From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: "Mickaël Salaün" <mic@digikod.net>
Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Arnd Bergmann <arnd@arndb.de>,
Casey Schaufler <casey@schaufler-ca.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Daniel Mack <daniel@zonque.org>,
David Drysdale <drysdale@google.com>,
"David S . Miller" <davem@davemloft.net>,
Elena Reshetova <elena.reshetova@intel.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
James Morris <james.l.morris@oracle.com>,
Kees Cook <keescook@chromium.org>, Paul Moore <pmoore@redhat.com>,
Sargun Dhillon <sargun@sargun.me>,
"Serge E . Hallyn" <serge@hallyn.com>, Tejun Heo <tj@kernel.org>,
Will Drewry <wad@chromium.org>,
kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
linux-security-module@vger.kernel.org, netdev@vger.kernel.org,
cgroups@vger.kernel.org
Subject: [kernel-hardening] Re: [RFC v3 14/22] bpf/cgroup: Make cgroup_bpf_update() return an error code
Date: Wed, 14 Sep 2016 14:16:10 -0700 [thread overview]
Message-ID: <20160914211608.GB57174@ast-mbp.thefacebook.com> (raw)
In-Reply-To: <20160914072415.26021-15-mic@digikod.net>
On Wed, Sep 14, 2016 at 09:24:07AM +0200, Mickaël Salaün wrote:
> This will be useful to support Landlock for the next commits.
>
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Daniel Mack <daniel@zonque.org>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Tejun Heo <tj@kernel.org>
I think this is good to do regardless. Sooner or later cgroup_bpf_update
will start rejecting the prog attach. Like we discussed to have a flag
that would dissallow processeses lower in the cgroup hierarchy to install
their own bpf programs.
It will be minimal change to bpf_prog_attach() error handling,
but will greatly help Mickael to build stuff on top.
DanielM can you refactor your patch to do that from the start ?
Thanks!
> ---
> include/linux/bpf-cgroup.h | 4 ++--
> kernel/bpf/cgroup.c | 3 ++-
> kernel/bpf/syscall.c | 10 ++++++----
> kernel/cgroup.c | 6 ++++--
> 4 files changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
> index 2234042d7f61..6cca7924ee17 100644
> --- a/include/linux/bpf-cgroup.h
> +++ b/include/linux/bpf-cgroup.h
> @@ -31,13 +31,13 @@ struct cgroup_bpf {
> void cgroup_bpf_put(struct cgroup *cgrp);
> void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent);
>
> -void __cgroup_bpf_update(struct cgroup *cgrp,
> +int __cgroup_bpf_update(struct cgroup *cgrp,
> struct cgroup *parent,
> struct bpf_prog *prog,
> enum bpf_attach_type type);
>
> /* Wrapper for __cgroup_bpf_update() protected by cgroup_mutex */
> -void cgroup_bpf_update(struct cgroup *cgrp,
> +int cgroup_bpf_update(struct cgroup *cgrp,
> struct bpf_prog *prog,
> enum bpf_attach_type type);
>
> diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
> index 782878ec4f2d..7b75fa692617 100644
> --- a/kernel/bpf/cgroup.c
> +++ b/kernel/bpf/cgroup.c
> @@ -83,7 +83,7 @@ void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
> *
> * Must be called with cgroup_mutex held.
