ClabureDB: Classified Bug-Reports Database

Project: Linux Kernel

Showing error 1889

User:	Jiri Slaby
Error type:	Invalid Pointer Dereference
Error type description:	A pointer which is invalid is being dereferenced
File location:	net/ipv4/ip_input.c
Line in file:	349
Project:	Linux Kernel
Project version:	2.6.28
Tools:	Smatch (1.59)
Entered:	2013-09-11 08:47:26 UTC
Source:

  1/*
  2 * INET                An implementation of the TCP/IP protocol suite for the LINUX
  3 *                operating system.  INET is implemented using the  BSD Socket
  4 *                interface as the means of communication with the user level.
  5 *
  6 *                The Internet Protocol (IP) module.
  7 *
  8 * Authors:        Ross Biro
  9 *                Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 10 *                Donald Becker, <becker@super.org>
 11 *                Alan Cox, <alan@lxorguk.ukuu.org.uk>
 12 *                Richard Underwood
 13 *                Stefan Becker, <stefanb@yello.ping.de>
 14 *                Jorge Cwik, <jorge@laser.satlink.net>
 15 *                Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 16 *
 17 *
 18 * Fixes:
 19 *                Alan Cox        :        Commented a couple of minor bits of surplus code
 20 *                Alan Cox        :        Undefining IP_FORWARD doesn't include the code
 21 *                                        (just stops a compiler warning).
 22 *                Alan Cox        :        Frames with >=MAX_ROUTE record routes, strict routes or loose routes
 23 *                                        are junked rather than corrupting things.
 24 *                Alan Cox        :        Frames to bad broadcast subnets are dumped
 25 *                                        We used to process them non broadcast and
 26 *                                        boy could that cause havoc.
 27 *                Alan Cox        :        ip_forward sets the free flag on the
 28 *                                        new frame it queues. Still crap because
 29 *                                        it copies the frame but at least it
 30 *                                        doesn't eat memory too.
 31 *                Alan Cox        :        Generic queue code and memory fixes.
 32 *                Fred Van Kempen :        IP fragment support (borrowed from NET2E)
 33 *                Gerhard Koerting:        Forward fragmented frames correctly.
 34 *                Gerhard Koerting:         Fixes to my fix of the above 8-).
 35 *                Gerhard Koerting:        IP interface addressing fix.
 36 *                Linus Torvalds        :        More robustness checks
 37 *                Alan Cox        :        Even more checks: Still not as robust as it ought to be
 38 *                Alan Cox        :        Save IP header pointer for later
 39 *                Alan Cox        :        ip option setting
 40 *                Alan Cox        :        Use ip_tos/ip_ttl settings
 41 *                Alan Cox        :        Fragmentation bogosity removed
 42 *                                        (Thanks to Mark.Bush@prg.ox.ac.uk)
 43 *                Dmitry Gorodchanin :        Send of a raw packet crash fix.
 44 *                Alan Cox        :        Silly ip bug when an overlength
 45 *                                        fragment turns up. Now frees the
 46 *                                        queue.
 47 *                Linus Torvalds/ :        Memory leakage on fragmentation
 48 *                Alan Cox        :        handling.
 49 *                Gerhard Koerting:        Forwarding uses IP priority hints
 50 *                Teemu Rantanen        :        Fragment problems.
 51 *                Alan Cox        :        General cleanup, comments and reformat
 52 *                Alan Cox        :        SNMP statistics
 53 *                Alan Cox        :        BSD address rule semantics. Also see
 54 *                                        UDP as there is a nasty checksum issue
 55 *                                        if you do things the wrong way.
 56 *                Alan Cox        :        Always defrag, moved IP_FORWARD to the config.in file
 57 *                Alan Cox        :         IP options adjust sk->priority.
 58 *                Pedro Roque        :        Fix mtu/length error in ip_forward.
 59 *                Alan Cox        :        Avoid ip_chk_addr when possible.
 60 *        Richard Underwood        :        IP multicasting.
 61 *                Alan Cox        :        Cleaned up multicast handlers.
 62 *                Alan Cox        :        RAW sockets demultiplex in the BSD style.
 63 *                Gunther Mayer        :        Fix the SNMP reporting typo
 64 *                Alan Cox        :        Always in group 224.0.0.1
 65 *        Pauline Middelink        :        Fast ip_checksum update when forwarding
 66 *                                        Masquerading support.
 67 *                Alan Cox        :        Multicast loopback error for 224.0.0.1
 68 *                Alan Cox        :        IP_MULTICAST_LOOP option.
