From patchwork Wed Jun 16 10:49:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12324763 X-Patchwork-Delegate: mat@martineau.name Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C76B9173 for ; Wed, 16 Jun 2021 10:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=bMErQq/RHb9+Nv55IT 915+/t6jItHEXB1wfDPx5DuKk=; b=RbV5RU0tnWstvdhOPEM4K8FGRMLRSRE2D8 sekEcSH5jIjvU9FV7aeYNnepLTizxTVUn+J+2W7CPoJQUbWY23RT3YNLgY64V/43 fy2VGhMS8g+7vBqQvwDULgGcVx8p9eDMHefFTIH+KIppVyav5Tacos+ysOBbirL3 oO4lj6D+k= Received: from localhost.localdomain (unknown [36.111.140.26]) by smtp11 (Coremail) with SMTP id D8CowAB33vY718lgxTs1AA--.106S3; Wed, 16 Jun 2021 18:50:32 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com, fw@strlen.de Subject: [PATCH v5 1/4] mptcp: fix warning in __skb_flow_dissect() when do syn cookie for subflow join Date: Wed, 16 Jun 2021 18:49:27 +0800 Message-Id: <1623840570-42004-2-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623840570-42004-1-git-send-email-wujianguo106@163.com> References: <1623840570-42004-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAB33vY718lgxTs1AA--.106S3 X-Coremail-Antispam: 1Uf129KBjvJXoWxAw4DCrWfZFy3AFy7Gr17KFg_yoWrAr13pr 45GrWDGrW8Jwn8Jr4YyFW7Xrn8Kr4qvFW8Gw1ayr1kJFs8Gwn2qFy8Jr40vFy7GrWYg347 Kr1DJ3WkKFn7ZaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jVOJ5UUUUU= X-Originating-IP: [36.111.140.26] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/xtbB+AmzkF2MZRlTUQAAs9 X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Jianguo Wu I got the following warning message while doing the test: [ 55.552626] TCP: request_sock_subflow: Possible SYN flooding on port 8099. Sending cookies. Check SNMP counters. [ 55.553024] ------------[ cut here ]------------ [ 55.553027] WARNING: CPU: 0 PID: 10 at net/core/flow_dissector.c:984 __skb_flow_dissect+0x280/0x1650 ... [ 55.553117] CPU: 0 PID: 10 Comm: ksoftirqd/0 Not tainted 5.12.0+ #18 [ 55.553121] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020 [ 55.553124] RIP: 0010:__skb_flow_dissect+0x280/0x1650 ... [ 55.553133] RSP: 0018:ffffb79580087770 EFLAGS: 00010246 [ 55.553137] RAX: 0000000000000000 RBX: ffffffff8ddb58e0 RCX: ffffb79580087888 [ 55.553139] RDX: ffffffff8ddb58e0 RSI: ffff8f7e4652b600 RDI: 0000000000000000 [ 55.553141] RBP: ffffb79580087858 R08: 0000000000000000 R09: 0000000000000008 [ 55.553143] R10: 000000008c622965 R11: 00000000d3313a5b R12: ffff8f7e4652b600 [ 55.553146] R13: ffff8f7e465c9062 R14: 0000000000000000 R15: ffffb79580087888 [ 55.553149] FS: 0000000000000000(0000) GS:ffff8f7f75e00000(0000) knlGS:0000000000000000 [ 55.553152] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 55.553154] CR2: 00007f73d1d19000 CR3: 0000000135e10004 CR4: 00000000003706f0 [ 55.553160] Call Trace: [ 55.553166] ? __sha256_final+0x67/0xd0 [ 55.553173] ? sha256+0x7e/0xa0 [ 55.553177] __skb_get_hash+0x57/0x210 [ 55.553182] subflow_init_req_cookie_join_save+0xac/0xc0 [ 55.553189] subflow_check_req+0x474/0x550 [ 55.553195] ? ip_route_output_key_hash+0x67/0x90 [ 55.553200] ? xfrm_lookup_route+0x1d/0xa0 [ 55.553207] subflow_v4_route_req+0x8e/0xd0 [ 55.553212] tcp_conn_request+0x31e/0xab0 [ 55.553218] ? selinux_socket_sock_rcv_skb+0x116/0x210 [ 55.553224] ? tcp_rcv_state_process+0x179/0x6d0 [ 55.553229] tcp_rcv_state_process+0x179/0x6d0 [ 55.553235] tcp_v4_do_rcv+0xaf/0x220 [ 55.553239] tcp_v4_rcv+0xce4/0xd80 [ 55.553243] ? ip_route_input_rcu+0x246/0x260 [ 55.553248] ip_protocol_deliver_rcu+0x35/0x1b0 [ 55.553253] ip_local_deliver_finish+0x44/0x50 [ 55.553258] ip_local_deliver+0x6c/0x110 [ 