Been playing with Winbio (Windows Hello) - finally getting it to work from B4J.
Convoluted path so far
Tried calling from Java directly using FFM - didn't work (so far)
Got it working in B4J with Python with a DLL bridge to WInbio.
The Python script spawns another Python script, running elevated privileges (needed for winbio).
As it stands it will confirm if a user is registered with Windows Hello. There are lots of other parts of Winbio I haven't used.
B4J Code calls py_runner.py with 2 params :
1, The path to Python (it has to spawn a new python)
2, The path of the second python script to run.
Code:
Private Sub chk_user As ResumableSub
wait for ((Py.RunCode("start", Array("D:/Python313/python.exe",getAssetFile("py_fp_test.py")), readAsset("py_runner.py")).fetch)) Complete (v As PyWrapper)
Return v.value
End Sub
The two routines gettAssetFile and readAsset are just convenience methods - the first returns the path, the second the contents of the file as a string.
Code:
Private Sub getAssetFile(name As String) As String
Dim tmp As String = File.GetUri(File.DirAssets,name)
If GetSystemProperty("os.name","").ToLowerCase.StartsWith("win") Then
Return tmp.ToLowerCase.Replace("file:/","")
Else
Return tmp.Replace("file:/","").Replace("File:/","")
End If
End Sub
private Sub readAsset(s As String) As String
Return File.ReadString("",getAssetFile(s))
End Sub
py_runner.py
This creates a socket (for the elevated python to talk to as pipes and stdout etc break across elevation)
Code:
import subprocess
import time
import socket
import os
def start(python_path,sub_process_path):
#create server here
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.bind(('localhost', 0))
port = serversocket.getsockname()[1]
serversocket.listen(1) # become a server socket, maximum 1 connections
python_exec = os.path.normpath(python_path.strip('"'))
sub_process_exec = os.path.normpath(sub_process_path.strip('"'))
# build command for elevated script
cmd = [
"powershell",
"-Command",
f"Start-Process -FilePath '{python_exec}' "
f"-ArgumentList '\"{sub_process_exec}\" \"{port}\"' "
"-Verb RunAs -Wait" # the runas causea elevation of the process
]
#run the subprocess with elevated privileges
subprocess.run(cmd)
reply = ""
print("waiting for reply")
# Wait for connection
while True:
connection, address = serversocket.accept()
buf = connection.recv(1024)
if len(buf) > 0:
reply = buf
break
# Read result
result = reply.decode().strip()
#print("result:", result)
#return result to B4J
serversocket.close()
return result
py_Fp_test.py
This runs as an elevated process so it can access Winbio (well the link dll)
Code:
import ctypes
import os
import sys
import time
import socket
def main():
os.system("title Press fingerprint reader now")
if len(sys.argv) < 2:
sys.exit()
# Load the DLL
port =int(sys.argv[1])
s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
dll_path = r"C:\Temp\MyFingerprintReader.dll"
fingerprint = ctypes.WinDLL(dll_path)
# Prepare reply buffer
reply = ctypes.create_string_buffer(1024)
# Define function signature
fingerprint.verifyFingerprint.argtypes = [ctypes.c_char_p]
fingerprint.verifyFingerprint.restype = None
# Call the function
fingerprint.verifyFingerprint(reply)
# send reply back
try:
s.connect(('localhost', port))
result = reply.value.decode('utf-8')
s.sendall(result.encode())
except Exception as e:
sys.exit()
finally:
time.sleep(1.0)
s.close()
sys.exit(0)
if __name__ == "__main__":
main()
Finally the dll source code (posted as source as you need to set the unitId for the reader you have) - compile to .dll (it is C++ code as its easier to interface to Winbio)
Code:
#include <windows.h>
#include <winbio.h>
#include <string>
class FingerprintVerifier {
public:
std::string verify() {
WINBIO_SESSION_HANDLE sessionHandle;
HRESULT hr = WinBioOpenSession(
WINBIO_TYPE_FINGERPRINT,
WINBIO_POOL_SYSTEM,
WINBIO_FLAG_DEFAULT,
NULL, 0,
WINBIO_DB_DEFAULT,
&sessionHandle);
if (FAILED(hr)) return "ERROR - Session";
WINBIO_UNIT_ID unitId = 3; // **** CHANGE THIS TO WHERE YOUR READER IS *****
WINBIO_IDENTITY identity;
WINBIO_BIOMETRIC_SUBTYPE subFactor;
WINBIO_REJECT_DETAIL rejectDetail;
hr = WinBioIdentify(sessionHandle, &unitId, &identity, &subFactor, &rejectDetail);
WinBioCloseSession(sessionHandle);
if (FAILED(hr)) return "FAILED - Unknown user";
return "VALID - User is known";
}
};
extern "C" __declspec(dllexport)
void verifyFingerprint(char* reply) {
FingerprintVerifier verifier;
std::string result = verifier.verify();
strncpy_s(reply, 1024, result.c_str(), _TRUNCATE); // allows for 1024 bytes to be sent back - I use about 21 in this
reply[1023] = '\0';
}
Was fun getting it to work - also UAC is triggered as the 2nd python script is fired off with elevated credentials.
Bits that may be of use - How to elevate a python script to Admin from a python script using Powershell with RunAs[/code]