 69 *                Alan Cox        :        Use notifiers.
 70 *                Bjorn Ekwall        :        Removed ip_csum (from slhc.c too)
 71 *                Bjorn Ekwall        :        Moved ip_fast_csum to ip.h (inline!)
 72 *                Stefan Becker   :       Send out ICMP HOST REDIRECT
 73 *        Arnt Gulbrandsen        :        ip_build_xmit
 74 *                Alan Cox        :        Per socket routing cache
 75 *                Alan Cox        :        Fixed routing cache, added header cache.
 76 *                Alan Cox        :        Loopback didn't work right in original ip_build_xmit - fixed it.
 77 *                Alan Cox        :        Only send ICMP_REDIRECT if src/dest are the same net.
 78 *                Alan Cox        :        Incoming IP option handling.
 79 *                Alan Cox        :        Set saddr on raw output frames as per BSD.
 80 *                Alan Cox        :        Stopped broadcast source route explosions.
 81 *                Alan Cox        :        Can disable source routing
 82 *                Takeshi Sone    :        Masquerading didn't work.
 83 *        Dave Bonn,Alan Cox        :        Faster IP forwarding whenever possible.
 84 *                Alan Cox        :        Memory leaks, tramples, misc debugging.
 85 *                Alan Cox        :        Fixed multicast (by popular demand 8))
 86 *                Alan Cox        :        Fixed forwarding (by even more popular demand 8))
 87 *                Alan Cox        :        Fixed SNMP statistics [I think]
 88 *        Gerhard Koerting        :        IP fragmentation forwarding fix
 89 *                Alan Cox        :        Device lock against page fault.
 90 *                Alan Cox        :        IP_HDRINCL facility.
 91 *        Werner Almesberger        :        Zero fragment bug
 92 *                Alan Cox        :        RAW IP frame length bug
 93 *                Alan Cox        :        Outgoing firewall on build_xmit
 94 *                A.N.Kuznetsov        :        IP_OPTIONS support throughout the kernel
 95 *                Alan Cox        :        Multicast routing hooks
 96 *                Jos Vos                :        Do accounting *before* call_in_firewall
 97 *        Willy Konynenberg        :        Transparent proxying support
 98 *
 99 *
100 *
101 * To Fix:
102 *                IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient
103 *                and could be made very efficient with the addition of some virtual memory hacks to permit
104 *                the allocation of a buffer that can then be 'grown' by twiddling page tables.
105 *                Output fragmentation wants updating along with the buffer management to use a single
106 *                interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet
107 *                output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause
108 *                fragmentation anyway.
109 *
110 *                This program is free software; you can redistribute it and/or
111 *                modify it under the terms of the GNU General Public License
112 *                as published by the Free Software Foundation; either version
113 *                2 of the License, or (at your option) any later version.
114 */
115
116#include <asm/system.h>
117#include <linux/module.h>
118#include <linux/types.h>
119#include <linux/kernel.h>
120#include <linux/string.h>
121#include <linux/errno.h>
122
123#include <linux/net.h>
124#include <linux/socket.h>
125#include <linux/sockios.h>
126#include <linux/in.h>
127#include <linux/inet.h>
128#include <linux/inetdevice.h>
129#include <linux/netdevice.h>
130#include <linux/etherdevice.h>
131
132#include <net/snmp.h>
133#include <net/ip.h>
134#include <net/protocol.h>
135#include <net/route.h>
136#include <linux/skbuff.h>
137#include <net/sock.h>
138#include <net/arp.h>
139#include <net/icmp.h>
140#include <net/raw.h>
141#include <net/checksum.h>
142#include <linux/netfilter_ipv4.h>
143#include <net/xfrm.h>
144#include <linux/mroute.h>
145#include <linux/netlink.h>
146
147/*
148 *        Process Router Attention IP option
149 */
150int ip_call_ra_chain(struct sk_buff *skb)
151{
152        struct ip_ra_chain *ra;
153        u8 protocol = ip_hdr(skb)->protocol;
154        struct sock *last = NULL;
155        struct net_device *dev = skb->dev;
156
157        read_lock(&ip_ra_lock);
158        for (ra = ip_ra_chain; ra; ra = ra->next) {
159                struct sock *sk = ra->sk;
160
161                /* If socket is bound to an interface, only report
162                 * the packet if it came  from that interface.
