From patchwork Tue Jan 21 05:07:04 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiayuan Chen X-Patchwork-Id: 13945659 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.4]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 657331ACEAC; Tue, 21 Jan 2025 05:09:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737436179; cv=none; b=oG2IlAmFg1VGc1amuEKZPA4PUs9UF/w7mn6da3x3E2Jc5l1wW5RA4J6sSKDit9qW+sX3Wd/dj0ykYqvo6U1b7PZrd5VfFVgzuW//g9PyBh/uegikPBWXXGP4PxbkIw7T3HaSc0BhYXTdE+PP+K4kPJNzNYg3aWjJ5LOSfvDZLOs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737436179; c=relaxed/simple; bh=hEImoseKWo0E9B2QFiXPKIHFFWsmwpeTSuHp7MefVr0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vbvtsek2kToazr8bGK9d1OP45jFlVsWMD1usqAElKMBSuPth4wbuw724yzDcLS0O5iGSWP/JaqCBQ+f5TVlMPyAonSZvxRw+005uFhST26UYOvIl37IgWNRt7a5FKlvclF8mb6Ih2qWehV4VO+By7dZtSflFUGdsBmmtcf0rPFE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=ivXF9FVh; arc=none smtp.client-ip=117.135.210.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="ivXF9FVh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-ID:MIME-Version; bh=jR9Ap pvosdVIS01cytFrRWp0HPq2UnOWrUcF+0NyLKQ=; b=ivXF9FVhZK2aev6aztgv8 Oh2Pc/nhsQ8esQjQcOLES+FlIN4APcomLohRzFRvE7sfGLziOKmz+RLKJ1G5nrl1 DaZSdvsZ5PHV/PbOJuxX/u4ax/ETu/uSxk/+dQrN6CtkMQJn9fjdBJqNxzq7HgcH iLPvMo4W9gpjC1aLYBcMbM= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g0-3 (Coremail) with SMTP id _____wBHwYeaK49nTErMHA--.41409S4; Tue, 21 Jan 2025 13:08:12 +0800 (CST) From: Jiayuan Chen To: bpf@vger.kernel.org, jakub@cloudflare.com, john.fastabend@gmail.com Cc: netdev@vger.kernel.org, martin.lau@linux.dev, ast@kernel.org, edumazet@google.com, davem@davemloft.net, dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com, linux-kernel@vger.kernel.org, song@kernel.org, andrii@kernel.org, mhal@rbox.co, yonghong.song@linux.dev, daniel@iogearbox.net, xiyou.wangcong@gmail.com, horms@kernel.org, corbet@lwn.net, eddyz87@gmail.com, cong.wang@bytedance.com, shuah@kernel.org, mykolal@fb.com, jolsa@kernel.org, haoluo@google.com, sdf@fomichev.me, kpsingh@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Jiayuan Chen Subject: [PATCH bpf v8 2/5] bpf: fix wrong copied_seq calculation Date: Tue, 21 Jan 2025 13:07:04 +0800 Message-ID: <20250121050707.55523-3-mrpre@163.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250121050707.55523-1-mrpre@163.com> References: <20250121050707.55523-1-mrpre@163.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: _____wBHwYeaK49nTErMHA--.41409S4 X-Coremail-Antispam: 1Uf129KBjvJXoWxKryrKFW5JFWkWFy3ZryUGFg_yoW3WFyrpF 1kA3yrCr9rGFyxuwn3AF97Gr1agw4rKFW7Cr18u3y3Zrs3Kr1fXF95KF1ayFW5Kr4Y9r1a qr4UGw43CwnrAa7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pETa0gUUUUU= X-CM-SenderInfo: xpus2vi6rwjhhfrp/1tbiWwnbp2ePHkP-dAACsS 'sk->copied_seq' was updated in the tcp_eat_skb() function when the action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS, the update logic for 'sk->copied_seq' was moved to tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature. It works for a single stream_verdict scenario, as it also modified 'sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb' to remove updating 'sk->copied_seq'. However, for programs where both stream_parser and stream_verdict are active(strparser purpose), tcp_read_sock() was used instead of tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock) tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated updates. In summary, for strparser + SK_PASS, copied_seq is redundantly calculated in both tcp_read_sock() and tcp_bpf_recvmsg_parser(). The issue causes incorrect copied_seq calculations, which prevent correct data reads from the recv() interface in user-land. We do not want to add new proto_ops to implement a new version of tcp_read_sock, as this would introduce code complexity [1]. We add new callback for strparser for customized read operation. [1]: https://lore.kernel.org/bpf/20241218053408.437295-1-mrpre@163.com Fixes: e5c6de5fa025 ("bpf, sockmap: Incorrectly handling copied_seq") Suggested-by: Jakub Sitnicki Signed-off-by: Jiayuan Chen --- include/linux/skmsg.h | 2 ++ include/net/tcp.h | 8 ++++++++ net/core/skmsg.c | 7 +++++++ net/ipv4/tcp.c | 29 ++++++++++++++++++++++++----- net/ipv4/tcp_bpf.