From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51F6DC10F14 for ; Tue, 8 Oct 2019 11:31:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 217B620673 for ; Tue, 8 Oct 2019 11:31:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cisco.com header.i=@cisco.com header.b="ISvpjAZl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730741AbfJHLbM (ORCPT ); Tue, 8 Oct 2019 07:31:12 -0400 Received: from aer-iport-2.cisco.com ([173.38.203.52]:8497 "EHLO aer-iport-2.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730375AbfJHLbK (ORCPT ); Tue, 8 Oct 2019 07:31:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=11885; q=dns/txt; s=iport; t=1570534269; x=1571743869; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=KV3fz+DpNTDA0n5op8Lc3s3vYTu+C0V3ugdzvlLCDj8=; b=ISvpjAZlwmyUI5vuHWPSAtJu2sPpBNByY4uAikpZPRgX9VRgvPPuH7hH IPabzovqjv4o7V1xFC7S1ct0+BCBxU8k3giCYPPsyESgCQLLaXPCFE97+ 1QPrl/WrKsSn4aIfufWZUivelv+sxEXayskpm4SZ+f1SnptcP52brAPXP M=; X-IronPort-AV: E=Sophos;i="5.67,270,1566864000"; d="scan'208";a="17754665" Received: from aer-iport-nat.cisco.com (HELO aer-core-2.cisco.com) ([173.38.203.22]) by aer-iport-2.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 08 Oct 2019 11:24:00 +0000 Received: from rdbuild16.cisco.com.rd.cisco.com (rdbuild16.cisco.com [10.47.15.16]) by aer-core-2.cisco.com (8.15.2/8.15.2) with ESMTP id x98BNe58031991; Tue, 8 Oct 2019 11:24:00 GMT From: Georg Kohmann To: netdev@vger.kernel.org Cc: Georg Kohmann , Peter Oskolkov , Eric Dumazet , Florian Westphal , "David S . Miller" Subject: [PATCH 4.4 stable 10/10] net: IP6 defrag: use rbtrees in nf_conntrack_reasm.c Date: Tue, 8 Oct 2019 13:23:09 +0200 Message-Id: <20191008112309.9571-11-geokohma@cisco.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20191008112309.9571-1-geokohma@cisco.com> References: <20191008112309.9571-1-geokohma@cisco.com> X-Outbound-SMTP-Client: 10.47.15.16, rdbuild16.cisco.com X-Outbound-Node: aer-core-2.cisco.com Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org commit 997dd9647164 ("net: IP6 defrag: use rbtrees in nf_conntrack_reasm.c") Currently, IPv6 defragmentation code drops non-last fragments that are smaller than 1280 bytes: see commit 0ed4229b08c1 ("ipv6: defrag: drop non-last frags smaller than min mtu") This behavior is not specified in IPv6 RFCs and appears to break compatibility with some IPv6 implemenations, as reported here: https://www.spinics.net/lists/netdev/msg543846.html This patch re-uses common IP defragmentation queueing and reassembly code in IP6 defragmentation in nf_conntrack, removing the 1280 byte restriction. Signed-off-by: Peter Oskolkov Reported-by: Tom Herbert Cc: Eric Dumazet Cc: Florian Westphal Signed-off-by: David S. Miller --- net/ipv6/netfilter/nf_conntrack_reasm.c | 256 +++++++++----------------------- 1 file changed, 72 insertions(+), 184 deletions(-) diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c index 49fd3c6..31b7745 100644 --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -51,14 +51,6 @@ static const char nf_frags_cache_name[] = "nf-frags"; -struct nf_ct_frag6_skb_cb -{ - struct inet6_skb_parm h; - int offset; -}; - -#define NFCT_FRAG6_CB(skb) ((struct nf_ct_frag6_skb_cb *)((skb)->cb)) - static struct inet_frags nf_frags; #ifdef CONFIG_SYSCTL @@ -144,6 +136,9 @@ static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net) } #endif +static int nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *skb, + struct sk_buff *prev_tail, struct net_device *dev); + static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h) { return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK); @@ -184,9 +179,10 @@ static struct frag_queue *fq_find(struct net *net, __be32 id, u32 user, static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, const struct frag_hdr *fhdr, int nhoff) { - struct sk_buff *prev, *next; unsigned int payload_len; - int offset, end; + struct net_device *dev; + struct sk_buff *prev; + int offset, end, err; u8 ecn; if (fq->q.flags & INET_FRAG_COMPLETE) { @@ -260,55 +256,19 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, goto err; } - /* Find out which fragments are in front and at the back of us - * in the chain of fragments so far. We must know where to put - * this fragment, right? - */ + /* Note : skb->rbnode and skb->dev share the same location. */ + dev = skb->dev; + /* Makes sure compiler wont do silly aliasing games */ + barrier(); + prev = fq->q.fragments_tail; - if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) { - next = NULL; - goto found; - } - prev = NULL; - for (next = fq->q.fragments; next != NULL; next = next->next) { - if (NFCT_FRAG6_CB(next)->offset >= offset) - break; /* bingo! */ - prev = next; - } + err = inet_frag_queue_insert(&fq->q, skb, offset, end); + if (err) + goto insert_error; -found: - /* RFC5722, Section 4: - * When reassembling an IPv6 datagram, if - * one or more its constituent fragments is determined to be an - * overlapping fragment, the entire datagram (and any constituent - * fragments, including those not yet received) MUST be silently - * discarded. - */ + if (dev) + fq->iif = dev->ifindex; - /* Check for overlap with preceding fragment. */ - if (prev && - (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset) - goto discard_fq; - - /* Look for overlap with succeeding segment. */ - if (next && NFCT_FRAG6_CB(next)->offset < end) - goto discard_fq; - - NFCT_FRAG6_CB(skb)->offset = offset; - - /* Insert this fragment in the chain of fragments. */ - skb->next = next; - if (!next) - fq->q.fragments_tail = skb; - if (prev) - prev->next = skb; - else - fq->q.fragments = skb; - - if (skb->dev) { - fq->iif = skb->dev->ifindex; - skb->dev = NULL; - } fq->q.stamp = skb->tstamp; fq->q.meat += skb->len; fq->ecn |= ecn; @@ -324,11 +284,25 @@ found: fq->q.flags |= INET_FRAG_FIRST_IN; } - return 0; + if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && + fq->q.meat == fq->q.len) { + unsigned long orefdst = skb->_skb_refdst; + + skb->_skb_refdst = 0UL; + err = nf_ct_frag6_reasm(fq, skb, prev, dev); + skb->_skb_refdst = orefdst; + return err; + } -discard_fq: + skb_dst_drop(skb); + return -EINPROGRESS; + +insert_error: + if (err == IPFRAG_DUP) + goto err; inet_frag_kill(&fq->q); err: + skb_dst_drop(skb); return -EINVAL; } @@ -338,141 +312,67 @@ err: * It is called with locked fq, and caller must check that * queue is eligible for reassembly i.e. it is not COMPLETE, * the last and the first frames arrived and all the bits are here. - * - * returns true if *prev skb has been transformed into the reassembled - * skb, false otherwise. */ -static bool -nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *prev, struct net_device *dev) +static int nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *skb, + struct sk_buff *prev_tail, struct net_device *dev) { - struct sk_buff *fp, *head = fq->q.fragments; - int payload_len; + void *reasm_data; + int payload_len; u8 ecn; inet_frag_kill(&fq->q); - WARN_ON(head == NULL); - WARN_ON(NFCT_FRAG6_CB(head)->offset != 0); - ecn = ip_frag_ecn_table[fq->ecn]; if (unlikely(ecn == 0xff)) - return false; + goto err; + + reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail); + if (!reasm_data) + goto err; - /* Unfragmented part is taken from the first segment. */ - payload_len = ((head->data - skb_network_header(head)) - + payload_len = ((skb->data - skb_network_header(skb)) - sizeof(struct ipv6hdr) + fq->q.len - sizeof(struct frag_hdr)); if (payload_len > IPV6_MAXPLEN) { net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n", payload_len); - return false; - } - - /* Head of list must not be cloned. */ - if (skb_unclone(head, GFP_ATOMIC)) - return false; - - /* If the first fragment is fragmented itself, we split - * it to two chunks: the first with data and paged part - * and the second, holding only fragments. */ - if (skb_has_frag_list(head)) { - struct sk_buff *clone; - int i, plen = 0; - - clone = alloc_skb(0, GFP_ATOMIC); - if (clone == NULL) - return false; - - clone->next = head->next; - head->next = clone; - skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; - skb_frag_list_init(head); - for (i = 0; i < skb_shinfo(head)->nr_frags; i++) - plen += skb_frag_size(&skb_shinfo(head)->frags[i]); - clone->len = clone->data_len = head->data_len - plen; - head->data_len -= clone->len; - head->len -= clone->len; - clone->csum = 0; - clone->ip_summed = head->ip_summed; - - add_frag_mem_limit(fq->q.net, clone->truesize); - } - - /* morph head into last received skb: prev. - * - * This