netdev - Re: [PATCH net-next 01/16] libeth: convert to netmem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAHS8izPope_UOF7saHHxaJSgqHWJWZvEKmp=0x6sB2OJAghqUw@mail.gmail.com>
Date: Tue, 27 May 2025 20:49:33 -0700
From: Mina Almasry <almasrymina@...gle.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Tony Nguyen <anthony.l.nguyen@...el.com>, davem@...emloft.net, pabeni@...hat.com, 
	edumazet@...gle.com, andrew+netdev@...n.ch, netdev@...r.kernel.org, 
	Alexander Lobakin <aleksander.lobakin@...el.com>, maciej.fijalkowski@...el.com, 
	magnus.karlsson@...el.com, michal.kubiak@...el.com, 
	przemyslaw.kitszel@...el.com, ast@...nel.org, daniel@...earbox.net, 
	hawk@...nel.org, john.fastabend@...il.com, horms@...nel.org, 
	bpf@...r.kernel.org
Subject: Re: [PATCH net-next 01/16] libeth: convert to netmem

On Tue, May 27, 2025 at 6:57 PM Jakub Kicinski <kuba@...nel.org> wrote:
> > -     dst = page_address(hdr->page) + hdr->offset + hdr->page->pp->p.offset;
> > -     src = page_address(buf->page) + buf->offset + buf->page->pp->p.offset;
> > -     memcpy(dst, src, LARGEST_ALIGN(copy));
> > +     hdr_page = __netmem_to_page(hdr->netmem);
> > +     buf_page = __netmem_to_page(buf->netmem);
> > +     dst = page_address(hdr_page) + hdr->offset + hdr_page->pp->p.offset;
> > +     src = page_address(buf_page) + buf->offset + buf_page->pp->p.offset;
> >
> > +     memcpy(dst, src, LARGEST_ALIGN(copy));
> >       buf->offset += copy;
> >
> >       return copy;
> > @@ -3302,11 +3306,12 @@ static u32 idpf_rx_hsplit_wa(const struct libeth_fqe *hdr,
> >   */
> >  struct sk_buff *idpf_rx_build_skb(const struct libeth_fqe *buf, u32 size)
> >  {
> > -     u32 hr = buf->page->pp->p.offset;
> > +     struct page *buf_page = __netmem_to_page(buf->netmem);
> > +     u32 hr = buf_page->pp->p.offset;
> >       struct sk_buff *skb;
> >       void *va;
> >
> > -     va = page_address(buf->page) + buf->offset;
> > +     va = page_address(buf_page) + buf->offset;
> >       prefetch(va + hr);
>
> If you don't want to have to validate the low bit during netmem -> page
> conversions - you need to clearly maintain the separation between
> the two in the driver. These __netmem_to_page() calls are too much of
> a liability.

Would it make sense to add a DEBUG_NET_WARN_ON_ONCE to
__netmem_to_page to catch misuse in a driver independent way? Or is
that not good enough because there may be latent issues only hit in
production where the debug is disabled.

-- 
Thanks,
Mina