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Commit 71f6f6dfdf7c7a67462386d9ea05c1095a89c555

Authored by Jesper Nilsson
Committed by David S. Miller
1 parent a170285772
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

ipv6: Plug sk_buff leak in ipv6_rcv (net/ipv6/ip6_input.c) 

Commit 778d80be52699596bf70e0eb0761cf5e1e46088d
(ipv6: Add disable_ipv6 sysctl to disable IPv6 operaion on specific interface)
seems to have introduced a leak of sk_buff's for ipv6 traffic,
at least in some configurations where idev is NULL, or when ipv6
is disabled via sysctl.

The problem is that if the first condition of the if-statement
returns non-NULL, it returns an skb with only one reference,
and when the other conditions apply, execution jumps to the "out"
label, which does not call kfree_skb for it.

To plug this leak, change to use the "drop" label instead.
(this relies on it being ok to call kfree_skb on NULL)
This also allows us to avoid calling rcu_read_unlock here,
and removes the only user of the "out" label.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Showing 1 changed file with 1 additions and 3 deletions Inline Diff

net/ipv6/ip6_input.c
Diff comments   View file @ 71f6f6d
1 /* 1 /*
2 * IPv6 input 2 * IPv6 input
3 * Linux INET6 implementation 3 * Linux INET6 implementation
4 * 4 *
5 * Authors: 5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt> 6 * Pedro Roque <roque@di.fc.ul.pt>
7 * Ian P. Morris <I.P.Morris@soton.ac.uk> 7 * Ian P. Morris <I.P.Morris@soton.ac.uk>
8 * 8 *
9 * Based in linux/net/ipv4/ip_input.c 9 * Based in linux/net/ipv4/ip_input.c
10 * 10 *
11 * This program is free software; you can redistribute it and/or 11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License 12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version 13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version. 14 * 2 of the License, or (at your option) any later version.
15 */ 15 */
16 /* Changes 16 /* Changes
17 * 17 *
18 * Mitsuru KANDA @USAGI and 18 * Mitsuru KANDA @USAGI and
19 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs(). 19 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
20 */ 20 */
21 21
22 #include <linux/errno.h> 22 #include <linux/errno.h>
23 #include <linux/types.h> 23 #include <linux/types.h>
24 #include <linux/socket.h> 24 #include <linux/socket.h>
25 #include <linux/sockios.h> 25 #include <linux/sockios.h>
26 #include <linux/net.h> 26 #include <linux/net.h>
27 #include <linux/netdevice.h> 27 #include <linux/netdevice.h>
28 #include <linux/in6.h> 28 #include <linux/in6.h>
29 #include <linux/icmpv6.h> 29 #include <linux/icmpv6.h>
30 #include <linux/mroute6.h> 30 #include <linux/mroute6.h>
31 31
32 #include <linux/netfilter.h> 32 #include <linux/netfilter.h>
33 #include <linux/netfilter_ipv6.h> 33 #include <linux/netfilter_ipv6.h>
34 34
35 #include <net/sock.h> 35 #include <net/sock.h>
36 #include <net/snmp.h> 36 #include <net/snmp.h>
37 37
38 #include <net/ipv6.h> 38 #include <net/ipv6.h>
39 #include <net/protocol.h> 39 #include <net/protocol.h>
40 #include <net/transp_v6.h> 40 #include <net/transp_v6.h>
41 #include <net/rawv6.h> 41 #include <net/rawv6.h>
42 #include <net/ndisc.h> 42 #include <net/ndisc.h>
43 #include <net/ip6_route.h> 43 #include <net/ip6_route.h>
44 #include <net/addrconf.h> 44 #include <net/addrconf.h>
45 #include <net/xfrm.h> 45 #include <net/xfrm.h>
46 46
47 47
48 48
49 inline int ip6_rcv_finish( struct sk_buff *skb) 49 inline int ip6_rcv_finish( struct sk_buff *skb)
50 { 50 {
51 if (skb->dst == NULL) 51 if (skb->dst == NULL)
52 ip6_route_input(skb); 52 ip6_route_input(skb);
53 53
54 return dst_input(skb); 54 return dst_input(skb);
55 } 55 }
56 56
57 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) 57 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
58 { 58 {
59 struct ipv6hdr *hdr; 59 struct ipv6hdr *hdr;
60 u32 pkt_len; 60 u32 pkt_len;
61 struct inet6_dev *idev; 61 struct inet6_dev *idev;
62 struct net *net = dev_net(skb->dev); 62 struct net *net = dev_net(skb->dev);
63 63
64 if (skb->pkt_type == PACKET_OTHERHOST) { 64 if (skb->pkt_type == PACKET_OTHERHOST) {
65 kfree_skb(skb); 65 kfree_skb(skb);
66 return 0; 66 return 0;
67 } 67 }
68 68
69 rcu_read_lock(); 69 rcu_read_lock();
70 70
71 idev = __in6_dev_get(skb->dev); 71 idev = __in6_dev_get(skb->dev);
72 72
73 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INRECEIVES); 73 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INRECEIVES);
74 74
75 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || 75 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
76 !idev || unlikely(idev->cnf.disable_ipv6)) { 76 !idev || unlikely(idev->cnf.disable_ipv6)) {
77 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); 77 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
78 rcu_read_unlock(); 78 goto drop;
79 goto out;
80 } 79 }
81 80
82 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); 81 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
83 82
84 /* 83 /*
85 * Store incoming device index. When the packet will 84 * Store incoming device index. When the packet will
86 * be queued, we cannot refer to skb->dev anymore. 85 * be queued, we cannot refer to skb->dev anymore.
