From patchwork Fri Jun 11 07:34:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12314977 Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 141DF173 for ; Fri, 11 Jun 2021 07:35:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=eKrJ39THeoi1fErkgd hVqGr7NdCfIYrnEdTvCoIpiG0=; b=BONWa2Tm7pwz/2PTcASG0k+nv6LCEZvFdX 53PxM1nSBQvF/vAXftGNwx6X3QVJhpnQzgK2ROpffrlEaXMNClHIHE27dyT5C//+ pRz/lnNl+d8GxuUc7G4saGQeR4lvwxxwO/Aj8ME6t2joz+mrk8ir13rhzey9q6AP rZYYdguaI= Received: from localhost.localdomain (unknown [110.80.1.45]) by smtp11 (Coremail) with SMTP id D8CowAD325gTEsNgpvWXAA--.80S3; Fri, 11 Jun 2021 15:34:53 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com Subject: [PATCH 1/4] mptcp: fix warning in __skb_flow_dissect() when do syn cookie for subflow join Date: Fri, 11 Jun 2021 15:34:39 +0800 Message-Id: <1623396882-2748-2-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623396882-2748-1-git-send-email-wujianguo106@163.com> References: <1623396882-2748-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAD325gTEsNgpvWXAA--.80S3 X-Coremail-Antispam: 1Uf129KBjvJXoWxuw43Jw1DWry3ZFW7Ar43ZFb_yoW7Kw4kpF 45GrZxGrWrJ3W3GF4SyrWUZrn09r4vkFZ8Kw13twn2yFn8Wwn2qFy8Jr4jvFy7GrW0ka47 KFs7K3WkKFn7ZaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jzLvZUUUUU= X-Originating-IP: [110.80.1.45] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/xtbBiB6ukFaD-Qi1xwAAs6 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, use 4-tuple derived hash. Fixes: 9466a1ccebbe("mptcp: enable JOIN requests even if cookies are in use"). Suggested-by: Paolo Abeni Signed-off-by: Jianguo Wu --- net/mptcp/syncookies.c | 46 ++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-) diff --git a/net/mptcp/syncookies.c b/net/mptcp/syncookies.c index abe0fd0..2ba09a7 100644 --- a/net/mptcp/syncookies.c +++ b/net/mptcp/syncookies.c @@ -35,13 +35,51 @@ struct join_entry { static struct join_entry join_entries[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp; static spinlock_t join_entry_locks[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp; -static u32 mptcp_join_entry_hash(struct sk_buff *skb, struct net *net) +static u32 mptcp_join_hashfn(const struct net *net, const __be32 laddr, + const __be16 lport, const __be32 faddr, + const __be16 fport) { - u32 i = skb_get_hash(skb) ^ net_hash_mix(net); + static u32 mptcp_join_hash_secret __read_mostly; + u32 i; + + net_get_random_once(&mptcp_join_hash_secret, + sizeof(mptcp_join_hash_secret)); + + i = jhash_3words((__force __u32)laddr, + (__force __u32)faddr, + ((__u32)lport) << 16 | (__force __u32)fport, + mptcp_join_hash_secret + net_hash_mix(net)); return i % ARRAY_SIZE(join_entries); } +static u32 mptcp_join_hashfn_inet6(const struct net *net, + const struct in6_addr *laddr, const __be16 lport, + const struct in6_addr *faddr, const __be16 fport) +{ + u32 i; + + i = inet6_ehashfn(net, laddr, (__force __u16)lport, faddr, fport); + + return i % ARRAY_SIZE(join_entries); +} + +static u32 mptcp_join_entry_hash(struct sk_buff *skb, struct net *net, + unsigned short family) +{ + struct tcphdr *th = tcp_hdr(skb); + +#if IS_ENABLED(CONFIG_IPV6) + if (family == AF_INET6 && + !ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) + return mptcp_join_hashfn_inet6(net, + &ipv6_hdr(skb)->daddr, th->dest, + &ipv6_hdr(skb)->saddr, th->source); +#endif + return mptcp_join_hashfn(net, ip_hdr(skb)->daddr, th->dest, + ip_hdr(skb)->saddr, th->source); +} + static void mptcp_join_store_state(struct join_entry *entry, const struct mptcp_subflow_request_sock *subflow_req) { @@ -58,7 +96,7 @@ void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock * struct sk_buff *skb) { struct net *net = read_pnet(&subflow_req->sk.req.ireq_net); - u32 i = mptcp_join_entry_hash(skb, net); + u32 i = mptcp_join_entry_hash(skb, net, subflow_req->sk.req.ireq_family); /* No use in waiting if other cpu is already using this slot -- * would overwrite the data that got stored. @@ -79,7 +117,7 @@ bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subfl struct sk_buff *skb) { struct net *net = read_pnet(&subflow_req->sk.req.ireq_net); - u32 i = mptcp_join_entry_hash(skb, net); + u32 i = mptcp_join_entry_hash(skb, net, subflow_req->sk.req.ireq_family); struct mptcp_sock *msk; struct join_entry *e; From patchwork Fri Jun 11 07:34:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12314979 Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9DA632FB8 for ; Fri, 11 Jun 2021 07:35:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=c/hCVgBOvIQfNVAKDP 4lvnA3f4Imf9aWnlkAZ8XFl68=; b=nKo7c0UxwClJncaO2wpdRi17mHNUzKOO16 