[PATCH v9 17/17] bpf,selinux: allocate bpf_security_struct per BPF token

[Andrii Nakryiko]

On Sun, Nov 5, 2023 at 9:01 PM Paul Moore <paul at paul-moore.com> wrote:
>
> On Nov  3, 2023 Andrii Nakryiko <andrii at kernel.org> wrote:
> >
> > Utilize newly added bpf_token_create/bpf_token_free LSM hooks to
> > allocate struct bpf_security_struct for each BPF token object in
> > SELinux. This just follows similar pattern for BPF prog and map.
> >
> > Signed-off-by: Andrii Nakryiko <andrii at kernel.org>
> > ---
> >  security/selinux/hooks.c | 25 +++++++++++++++++++++++++
> >  1 file changed, 25 insertions(+)
>
> Thanks Andrii, we'll need some additional code to fully enable the
> BPF tokens on a SELinux system but I can help provide that if you'd
> like.  Although I might not be able to get to that until after the
> merge window closes.

Yep, I'd appreciate your help with the SELinux side. Until after the
merge window is fine, yes.

Thanks for reviewing the patch set!

>
> > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> > index 002351ab67b7..1501e95366a1 100644
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -6828,6 +6828,29 @@ static void selinux_bpf_prog_free(struct bpf_prog *prog)
> >       prog->aux->security = NULL;
> >       kfree(bpfsec);
> >  }
> > +
> > +static int selinux_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
> > +                                 struct path *path)
> > +{
> > +     struct bpf_security_struct *bpfsec;
> > +
> > +     bpfsec = kzalloc(sizeof(*bpfsec), GFP_KERNEL);
> > +     if (!bpfsec)
> > +             return -ENOMEM;
> > +
> > +     bpfsec->sid = current_sid();
> > +     token->security = bpfsec;
> > +
> > +     return 0;
> > +}
> > +
> > +static void selinux_bpf_token_free(struct bpf_token *token)
> > +{
> > +     struct bpf_security_struct *bpfsec = token->security;
> > +
> > +     token->security = NULL;
> > +     kfree(bpfsec);
> > +}
> >  #endif
> >
> >  struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = {
> > @@ -7183,6 +7206,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
> >       LSM_HOOK_INIT(bpf_prog, selinux_bpf_prog),
> >       LSM_HOOK_INIT(bpf_map_free, selinux_bpf_map_free),
> >       LSM_HOOK_INIT(bpf_prog_free, selinux_bpf_prog_free),
> > +     LSM_HOOK_INIT(bpf_token_free, selinux_bpf_token_free),
> >  #endif
> >
> >  #ifdef CONFIG_PERF_EVENTS
> > @@ -7241,6 +7265,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
> >  #ifdef CONFIG_BPF_SYSCALL
> >       LSM_HOOK_INIT(bpf_map_create, selinux_bpf_map_create),
> >       LSM_HOOK_INIT(bpf_prog_load, selinux_bpf_prog_load),
> > +     LSM_HOOK_INIT(bpf_token_create, selinux_bpf_token_create),
> >  #endif
> >  #ifdef CONFIG_PERF_EVENTS
> >       LSM_HOOK_INIT(perf_event_alloc, selinux_perf_event_alloc),
> > --
> > 2.34.1
>
> --
> paul-moore.com