163                 */
164                if (sk && inet_sk(sk)->num == protocol &&
165                    (!sk->sk_bound_dev_if ||
166                     sk->sk_bound_dev_if == dev->ifindex) &&
167                    sock_net(sk) == dev_net(dev)) {
168                        if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
169                                if (ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN)) {
170                                        read_unlock(&ip_ra_lock);
171                                        return 1;
172                                }
173                        }
174                        if (last) {
175                                struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
176                                if (skb2)
177                                        raw_rcv(last, skb2);
178                        }
179                        last = sk;
180                }
181        }
182
183        if (last) {
184                raw_rcv(last, skb);
185                read_unlock(&ip_ra_lock);
186                return 1;
187        }
188        read_unlock(&ip_ra_lock);
189        return 0;
190}
191
192static int ip_local_deliver_finish(struct sk_buff *skb)
193{
194        struct net *net = dev_net(skb->dev);
195
196        __skb_pull(skb, ip_hdrlen(skb));
197
198        /* Point into the IP datagram, just past the header. */
199        skb_reset_transport_header(skb);
200
201        rcu_read_lock();
202        {
203                int protocol = ip_hdr(skb)->protocol;
204                int hash, raw;
205                struct net_protocol *ipprot;
206
207        resubmit:
208                raw = raw_local_deliver(skb, protocol);
209
210                hash = protocol & (MAX_INET_PROTOS - 1);
211                ipprot = rcu_dereference(inet_protos[hash]);
212                if (ipprot != NULL) {
213                        int ret;
214
215                        if (!net_eq(net, &init_net) && !ipprot->netns_ok) {
216                                if (net_ratelimit())
217                                        printk("%s: proto %d isn't netns-ready\n",
218                                                __func__, protocol);
219                                kfree_skb(skb);
220                                goto out;
221                        }
222
223                        if (!ipprot->no_policy) {
224                                if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
225                                        kfree_skb(skb);
226                                        goto out;
227                                }
228                                nf_reset(skb);
229                        }
230                        ret = ipprot->handler(skb);
231                        if (ret < 0) {
232                                protocol = -ret;
233                                goto resubmit;
234                        }
235                        IP_INC_STATS_BH(net, IPSTATS_MIB_INDELIVERS);
236                } else {
237                        if (!raw) {
238                                if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
239                                        IP_INC_STATS_BH(net, IPSTATS_MIB_INUNKNOWNPROTOS);
240                                        icmp_send(skb, ICMP_DEST_UNREACH,
241                                                  ICMP_PROT_UNREACH, 0);
242                                }
243                        } else
244                                IP_INC_STATS_BH(net, IPSTATS_MIB_INDELIVERS);
245                        kfree_skb(skb);
246                }
247        }
248 out:
249        rcu_read_unlock();
250
251        return 0;
252}
253
254/*
255 *         Deliver IP Packets to the higher protocol layers.
256 */
257int ip_local_deliver(struct sk_buff *skb)
258{
259        /*
260         *        Reassemble IP fragments.
261         */
262
263        if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
264                if (ip_defrag(skb, IP_DEFRAG_LOCAL_DELIVER))
265                        return 0;
266        }
267
268        return NF_HOOK(PF_INET, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
269                       ip_local_deliver_finish);
270}
271
272static inline int ip_rcv_options(struct sk_buff *skb)
273{
274        struct ip_options *opt;
275        struct iphdr *iph;
276        struct net_device *dev = skb->dev;
277
278        /* It looks as overkill, because not all
279           IP options require packet mangling.
280           But it is the easiest for now, especially taking
281           into account that combination of IP options
282           and running sniffer is extremely rare condition.
283                                              --ANK (980813)
284        */
285        if (skb_cow(skb, skb_headroom(skb))) {
286                IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
287                goto drop;
288        }
289
290        iph = ip_hdr(skb);
291        opt = &(IPCB(skb)->opt);
292        opt->optlen = iph->ihl*4 - sizeof(struct iphdr);
293
294        if (ip_options_compile(dev_net(dev), opt, skb)) {
295                IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
296                goto drop;
297        }
298
299        if (unlikely(opt->srr)) {
300                struct in_device *in_dev = in_dev_get(dev);
301                if (in_dev) {
302                        if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
303                                if (IN_DEV_LOG_MARTIANS(in_dev) &&
304                                    net_ratelimit())
305                                        printk(KERN_INFO "source route option "
306                                               NIPQUAD_FMT " -> " NIPQUAD_FMT "\n",
307                                               NIPQUAD(iph->saddr),
308                                               NIPQUAD(iph->daddr));
309                                in_dev_put(in_dev);
310                                goto drop;
311                        }
312
313                        in_dev_put(in_dev);
314                }
315
316                if (ip_options_rcv_srr(skb))
317                        goto drop;
318        }
319
320        return 0;
321drop:
322        return -1;
323}
324
325static int ip_rcv_finish(struct sk_buff *skb)
326{
327        const struct iphdr *iph = ip_hdr(skb);
328        struct rtable *rt;
329
330        /*
331         *        Initialise the virtual path cache for the packet. It describes
332         *        how the packet travels inside Linux networking.
