABGR32 when converting to 32bpp
and CLRCONV_ALPHA is set.
* libfreerdp/core/orders.c: Color data from drawing orders is
interpreted in big endian mode.
* libfreerdp/core/update.c (update_read_palette): Likewise.
* libfreerdp/gdi/16bpp.c (gdi_get_color_16bpp): GDI colors are stored as
RGB now.
* libfreerdp/gdi/32bpp.c (gdi_get_color_32bpp): Likewise.
* libfreerdp/gdi/gdi.c:
Use freerdp_color_convert_drawing_order_color_to_gdi_color() to convert
from drawing order color representation to GDI color representation
troughout.
* libfreerdp/gdi/graphics.c (gdi_Glyph_BeginDraw): Likewise.
(gdi_Glyph_EndDraw): Likewise.
transport_check_fds and transport_read_pdu had almost the same
functionality: reading and validating one pdu at a time.
Now transport_read_pdu reads one pdu from the transport layer and verifies
that the pdu data is valid - as before.
transport_read_pdu also ensures that the stream is sealed and
rewound when the pdu is received completely.
transport_check_fds just uses transport_read_pdu and does *not* do
the verification a second time based on the stream.
Besides the clean up this fixes the following problems:
* transport_read always read 4 bytes. Fast-path input synchronize pdus
are only 3 bytes long. In this case on byte got lost in the stream
buffer which lead to "de-synchronization" of server and
client.
* Size check in tpdu_read_connection_confirm - already read bytes
weren't taken into account.
* make sure fast-path packages are not fragmented if no
multifragment support was announced
* handle special server side case where the multifragment size
received from the client is smaller than one maximum fast-path
PDU size
This adds 2 arguments:
/tls-ciphers List of permitted openssl ciphers - see ciphers(1)
/tls-ciphers-netmon Use tls ciphers that netmon can parse
With KB2919355, client/server negotiate the use of
TLS cipher TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
which works fine except that netmon can't parse it.
By adding commandline /tls-ciphers-netmon, we restrict
the available ciphers to a list that netmon can
deal with. Also adds /tls-ciphers, which
accepts a string arg, for further customization.
winpr is now always build as single library.
The build option MONOLITHIC_BUILD doesn't influence this behavior anymore.
The only exception is winpr-makecert-tool which is still build as extra
library.
This obsoletes complex_libraries for winpr.
# By Marc-André Moreau (20) and others
# Via Mike McDonald (6) and others
* 'master' of git://github.com/awakecoding/FreeRDP: (26 commits)
libfreerdp-codec: fix C++ headers
libfreerdp-codec: fix ClearCodec short vbar cache hit
libfreerdp-codec: improve ClearCodec error checking
libfreerdp-codec: fix ClearCodec RLEX decoding
libfreerdp-codec: ClearCodec fix error codes and wrapping around of cursors
libfreerdp-codec: fix some ClearCodec flag checking
Fixed issue with last merge.
Added #ifdef WITH_OPENH264 ... #endif to appropriate places in the code.
libfreerdp-codec: handle long vbar length mismatch
channels/rdpgfx: add egfx command line options and settings
libfreerdp-codec: reduce number of variables
libfreerdp-codec: improve ClearCodec robustness
libfreerdp-codec: simplify ClearCodec code
Initial implementation of H.264 decoder for MS-RDPEGFX
libfreerdp-codec: improve ClearCodec subcodec xStart, yStart handling
libfreerdp-codec: improve ClearCodec subcodec support
libfreerdp-codec: improve ClearCodec error checking
libfreerdp-codec: more ClearCodec vBar caching
channels/rdpgfx: harden parsing code
libfreerdp-codec: add ClearCodec glyph cache
...
select() has the major drawback that it cannot handle file descriptor
that are bigger than 1024. This patch makes use of poll() instead of
select() when poll() support is available.
This patch introduce misc checks when receiving pointer updates. We check
that the cursor are in the bounds defined by the spec. We also check that
the announced mask sizes are what they should be.
This big patch allows to have non-blocking writes. To achieve
this, it slightly changes the way transport is handled. The misc transport
layers are handled with OpenSSL BIOs. In the chain we insert a
bufferedBIO that will bufferize write calls that couldn't be honored.
For an access with Tls security the BIO chain would look like this:
FreeRdp Code ===> SSL bio ===> buffered BIO ===> socket BIO
The buffered BIO will store bytes that couldn't be send because of
blocking write calls.
This patch also rework TSG so that it would look like this in the
case of SSL security with TSG:
(TSG in)
> SSL BIO => buffered BIO ==> socket BIO
/
FreeRdp => SSL BIO => TSG BIO
\
> SSL BIO => buffered BIO ==> socket BIO
(TSG out)
So from the FreeRDP point of view sending something is only BIO_writing
on the frontBio (last BIO on the left).
This patch changes the prototype for decode_base64 so that the encode / decode
method are consistant (encode(BYTE *) => char* and decode(char*) => BYTE*).
It also does some improvements with unrolling loops so that end conditions are
tested only at the end.
The patch also adds some unitary tests.
Before the patch base64_decode() made valgrind complain about uninitialized
bits, after valgrind is happy and very quiet.
# By Marc-André Moreau
# Via Benoit LeBlanc (1) and Marc-André Moreau (1)
* 'master' of https://github.com/mrthebunny/FreeRDP:
libfreerdp-core: fix potential crash on session redirection failure
