The FreeRDP library is intended to be threadsafe, but is not reliably so
with respect to legacy RDP encryption and outbound messages. When
outbound messages are sent by multiple threads, the encryption key used
for legacy RDP encryption may not be updated correctly, resulting in a
fatal connection error like:
"ERRINFO_DECRYPT_FAILED (0x00001192):(a) Decryption using Standard RDP
Security mechanisms (section 5.3.6) failed. (b) Session key creation
using Standard RDP Security mechanisms (section 5.3.5) failed."
On some platforms, the libguacai-client.so plugin for FreeRDP reports an
unlinked symbol:
undefined symbol: guac_freerdp_dynamic_channel_collection_add (/usr/local/lib/freerdp2/libguacai-client.so)
This symbol is actually unused within the plugin, but may be referenced
due to being defined within a function in a common piece of source
shared between the plugin and the RDP support.
Separating the actual common components such that they can be included
by both the RDP support and the libguacai-client.so plugin removes the
potential for unused pieces being flagged as missing.
