Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1219320

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

Show all headers | View raw

On Fri, Sep 04, 2015 at 01:17:47PM -0700, Alexei Starovoitov wrote:
> On Fri, Sep 04, 2015 at 10:04:19AM -0600, Tycho Andersen wrote:
> > seccomp uses eBPF as its underlying storage and execution format, and eBPF
> > has features that seccomp would like to make use of in the future. This
> > patch adds a formal seccomp type to the eBPF verifier.
> > 
> > The current implementation of the seccomp eBPF type is very limited, and
> > doesn't support some interesting features (notably, maps) of eBPF. However,
> > the primary motivation for this patchset is to enable checkpoint/restore
> > for seccomp filters later in the series, to this limited feature set is ok
> > for now.
> 
> yes. good compromise to start.
> 
> > +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.
> 
> Just disabling bpf_map_lookup/update() helpers (the way you did here)
> is enough. The prorgram can still have references to maps, but since they
> won't be accessed it's safe.
> 
> > +	 *
> > +	 * 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;
> > +	case BPF_FUNC_get_smp_processor_id:
> > +		return &bpf_get_smp_processor_id_proto;
> > +	case BPF_FUNC_tail_call:
> > +		return &bpf_tail_call_proto;
> > +	case BPF_FUNC_get_current_pid_tgid:
> > +		return &bpf_get_current_pid_tgid_proto;
> > +	case BPF_FUNC_get_current_uid_gid:
> > +		return &bpf_get_current_uid_gid_proto;
> > +	case BPF_FUNC_get_current_comm:
> > +		return &bpf_get_current_comm_proto;
> 
> the list looks good to start with.
> 
> >  
> > +static u32 seccomp_convert_ctx_access(enum bpf_access_type type, int dst_reg,
> > +				      int src_reg, int ctx_off,
> > +				      struct bpf_insn *insn_buf)
> > +{
> > +	struct bpf_insn *insn = insn_buf;
> > +
> > +	switch (ctx_off) {
> > +	case offsetof(struct seccomp_data, nr):
> 
> the conversion of seccomp_data fields is unnecessary.
> We're doing conversion for sk_buff, because sk_buff and __sk_buff aree two
> different structures. __sk_buff is user ABI with its own fields that losely
> correspond to in-kernel struct sk_buff.
> seccomp_data is already part of user ABI, so it's ok to access as-is.

Ok, I noticed this but somehow didn't put it all together. I'll axe
this for the next version, thanks.

Tycho
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

c/r of seccomp filters via underlying eBPF Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 18:10 +0200
  [PATCH 5/6] seccomp: add a way to attach a filter via eBPF fd Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 18:10 +0200
    Re: [PATCH 5/6] seccomp: add a way to attach a filter via eBPF fd Kees Cook <keescook@chromium.org> - 2015-09-04 22:50 +0200
      Re: [PATCH 5/6] seccomp: add a way to attach a filter via eBPF fd "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-09-05 09:20 +0200
    Re: [PATCH 5/6] seccomp: add a way to attach a filter via eBPF fd Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-04 22:50 +0200
  [PATCH 4/6] seccomp: add a way to access filters via bpf fds Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 18:10 +0200
    Re: [PATCH 4/6] seccomp: add a way to access filters via bpf fds Kees Cook <keescook@chromium.org> - 2015-09-04 22:30 +0200
      Re: [PATCH 4/6] seccomp: add a way to access filters via bpf fds Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-04 22:40 +0200
        Re: [PATCH 4/6] seccomp: add a way to access filters via bpf fds Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 23:00 +0200
  [PATCH 6/6] ebpf: allow BPF_REG_X in src_reg conditional jumps Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 18:10 +0200
    Re: [PATCH 6/6] ebpf: allow BPF_REG_X in src_reg conditional jumps Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-04 23:10 +0200
      Re: [PATCH 6/6] ebpf: allow BPF_REG_X in src_reg conditional jumps Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-05 00:50 +0200
        Re: [PATCH 6/6] ebpf: allow BPF_REG_X in src_reg conditional jumps Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-05 06:20 +0200
  [PATCH 1/6] ebpf: add a seccomp program type Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 18:10 +0200
    Re: [PATCH 1/6] ebpf: add a seccomp program type Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-04 22:20 +0200
      Re: [PATCH 1/6] ebpf: add a seccomp program type Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 23:10 +0200
    Re: [PATCH 1/6] ebpf: add a seccomp program type Kees Cook <keescook@chromium.org> - 2015-09-04 22:40 +0200
      Re: [PATCH 1/6] ebpf: add a seccomp program type Kees Cook <keescook@chromium.org> - 2015-09-04 23:10 +0200
      Re: [PATCH 1/6] ebpf: add a seccomp program type Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 23:10 +0200
    Re: [PATCH 1/6] ebpf: add a seccomp program type Andy Lutomirski <luto@amacapital.net> - 2015-09-05 00:00 +0200
  [PATCH 3/6] ebpf: add a way to dump an eBPF program Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 18:10 +0200
    Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Kees Cook <keescook@chromium.org> - 2015-09-04 22:20 +0200
      Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 22:50 +0200
        Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-04 23:00 +0200
          Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 23:10 +0200
        Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Kees Cook <keescook@chromium.org> - 2015-09-04 23:00 +0200
        Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Andy Lutomirski <luto@amacapital.net> - 2015-09-04 23:50 +0200
          Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-05 00:30 +0200
            Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Andy Lutomirski <luto@amacapital.net> - 2015-09-05 01:10 +0200
              Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-05 02:30 +0200
            Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Kees Cook <keescook@chromium.org> - 2015-09-05 01:30 +0200
              Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Andy Lutomirski <luto@amacapital.net> - 2015-09-05 02:10 +0200
    Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-09-04 22:30 +0200
      Re: [PATCH 3/6] ebpf: add a way to dump an eBPF program Tycho Andersen <tycho.andersen@canonical.com> - 2015-09-04 22:50 +0200

csiph-web