allows callers of ipv6 conntrack defrag to continue - * to use the last skb(frag) passed into the reasm engine. - * The last skb frag 'silently' turns into the full reassembled skb. - * - * Since prev is also part of q->fragments we have to clone it first. - */ - if (head != prev) { - struct sk_buff *iter; - - fp = skb_clone(prev, GFP_ATOMIC); - if (!fp) - return false; - - fp->next = prev->next; - - iter = head; - while (iter) { - if (iter->next == prev) { - iter->next = fp; - break; - } - iter = iter->next; - } - - skb_morph(prev, head); - prev->next = head->next; - consume_skb(head); - head = prev; + goto err; } /* We have to remove fragment header from datagram and to relocate * header in order to calculate ICV correctly. */ - skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0]; - memmove(head->head + sizeof(struct frag_hdr), head->head, - (head->data - head->head) - sizeof(struct frag_hdr)); - head->mac_header += sizeof(struct frag_hdr); - head->network_header += sizeof(struct frag_hdr); - - skb_shinfo(head)->frag_list = head->next; - skb_reset_transport_header(head); - skb_push(head, head->data - skb_network_header(head)); - - for (fp = head->next; fp; fp = fp->next) { - head->data_len += fp->len; - head->len += fp->len; - if (head->ip_summed != fp->ip_summed) - head->ip_summed = CHECKSUM_NONE; - else if (head->ip_summed == CHECKSUM_COMPLETE) - head->csum = csum_add(head->csum, fp->csum); - head->truesize += fp->truesize; - fp->sk = NULL; - } - sub_frag_mem_limit(fq->q.net, head->truesize); + skb_network_header(skb)[fq->nhoffset] = skb_transport_header(skb)[0]; + memmove(skb->head + sizeof(struct frag_hdr), skb->head, + (skb->data - skb->head) - sizeof(struct frag_hdr)); + skb->mac_header += sizeof(struct frag_hdr); + skb->network_header += sizeof(struct frag_hdr); + + skb_reset_transport_header(skb); - head->ignore_df = 1; - head->next = NULL; - head->dev = dev; - head->tstamp = fq->q.stamp; - ipv6_hdr(head)->payload_len = htons(payload_len); - ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn); - IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size; + inet_frag_reasm_finish(&fq->q, skb, reasm_data); + + skb->ignore_df = 1; + skb->dev = dev; + ipv6_hdr(skb)->payload_len = htons(payload_len); + ipv6_change_dsfield(ipv6_hdr(skb), 0xff, ecn); + IP6CB(skb)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size; /* Yes, and fold redundant checksum back. 8) */ - if (head->ip_summed == CHECKSUM_COMPLETE) - head->csum = csum_partial(skb_network_header(head), - skb_network_header_len(head), - head->csum); + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->csum = csum_partial(skb_network_header(skb), + skb_network_header_len(skb), + skb->csum); fq->q.fragments = NULL; fq->q.rb_fragments = RB_ROOT; fq->q.fragments_tail = NULL; + fq->q.last_run_head = NULL; + + return 0; - return true; +err: + inet_frag_kill(&fq->q); + return -EINVAL; } /* @@ -541,7 +441,6 @@ find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff) int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) { u16 savethdr = skb->transport_header; - struct net_device *dev = skb->dev; int fhoff, nhoff, ret; struct frag_hdr *fhdr; struct frag_queue *fq; @@ -564,10 +463,6 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) hdr = ipv6_hdr(skb); fhdr = (struct frag_hdr *)skb_transport_header(skb); - if (clone->len - skb_network_offset(clone) < IPV6_MIN_MTU && - fhdr->frag_off & htons(IP6_MF)) - goto ret_orig; - skb_orphan(skb); fq = fq_find(net, fhdr->identification, user, hdr, skb->dev ? skb->dev->ifindex : 0); @@ -576,24 +471,17 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) spin_lock_bh(&fq->q.lock); ret = nf_ct_frag6_queue(fq, skb, fhdr, nhoff); - if (ret < 0) { - if (ret == -EPROTO) { - skb->transport_header = savethdr; - ret = 0; - } - goto out_unlock; + if (ret == -EPROTO) { + skb->transport_header = savethdr; + ret = 0; } /* after queue has assumed skb ownership, only 0 or -EINPROGRESS * must be returned. */ - ret = -EINPROGRESS; - if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && - fq->q.meat == fq->q.len && - nf_ct_frag6_reasm(fq, skb, dev)) - ret = 0; + if (ret) + ret = -EINPROGRESS; -out_unlock: spin_unlock_bh(&fq->q.lock); inet_frag_put(&fq->q); return ret; -- 2.10.2