87 * 86 *
88 * BTW, when we send a packet for our own local address on a 87 * BTW, when we send a packet for our own local address on a
89 * non-loopback interface (e.g. ethX), it is being delivered 88 * non-loopback interface (e.g. ethX), it is being delivered
90 * via the loopback interface (lo) here; skb->dev = loopback_dev. 89 * via the loopback interface (lo) here; skb->dev = loopback_dev.
91 * It, however, should be considered as if it is being 90 * It, however, should be considered as if it is being
92 * arrived via the sending interface (ethX), because of the 91 * arrived via the sending interface (ethX), because of the
93 * nature of scoping architecture. --yoshfuji 92 * nature of scoping architecture. --yoshfuji
94 */ 93 */
95 IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex; 94 IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;
96 95
97 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr)))) 96 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
98 goto err; 97 goto err;
99 98
100 hdr = ipv6_hdr(skb); 99 hdr = ipv6_hdr(skb);
101 100
102 if (hdr->version != 6) 101 if (hdr->version != 6)
103 goto err; 102 goto err;
104 103
105 /* 104 /*
106 * RFC4291 2.5.3 105 * RFC4291 2.5.3
107 * A packet received on an interface with a destination address 106 * A packet received on an interface with a destination address
108 * of loopback must be dropped. 107 * of loopback must be dropped.
109 */ 108 */
110 if (!(dev->flags & IFF_LOOPBACK) && 109 if (!(dev->flags & IFF_LOOPBACK) &&
111 ipv6_addr_loopback(&hdr->daddr)) 110 ipv6_addr_loopback(&hdr->daddr))
112 goto err; 111 goto err;
113 112
114 skb->transport_header = skb->network_header + sizeof(*hdr); 113 skb->transport_header = skb->network_header + sizeof(*hdr);
115 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 114 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
116 115
117 pkt_len = ntohs(hdr->payload_len); 116 pkt_len = ntohs(hdr->payload_len);
118 117
119 /* pkt_len may be zero if Jumbo payload option is present */ 118 /* pkt_len may be zero if Jumbo payload option is present */
120 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { 119 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
121 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { 120 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
122 IP6_INC_STATS_BH(net, 121 IP6_INC_STATS_BH(net,
123 idev, IPSTATS_MIB_INTRUNCATEDPKTS); 122 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
124 goto drop; 123 goto drop;
125 } 124 }
126 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 125 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
127 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 126 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
128 goto drop; 127 goto drop;
129 } 128 }
130 hdr = ipv6_hdr(skb); 129 hdr = ipv6_hdr(skb);
131 } 130 }
132 131
133 if (hdr->nexthdr == NEXTHDR_HOP) { 132 if (hdr->nexthdr == NEXTHDR_HOP) {
134 if (ipv6_parse_hopopts(skb) < 0) { 133 if (ipv6_parse_hopopts(skb) < 0) {
135 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 134 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
136 rcu_read_unlock(); 135 rcu_read_unlock();
137 return 0; 136 return 0;
138 } 137 }
139 } 138 }
140 139
141 rcu_read_unlock(); 140 rcu_read_unlock();
142 141
143 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL, 142 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL,
144 ip6_rcv_finish); 143 ip6_rcv_finish);
145 err: 144 err:
146 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 145 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
147 drop: 146 drop:
148 rcu_read_unlock(); 147 rcu_read_unlock();
149 kfree_skb(skb); 148 kfree_skb(skb);
150 out:
151 return 0; 149 return 0;
152 } 150 }
153 151
154 /* 152 /*
155 * Deliver the packet to the host 153 * Deliver the packet to the host
156 */ 154 */
157 155
158 156
159 static int ip6_input_finish(struct sk_buff *skb) 157 static int ip6_input_finish(struct sk_buff *skb)
160 { 158 {
161 struct inet6_protocol *ipprot; 159 struct inet6_protocol *ipprot;
162 unsigned int nhoff; 160 unsigned int nhoff;
163 int nexthdr, raw; 161 int nexthdr, raw;
164 u8 hash; 162 u8 hash;
165 struct inet6_dev *idev; 163 struct inet6_dev *idev;
166 struct net *net = dev_net(skb->dst->dev); 164 struct net *net = dev_net(skb->dst->dev);
167 165
168 /* 166 /*
169 * Parse extension headers 167 * Parse extension headers
170 */ 168 */
171 169
172 rcu_read_lock(); 170 rcu_read_lock();
173 resubmit: 171 resubmit:
174 idev = ip6_dst_idev(skb->dst); 172 idev = ip6_dst_idev(skb->dst);
175 if (!pskb_pull(skb, skb_transport_offset(skb))) 173 if (!pskb_pull(skb, skb_transport_offset(skb)))
176 goto discard; 174 goto discard;
