Re: [lvc-project] [PATCH] netfilter: xt_recent: Fix attempt to update removed entry

[Florian Westphal]

Jan Engelhardt <jengelh@xxxxxxx> wrote:
> On Thursday 2023-02-09 16:07, Florian Westphal wrote:
> 
> >Igor Artemiev <Igor.A.Artemiev@xxxxxxx> wrote:
> >> When both --remove and --update flag are specified, there's a code
> >> path at which the entry to be updated is removed beforehand,
> >> that leads to kernel crash. Update entry, if --remove flag
> >> don't specified.
> >> 
> >> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >
> >How did you manage to do this?  --update and --remove are supposed
> >to be mutually exclusive.
> 
> I suppose the exclusivity is only checked at the iptables command-line
> and neverwhere else.

Removing the userspace check gives me an -EINVAL from checkentry.