Re: [PATCH bpf-next v3 2/6] bpf: Verify signed loader metadata at load time

Paul Moore <[email protected]>
Newsgroups org.kernel.vger.linux-security-module,org.kernel.vger.bpf
Message-ID <CAHC9VhRk=j4_cNH5v+iCvSpJXz2g=dTK_+1O-kgT=E+OESENiA@mail.gmail.com>
On Thu, Jul 2, 2026 at 6:33 PM Alexei Starovoitov
<[email protected]> wrote:
> On Thu Jul 2, 2026 at 3:05 PM PDT, Paul Moore wrote:

...

> > With this patch, even in cases where SELinux will prevent the BPF
> > program load operation, it is not able to do so before the process
> > triggers a potential sizable memory allocation, opening the door for a
> > local DoS attack.
>
> Not true either. Worst case is 1M which is 8Mbyte.
> Not even close to anything DoS worthy.

That's 8MB in a single allocation that can be triggered directly by
userspace.  I suspect most systems allow a fair number of processes
per user; that 8MB allocation can quickly multiply into a big number,
especially for more modest, non-server systems/VMs.

-- 
paul-moore.com
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