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Miller" CC: , , References: <20200819011244.2027725-1-udippant@fb.com> From: Yonghong Song Message-ID: Date: Tue, 18 Aug 2020 23:03:45 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 In-Reply-To: <20200819011244.2027725-1-udippant@fb.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MN2PR11CA0005.namprd11.prod.outlook.com (2603:10b6:208:23b::10) To BYAPR15MB4088.namprd15.prod.outlook.com (2603:10b6:a02:c3::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [IPv6:2620:10d:c0a8:11e8::10d3] (2620:10d:c091:480::1:374f) by MN2PR11CA0005.namprd11.prod.outlook.com (2603:10b6:208:23b::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3305.24 via Frontend Transport; Wed, 19 Aug 2020 06:03:48 +0000 X-Originating-IP: [2620:10d:c091:480::1:374f] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: b4ce6b35-374b-4e7e-1f88-08d84405a505 X-MS-TrafficTypeDiagnostic: BYAPR15MB2583: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-FB-Source: Internal X-MS-Oob-TLC-OOBClassifiers: OLM:5797; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: ub5BJlenDCcEAz2U93iMQCaZK5CkWZ+JjN7AO7WC/2LOXDwUmfTDNao2/s16IUeNZ+yAJE+onbrS89rSdZlUUdrcfdLLjtDrSB+kJ6tSS9BeAXMG5OGl8OEPJCIkp0fIT5r887e3wnPF6PoOqLai3B9Ab8k4EWIpbpmqiFAaktm/ladTwE/f5B0XaCqjzULZ1ZbE4VRwcRdmVICu6oglevT1zmSi5BXNWVr5ItZ5n6bOa2SNiV7v5ZoxMC0zfnfhtZB0bgRDs73rvM6N6vFWBZ2LANi0qhsgww4FPFfc6MzN76B2AumPwKVfKr7sAjZAVfdg6OOqnZiWLY8FQWdngb4m0peAMHqpflKKPefVAwTcukY8UdWzYUprQz1RyL07 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR15MB4088.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFS:(136003)(376002)(346002)(366004)(396003)(39860400002)(6486002)(478600001)(36756003)(8676002)(83380400001)(186003)(31696002)(31686004)(5660300002)(4326008)(2906002)(52116002)(16526019)(86362001)(66946007)(66476007)(6666004)(53546011)(66556008)(8936002)(316002)(2616005)(110136005)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData: 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 X-MS-Exchange-CrossTenant-Network-Message-Id: b4ce6b35-374b-4e7e-1f88-08d84405a505 X-MS-Exchange-CrossTenant-AuthSource: BYAPR15MB4088.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Aug 2020 06:03:50.8845 (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: 1kf8e6AiWH4UCsmh7BTSfLv//iVFtPzqYhL9s7+ymTWaCKv92D7tbZNv0fp+2XYu X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2583 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-19_04:2020-08-18,2020-08-19 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 impostorscore=0 spamscore=0 bulkscore=0 mlxlogscore=999 clxscore=1015 priorityscore=1501 malwarescore=0 lowpriorityscore=0 suspectscore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008190051 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/18/20 6:12 PM, Udip Pant wrote: > While using dynamic program extension (of type BPF_PROG_TYPE_EXT), we > need to check the program type of the target program to grant the read / > write access to the packet data. > > The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB > and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a > placeholder for those, we need this extended check for those target > programs to actually work while using this option. > > Tested this with a freplace xdp program. Without this patch, the > verifier fails with error 'cannot write into packet'. Could you add a selftest for this? FYI, current selftests/bpf have 4 freplace programs: fexit_bpf2bpf.c:SEC("freplace/get_skb_len") fexit_bpf2bpf.c:SEC("freplace/get_skb_ifindex") fexit_bpf2bpf.c:SEC("freplace/get_constant") freplace_connect4.c:SEC("freplace/do_bind") > > Signed-off-by: Udip Pant > --- > kernel/bpf/verifier.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index ef938f17b944..4d7604430994 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -2629,7 +2629,11 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, > const struct bpf_call_arg_meta *meta, > enum bpf_access_type t) > { > - switch (env->prog->type) { > + struct bpf_prog *prog = env->prog; > + enum bpf_prog_type prog_type = prog->aux->linked_prog ? > + prog->aux->linked_prog->type : prog->type; > + > + switch (prog_type) { > /* Program types only with direct read access go here! */ > case BPF_PROG_TYPE_LWT_IN: > case BPF_PROG_TYPE_LWT_OUT: >