From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FCFE27700 for ; Wed, 12 Jul 2023 14:48:28 +0000 (UTC) Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CB871BF3 for ; Wed, 12 Jul 2023 07:48:25 -0700 (PDT) Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id 789F45C0068; Wed, 12 Jul 2023 10:48:24 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Wed, 12 Jul 2023 10:48:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; t=1689173304; x=1689259704; bh=dDGB6dk3gveHu vxXP5ggp8ZAFoaeoltwyPWmhEfJpaQ=; b=h6TA0lx6uUC0QidHKNG3uLRNXI+Xe ggO01FzNFrXwpAEORttpEYlqIME3ANVI7BaixFC7BcGTauCjmYzhzgW7lXnpldqK NsinlvILHxMb6MrBCUUBPOA7CoEKEvGbNbOx3Uy7Pm4K8AUMHkH2lEjhRroMpEXd DHrBYNNrD9NTKfPsJbLjxEJF3s/mzH8AiQ7z/u4gRiJjXf0Ef2h+XGxWOKam0kTY 0/Zqjnrlj7/oPL4w8VuHuYlfx2tB+cG1AhUuQTIkmIpJMOGPCRHs4sebw6S3A34P jGu6vBSp0ZaGV6DOv19cLxUgie0EkmPNjeDCmXPOrusF69rqRmCELtQbQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedviedrfedvgdekudcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvvefukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpefkughoucfu tghhihhmmhgvlhcuoehiughoshgthhesihguohhstghhrdhorhhgqeenucggtffrrghtth gvrhhnpeehhfdtjedviefffeduuddvffegteeiieeguefgudffvdfftdefheeijedthfej keenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivgeptd enucfrrghrrghmpehmrghilhhfrhhomhepihguohhstghhsehiughoshgthhdrohhrgh X-ME-Proxy: Feedback-ID: i494840e7:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 12 Jul 2023 10:48:22 -0400 (EDT) Date: Wed, 12 Jul 2023 17:48:20 +0300 From: Ido Schimmel To: Kuniyuki Iwashima Cc: Roopa Prabhu , Nikolay Aleksandrov , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Eric W. Biederman" , Kuniyuki Iwashima , netdev@vger.kernel.org, bridge@lists.linux-foundation.org, Harry Coin Subject: Re: [PATCH v1 net] bridge: Return an error when enabling STP in netns. Message-ID: References: <20230711235415.92166-1-kuniyu@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230711235415.92166-1-kuniyu@amazon.com> X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_PASS,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED 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 Tue, Jul 11, 2023 at 04:54:15PM -0700, 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 I'm not sure that's accurate. I read his response in the link below and he says "I'd rather be warned than blocked" and "But better warned and awaiting a fix than blocked", which I agree with. The patch has the potential to cause a lot of regressions, but without actually fixing the problem. How about simply removing the error [1]? Since iproute2 commit 844c37b42373 ("libnetlink: Handle extack messages for non-error case"), it can print extack warnings and not only errors. With the diff below: # unshare -n # ip link add name br0 type bridge # ip link set dev br0 type bridge stp_state 1 Warning: bridge: STP can't be enabled in non-root netns. # echo $? 0 [1] diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c index a807996ac56b..b5143de37938 100644 --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c @@ -201,10 +201,8 @@ int br_stp_set_enabled(struct net_bridge *br, unsigned long val, { ASSERT_RTNL(); - if (!net_eq(dev_net(br->dev), &init_net)) { + 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, > 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"); > -- > 2.30.2 > >