Re: [PATCH v5 01/11] net: qrtr: ns: validate msglen before ctrl_pkt use

[Mihai Moldovan]

* On 8/15/25 20:09, Jakub Kicinski wrote:
> If this is a fix it has to go to net, then once it reaches Linus's tree
> the dependent patches should be reposted for net-next.

Thanks.

Will split out the two commits and resend the resend of the series later on 
after the fixes have been merged.

Might take me a few weeks, I'm currently very limited on time and internet access.


> > diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
> > index 3de9350cbf30..2bcfe539dc3e 100644
> > --- a/net/qrtr/ns.c
> > +++ b/net/qrtr/ns.c
> > @@ -619,6 +619,9 @@ static void qrtr_ns_worker(struct work_struct *work)
> >   			break;
> >   		}
> >   
> > +		if ((size_t)msglen < sizeof(*pkt))
> > +			break;
>
> why not continue?

I don't really know and am not familiar with the QRTR protocol, but here's my 
best guess:

Since we're using non-blocking I/O, it doesn't seem to make sense to continue, 
because the next receive call would just break out anyway once it returns no 
data at all. Notice that we're also breaking out for -EAGAIN.

Also, if we somehow got a short read, and we're currently dropping the buffer we 
just read, any additional data after a subsequent receive would be garbage to us 
anyway. We'd probably have to keep the old buffer content around and concatenate 
it with data returned from a new receive call.



Mihai