From: Chuck Lever <[email protected]> The svcsock TCP receive path uses sock_recvmsg() with ancillary data buffers to detect TLS alerts when kTLS is active. This CMSG-based approach requires a MSG_CTRUNC recovery dance on every receive and cannot deliver control records through the read_sock interface.
When the socket provides a read_sock_rectype method (now set by kTLS), svc_tcp_recvfrom() now dispatches to a new svc_tcp_recvfrom_readsock() path. Two actor callbacks handle the data: svc_tcp_recv_actor() parses the RPC record byte stream directly from skbs. Fragment header bytes fill sk_marker first; subsequent body bytes are copied into rq_pages at the position tracked by sk_datalen. When the last fragment of a complete RPC message arrives, the actor sets desc->count to zero, stopping the read loop. svc_tcp_rectype_actor() handles non-data TLS records. For fatal alerts, the transport is marked for deferred close and the read loop is stopped via desc->count. All non-data records are consumed by returning 0 so that subsequent data records remain deliverable. Sockets without read_sock_rectype (plain TCP, non-kTLS) continue to use the existing sock_recvmsg() path unchanged. A follow-up patch retires that path in favor of read_sock. Signed-off-by: Chuck Lever <[email protected]> --- net/sunrpc/svcsock.c | 244 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 244 insertions(+) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 50e5e7f5b762..e40931d11491 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1134,6 +1134,247 @@ static void svc_tcp_fragment_received(struct svc_sock *svsk) svsk->sk_marker = xdr_zero; } +/* + * read_sock_rectype data actor: receives decrypted application data + * from the TLS layer, parsing the RPC record stream (fragment + * headers and message bodies) and assembling complete RPC messages + * into rqstp->rq_pages. + */ +static int svc_tcp_recv_actor(read_descriptor_t *desc, + struct sk_buff *skb, + unsigned int offset, size_t len) +{ + struct svc_rqst *rqstp = desc->arg.data; + struct svc_sock *svsk = + container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt); + size_t reclen, received, want, take, done, n; + size_t consumed = 0; + + if (!desc->count) + return 0; + + if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) { + want = sizeof(rpc_fraghdr) - svsk->sk_tcplen; + n = min(want, len); + + if (skb_copy_bits(skb, offset, + (char *)&svsk->sk_marker + + svsk->sk_tcplen, n)) + goto fault; + svsk->sk_tcplen += n; + offset += n; + len -= n; + consumed += n; + + if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) + return consumed; + + trace_svcsock_marker(&svsk->sk_xprt, svsk->sk_marker); + if (svc_sock_reclen(svsk) + svsk->sk_datalen > + svsk->sk_xprt.xpt_server->sv_max_mesg) { + net_notice_ratelimited("svc: %s oversized RPC fragment (%u octets) from %pISpc\n", + svsk->sk_xprt.xpt_server->sv_name, + svc_sock_reclen(svsk), + (struct sockaddr *)&svsk->sk_xprt.xpt_remote); + desc->error = -EMSGSIZE; + desc->count = 0; + return consumed; + } + } + + reclen = svc_sock_reclen(svsk); + received = svsk->sk_tcplen - sizeof(rpc_fraghdr); + want = reclen - received; + take = min(want, len); + done = 0; + + while (done < take) { + unsigned int pg = svsk->sk_datalen >> PAGE_SHIFT; + unsigned int pg_off = svsk->sk_datalen & (PAGE_SIZE - 1); + size_t chunk = min(take - done, + PAGE_SIZE - (size_t)pg_off); + + if (skb_copy_bits(skb, offset, + page_address(rqstp->rq_pages[pg]) + pg_off, + chunk)) + goto fault; + flush_dcache_page(rqstp->rq_pages[pg]); + offset += chunk; + done += chunk; + svsk->sk_datalen += chunk; + } + svsk->sk_tcplen += take; + consumed += take; + + if (svsk->sk_tcplen - sizeof(rpc_fraghdr) >= reclen) { + if (svc_sock_final_rec(svsk)) + desc->count = 0; + else + svc_tcp_fragment_received(svsk); + } + + return consumed; + +fault: + desc->error = -EFAULT; + desc->count = 0; + return consumed; +} + +/* + * read_sock_rectype non-data record actor: receives non-data TLS + * records (alerts, handshake messages) and translates them into + * transport-level actions. + * + * Returns 0 to consume the record and allow the TLS layer to + * continue delivering subsequent records. A negative return + * causes the