// Initiate a ClientHello message and generate a token.
SECURITY_STATUS chs_hello (void)
{
DWORD dwFlagsIn, dwFlagsOut;
SecBuffer sb[1];
SecBufferDesc hs;
dwFlagsIn = ISC_REQ_SEQUENCE_DETECT |
ISC_REQ_REPLAY_DETECT |
ISC_REQ_CONFIDENTIALITY |
ISC_RET_EXTENDED_ERROR |
ISC_REQ_ALLOCATE_MEMORY |
ISC_REQ_STREAM;
sb[0].pvBuffer = NULL;
sb[0].BufferType = SECBUFFER_TOKEN;
sb[0].cbBuffer = 0;
hs.cBuffers = 1;
hs.pBuffers = sb;
hs.ulVersion = SECBUFFER_VERSION;
ss = sspi->InitializeSecurityContextA (&hClientCreds, NULL, pszServer, dwFlagsIn,
0, SECURITY_NATIVE_DREP, NULL, 0, &hContext, &hs, &dwFlagsOut, &ts);
// should indicate continuing
if (ss==SEC_I_CONTINUE_NEEDED) {
// send data
if (sb[0].cbBuffer != 0) {
send (s, sb[0].pvBuffer, sb[0].cbBuffer, 0);
ss = sspi->FreeContextBuffer (sb[0].pvBuffer);
}
}
return ss;
}
// perform SSL handshake with remote system
SECURITY_STATUS chs (void)
{
DWORD dwFlagsIn, dwFlagsOut;
SecBuffer ib[2], ob[1];
SecBufferDesc in, out;
DWORD cbIoBuffer=0;
PBYTE IoBuffer;
int len;
BOOL bRead=TRUE;
// 8192 should be enough for handshake but
// if you see any errors, try increasing it.
IoBuffer = LocalAlloc (LMEM_FIXED, 8192);
if ((ss=chs_hello())!=SEC_E_OK) {
return ss;
}
dwFlagsIn = ISC_REQ_SEQUENCE_DETECT |
ISC_REQ_REPLAY_DETECT |
ISC_REQ_CONFIDENTIALITY |
ISC_RET_EXTENDED_ERROR |
ISC_REQ_ALLOCATE_MEMORY |
ISC_REQ_STREAM;
ss=SEC_I_CONTINUE_NEEDED;
while (ss==SEC_I_CONTINUE_NEEDED || ss==SEC_E_INCOMPLETE_MESSAGE)
{
if (ss==SEC_E_INCOMPLETE_MESSAGE || cbIoBuffer==0)
{
if (bRead)
{
len=recv (s, &IoBuffer[cbIoBuffer], 8192, 0);
// some socket error
if (len<=0) {
break;
}
cbIoBuffer += len;
} else {
bRead=TRUE;
}
}
ib[0].pvBuffer = IoBuffer;
ib[0].cbBuffer = cbIoBuffer;
ib[0].BufferType = SECBUFFER_TOKEN;
ib[1].pvBuffer = NULL;
ib[1].cbBuffer = 0;
ib[1].BufferType = SECBUFFER_EMPTY;
in.cBuffers = 2;
in.pBuffers = ib;
in.ulVersion = SECBUFFER_VERSION;
ob[0].pvBuffer = NULL;
ob[0].BufferType = SECBUFFER_TOKEN;
ob[0].cbBuffer = 0;
out.cBuffers = 1;
out.pBuffers = ob;
out.ulVersion = SECBUFFER_VERSION;
ss = sspi->InitializeSecurityContextA (&hClientCreds, &hContext,
NULL, dwFlagsIn, 0, SECURITY_NATIVE_DREP, &in, 0, NULL,
&out, &dwFlagsOut, &ts);
// might get SEC_E_ILLEGAL_MESSAGE here
if (ss==SEC_E_OK ||
ss==SEC_I_CONTINUE_NEEDED ||
FAILED (ss) && (dwFlagsOut & ISC_RET_EXTENDED_ERROR))
{
if (ob[0].cbBuffer != 0) {
len=send (s, ob[0].pvBuffer, ob[0].cbBuffer, 0);
// socket error
if (len<=0) {
break;
}
sspi->FreeContextBuffer (ob[0].pvBuffer);
}
}
if (ss==SEC_E_INCOMPLETE_MESSAGE) continue;
if (ss==SEC_E_OK) {
if (ib[1].BufferType==SECBUFFER_EXTRA) {
// i don't handle extra data here but it should be.
}
break;
}
// Copy any leftover data from the "extra" buffer, and go around again.
if ( ib[1].BufferType == SECBUFFER_EXTRA )
{
MoveMemory (IoBuffer, &IoBuffer[cbIoBuffer - ib[1].cbBuffer], ib[1].cbBuffer);
cbIoBuffer = ib[1].cbBuffer;
}
else
cbIoBuffer = 0;
}
LocalFree (IoBuffer);
return ss;
}
