On Mon, Jan 23, 2017 at 11:25:56AM +0000, David Laight wrote:
> From: Xin Long
> > Sent: 19 January 2017 17:19
> > This patch is to implement Sender-Side Procedures for the Add
> > Outgoing and Incoming Streams Request Parameter described in
> > rfc6525 section 5.1.5-5.1.6.
> >
> > It is also to add sockopt SCTP_ADD_STREAMS in rfc6525 section
> > 6.3.4 for users.
> ...
> > + out = params->sas_outstrms;
> > + in = params->sas_instrms;
> > +
> > + if (!out && !in)
> > + goto out;
> > +
> > + if (out) {
> > + __u16 nums = stream->outcnt + out;
>
> Make nums 'unsigned int', the code will be smaller and you can
> use the value for the overflow check.
Smaller as in to avoid the sum below?
>
> > + /* Check for overflow, can't use nums here */
> > + if (stream->outcnt + out > SCTP_MAX_STREAM)
> > + goto out;
> > +
> > + /* Use ksize to check if stream array really needs to realloc */
> > + if (ksize(stream->out) / sizeof(*stream->out) < nums) {
> > + struct sctp_stream_out *streamout;
> > +
> > + streamout = kcalloc(nums, sizeof(*streamout),
> > + GFP_KERNEL);
> > + if (!streamout) {
> > + retval = -ENOMEM;
> > + goto out;
> > + }
> > +
> > + memcpy(streamout, stream->out,
> > + sizeof(*streamout) * stream->outcnt);
> > +
> > + kfree(stream->out);
> > + stream->out = streamout;
> > + }
>
> Does kcalloc() zero the entire area, or just the length you ask for?
> If the latter you need to zero the rest here.
> ...
>
> David
>
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