On 25/08/2016 13:05, Andy Lutomirski wrote:

On Thu, Aug 25, 2016 at 3:32 AM, Mickaël Salaün [off-list ref] wrote:

quoted

Hi,

This series is a proof of concept to fill some missing part of seccomp as the
ability to check syscall argument pointers or creating more dynamic security
policies. The goal of this new stackable Linux Security Module (LSM) called
Landlock is to allow any process, including unprivileged ones, to create
powerful security sandboxes comparable to the Seatbelt/XNU Sandbox or the
OpenBSD Pledge. This kind of sandbox help to mitigate the security impact of
bugs or unexpected/malicious behaviors in userland applications.

Maybe I'm missing an obvious description, but: do you have a
description of the eBPF API to landlock?  What function do you
provide, when is it called, what functions can it call, what does the
fancy new arraymap do, etc?

--Andy

The eBPF context is described in "[RFC v2 06/10] landlock: Add LSM hooks".

The provided eBPF functions are described in "[RFC v2 08/10] landlock:
Handle file system comparisons"
(bpf_landlock_cmp_fs_prop_with_struct_file and
bpf_landlock_cmp_fs_beneath_with_struct_file) and "[RFC v2 09/10]
landlock: Handle cgroups" (bpf_landlock_cmp_cgroup_beneath). The
function descriptions are summarized in include/uapi/linux/bpf.h .

This functions can be called by an eBPF program of type
BPF_PROG_TYPE_LANDLOCK_FILE_OPEN, BPF_PROG_TYPE_LANDLOCK_FILE_PERMISSION
and BPF_PROG_TYPE_LANDLOCK_MMAP_FILE as described in "[RFC v2 06/10]
landlock: Add LSM hooks".

I tried to split the commits as much as possible to ease the review. The
"[RFC v2 10/10] samples/landlock: Add sandbox example" may help to see
the whole picture.

Hope this helps,
 Mickaël