From: Breno Leitao <leitao@debian.org>
To: Stanislav Fomichev <sdf.kernel@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Kuniyuki Iwashima <kuniyu@google.com>,
Willem de Bruijn <willemb@google.com>,
David Ahern <dsahern@kernel.org>,
Ido Schimmel <idosch@nvidia.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
david.laight.linux@gmail.com, kernel-team@meta.com
Subject: Re: [PATCH net-next 1/2] net: add sockopt_expand_out()
Date: Fri, 11 Sep 2026 09:09:22 -0700 [thread overview]
Message-ID: <aqQnF9vWKVk3GkTp@gmail.com> (raw)
In-Reply-To: <aqQkImqiHPorszOY@devvm7509.cco0.facebook.com>
On Fri, Sep 11, 2026 at 08:56:23AM -0700, Stanislav Fomichev wrote:
> On 09/10, Breno Leitao wrote:
> >
> > + if (size <= iov_iter_count(&opt->iter_out))
> > + return 0;
> > +
> > + if (WARN_ON_ONCE(!iter_is_ubuf(&opt->iter_out)))
> > + return -EINVAL;
>
> nit: if you end up re-spinning for some reason, maybe swap these two?
I am not sure we want to swap these two. This is the reason:
1) The first check (size <= iov_iter_count(&opt->iter_out)), check if we
need the "hack" or not.
a) If we don't need the tack, then we are fine and this could be called
from user or kernel.
b) for the hack (which happens in the next line -- iov_iter_ubuf()), it
needs to be ubuf.
So, this force kernel callers to use the right optlen, avoiding hitting
the same issue as userspace.
next prev parent reply other threads:[~2026-09-11 16:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-10 9:47 [PATCH net-next 0/2] net: a sockopt_t quirk for the options that write past optlen Breno Leitao
2026-09-10 9:47 ` [PATCH net-next 1/2] net: add sockopt_expand_out() Breno Leitao
2026-09-11 15:56 ` Stanislav Fomichev
2026-09-11 16:09 ` Breno Leitao [this message]
2026-09-11 18:10 ` David Laight
2026-09-11 21:17 ` Stanislav Fomichev
2026-09-10 9:47 ` [PATCH net-next 2/2] ipv4: igmp: convert ip_mc_msfget() to sockopt_t Breno Leitao
2026-09-11 15:56 ` Stanislav Fomichev
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