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SubjectRe: NCPFS and brittle connections
Pierre Ossman wrote:
> Ok... how about this baby instead. I've replaced the stack allocated
> request structure by one allocated with kmalloc() and reference counted
> using an atomic_t. I couldn't see anything else that was associated to
> the process, so I believe this should suffice.
>
> (This is just a RFC. Once I get an ok from you I'll put together a more
> proper patch mail)
>
> - req.tx_type = *(u_int16_t*)server->packet;
> -
> - result = ncp_add_request(server, &req);
> + struct ncp_request_reply *req;
> +
> + req = ncp_alloc_req();
> + if (!req)
> + return -ENOMEM;
> +
> + req->reply_buf = reply_buf;
> + req->datalen = max_reply_size;
> + req->tx_iov[1].iov_base = server->packet;
> + req->tx_iov[1].iov_len = size;
> + req->tx_iovlen = 1;
> + req->tx_totallen = size;
> + req->tx_type = *(u_int16_t*)server->packet;

Problem is with these pointers - reply_buf & server->packet. Now code
will just read packet from server->packet, and write result to
reply_buf, most probably transmiting some random data to network, and
overwriting innocent memory on receiption... I believe that you need to
make copies of server->packet/size for transmission, and some simillar
solution for receive as well. As both request & response can be up to
~66000 bytes.
Petr

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