> */
> -void __cgroup_bpf_update(struct cgroup *cgrp,
> +int __cgroup_bpf_update(struct cgroup *cgrp,
> struct cgroup *parent,
> struct bpf_prog *prog,
> enum bpf_attach_type type)
> @@ -117,6 +117,7 @@ void __cgroup_bpf_update(struct cgroup *cgrp,
> bpf_prog_put(old_pinned.prog);
> static_branch_dec(&cgroup_bpf_enabled_key);
> }
> + return 0;
> }
>
> /**
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 45a91d511119..c978f2d9a1b3 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -831,6 +831,7 @@ static int bpf_prog_attach(const union bpf_attr *attr)
> {
> struct bpf_prog *prog;
> struct cgroup *cgrp;
> + int result;
>
> if (!capable(CAP_NET_ADMIN))
> return -EPERM;
> @@ -858,10 +859,10 @@ static int bpf_prog_attach(const union bpf_attr *attr)
> return PTR_ERR(cgrp);
> }
>
> - cgroup_bpf_update(cgrp, prog, attr->attach_type);
> + result = cgroup_bpf_update(cgrp, prog, attr->attach_type);
> cgroup_put(cgrp);
>
> - return 0;
> + return result;
> }
>
> #define BPF_PROG_DETACH_LAST_FIELD attach_type
> @@ -869,6 +870,7 @@ static int bpf_prog_attach(const union bpf_attr *attr)
> static int bpf_prog_detach(const union bpf_attr *attr)
> {
> struct cgroup *cgrp;
> + int result = 0;
>
> if (!capable(CAP_NET_ADMIN))
> return -EPERM;
> @@ -883,7 +885,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
> if (IS_ERR(cgrp))
> return PTR_ERR(cgrp);
>
> - cgroup_bpf_update(cgrp, NULL, attr->attach_type);
> + result = cgroup_bpf_update(cgrp, NULL, attr->attach_type);
> cgroup_put(cgrp);
> break;
>
> @@ -891,7 +893,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
> return -EINVAL;
> }
>
> - return 0;
> + return result;
> }
> #endif /* CONFIG_CGROUP_BPF */
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 87324ce481b1..48b650a640a9 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -6450,15 +6450,17 @@ static __init int cgroup_namespaces_init(void)
> subsys_initcall(cgroup_namespaces_init);
>
> #ifdef CONFIG_CGROUP_BPF
> -void cgroup_bpf_update(struct cgroup *cgrp,
> +int cgroup_bpf_update(struct cgroup *cgrp,
> struct bpf_prog *prog,
> enum bpf_attach_type type)
> {
> struct cgroup *parent = cgroup_parent(cgrp);
> + int result;
>
> mutex_lock(&cgroup_mutex);
> - __cgroup_bpf_update(cgrp, parent, prog, type);
> + result = __cgroup_bpf_update(cgrp, parent, prog, type);
> mutex_unlock(&cgroup_mutex);
> + return result;
> }
> #endif /* CONFIG_CGROUP_BPF */
>
> --
> 2.9.3
>
next prev parent reply other threads:[~2016-09-14 21:16 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-14 7:23 [kernel-hardening] [RFC v3 00/22] Landlock LSM: Unprivileged sandboxing Mickaël Salaün
2016-09-14 7:23 ` [kernel-hardening] [RFC v3 01/22] landlock: Add Kconfig Mickaël Salaün
2016-09-14 7:23 ` [kernel-hardening] [RFC v3 02/22] bpf: Move u64_to_ptr() to BPF headers and inline it Mickaël Salaün
2016-09-14 7:23 ` [kernel-hardening] [RFC v3 03/22] bpf,landlock: Add a new arraymap type to deal with (Landlock) handles Mickaël Salaün
2016-09-14 18:51 ` [kernel-hardening] " Alexei Starovoitov
2016-09-14 23:22 ` Mickaël Salaün
2016-09-14 23:28 ` Alexei Starovoitov
2016-09-15 21:51 ` Mickaël Salaün
2016-10-03 23:53 ` Kees Cook
2016-10-05 22:02 ` Mickaël Salaün
2016-09-14 7:23 ` [kernel-hardening] [RFC v3 04/22] bpf: Set register type according to is_valid_access() Mickaël Salaün
2016-10-19 14:54 ` [kernel-hardening] " Thomas Graf
2016-10-19 15:10 ` Daniel Borkmann
2016-09-14 7:23 ` [kernel-hardening] [RFC v3 05/22] bpf,landlock: Add eBPF program subtype and is_valid_subtype() verifier Mickaël Salaün
2016-10-19 15:01 ` [kernel-hardening] " Thomas Graf
2016-09-14 7:23 ` [kernel-hardening] [RFC v3 06/22] landlock: Add LSM hooks Mickaël Salaün
