SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data)
{
	int rc;
	struct cifs_ses *ses = sess_data->ses;
	struct smb2_sess_setup_req *req;
	struct smb2_sess_setup_rsp *rsp = NULL;
	unsigned char *ntlmssp_blob = NULL;
	bool use_spnego = false; /* else use raw ntlmssp */
	u16 blob_length = 0;

	rc = SMB2_sess_alloc_buffer(sess_data);
	if (rc)
		goto out;

	req = (struct smb2_sess_setup_req *) sess_data->iov[0].iov_base;
	req->sync_hdr.SessionId = ses->Suid;

	rc = build_ntlmssp_auth_blob(&ntlmssp_blob, &blob_length, ses,
					sess_data->nls_cp);
	if (rc) {
		cifs_dbg(FYI, "build_ntlmssp_auth_blob failed %d\n", rc);
		goto out;
	}

	if (use_spnego) {
		/* BB eventually need to add this */
		cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
		rc = -EOPNOTSUPP;
		goto out;
	}
	sess_data->iov[1].iov_base = ntlmssp_blob;
	sess_data->iov[1].iov_len = blob_length;

	rc = SMB2_sess_sendreceive(sess_data);
	if (rc)
		goto out;

	rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;

	ses->Suid = rsp->sync_hdr.SessionId;
	ses->session_flags = le16_to_cpu(rsp->SessionFlags);

	rc = SMB2_sess_establish_session(sess_data);
out:
	kfree(ntlmssp_blob);
	SMB2_sess_free_buffer(sess_data);
	kfree(ses->ntlmssp);
	ses->ntlmssp = NULL;
	sess_data->result = rc;
	sess_data->func = NULL;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.