netdev - Re: [PATCH 1/6] ebpf: add a seccomp program type

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 09 Sep 2015 18:13:57 +0200
From:	Daniel Borkmann <daniel@...earbox.net>
To:	Andy Lutomirski <luto@...capital.net>,
	Tycho Andersen <tycho.andersen@...onical.com>
CC:	Kees Cook <keescook@...omium.org>,
	Alexei Starovoitov <ast@...nel.org>,
	Will Drewry <wad@...omium.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Pavel Emelyanov <xemul@...allels.com>,
	"Serge E. Hallyn" <serge.hallyn@...ntu.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH 1/6] ebpf: add a seccomp program type

On 09/04/2015 11:50 PM, Andy Lutomirski wrote:
> On Fri, Sep 4, 2015 at 9:04 AM, Tycho Andersen
[...]
>> +static const struct bpf_func_proto *
>> +seccomp_func_proto(enum bpf_func_id func_id)
>> +{
>> +       /* Right now seccomp eBPF loading doesn't support maps; seccomp filters
>> +        * are considered to be read-only after they're installed, so map fds
>> +        * probably need to be invalidated when a seccomp filter with maps is
>> +        * installed.
>> +        *
>> +        * The rest of these might be reasonable to call from seccomp, so we
>> +        * export them.
>> +        */
>> +       switch (func_id) {
>> +       case BPF_FUNC_ktime_get_ns:
>> +               return &bpf_ktime_get_ns_proto;
>> +       case BPF_FUNC_trace_printk:
>> +               return bpf_get_trace_printk_proto();
>> +       case BPF_FUNC_get_prandom_u32:
>> +               return &bpf_get_prandom_u32_proto;
>
> I don't think we should expose prandom to unprivileged userspace.
> This may be an attack vector.

Agreed, it should not be exposed for unpriv'ed users.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html