0x3hu98UZnt5D3FWQYDKaIi96und4UqAsvhNyrHOnoUKgaPMgriZDDIzbahSlPmt OP1PFy7BWR4028esBV5zsvrxyk1IFAL0KCyZznLr2uXq2Lg6lTa8x5fWJEdjfS9s D1DbrdUkY= Received: from localhost.localdomain (unknown [110.80.1.45]) by smtp11 (Coremail) with SMTP id D8CowAD325gTEsNgpvWXAA--.80S4; Fri, 11 Jun 2021 15:34:54 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com Subject: [PATCH 2/4] mptcp: remove redundant req destruct in subflow_check_req() Date: Fri, 11 Jun 2021 15:34:40 +0800 Message-Id: <1623396882-2748-3-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623396882-2748-1-git-send-email-wujianguo106@163.com> References: <1623396882-2748-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAD325gTEsNgpvWXAA--.80S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7Cr4Dtw47WFWrtryktF4ktFb_yoW8Gryfpr sxXw1YyrZxZFyakF4rJF4DZrn0gayFvFn8GFyY93sxJr4qqws3KF1UWr48uFy3Aa1kKay7 GFsxtFnxX3ZF9aUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jqFALUUUUU= X-Originating-IP: [110.80.1.45] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/1tbiNx6ukFWBkxL-pQAAsY 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 6b1cd42..75ed530 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 Fri Jun 11 07:34:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12314981 Received: from m12-15.163.com (m12-15.163.com [220.181.12.15]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 50055173 for ; Fri, 11 Jun 2021 07:35:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=iyRuSN4ZPsQ0Nb6yc5 jhGaB5VFkg4g2CWpoz+5gGUlA=; b=N/2UTCJbpqBb9nQUkZtmR6lIs7DNwXcDKd GtCf/Afy5DKCjr6uPii8FE0QxyveFzX7JI74cjtTG3QnN4H3HRhiuokB85pX6ubL ZMxv6lrPxb7MHsij3f7VYIMftoboch6av8A8B797JJko8Kay5mCgpsrg2R7KqY0r TSm/TkMHc= Received: from localhost.localdomain (unknown [110.80.1.45]) by smtp11 (Coremail) with SMTP id D8CowAD325gTEsNgpvWXAA--.80S5; Fri, 11 Jun 2021 15:34:54 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com Subject: [PATCH 3/4] mptcp: fix syncookie process if mptcp can not_accept new subflow Date: Fri, 11 Jun 2021 15:34:41 +0800 Message-Id: <1623396882-2748-4-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623396882-2748-1-git-send-email-wujianguo106@163.com> References: <1623396882-2748-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAD325gTEsNgpvWXAA--.80S5 X-Coremail-Antispam: 1Uf129KBjvJXoWxAryrJFW3Kr1rCFW5GF45Wrg_yoW5Ww13pr 4UXrWxtr1fJFy3GF4ftr4DZw1UWFZYyrZxJa15K347Awn8Zws3Kry8KF1xKryxCFs7Ga45 Xr4vq3WqvFnrCaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jWT5dUUUUU= X-Originating-IP: [110.80.1.45] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/xtbB9waukF2MZNtbQQAAs7 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 75ed530..6d98e19 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 Fri Jun 11 07:34:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianguo Wu X-Patchwork-Id: 12315019 Received: from m12-16.163.com (m12-16.163.com [220.181.12.16]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 27AB6173 for ; Fri, 11 Jun 2021 07:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=2lEftx1f6zZRnabHis OW/+1xVPCYQBATtPKGQbN7Q4I=; b=MxCPygC9mIglCoRFtm9BTT2j1ctvTcytnk mFFA9WaJ1cdI4I7EydRUZCjvk9370zHiryA0RRi6I5PoEKmh4vkjLrBouB44/pbk tupr7Chtg3kTxq86s3sRfJJDRS1G1b/R8+0+8KS3f3Cq1PL/v8uOq0Eq58Sr8qPA 460F7GAZA= Received: from localhost.localdomain (unknown [110.80.1.45]) by smtp11 (Coremail) with SMTP id D8CowAD325gTEsNgpvWXAA--.80S6; Fri, 11 Jun 2021 15:34:54 +0800 (CST) From: wujianguo106@163.com To: mptcp@lists.linux.dev Cc: pabeni@redhat.com Subject: [PATCH 4/4] mptcp: avoid processing packet if a subflow reset Date: Fri, 11 Jun 2021 15:34:42 +0800 Message-Id: <1623396882-2748-5-git-send-email-wujianguo106@163.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1623396882-2748-1-git-send-email-wujianguo106@163.com> References: <1623396882-2748-1-git-send-email-wujianguo106@163.com> X-CM-TRANSID: D8CowAD325gTEsNgpvWXAA--.80S6 X-Coremail-Antispam: 1Uf129KBjvdXoWrZFyrKr1UKry3Xr4xCr1DAwb_yoWDGFb_Jw n3t3y8Jr4SyayjkFW7GrW5AFZ5Z3yDGFWUGws2ga4UJw1UGa1vqrWDJF13Wr18C390ya45 u3ZIka45KFn5KjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IUnzBTUUUUUU== X-Originating-IP: [110.80.1.45] X-CM-SenderInfo: 5zxmxt5qjx0iiqw6il2tof0z/1tbiJx+ukF5u+r4UeAAAse 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 | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 1aec016..01a1bf6 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -926,6 +926,8 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, return true; reset: + TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq; + mptcp_subflow_reset(ssk); return false; }