177 nhoff = IP6CB(skb)->nhoff; 175 nhoff = IP6CB(skb)->nhoff;
178 nexthdr = skb_network_header(skb)[nhoff]; 176 nexthdr = skb_network_header(skb)[nhoff];
179 177
180 raw = raw6_local_deliver(skb, nexthdr); 178 raw = raw6_local_deliver(skb, nexthdr);
181 179
182 hash = nexthdr & (MAX_INET_PROTOS - 1); 180 hash = nexthdr & (MAX_INET_PROTOS - 1);
183 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 181 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
184 int ret; 182 int ret;
185 183
186 if (ipprot->flags & INET6_PROTO_FINAL) { 184 if (ipprot->flags & INET6_PROTO_FINAL) {
187 struct ipv6hdr *hdr; 185 struct ipv6hdr *hdr;
188 186
189 /* Free reference early: we don't need it any more, 187 /* Free reference early: we don't need it any more,
190 and it may hold ip_conntrack module loaded 188 and it may hold ip_conntrack module loaded
191 indefinitely. */ 189 indefinitely. */
192 nf_reset(skb); 190 nf_reset(skb);
193 191
194 skb_postpull_rcsum(skb, skb_network_header(skb), 192 skb_postpull_rcsum(skb, skb_network_header(skb),
195 skb_network_header_len(skb)); 193 skb_network_header_len(skb));
196 hdr = ipv6_hdr(skb); 194 hdr = ipv6_hdr(skb);
197 if (ipv6_addr_is_multicast(&hdr->daddr) && 195 if (ipv6_addr_is_multicast(&hdr->daddr) &&
198 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 196 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
199 &hdr->saddr) && 197 &hdr->saddr) &&
200 !ipv6_is_mld(skb, nexthdr)) 198 !ipv6_is_mld(skb, nexthdr))
201 goto discard; 199 goto discard;
202 } 200 }
203 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 201 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
204 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 202 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
205 goto discard; 203 goto discard;
206 204
207 ret = ipprot->handler(skb); 205 ret = ipprot->handler(skb);
208 if (ret > 0) 206 if (ret > 0)
209 goto resubmit; 207 goto resubmit;
210 else if (ret == 0) 208 else if (ret == 0)
211 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 209 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
212 } else { 210 } else {
213 if (!raw) { 211 if (!raw) {
214 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 212 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
215 IP6_INC_STATS_BH(net, idev, 213 IP6_INC_STATS_BH(net, idev,
216 IPSTATS_MIB_INUNKNOWNPROTOS); 214 IPSTATS_MIB_INUNKNOWNPROTOS);
217 icmpv6_send(skb, ICMPV6_PARAMPROB, 215 icmpv6_send(skb, ICMPV6_PARAMPROB,
218 ICMPV6_UNK_NEXTHDR, nhoff, 216 ICMPV6_UNK_NEXTHDR, nhoff,
219 skb->dev); 217 skb->dev);
220 } 218 }
221 } else 219 } else
222 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 220 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
223 kfree_skb(skb); 221 kfree_skb(skb);
224 } 222 }
225 rcu_read_unlock(); 223 rcu_read_unlock();
226 return 0; 224 return 0;
227 225
228 discard: 226 discard:
229 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); 227 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
230 rcu_read_unlock(); 228 rcu_read_unlock();
231 kfree_skb(skb); 229 kfree_skb(skb);
232 return 0; 230 return 0;
233 } 231 }
234 232
235 233
236 int ip6_input(struct sk_buff *skb) 234 int ip6_input(struct sk_buff *skb)
237 { 235 {
238 return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, 236 return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
239 ip6_input_finish); 237 ip6_input_finish);
240 } 238 }
241 239
242 int ip6_mc_input(struct sk_buff *skb) 240 int ip6_mc_input(struct sk_buff *skb)
243 { 241 {
244 struct ipv6hdr *hdr; 242 struct ipv6hdr *hdr;
245 int deliver; 243 int deliver;
246 244
247 IP6_INC_STATS_BH(dev_net(skb->dst->dev), 245 IP6_INC_STATS_BH(dev_net(skb->dst->dev),
248 ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS); 246 ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
249 247
250 hdr = ipv6_hdr(skb); 248 hdr = ipv6_hdr(skb);
251 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 249 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
252 250
253 #ifdef CONFIG_IPV6_MROUTE 251 #ifdef CONFIG_IPV6_MROUTE
254 /* 252 /*
255 * IPv6 multicast router mode is now supported ;) 253 * IPv6 multicast router mode is now supported ;)
256 */ 254 */
257 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && 255 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
258 !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) && 256 !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) &&
259 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { 257 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
260 /* 258 /*
261 * Okay, we try to forward - split and duplicate 259 * Okay, we try to forward - split and duplicate
262 * packets. 260 * packets.