55.553262] ? ip_rcv_finish_core.isra.19+0x5a/0x400 [ 55.553267] ip_rcv+0xd1/0xe0 ... After debugging, I found in __skb_flow_dissect(), skb->dev and skb->sk are both NULL, then net is NULL, and trigger WARN_ON_ONCE(!net), actually net is always NULL in this code path, as skb->dev is set to NULL in tcp_v4_rcv(), and skb->sk is never set. Code snippet in __skb_flow_dissect() that trigger warning: 975 if (skb) { 976 if (!net) { 977 if (skb->dev) 978 net = dev_net(skb->dev); 979 else if (skb->sk) 980 net = sock_net(skb->sk); 981 } 982 } 983 984 WARN_ON_ONCE(!net); So, using seq and transport header derived hash. Fixes: 9466a1ccebbe("mptcp: enable JOIN requests even if cookies are in use"). Suggested-by: Paolo Abeni Suggested-by: Florian Westphal Signed-off-by: Jianguo Wu --- net/mptcp/syncookies.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/net/mptcp/syncookies.c b/net/mptcp/syncookies.c index abe0fd099746..37127781aee9 100644 --- a/net/mptcp/syncookies.c +++ b/net/mptcp/syncookies.c @@ -37,7 +37,21 @@ struct join_entry { static u32 mptcp_join_entry_hash(struct sk_buff *skb, struct net *net) { - u32 i = skb_get_hash(skb) ^ net_hash_mix(net); + static u32 mptcp_join_hash_secret __read_mostly; + struct tcphdr *th = tcp_hdr(skb); + u32 seq, i; + + net_get_random_once(&mptcp_join_hash_secret, + sizeof(mptcp_join_hash_secret)); + + if (th->syn) + seq = TCP_SKB_CB(skb)->seq; + else + seq = TCP_SKB_CB(skb)->seq - 1; + + i = jhash_3words(seq, net_hash_mix(net), + (__force __u32)th->source << 16 | (__force __u32)th->dest, + mptcp_join_hash_secret); return i % ARRAY_SIZE(join_entries); } From patchwork Wed Jun 16 10:49:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12324761 X-Patchwork-Delegate: mat@martineau.name Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 69949173 for ; Wed, 16 Jun 2021 10:50:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=LtwwSfKH64AUddqgd7 0rafjih+T5w5SjpqFt6dRKttM=; b=bjOQrCdb+ewvdjEtW3LeRutmfqM/MwB2NV gpTGOTVMngjfMoB7vQcw3zmoqGAsFOiLipY9Ix4Op4DwK0og1+94qHL67CjNB/tO gU9TR7b+wgOuvv2YRK1aGdSMCAAZfOyWcqCYFtQUWZJ/oAEdXD8RACKQHNrvRIez wkF/tIEC8= Received: from localhost.localdomain (unknown [36.111.140.26]) by smtp11 (Coremail) with SMTP id D8CowAB33vY718lgxTs1AA--.106S4; Wed, 16 Jun 2021 18:50:33 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com, fw@strlen.de Subject: [PATCH v5 2/4] mptcp: remove redundant req destruct in subflow_check_req() Date: Wed, 16 Jun 2021 18:49:28 +0800 Message-Id: <1623840570-42004-3-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623840570-42004-1-git-send-email-wujianguo106@163.com> References: <1623840570-42004-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAB33vY718lgxTs1AA--.106S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7Cr4Dtw47WFWrtryktF4ktFb_yoW8GrWfpr sxXw1YyrZxZFyakF4rJF4DZrn0gayFvFn5GFyY93sxJr4qqws3KF1UWF48uFy3Aan7Kay7 GFsxtFnxX3ZF9aUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j6PfdUUUUU= X-Originating-IP: [36.111.140.26] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/xtbB+AmzkF2MZRlTUQABs8 X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Jianguo Wu In subflow_check_req(), if subflow sport is mismatch, will put msk, destroy token, and destruct req, then return -EPERM, which can be done by subflow_req_destructor() via: tcp_conn_request() |--__reqsk_free() |--subflow_req_destructor() So we should remove these redundant code, otherwise will call tcp_v4_reqsk_destructor() twice, and may double free inet_rsk(req)->ireq_opt. Fixes: 5bc56388c74f ("mptcp: add port number check for MP_JOIN") Signed-off-by: Jianguo Wu --- net/mptcp/subflow.