Class SMBStreamSocket

scapy/layers/smb2.py:4702–4776

A modified StreamSocket to dissect SMB compounded requests [MS-SMB2] 3.3.5.2.7

class SMBStreamSocket(StreamSocket):
    """
    A modified StreamSocket to dissect SMB compounded requests
    [MS-SMB2] 3.3.5.2.7
    """

    def __init__(self, *args, **kwargs):
        self.queue = collections.deque()
        self.session = SMBSession()
        super(SMBStreamSocket, self).__init__(*args, **kwargs)

    def recv(self, x=None):
        # note: normal StreamSocket takes care of NBTSession / DirectTCP fragments.
        # this takes care of splitting compounded requests
        if self.queue:
            pkt = self.queue.popleft()
        else:
            pkt = super(SMBStreamSocket, self).recv(x)

        # If there are multiple SMB2_Header requests (aka. compounded),
        # take the first and store the rest in a queue.
        if pkt is not None and (
            SMB2_Header in pkt
            or SMB2_Transform_Header in pkt
            or SMB2_Compression_Transform_Header in pkt
        ):
            pkt = self.session.in_pkt(pkt)
            smbh = pkt[SMB2_Header]
            pay = smbh.payload
            while SMB2_Header in pay:
                pay = pay[SMB2_Header]
                pay._decrypted = smbh._decrypted  # Keep the _decrypted flag
                pay.underlayer.remove_payload()
                self.queue.append(pay)
                if not pay.NextCommand:
                    break
                pay = pay.payload

        # Verify the signature if required.
        # This happens here because we must have split compounded requests first.
        smbh = pkt.getlayer(SMB2_Header)
        if (
            smbh
            and self.session.Dialect
            and self.session.SigningKey
            and self.session.SigningRequired
            # [MS-SMB2] sect 3.2.5.1.3 Verifying the Signature
            # "The client MUST skip the processing in this section if any of:"
            # - [...] decryption in section 3.2.5.1.1.1 succeeds
            and not smbh._decrypted
            # - MessageId is 0xFFFFFFFFFFFFFFFF
            and smbh.MID != 0xFFFFFFFFFFFFFFFF
            # - Status in the SMB2 header is STATUS_PENDING
            and smbh.Status != 0x00000103
        ):
            smbh.verify(
                self.session.Dialect,
                self.session.SigningKey,