333         */
334        if (skb->dst == NULL) {
335                int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
336                                         skb->dev);
337                if (unlikely(err)) {
338                        if (err == -EHOSTUNREACH)
339                                IP_INC_STATS_BH(dev_net(skb->dev),
340                                                IPSTATS_MIB_INADDRERRORS);
341                        else if (err == -ENETUNREACH)
342                                IP_INC_STATS_BH(dev_net(skb->dev),
343                                                IPSTATS_MIB_INNOROUTES);
344                        goto drop;
345                }
346        }
347
348#ifdef CONFIG_NET_CLS_ROUTE
349        if (unlikely(skb->dst->tclassid)) {
350                struct ip_rt_acct *st = per_cpu_ptr(ip_rt_acct, smp_processor_id());
351                u32 idx = skb->dst->tclassid;
352                st[idx&0xFF].o_packets++;
353                st[idx&0xFF].o_bytes+=skb->len;
354                st[(idx>>16)&0xFF].i_packets++;
355                st[(idx>>16)&0xFF].i_bytes+=skb->len;
356        }
357#endif
358
359        if (iph->ihl > 5 && ip_rcv_options(skb))
360                goto drop;
361
362        rt = skb->rtable;
363        if (rt->rt_type == RTN_MULTICAST)
364                IP_INC_STATS_BH(dev_net(rt->u.dst.dev), IPSTATS_MIB_INMCASTPKTS);
365        else if (rt->rt_type == RTN_BROADCAST)
366                IP_INC_STATS_BH(dev_net(rt->u.dst.dev), IPSTATS_MIB_INBCASTPKTS);
367
368        return dst_input(skb);
369
370drop:
371        kfree_skb(skb);
372        return NET_RX_DROP;
373}
374
375/*
376 *         Main IP Receive routine.
377 */
378int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
379{
380        struct iphdr *iph;
381        u32 len;
382
383        /* When the interface is in promisc. mode, drop all the crap
384         * that it receives, do not try to analyse it.
385         */
386        if (skb->pkt_type == PACKET_OTHERHOST)
387                goto drop;
388
389        IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INRECEIVES);
390
391        if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
392                IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
393                goto out;
394        }
395
396        if (!pskb_may_pull(skb, sizeof(struct iphdr)))
397                goto inhdr_error;
398
399        iph = ip_hdr(skb);
400
401        /*
402         *        RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum.
403         *
404         *        Is the datagram acceptable?
405         *
406         *        1.        Length at least the size of an ip header
407         *        2.        Version of 4
408         *        3.        Checksums correctly. [Speed optimisation for later, skip loopback checksums]
409         *        4.        Doesn't have a bogus length
410         */
411
412        if (iph->ihl < 5 || iph->version != 4)
413                goto inhdr_error;
414
415        if (!pskb_may_pull(skb, iph->ihl*4))
416                goto inhdr_error;
417
418        iph = ip_hdr(skb);
419
420        if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
421                goto inhdr_error;
422
423        len = ntohs(iph->tot_len);
424        if (skb->len < len) {
425                IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INTRUNCATEDPKTS);
426                goto drop;
427        } else if (len < (iph->ihl*4))
428                goto inhdr_error;
429
430        /* Our transport medium may have padded the buffer out. Now we know it
431         * is IP we can trim to the true length of the frame.
432         * Note this now means skb->len holds ntohs(iph->tot_len).
433         */
434        if (pskb_trim_rcsum(skb, len)) {
435                IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
436                goto drop;
437        }
438
439        /* Remove any debris in the socket control block */
440        memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
441
442        return NF_HOOK(PF_INET, NF_INET_PRE_ROUTING, skb, dev, NULL,
443                       ip_rcv_finish);
444
445inhdr_error:
446        IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
447drop:
448        kfree_skb(skb);
449out:
450        return NET_RX_DROP;
451}