Re: CVE-2018-1130: Linux kernel: dccp: a null pointer dereference in net/dccp/output.c:dccp_write_xmit

[Andrey Konovalov <andreyknvl () gmail com>]

On Wed, May 23, 2018 at 4:57 PM, Kurt Seifried <kseifried () redhat com> wrote:
> On Wed, May 23, 2018 at 8:49 AM, Andrey Konovalov <andreyknvl () gmail com>
> wrote:
>
> > On Thu, May 10, 2018 at 2:05 PM, Vladis Dronov <vdronov () redhat com> wrote:
> > > Hello,
> > >
> > > A null pointer dereference in dccp_write_xmit() function in
> > net/dccp/output.c
> > > in the Linux kernel before v4.16-rc7 allows a local user to cause a
> > denial of
> > > service by a number of certain crafted system calls.
>
>
> So the classic CVE statement for this is "does it cross/violate a trust
> boundary". Yeah I know, not super helpful.
>
> In general when I look at something and need to decide whether or not it
> deserves/needs a CVE the fundamentals are:
>
> 1) Can an attacker use this vulnerability to gain access, additional
> privileges, basically is there an impact to
> Confidentiality/Availability/Integrity? This is really two tests: is there
> an impact, and is there a way for the attacker to trigger or exploit it?
> That's a CVE.
>
> 2) Does the software/system make a specific security claim that they then
> fail to meet? E.g. "we include a firewall that blocks access to everything
> inbound except for port 22", if they were to then also allow port 80,
> that'd be a CVE.
>
> So for the syzbot stuff mostly what you need to determine is:
>
> a) is there a security related impact?
> AND
> b) can an attacker trigger it?
>
> If both are yes, then a CVE is warranted.

Hi Kurt,

Perhaps I should've been more clear. I wasn't asking "what qualifies
for a CVE?", but rather "There are a 100 bugs that qualify for CVEs,
how do single out 10 of them to actually request CVEs for?".

In particular, the 100 bugs that I'm referring to are the bugs
reported by syzbot (perhaps there's even more:
https://syzkaller.appspot.com/?fixed=upstream) and the 10 bugs (or so)
are the ones Vladis announced on oss-security over the last few
months. I'm just curious how did he choose those 10 bugs out of that
100+.

Thanks!