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From:   Andy Lutomirski <luto@amacapital.net>
Date:   Thu, 4 Oct 2018 12:51:00 -0700
Message-ID: <CALCETrUp69Y01v628KydCNxEqzGHSgs6dQQJxrzVAgs7DhPMxA@mail.gmail.com>
Subject: Re: [PATCH bpf-next 1/6] bpf: introduce BPF_PROG_TYPE_FILE_FILTER
To:     Roman Gushchin <guro@fb.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel-team <Kernel-team@fb.com>
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On Thu, Oct 4, 2018 at 12:41 PM Roman Gushchin <guro@fb.com> wrote:
>
> On Wed, Oct 03, 2018 at 07:57:45PM -0700, Alexei Starovoitov wrote:
> > Similar to networking sandboxing programs and cgroup-v2 based hooks
> > (BPF_CGROUP_INET_[INGRESS|EGRESS,] BPF_CGROUP_INET[4|6]_[BIND|CONNECT], etc)
> > introduce basic per-container sandboxing for file access via
> > new BPF_PROG_TYPE_FILE_FILTER program type that attaches after
> > security_file_open() LSM hook and works as additional file_open filter.
> > The new cgroup bpf hook is called BPF_CGROUP_FILE_OPEN.
> >
> > Just like other cgroup-bpf programs new BPF_PROG_TYPE_FILE_FILTER type
> > is only available to root.
> >
> > This program type has access to single argument 'struct bpf_file_info'
> > that contains standard sys_stat fields:
> > struct bpf_file_info {
> >         __u64 inode;
> >         __u32 dev_major;
> >         __u32 dev_minor;
> >         __u32 fs_magic;
> >         __u32 mnt_id;
> >         __u32 nlink;
> >         __u32 mode;     /* file mode S_ISDIR, S_ISLNK, 0755, etc */
> >         __u32 flags;    /* open flags O_RDWR, O_CREAT, etc */
> > };
>
> It's probably nice to have file uid/gid as well.

And an indication of which mount namespace we're looking at.

--Andy