Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Roman Gushchin <guro@fb.com>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        "bpf@vger.kernel.org" <bpf@vger.kernel.org>
CC:     Kernel Team <Kernel-team@fb.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Yonghong Song <yhs@fb.com>
Subject: Re: [PATCH bpf-next] bpf: allow CGROUP_SKB programs to use
 bpf_get_current_cgroup_id() helper
Thread-Topic: [PATCH bpf-next] bpf: allow CGROUP_SKB programs to use
 bpf_get_current_cgroup_id() helper
Thread-Index: AQHVHJn5xFnlIJGy00O8LdScbBruEqaO/RaA
Date:   Thu, 6 Jun 2019 19:08:00 +0000
Message-ID: <20190606190752.GA28743@tower.DHCP.thefacebook.com>
References: <20190606185911.4089151-1-guro@fb.com>
In-Reply-To: <20190606185911.4089151-1-guro@fb.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-messagesentrepresentingtype: 1
x-originating-ip: [2620:10d:c090:200::1:aba7]
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: afd23bf9-0c5b-4cdb-47bb-08d6eab24b07
x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020);SRVR:BN8PR15MB2657;
x-ms-traffictypediagnostic: BN8PR15MB2657:
x-microsoft-antispam-prvs: <BN8PR15MB26579313A097ECB739774AC6BE170@BN8PR15MB2657.namprd15.prod.outlook.com>
x-ms-oob-tlc-oobclassifiers: OLM:7691;
x-forefront-prvs: 00603B7EEF
x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(376002)(39860400002)(136003)(366004)(346002)(396003)(199004)(54094003)(189003)(6486002)(6436002)(86362001)(186003)(9686003)(6512007)(8936002)(25786009)(5660300002)(478600001)(6246003)(6506007)(7736002)(66946007)(229853002)(46003)(386003)(68736007)(102836004)(11346002)(71190400001)(476003)(53936002)(446003)(71200400001)(1076003)(14454004)(256004)(4744005)(2906002)(64756008)(81166006)(73956011)(6116002)(81156014)(4326008)(316002)(110136005)(33656002)(8676002)(99286004)(305945005)(2501003)(76176011)(486006)(54906003)(66556008)(66446008)(52116002)(66476007);DIR:OUT;SFP:1102;SCL:1;SRVR:BN8PR15MB2657;H:BN8PR15MB2626.namprd15.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1;
received-spf: None (protection.outlook.com: fb.com does not designate
 permitted sender hosts)
x-ms-exchange-senderadcheck: 1
x-microsoft-antispam-message-info: C7y89wBLiqkfwJBVnQbNvBbaWCql3r4ndxLz9LSdcpen/xjUrSoNGTgVayFsuN+5y0nfwzf0o8IkAlItLpKMycGw49l/O5HZtfX60LYAFz/GhOAJE752m8cgUooiuOGpkkGVskCycARFF3P2r3RSFYiv9mDSy9T8NWPISJ8lSoauxI0Um5qH6f9Dp0P3MsU4uZzW8G8TyX/qB2bOxPDAUqweHHKVopCnhUYOScBsgr5QkoQSwLgY+wSOOrCHE3ojfK7Sz/d0ws2kv4RMjANfb3AeDtYR0dwGEn4sPCyeVGEJEG260R2QGmvrkki6TJ7Y44T+VWThjEOnARm0QlYewN+Pkcp3DDt2tT5fbtHFlgS/DyI8HdOWW9dErmVSGAcnHzhUeL37Zno2ABouLG2QQEhV9htvpcE7kEAybA2HlbM=
Content-Type: text/plain; charset="us-ascii"
Content-ID: <3ABAF4E2EE5B3242850320709B05A5AF@namprd15.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: afd23bf9-0c5b-4cdb-47bb-08d6eab24b07
X-MS-Exchange-CrossTenant-originalarrivaltime: 06 Jun 2019 19:08:00.7288
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: guro@fb.com
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN8PR15MB2657
X-OriginatorOrg: fb.com
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-06_13:,,
 signatures=0
X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501
 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0
 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0
 mlxlogscore=806 adultscore=0 classifier=spam adjust=0 reason=mlx
 scancount=1 engine=8.0.1-1810050000 definitions=main-1906060127
X-FB-Internal: deliver
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Jun 06, 2019 at 11:59:11AM -0700, Roman Gushchin wrote:
> Currently bpf_get_current_cgroup_id() is not supported for
> CGROUP_SKB programs. An attempt to load such a program generates an
> error like this:
>     libbpf:
>     0: (b7) r6 =3D 0
>     ...
>     8: (63) *(u32 *)(r10 -28) =3D r6
>     9: (85) call bpf_get_current_cgroup_id#80
>     unknown func bpf_get_current_cgroup_id#80
>=20
> There are no particular reasons for denying it,
> and we have some use cases where it might be useful.

Ah, sorry, it's not so simple, as we probably need to take
the cgroup pointer from the socket, not from current.

So the implementation of the helper should be different
for this type of programs.

So I wonder if it's better to introduce a new helper
bpf_get_sock_cgroup_id()?

What do you think?

Thanks!