![Alexander Aring](/assets/img/avatar_default.png)
This patch fix byte order handling in reassembly code of 802.15.4 6LoWPAN fragmentation handling. net/ieee802154/reassembly.c:58:43: warning: restricted __be16 degrades to integer Signed-off-by: Alexander Aring <alex.aring@gmail.com> Reported-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
586 lines
14 KiB
C
586 lines
14 KiB
C
/* 6LoWPAN fragment reassembly
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*
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*
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* Authors:
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* Alexander Aring <aar@pengutronix.de>
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*
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* Based on: net/ipv6/reassembly.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) "6LoWPAN: " fmt
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#include <linux/net.h>
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#include <linux/list.h>
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#include <linux/netdevice.h>
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#include <linux/random.h>
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#include <linux/jhash.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <net/ieee802154_netdev.h>
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#include <net/6lowpan.h>
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#include <net/ipv6.h>
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#include <net/inet_frag.h>
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#include "reassembly.h"
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static const char lowpan_frags_cache_name[] = "lowpan-frags";
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struct lowpan_frag_info {
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u16 d_tag;
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u16 d_size;
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u8 d_offset;
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};
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static struct lowpan_frag_info *lowpan_cb(struct sk_buff *skb)
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{
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return (struct lowpan_frag_info *)skb->cb;
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}
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static struct inet_frags lowpan_frags;
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static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
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struct sk_buff *prev, struct net_device *dev);
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static unsigned int lowpan_hash_frag(u16 tag, u16 d_size,
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const struct ieee802154_addr *saddr,
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const struct ieee802154_addr *daddr)
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{
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net_get_random_once(&lowpan_frags.rnd, sizeof(lowpan_frags.rnd));
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return jhash_3words(ieee802154_addr_hash(saddr),
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ieee802154_addr_hash(daddr),
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(__force u32)(tag + (d_size << 16)),
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lowpan_frags.rnd);
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}
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static unsigned int lowpan_hashfn(const struct inet_frag_queue *q)
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{
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const struct lowpan_frag_queue *fq;
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fq = container_of(q, struct lowpan_frag_queue, q);
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return lowpan_hash_frag(fq->tag, fq->d_size, &fq->saddr, &fq->daddr);
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}
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static bool lowpan_frag_match(const struct inet_frag_queue *q, const void *a)
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{
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const struct lowpan_frag_queue *fq;
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const struct lowpan_create_arg *arg = a;
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fq = container_of(q, struct lowpan_frag_queue, q);
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return fq->tag == arg->tag && fq->d_size == arg->d_size &&
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ieee802154_addr_equal(&fq->saddr, arg->src) &&
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ieee802154_addr_equal(&fq->daddr, arg->dst);
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}
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static void lowpan_frag_init(struct inet_frag_queue *q, const void *a)
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{
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const struct lowpan_create_arg *arg = a;
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struct lowpan_frag_queue *fq;
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fq = container_of(q, struct lowpan_frag_queue, q);
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fq->tag = arg->tag;
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fq->d_size = arg->d_size;
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fq->saddr = *arg->src;
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fq->daddr = *arg->dst;
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}
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static void lowpan_frag_expire(unsigned long data)
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{
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struct frag_queue *fq;
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struct net *net;
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fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
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net = container_of(fq->q.net, struct net, ieee802154_lowpan.frags);
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spin_lock(&fq->q.lock);
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if (fq->q.flags & INET_FRAG_COMPLETE)
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goto out;
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inet_frag_kill(&fq->q, &lowpan_frags);
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out:
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spin_unlock(&fq->q.lock);
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inet_frag_put(&fq->q, &lowpan_frags);
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}
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static inline struct lowpan_frag_queue *
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fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
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const struct ieee802154_addr *src,
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const struct ieee802154_addr *dst)
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{
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struct inet_frag_queue *q;
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struct lowpan_create_arg arg;
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unsigned int hash;
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struct netns_ieee802154_lowpan *ieee802154_lowpan =
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net_ieee802154_lowpan(net);
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arg.tag = frag_info->d_tag;
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arg.d_size = frag_info->d_size;
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arg.src = src;
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arg.dst = dst;
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hash = lowpan_hash_frag(frag_info->d_tag, frag_info->d_size, src, dst);
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q = inet_frag_find(&ieee802154_lowpan->frags,
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&lowpan_frags, &arg, hash);
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if (IS_ERR_OR_NULL(q)) {
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inet_frag_maybe_warn_overflow(q, pr_fmt());
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return NULL;
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}
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return container_of(q, struct lowpan_frag_queue, q);
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}
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static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
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struct sk_buff *skb, const u8 frag_type)
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{
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struct sk_buff *prev, *next;
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struct net_device *dev;
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int end, offset;
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if (fq->q.flags & INET_FRAG_COMPLETE)
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goto err;
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offset = lowpan_cb(skb)->d_offset << 3;
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end = lowpan_cb(skb)->d_size;
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/* Is this the final fragment? */
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if (offset + skb->len == end) {
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/* If we already have some bits beyond end
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* or have different end, the segment is corrupted.