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 6b1cd4257edf..75ed530706c0 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -213,11 +213,6 @@ static int subflow_check_req(struct request_sock *req, ntohs(inet_sk(sk_listener)->inet_sport), ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport)); if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) { - sock_put((struct sock *)subflow_req->msk); - mptcp_token_destroy_request(req); - tcp_request_sock_ops.destructor(req); - subflow_req->msk = NULL; - subflow_req->mp_join = 0; SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX); return -EPERM; } From patchwork Wed Jun 16 10:49:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12324765 X-Patchwork-Delegate: mat@martineau.name Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B726D17F for ; Wed, 16 Jun 2021 10:50:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=fc7DM/nfCFc+ak5COu 7ol9l9KbcCLFVkNjQTdR7mWSs=; b=hqdpP/qHjd95e5u55lmpZUm/fKAMVEpWD2 gnCS9wO52JgnMq1W4E/7NV0px77WufGL7Ka/4lzKBoxasKOKtgOOryURQ41dqA4n EeCbkOmvCPK+bC1OOVSCsQ4oMtzjpEdxjS3z3k9Ne4zDOyDPVhil8lJ2oWMMYpFY I6l4cTYu4= Received: from localhost.localdomain (unknown [36.111.140.26]) by smtp11 (Coremail) with SMTP id D8CowAB33vY718lgxTs1AA--.106S5; Wed, 16 Jun 2021 18:50:34 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com, fw@strlen.de Subject: [PATCH v5 3/4] mptcp: fix syncookie process if mptcp can not_accept new subflow Date: Wed, 16 Jun 2021 18:49:29 +0800 Message-Id: <1623840570-42004-4-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623840570-42004-1-git-send-email-wujianguo106@163.com> References: <1623840570-42004-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAB33vY718lgxTs1AA--.106S5 X-Coremail-Antispam: 1Uf129KBjvJXoWxAryrJFW3Kr1rCFW5GF45Wrg_yoW5Ww43pr 4UXrWxtr1fJFy3GF4ftr4DZw1UWFZYyrZxJa15K347Awn8Zws3Kry8KF1xKryxCFs7GFy5 Xr4vq3WqvFnrCaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j_EfrUUUUU= X-Originating-IP: [36.111.140.26] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/xtbBSRSzkFaD+62aYgAAsF X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Jianguo Wu Lots of "TCP: tcp_fin: Impossible, sk->sk_state=7" in client side when doing stress testing. There are at least two cases may trigger this warning: 1.mptcp is in syncookie, and server recv MP_JOIN SYN request, in subflow_check_req(), the mptcp_can_accept_new_subflow() return false, so subflow_init_req_cookie_join_save() isn't called, i.e. not store the data present in the MP_JOIN syn request and the random nonce in hash table - join_entries[], but still send synack. When recv 3rd-ack, mptcp_token_join_cookie_init_state() will return false, and 3rd-ack is dropped, then if mptcp conn is closed by client, client will send a DATA_FIN and a MPTCP FIN, the DATA_FIN doesn't have MP_CAPABLE or MP_JOIN, so mptcp_subflow_init_cookie_req() will return 0, and pass the cookie check, MP_JOIN request is fallback to normal TCP. Server will send a TCP FIN if closed, in client side, when process TCP FIN, it will do reset, the code path is: tcp_data_queue()->mptcp_incoming_options() ->check_fully_established()->mptcp_subflow_reset(). mptcp_subflow_reset() will set sock state to TCP_CLOSE, so tcp_fin will hit TCP_CLOSE, and print the warning. 