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[62.73.72.43]) by smtp.gmail.com with ESMTPSA id j1-20020a1709064b4100b0098e025cda3bsm2117917ejv.141.2023.07.11.23.38.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 11 Jul 2023 23:38:22 -0700 (PDT) Message-ID: <18cfa70a-35b6-da02-3dd4-0c8ab6639b9b@blackwall.org> Date: Wed, 12 Jul 2023 09:38:21 +0300 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v1 net] bridge: Return an error when enabling STP in netns. Content-Language: en-US To: Kuniyuki Iwashima , Roopa Prabhu , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: "Eric W. Biederman" , Kuniyuki Iwashima , netdev@vger.kernel.org, bridge@lists.linux-foundation.org, Harry Coin References: <20230711235415.92166-1-kuniyu@amazon.com> From: Nikolay Aleksandrov In-Reply-To: <20230711235415.92166-1-kuniyu@amazon.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,NICE_REPLY_A,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 12/07/2023 02:54, Kuniyuki Iwashima wrote: > When we create an L2 loop on a bridge in netns, we will see packets storm > even if STP is enabled. > > # unshare -n > # ip link add br0 type bridge > # ip link add veth0 type veth peer name veth1 > # ip link set veth0 master br0 up > # ip link set veth1 master br0 up > # ip link set br0 type bridge stp_state 1 > # ip link set br0 up > # sleep 30 > # ip -s link show br0 > 2: br0: mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 > link/ether b6:61:98:1c:1c:b5 brd ff:ff:ff:ff:ff:ff > RX: bytes packets errors dropped missed mcast > 956553768 12861249 0 0 0 12861249 <-. Keep > TX: bytes packets errors dropped carrier collsns | increasing > 1027834 11951 0 0 0 0 <-' rapidly > > This is because llc_rcv() drops all packets in non-root netns and BPDU > is dropped. > > Let's show an error when enabling STP in netns. > > # unshare -n > # ip link add br0 type bridge > # ip link set br0 type bridge stp_state 1 > Error: bridge: STP can't be enabled in non-root netns. > > Note this commit will be reverted later when we namespacify the whole LLC > infra. > > Fixes: e730c15519d0 ("[NET]: Make packet reception network namespace safe") > Suggested-by: Harry Coin > Link: https://lore.kernel.org/netdev/0f531295-e289-022d-5add-5ceffa0df9bc@quietfountain.com/ > Signed-off-by: Kuniyuki Iwashima > --- > net/bridge/br_stp_if.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c > index 75204d36d7f9..a807996ac56b 100644 > --- a/net/bridge/br_stp_if.c > +++ b/net/bridge/br_stp_if.c > @@ -201,6 +201,11 @@ int br_stp_set_enabled(struct net_bridge *br, unsigned long val, > { > ASSERT_RTNL(); > > + if (!net_eq(dev_net(br->dev), &init_net)) { > + NL_SET_ERR_MSG_MOD(extack, "STP can't be enabled in non-root netns"); > + return -EINVAL; > + } > + > if (br_mrp_enabled(br)) { > NL_SET_ERR_MSG_MOD(extack, > "STP can't be enabled if MRP is already enabled"); Oh well, I guess this should do for now. Hopefully we don't break scripts that rely on configuring the bridge without any errors. Thanks for the patch, Acked-by: Nikolay Aleksandrov