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*/
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if (end < fq->q.len ||
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((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
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goto err;
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fq->q.flags |= INET_FRAG_LAST_IN;
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fq->q.len = end;
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} else {
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if (end > fq->q.len) {
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/* Some bits beyond end -> corruption. */
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if (fq->q.flags & INET_FRAG_LAST_IN)
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goto err;
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fq->q.len = end;
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}
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}
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/* Find out which fragments are in front and at the back of us
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* in the chain of fragments so far. We must know where to put
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* this fragment, right?
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*/
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prev = fq->q.fragments_tail;
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if (!prev || lowpan_cb(prev)->d_offset < lowpan_cb(skb)->d_offset) {
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next = NULL;
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goto found;
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}
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prev = NULL;
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for (next = fq->q.fragments; next != NULL; next = next->next) {
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if (lowpan_cb(next)->d_offset >= lowpan_cb(skb)->d_offset)
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break; /* bingo! */
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prev = next;
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}
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found:
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/* Insert this fragment in the chain of fragments. */
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skb->next = next;
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if (!next)
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fq->q.fragments_tail = skb;
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if (prev)
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prev->next = skb;
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else
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fq->q.fragments = skb;
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dev = skb->dev;
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if (dev)
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skb->dev = NULL;
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fq->q.stamp = skb->tstamp;
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if (frag_type == LOWPAN_DISPATCH_FRAG1) {
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/* Calculate uncomp. 6lowpan header to estimate full size */
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fq->q.meat += lowpan_uncompress_size(skb, NULL);
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fq->q.flags |= INET_FRAG_FIRST_IN;
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} else {
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fq->q.meat += skb->len;
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}
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add_frag_mem_limit(&fq->q, skb->truesize);
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if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
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fq->q.meat == fq->q.len) {
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int res;
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unsigned long orefdst = skb->_skb_refdst;
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skb->_skb_refdst = 0UL;
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res = lowpan_frag_reasm(fq, prev, dev);
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skb->_skb_refdst = orefdst;
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return res;
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}
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return -1;
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err:
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kfree_skb(skb);
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return -1;
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}
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/* Check if this packet is complete.
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* Returns NULL on failure by any reason, and pointer
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* to current nexthdr field in reassembled frame.
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*
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* It is called with locked fq, and caller must check that
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* queue is eligible for reassembly i.e. it is not COMPLETE,
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* the last and the first frames arrived and all the bits are here.
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*/
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static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *prev,
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struct net_device *dev)
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{
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struct sk_buff *fp, *head = fq->q.fragments;
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int sum_truesize;
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inet_frag_kill(&fq->q, &lowpan_frags);
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/* Make the one we just received the head. */
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if (prev) {
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head = prev->next;
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fp = skb_clone(head, GFP_ATOMIC);
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if (!fp)
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goto out_oom;
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fp->next = head->next;
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if (!fp->next)
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fq->q.fragments_tail = fp;
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prev->next = fp;
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skb_morph(head, fq->q.fragments);
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head->next = fq->q.fragments->next;
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consume_skb(fq->q.fragments);
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fq->q.fragments = head;
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}
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/* Head of list must not be cloned. */
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if (skb_unclone(head, GFP_ATOMIC))
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goto out_oom;
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/* If the first fragment is fragmented itself, we split
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* it to two chunks: the first with data and paged part
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* and the second, holding only fragments.
