R devel - Oct 2021 - int overflow writing long vectors to socketConnection

Hi,

Writing >=2GB to a socketConnection (e.g. via writeBin) does not work
correctly, because of this int typecast in
modules/internet/sockconn.c:
> static size_t sock_write(const void *ptr, size_t size, size_t nitems,
> 			 Rconnection con)
> {
>     Rsockconn this = (Rsockconn)con->private;
>     ssize_t n = R_SockWrite(this->fd, ptr, (int)(size * nitems),
> 			    this->timeout)/((ssize_t)size);
>     return n > 0 ? n : 0;
> }
which seems uncalled for, given:
> ssize_t R_SockWrite(int sockp, const void *buf, size_t len, int timeout)

Is there a rationale for it, or should it be fixed?

Best,
--
Zafer


	[[alternative HTML version deleted]]

>>>>> Zafer Barutcuoglu 
>>>>>     on Tue, 12 Oct 2021 02:04:40 -0400 writes:
    > Hi,

    > Writing >=2GB to a socketConnection (e.g. via writeBin) does not
work correctly, because of this int typecast in modules/internet/sockconn.c:
    >> static size_t sock_write(const void *ptr, size_t size, size_t
nitems,
    >> Rconnection con)
    >> {
    >> Rsockconn this = (Rsockconn)con->private;
    >> ssize_t n = R_SockWrite(this->fd, ptr, (int)(size * nitems),
    this-> timeout)/((ssize_t)size);
    >> return n > 0 ? n : 0;
    >> }
    > which seems uncalled for, given:
    >> ssize_t R_SockWrite(int sockp, const void *buf, size_t len, int
timeout)


    > Is there a rationale for it, or should it be fixed?

I've fixed it; it's clearly been a  "typo" introduced at the
same when the type of 'len' in the R_SockWrite() header was
changed from int to size_t .. and the intent must have been to
do the same inside sock_write().

    > Best,
    > --
    > Zafer

Thank you for the report!

Martin Maechler
ETH Zurich  and  R Core