2016-10-19 15:19 ` [kernel-hardening] " Thomas Graf
2016-10-19 22:42 ` Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 07/22] landlock: Handle file comparisons Mickaël Salaün
2016-09-14 19:07 ` [kernel-hardening] " Jann Horn
2016-09-14 22:39 ` Mickaël Salaün
2016-09-14 21:06 ` Alexei Starovoitov
2016-09-14 23:02 ` Mickaël Salaün
2016-09-14 23:24 ` Alexei Starovoitov
2016-09-15 21:25 ` Mickaël Salaün
2016-09-20 0:12 ` [kernel-hardening] lsm naming dilemma. " Alexei Starovoitov
2016-09-20 1:10 ` [kernel-hardening] " Sargun Dhillon
2016-09-20 16:58 ` Mickaël Salaün
2016-10-03 23:30 ` [kernel-hardening] " Kees Cook
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 08/22] seccomp: Fix documentation for struct seccomp_filter Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 09/22] seccomp: Move struct seccomp_filter in seccomp.h Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 10/22] seccomp: Split put_seccomp_filter() with put_seccomp() Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 11/22] seccomp,landlock: Handle Landlock hooks per process hierarchy Mickaël Salaün
2016-09-14 18:43 ` [kernel-hardening] " Andy Lutomirski
2016-09-14 22:34 ` Mickaël Salaün
2016-10-03 23:52 ` Kees Cook
2016-10-05 21:05 ` Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 12/22] bpf: Cosmetic change for bpf_prog_attach() Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 13/22] bpf/cgroup: Replace struct bpf_prog with union bpf_object Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 14/22] bpf/cgroup: Make cgroup_bpf_update() return an error code Mickaël Salaün
2016-09-14 21:16 ` Alexei Starovoitov [this message]
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 15/22] bpf/cgroup: Move capability check Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 16/22] bpf/cgroup,landlock: Handle Landlock hooks per cgroup Mickaël Salaün
2016-10-03 23:43 ` [kernel-hardening] " Kees Cook
2016-10-05 20:58 ` Mickaël Salaün
2016-10-05 21:25 ` Kees Cook
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 17/22] cgroup: Add access check for cgroup_get_from_fd() Mickaël Salaün
2016-09-14 22:06 ` [kernel-hardening] " Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 18/22] cgroup,landlock: Add CGRP_NO_NEW_PRIVS to handle unprivileged hooks Mickaël Salaün
2016-09-14 18:27 ` [kernel-hardening] " Andy Lutomirski
2016-09-14 22:11 ` Mickaël Salaün
2016-09-15 1:25 ` Andy Lutomirski
2016-09-15 2:19 ` Alexei Starovoitov
2016-09-15 2:27 ` Andy Lutomirski
2016-09-15 4:00 ` Alexei Starovoitov
2016-09-15 4:08 ` Andy Lutomirski
2016-09-15 4:31 ` Alexei Starovoitov
2016-09-15 4:38 ` Andy Lutomirski
2016-09-15 4:48 ` Alexei Starovoitov
2016-09-15 19:41 ` Mickaël Salaün
2016-09-20 4:37 ` Sargun Dhillon
2016-09-20 17:02 ` Mickaël Salaün
2016-09-15 19:35 ` Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 19/22] landlock: Add interrupted origin Mickaël Salaün
2016-09-14 18:29 ` [kernel-hardening] " Andy Lutomirski
2016-09-14 22:14 ` Mickaël Salaün
2016-09-15 1:19 ` Andy Lutomirski
2016-10-03 23:46 ` Kees Cook
2016-10-05 21:01 ` Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 20/22] landlock: Add update and debug access flags Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 21/22] bpf,landlock: Add optional skb pointer in the Landlock context Mickaël Salaün
2016-09-14 21:20 ` [kernel-hardening] " Alexei Starovoitov
2016-09-14 22:46 ` Mickaël Salaün
2016-09-14 7:24 ` [kernel-hardening] [RFC v3 22/22] samples/landlock: Add sandbox example Mickaël Salaün
2016-09-14 21:24 ` [kernel-hardening] " Alexei Starovoitov
2016-09-14 14:36 ` [kernel-hardening] RE: [RFC v3 00/22] Landlock LSM: Unprivileged sandboxing David Laight
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