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*/
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if (skb_has_frag_list(head)) {
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struct sk_buff *clone;
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int i, plen = 0;
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clone = alloc_skb(0, GFP_ATOMIC);
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if (!clone)
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goto out_oom;
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clone->next = head->next;
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head->next = clone;
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skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
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skb_frag_list_init(head);
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for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
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plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
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clone->len = head->data_len - plen;
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clone->data_len = clone->len;
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head->data_len -= clone->len;
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head->len -= clone->len;
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add_frag_mem_limit(&fq->q, clone->truesize);
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}
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WARN_ON(head == NULL);
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sum_truesize = head->truesize;
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for (fp = head->next; fp;) {
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bool headstolen;
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int delta;
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struct sk_buff *next = fp->next;
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sum_truesize += fp->truesize;
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if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
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kfree_skb_partial(fp, headstolen);
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} else {
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if (!skb_shinfo(head)->frag_list)
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skb_shinfo(head)->frag_list = fp;
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head->data_len += fp->len;
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head->len += fp->len;
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head->truesize += fp->truesize;
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}
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fp = next;
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}
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sub_frag_mem_limit(&fq->q, sum_truesize);
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head->next = NULL;
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head->dev = dev;
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head->tstamp = fq->q.stamp;
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fq->q.fragments = NULL;
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fq->q.fragments_tail = NULL;
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return 1;
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out_oom:
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net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
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return -1;
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}
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static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
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struct lowpan_frag_info *frag_info)
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{
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bool fail;
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u8 pattern = 0, low = 0;
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__be16 d_tag = 0;
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fail = lowpan_fetch_skb(skb, &pattern, 1);
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fail |= lowpan_fetch_skb(skb, &low, 1);
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frag_info->d_size = (pattern & 7) << 8 | low;
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fail |= lowpan_fetch_skb(skb, &d_tag, 2);
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frag_info->d_tag = ntohs(d_tag);
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if (frag_type == LOWPAN_DISPATCH_FRAGN) {
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fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1);
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} else {
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skb_reset_network_header(skb);
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frag_info->d_offset = 0;
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}
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if (unlikely(fail))
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return -EIO;
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return 0;
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}
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int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
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{
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struct lowpan_frag_queue *fq;
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struct net *net = dev_net(skb->dev);
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struct lowpan_frag_info *frag_info = lowpan_cb(skb);
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struct ieee802154_addr source, dest;
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int err;
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source = mac_cb(skb)->source;
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dest = mac_cb(skb)->dest;
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err = lowpan_get_frag_info(skb, frag_type, frag_info);
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if (err < 0)
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goto err;
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if (frag_info->d_size > IPV6_MIN_MTU) {
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net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
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goto err;
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}
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fq = fq_find(net, frag_info, &source, &dest);
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if (fq != NULL) {
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int ret;
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spin_lock(&fq->q.lock);
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ret = lowpan_frag_queue(fq, skb, frag_type);
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spin_unlock(&fq->q.lock);
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inet_frag_put(&fq->q, &lowpan_frags);
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return ret;
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}
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err:
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kfree_skb(skb);
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return -1;
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}
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EXPORT_SYMBOL(lowpan_frag_rcv);
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#ifdef CONFIG_SYSCTL
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static int zero;
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static struct ctl_table lowpan_frags_ns_ctl_table[] = {
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{
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.procname = "6lowpanfrag_high_thresh",