2.mptcp is in syncookie, and server recv 3rd-ack, in mptcp_subflow_init_cookie_req(), mptcp_can_accept_new_subflow() return false, and subflow_req->mp_join is not set to 1, so in subflow_syn_recv_sock() will not reset the MP_JOIN subflow, but fallback to normal TCP, and then the same thing happens when server will send a TCP FIN if closed. For case1, subflow_check_req() return -EPERM, then tcp_conn_request() will drop MP_JOIN SYN. For case2, let subflow_syn_recv_sock() call mptcp_can_accept_new_subflow(), and do fatal fallback, send reset. Fixes: 9466a1ccebbe("mptcp: enable JOIN requests even if cookies are in use") Signed-off-by: Jianguo Wu --- net/mptcp/subflow.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 75ed530706c0..6d98e19a20aa 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -224,6 +224,8 @@ static int subflow_check_req(struct request_sock *req, if (unlikely(req->syncookie)) { if (mptcp_can_accept_new_subflow(subflow_req->msk)) subflow_init_req_cookie_join_save(subflow_req, skb); + else + return -EPERM; } pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, @@ -263,9 +265,7 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req, if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) return -EINVAL; - if (mptcp_can_accept_new_subflow(subflow_req->msk)) - subflow_req->mp_join = 1; - + subflow_req->mp_join = 1; subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; } From patchwork Wed Jun 16 10:49:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12324767 X-Patchwork-Delegate: mat@martineau.name Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A36EF2FAE for ; Wed, 16 Jun 2021 10:50:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=NlxZ4LjKhbE6K+Zwzy +Du1mrx+RNqn9miuRvV8pYLDI=; b=nsZFCJzna5SspahstZhpDgB7rwZe87EmiW CXW3Gi76GokYL3cRzvSTVXyBKwhDvRfLfHdC+PUR8hHEDe+m+uncYWI/whyqz0D7 lNQ4Xiq/kNnwzUC7UcbB0sL0DFsqGVQdueIpHvlSABx7Av6jIkbDrgjQ51tCSWlr B1GBgNNVY= Received: from localhost.localdomain (unknown [36.111.140.26]) by smtp11 (Coremail) with SMTP id D8CowAB33vY718lgxTs1AA--.106S6; Wed, 16 Jun 2021 18:50:35 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com, fw@strlen.de Subject: [PATCH v5 4/4] mptcp: avoid processing packet if a subflow reset Date: Wed, 16 Jun 2021 18:49:30 +0800 Message-Id: <1623840570-42004-5-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623840570-42004-1-git-send-email-wujianguo106@163.com> References: <1623840570-42004-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAB33vY718lgxTs1AA--.106S6 X-Coremail-Antispam: 1Uf129KBjvdXoWrZFyrKr1UKry3Xr4xCr1DAwb_yoWkuFc_Jw n3t3y8XFsayayUKFWUGrW5AFWrW39rGFyUWwnFga47t34UGa1vqrWkJF13uF18C390yFy5 u3Z0ka45tFn5KjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IUnjQ6JUUUUU== X-Originating-IP: [36.111.140.26] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/1tbiNxuzkFWBk1APngAAsJ X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Jianguo Wu If check_fully_established() causes a subflow reset, it should not continue to process the packet in tcp_data_queue(). setting: TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq; so that the following check will drop the pkt in tcp_data_queue(): if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { __kfree_skb(skb); return; } Fixes: d582484726c4 ("mptcp: fix fallback for MP_JOIN subflows") Signed-off-by: Jianguo Wu --- net/mptcp/options.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 1aec01686c1a..be435c5421cd 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -926,6 +926,12 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, return true; reset: + /* If a subflow is reset, the packet should not continue to be + * processed in tcp_data_queue(), so setting: end_seq = seq, + * then tcp_data_queue() will drop the packet. + */ + TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq; + mptcp_subflow_reset(ssk); return false; }