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 83 insertions(+), 5 deletions(-) diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index 2cbe0c22a32f..0b9095a281b8 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -91,6 +91,8 @@ struct sk_psock { struct sk_psock_progs progs; #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER) struct strparser strp; + u32 copied_seq; + u32 ingress_bytes; #endif struct sk_buff_head ingress_skb; struct list_head ingress_msg; diff --git a/include/net/tcp.h b/include/net/tcp.h index e9b37b76e894..06affc653247 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -729,6 +729,9 @@ void tcp_get_info(struct sock *, struct tcp_info *); /* Read 'sendfile()'-style from a TCP socket */ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, sk_read_actor_t recv_actor); +int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor, bool noack, + u32 *copied_seq); int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off); void tcp_read_done(struct sock *sk, size_t len); @@ -2599,6 +2602,11 @@ struct sk_psock; #ifdef CONFIG_BPF_SYSCALL int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); +#ifdef CONFIG_BPF_STREAM_PARSER +struct strparser; +int tcp_bpf_strp_read_sock(struct strparser *strp, read_descriptor_t *desc, + sk_read_actor_t recv_actor); +#endif /* CONFIG_BPF_STREAM_PARSER */ #endif /* CONFIG_BPF_SYSCALL */ #ifdef CONFIG_INET diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 61f3f3d4e528..0ddc4c718833 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -549,6 +549,9 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, return num_sge; } +#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER) + psock->ingress_bytes += len; +#endif copied = len; msg->sg.start = 0; msg->sg.size = copied; @@ -1144,6 +1147,10 @@ int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock) if (!ret) sk_psock_set_state(psock, SK_PSOCK_RX_STRP_ENABLED); + if (sk_is_tcp(sk)) { + psock->strp.cb.read_sock = tcp_bpf_strp_read_sock; + psock->copied_seq = tcp_sk(sk)->copied_seq; + } return ret; } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 0d704bda6c41..285678d8ce07 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1565,12 +1565,13 @@ EXPORT_SYMBOL(tcp_recv_skb); * or for 'peeking' the socket using this routine * (although both would be easy to implement). */ -int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, - sk_read_actor_t recv_actor) +static int __tcp_read_sock(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor, bool noack, + u32 *copied_seq) { struct sk_buff *skb; struct tcp_sock *tp = tcp_sk(sk); - u32 seq = tp->copied_seq; + u32 seq = *copied_seq; u32 offset; int copied = 0; @@ -1624,9 +1625,12 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, tcp_eat_recv_skb(sk, skb); if (!desc->count) break; - WRITE_ONCE(tp->copied_seq, seq); + WRITE_ONCE(*copied_seq, seq); } - WRITE_ONCE(tp->copied_seq, seq); + WRITE_ONCE(*copied_seq, seq); + + if (noack) + goto out; tcp_rcv_space_adjust(sk); @@ -1635,10 +1639,25 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, tcp_recv_skb(sk, seq, &offset); tcp_cleanup_rbuf(sk, copied); } +out: return copied; } + +int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor) +{ + return __tcp_read_sock(sk, desc, recv_actor, false, + &tcp_sk(sk)->copied_seq); +} EXPORT_SYMBOL(tcp_read_sock); +int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor, bool noack, + u32 *copied_seq) +{ + return __tcp_read_sock(sk, desc, recv_actor, noack, copied_seq); +} + int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor) { struct sk_buff *skb; diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 47f65b1b70ca..4dcf88ad8275 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -646,6 +646,48 @@ static int tcp_bpf_assert_proto_ops(struct proto *ops) ops->sendmsg == tcp_sendmsg ? 0 : -ENOTSUPP; } +#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER) +int tcp_bpf_strp_read_sock(struct strparser *strp, read_descriptor_t *desc, + sk_read_actor_t recv_actor) +{ + struct sock *sk = strp->sk; + struct sk_psock *psock; + struct tcp_sock *tp; + int copied = 0; + + tp = tcp_sk(sk); + rcu_read_lock(); + psock = sk_psock(sk); + if (WARN_ON(!psock)) { + desc->error = -EINVAL; + goto out; + } + + psock->ingress_bytes = 0; + /* We could easily add copied_seq and noack into desc then call + * ops->read_sock without calling symbol directly. But unfortunately + * most descriptors used by other modules are not inited with zero. + * Also it not work by replacing ops->read_sock without introducing + * new ops as ops itself is located in rodata segment. + */ + copied = tcp_read_sock_noack(sk, desc, recv_actor, true, + &psock->copied_seq); + if (copied < 0) + goto out; + /* recv_actor may redirect skb to another socket(SK_REDIRECT) or + * just put skb into ingress queue of current socket(SK_PASS). + * For SK_REDIRECT, we need 'ack' the frame immediately but for + * SK_PASS, the 'ack' was delay to tcp_bpf_recvmsg_parser() + */ + tp->copied_seq = psock->copied_seq - psock->ingress_bytes; + tcp_rcv_space_adjust(sk); + __tcp_cleanup_rbuf(sk, copied - psock->ingress_bytes); +out: + rcu_read_unlock(); + return copied; +} +#endif /* CONFIG_BPF_STREAM_PARSER */ + int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) { int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;