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.data = &init_net.ieee802154_lowpan.frags.high_thresh,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &init_net.ieee802154_lowpan.frags.low_thresh
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},
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{
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.procname = "6lowpanfrag_low_thresh",
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.data = &init_net.ieee802154_lowpan.frags.low_thresh,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &zero,
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.extra2 = &init_net.ieee802154_lowpan.frags.high_thresh
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},
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{
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.procname = "6lowpanfrag_time",
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.data = &init_net.ieee802154_lowpan.frags.timeout,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_jiffies,
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},
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{ }
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};
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/* secret interval has been deprecated */
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static int lowpan_frags_secret_interval_unused;
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static struct ctl_table lowpan_frags_ctl_table[] = {
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{
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.procname = "6lowpanfrag_secret_interval",
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.data = &lowpan_frags_secret_interval_unused,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_jiffies,
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},
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{ }
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};
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static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
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{
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struct ctl_table *table;
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struct ctl_table_header *hdr;
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struct netns_ieee802154_lowpan *ieee802154_lowpan =
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net_ieee802154_lowpan(net);
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table = lowpan_frags_ns_ctl_table;
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if (!net_eq(net, &init_net)) {
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table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
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GFP_KERNEL);
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if (table == NULL)
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goto err_alloc;
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table[0].data = &ieee802154_lowpan->frags.high_thresh;
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table[0].extra1 = &ieee802154_lowpan->frags.low_thresh;
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table[0].extra2 = &init_net.ieee802154_lowpan.frags.high_thresh;
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table[1].data = &ieee802154_lowpan->frags.low_thresh;
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table[1].extra2 = &ieee802154_lowpan->frags.high_thresh;
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table[2].data = &ieee802154_lowpan->frags.timeout;
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/* Don't export sysctls to unprivileged users */
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if (net->user_ns != &init_user_ns)
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table[0].procname = NULL;
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}
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hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
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if (hdr == NULL)
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goto err_reg;
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ieee802154_lowpan->sysctl.frags_hdr = hdr;
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return 0;
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err_reg:
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if (!net_eq(net, &init_net))
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kfree(table);
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err_alloc:
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return -ENOMEM;
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}
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static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
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{
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struct ctl_table *table;
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struct netns_ieee802154_lowpan *ieee802154_lowpan =
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net_ieee802154_lowpan(net);
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table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
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unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
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if (!net_eq(net, &init_net))
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kfree(table);
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}
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|
|
|
static struct ctl_table_header *lowpan_ctl_header;
|
|
|
|
static int __init lowpan_frags_sysctl_register(void)
|
|
{
|
|
lowpan_ctl_header = register_net_sysctl(&init_net,
|
|
"net/ieee802154/6lowpan",
|
|
lowpan_frags_ctl_table);
|
|
return lowpan_ctl_header == NULL ? -ENOMEM : 0;
|
|
}
|
|
|
|
static void lowpan_frags_sysctl_unregister(void)
|
|
{
|
|
unregister_net_sysctl_table(lowpan_ctl_header);
|
|
}
|
|
#else
|
|
static inline int lowpan_frags_ns_sysctl_register(struct net *net)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
|
|
{
|
|
}
|
|
|
|
static inline int __init lowpan_frags_sysctl_register(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void lowpan_frags_sysctl_unregister(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static int __net_init lowpan_frags_init_net(struct net *net)
|
|
{
|
|
struct netns_ieee802154_lowpan *ieee802154_lowpan =
|
|
net_ieee802154_lowpan(net);
|
|
|
|
ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
|
|
ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH;
|
|
ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT;
|
|
|
|
inet_frags_init_net(&ieee802154_lowpan->frags);
|
|
|
|
return lowpan_frags_ns_sysctl_register(net);
|
|
}
|
|
|
|
static void __net_exit lowpan_frags_exit_net(struct net *net)
|
|
{
|
|
struct netns_ieee802154_lowpan *ieee802154_lowpan =
|
|
net_ieee802154_lowpan(net);
|
|
|
|
lowpan_frags_ns_sysctl_unregister(net);
|
|
inet_frags_exit_net(&ieee802154_lowpan->frags, &lowpan_frags);
|
|
}
|
|
|
|
static struct pernet_operations lowpan_frags_ops = {
|
|
.init = lowpan_frags_init_net,
|
|
.exit = lowpan_frags_exit_net,
|
|
};
|
|
|
|
int __init lowpan_net_frag_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = lowpan_frags_sysctl_register();
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = register_pernet_subsys(&lowpan_frags_ops);
|
|
if (ret)
|
|
goto err_pernet;
|
|
|
|
lowpan_frags.hashfn = lowpan_hashfn;
|
|
lowpan_frags.constructor = lowpan_frag_init;
|
|
lowpan_frags.destructor = NULL;
|
|
lowpan_frags.skb_free = NULL;
|
|
lowpan_frags.qsize = sizeof(struct frag_queue);
|
|
lowpan_frags.match = lowpan_frag_match;
|
|
lowpan_frags.frag_expire = lowpan_frag_expire;
|
|
lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
|
|
ret = inet_frags_init(&lowpan_frags);
|
|
if (ret)
|
|
goto err_pernet;
|
|
|
|
return ret;
|
|
err_pernet:
|
|
lowpan_frags_sysctl_unregister();
|
|
return ret;
|
|
}
|
|
|
|
void lowpan_net_frag_exit(void)
|
|
{
|
|
inet_frags_fini(&lowpan_frags);
|
|
lowpan_frags_sysctl_unregister();
|
|
unregister_pernet_subsys(&lowpan_frags_ops);
|
|
}
|