263 */ 261 */
264 struct sk_buff *skb2; 262 struct sk_buff *skb2;
265 struct inet6_skb_parm *opt = IP6CB(skb); 263 struct inet6_skb_parm *opt = IP6CB(skb);
266 264
267 /* Check for MLD */ 265 /* Check for MLD */
268 if (unlikely(opt->ra)) { 266 if (unlikely(opt->ra)) {
269 /* Check if this is a mld message */ 267 /* Check if this is a mld message */
270 u8 *ptr = skb_network_header(skb) + opt->ra; 268 u8 *ptr = skb_network_header(skb) + opt->ra;
271 struct icmp6hdr *icmp6; 269 struct icmp6hdr *icmp6;
272 u8 nexthdr = hdr->nexthdr; 270 u8 nexthdr = hdr->nexthdr;
273 int offset; 271 int offset;
274 272
275 /* Check if the value of Router Alert 273 /* Check if the value of Router Alert
276 * is for MLD (0x0000). 274 * is for MLD (0x0000).
277 */ 275 */
278 if ((ptr[2] | ptr[3]) == 0) { 276 if ((ptr[2] | ptr[3]) == 0) {
279 deliver = 0; 277 deliver = 0;
280 278
281 if (!ipv6_ext_hdr(nexthdr)) { 279 if (!ipv6_ext_hdr(nexthdr)) {
282 /* BUG */ 280 /* BUG */
283 goto out; 281 goto out;
284 } 282 }
285 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), 283 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
286 &nexthdr); 284 &nexthdr);
287 if (offset < 0) 285 if (offset < 0)
288 goto out; 286 goto out;
289 287
290 if (nexthdr != IPPROTO_ICMPV6) 288 if (nexthdr != IPPROTO_ICMPV6)
291 goto out; 289 goto out;
292 290
293 if (!pskb_may_pull(skb, (skb_network_header(skb) + 291 if (!pskb_may_pull(skb, (skb_network_header(skb) +
294 offset + 1 - skb->data))) 292 offset + 1 - skb->data)))
295 goto out; 293 goto out;
296 294
297 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 295 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
298 296
299 switch (icmp6->icmp6_type) { 297 switch (icmp6->icmp6_type) {
300 case ICMPV6_MGM_QUERY: 298 case ICMPV6_MGM_QUERY:
301 case ICMPV6_MGM_REPORT: 299 case ICMPV6_MGM_REPORT:
302 case ICMPV6_MGM_REDUCTION: 300 case ICMPV6_MGM_REDUCTION:
303 case ICMPV6_MLD2_REPORT: 301 case ICMPV6_MLD2_REPORT:
304 deliver = 1; 302 deliver = 1;
305 break; 303 break;
306 } 304 }
307 goto out; 305 goto out;
308 } 306 }
309 /* unknown RA - process it normally */ 307 /* unknown RA - process it normally */
310 } 308 }
311 309
312 if (deliver) 310 if (deliver)
313 skb2 = skb_clone(skb, GFP_ATOMIC); 311 skb2 = skb_clone(skb, GFP_ATOMIC);
314 else { 312 else {
315 skb2 = skb; 313 skb2 = skb;
316 skb = NULL; 314 skb = NULL;
317 } 315 }
318 316
319 if (skb2) { 317 if (skb2) {
320 ip6_mr_input(skb2); 318 ip6_mr_input(skb2);
321 } 319 }
322 } 320 }
323 out: 321 out:
324 #endif 322 #endif
325 if (likely(deliver)) 323 if (likely(deliver))
326 ip6_input(skb); 324 ip6_input(skb);
327 else { 325 else {
328 /* discard */ 326 /* discard */
329 kfree_skb(skb); 327 kfree_skb(skb);
330 } 328 }
331 329
332 return 0; 330 return 0;
333 } 331 }
334 332