From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, cake@lists.bufferbloat.net
Subject: Re: [PATCH net 2/2] sch_cake: Make sure we can write the IP header before changing DSCP bits
Date: Thu, 04 Apr 2019 22:44:33 +0200 [thread overview]
Message-ID: <87y34p1owe.fsf@toke.dk> (raw)
In-Reply-To: <20190404123536.3c966937@shemminger-XPS-13-9360>
Stephen Hemminger <stephen@networkplumber.org> writes:
> On Thu, 04 Apr 2019 15:01:33 +0200
> Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
>> static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
>> {
>> + int wlen = skb_network_offset(skb);
>
> In theory this could be negative, you should handle that?
> Rather than calling may_pull() with a huge unsigned value.
Huh, that would imply that skb->network_header points to before
skb->head; when does that happen?
Also, pskb_may_pull() does check for len > skb->len, so I guess a
follow-up question would be, "does it happen often enough to warrant
handling at this level"?
Also, I copied that bit from sch_dsmark, so if you really thing it needs
to be fixed, I guess we should fix both...
-Toke
next prev parent reply other threads:[~2019-04-04 20:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-04 13:01 [PATCH net 0/2] sched: A few small fixes for sch_cake Toke Høiland-Jørgensen
2019-04-04 13:01 ` [PATCH net 1/2] sch_cake: Use tc_skb_protocol() helper for getting packet protocol Toke Høiland-Jørgensen
2019-04-04 13:01 ` [PATCH net 2/2] sch_cake: Make sure we can write the IP header before changing DSCP bits Toke Høiland-Jørgensen
2019-04-04 19:35 ` Stephen Hemminger
2019-04-04 20:44 ` Toke Høiland-Jørgensen [this message]
2019-04-04 21:40 ` Stephen Hemminger
2019-04-04 21:55 ` Toke Høiland-Jørgensen
2019-04-04 17:56 ` [PATCH net 0/2] sched: A few small fixes for sch_cake David Miller
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