TLS layer to requeue the skb on its rx_list, + * blocking all further record delivery on this connection. + */ +static int svc_tcp_rectype_actor(read_descriptor_t *desc, + struct sk_buff *skb, + unsigned int offset, size_t len, + u8 rectype) +{ + struct svc_rqst *rqstp = desc->arg.data; + struct svc_sock *svsk = + container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt); + + switch (rectype) { + case TLS_RECORD_TYPE_ALERT: { + u8 alert[2] = {}, level, description; + struct kvec kvec = { + .iov_base = alert, + .iov_len = sizeof(alert), + }; + struct msghdr msg = {}; + + if (skb_copy_bits(skb, offset, alert, min(len, sizeof(alert)))) + break; + iov_iter_kvec(&msg.msg_iter, ITER_DEST, &kvec, 1, sizeof(alert)); + tls_alert_recv(svsk->sk_sk, &msg, &level, &description); + if (level == TLS_ALERT_LEVEL_FATAL) { + svc_xprt_deferred_close(&svsk->sk_xprt); + desc->error = -ENOTCONN; + desc->count = 0; + } + break; + } + default: + break; + } + return 0; +} + +static int svc_tcp_recvfrom_readsock(struct svc_rqst *rqstp) +{ + struct svc_sock *svsk = + container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt); + struct svc_serv *serv = svsk->sk_xprt.xpt_server; + struct sock *sk = svsk->sk_sk; + read_descriptor_t desc = { + .arg.data = rqstp, + }; + ssize_t len; + __be32 *p; + __be32 calldir; + + clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); + + svc_tcp_restore_pages(svsk, rqstp); + rqstp->rq_arg.head[0].iov_base = page_address(rqstp->rq_pages[0]); + + desc.count = serv->sv_max_mesg; + lock_sock(sk); + len = svsk->sk_sock->ops->read_sock_rectype(sk, &desc, + svc_tcp_recv_actor, + svc_tcp_rectype_actor); + release_sock(sk); + + if (desc.error < 0) { + len = desc.error; + goto err_discard; + } + if (desc.count != 0) { + if (len > 0) + set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); + goto err_incomplete; + } + + if (svsk->sk_datalen < 8) + goto err_nuts; + + rqstp->rq_arg.len = svsk->sk_datalen; + rqstp->rq_arg.page_base = 0; + if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) { + rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len; + rqstp->rq_arg.page_len = 0; + } else { + rqstp->rq_arg.page_len = rqstp->rq_arg.len - + rqstp->rq_arg.head[0].iov_len; + } + + rqstp->rq_xprt_ctxt = NULL; + rqstp->rq_prot = IPPROTO_TCP; + if (test_bit(XPT_LOCAL, &svsk->sk_xprt.xpt_flags)) + set_bit(RQ_LOCAL, &rqstp->rq_flags); + else + clear_bit(RQ_LOCAL, &rqstp->rq_flags); + + p = (__be32 *)rqstp->rq_arg.head[0].iov_base; + calldir = p[1]; + if (calldir) + len = receive_cb_reply(svsk, rqstp); + + /* Reset TCP read info */ + svsk->sk_datalen = 0; + svc_tcp_fragment_received(svsk); + + if (len < 0) + goto error; + + trace_svcsock_tcp_recv(&svsk->sk_xprt, rqstp->rq_arg.len); + svc_xprt_copy_addrs(rqstp, &svsk->sk_xprt); + if (serv->sv_stats) + serv->sv_stats->nettcpcnt++; + + svc_sock_secure_port(rqstp); + set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); + svc_xprt_received(rqstp->rq_xprt); + return rqstp->rq_arg.len; + +err_incomplete: + svc_tcp_save_pages(svsk, rqstp); + if (len < 0 && len != -EAGAIN) + goto err_delete; + if (svsk->sk_tcplen >= sizeof(rpc_fraghdr)) + trace_svcsock_tcp_recv_short(&svsk->sk_xprt, + svc_sock_reclen(svsk), + svsk->sk_tcplen - sizeof(rpc_fraghdr)); + goto err_noclose; +error: + if (len != -EAGAIN) + goto err_delete; + trace_svcsock_tcp_recv_eagain(&svsk->sk_xprt, 0); + goto err_noclose; +err_nuts: + svsk->sk_datalen = 0; + goto err_delete; +err_discard: + /* + * Clear sk_datalen so the teardown-time + * svc_tcp_clear_pages() does not walk the emptied + * svsk->sk_pages[]. + */ + svsk->sk_datalen = 0; +err_delete: + trace_svcsock_tcp_recv_err(&svsk->sk_xprt, len); + svc_xprt_deferred_close(&svsk->sk_xprt); +err_noclose: + svc_xprt_received(rqstp->rq_xprt); + return 0; +} + /** * svc_tcp_recvfrom - Receive data from a TCP socket * @rqstp: request structure into which to receive an RPC Call @@ -1162,6 +1403,9 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp) __be32 *p; __be32 calldir; + if (svsk->sk_sock->ops->read_sock_rectype) + return svc_tcp_recvfrom_readsock(rqstp); + clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); len = svc_tcp_read_marker(svsk, rqstp); if (len < 0) -- 2.54.0
