~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/bridge/netfilter/ebt_among.c

Version: ~ [ linux-5.1-rc1 ] ~ [ linux-5.0.3 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.30 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.107 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.164 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.176 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.136 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *  ebt_among
  3  *
  4  *      Authors:
  5  *      Grzegorz Borowiak <grzes@gnu.univ.gda.pl>
  6  *
  7  *  August, 2003
  8  *
  9  */
 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 11 #include <linux/ip.h>
 12 #include <linux/if_arp.h>
 13 #include <linux/module.h>
 14 #include <linux/netfilter/x_tables.h>
 15 #include <linux/netfilter_bridge/ebtables.h>
 16 #include <linux/netfilter_bridge/ebt_among.h>
 17 
 18 static bool ebt_mac_wormhash_contains(const struct ebt_mac_wormhash *wh,
 19                                       const char *mac, __be32 ip)
 20 {
 21         /* You may be puzzled as to how this code works.
 22          * Some tricks were used, refer to
 23          *      include/linux/netfilter_bridge/ebt_among.h
 24          * as there you can find a solution of this mystery.
 25          */
 26         const struct ebt_mac_wormhash_tuple *p;
 27         int start, limit, i;
 28         uint32_t cmp[2] = { 0, 0 };
 29         int key = ((const unsigned char *)mac)[5];
 30 
 31         ether_addr_copy(((char *) cmp) + 2, mac);
 32         start = wh->table[key];
 33         limit = wh->table[key + 1];
 34         if (ip) {
 35                 for (i = start; i < limit; i++) {
 36                         p = &wh->pool[i];
 37                         if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0])
 38                                 if (p->ip == 0 || p->ip == ip)
 39                                         return true;
 40                 }
 41         } else {
 42                 for (i = start; i < limit; i++) {
 43                         p = &wh->pool[i];
 44                         if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0])
 45                                 if (p->ip == 0)
 46                                         return true;
 47                 }
 48         }
 49         return false;
 50 }
 51 
 52 static int ebt_mac_wormhash_check_integrity(const struct ebt_mac_wormhash
 53                                             *wh)
 54 {
 55         int i;
 56 
 57         for (i = 0; i < 256; i++) {
 58                 if (wh->table[i] > wh->table[i + 1])
 59                         return -0x100 - i;
 60                 if (wh->table[i] < 0)
 61                         return -0x200 - i;
 62                 if (wh->table[i] > wh->poolsize)
 63                         return -0x300 - i;
 64         }
 65         if (wh->table[256] > wh->poolsize)
 66                 return -0xc00;
 67         return 0;
 68 }
 69 
 70 static int get_ip_dst(const struct sk_buff *skb, __be32 *addr)
 71 {
 72         if (eth_hdr(skb)->h_proto == htons(ETH_P_IP)) {
 73                 const struct iphdr *ih;
 74                 struct iphdr _iph;
 75 
 76                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 77                 if (ih == NULL)
 78                         return -1;
 79                 *addr = ih->daddr;
 80         } else if (eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) {
 81                 const struct arphdr *ah;
 82                 struct arphdr _arph;
 83                 const __be32 *bp;
 84                 __be32 buf;
 85 
 86                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 87                 if (ah == NULL ||
 88                     ah->ar_pln != sizeof(__be32) ||
 89                     ah->ar_hln != ETH_ALEN)
 90                         return -1;
 91                 bp = skb_header_pointer(skb, sizeof(struct arphdr) +
 92                                         2 * ETH_ALEN + sizeof(__be32),
 93                                         sizeof(__be32), &buf);
 94                 if (bp == NULL)
 95                         return -1;
 96                 *addr = *bp;
 97         }
 98         return 0;
 99 }
100 
101 static int get_ip_src(const struct sk_buff *skb, __be32 *addr)
102 {
103         if (eth_hdr(skb)->h_proto == htons(ETH_P_IP)) {
104                 const struct iphdr *ih;
105                 struct iphdr _iph;
106 
107                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
108                 if (ih == NULL)
109                         return -1;
110                 *addr = ih->saddr;
111         } else if (eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) {
112                 const struct arphdr *ah;
113                 struct arphdr _arph;
114                 const __be32 *bp;
115                 __be32 buf;
116 
117                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
118                 if (ah == NULL ||
119                     ah->ar_pln != sizeof(__be32) ||
120                     ah->ar_hln != ETH_ALEN)
121                         return -1;
122                 bp = skb_header_pointer(skb, sizeof(struct arphdr) +
123                                         ETH_ALEN, sizeof(__be32), &buf);
124                 if (bp == NULL)
125                         return -1;
126                 *addr = *bp;
127         }
128         return 0;
129 }
130 
131 static bool
132 ebt_among_mt(const struct sk_buff *skb, struct xt_action_param *par)
133 {
134         const struct ebt_among_info *info = par->matchinfo;
135         const char *dmac, *smac;
136         const struct ebt_mac_wormhash *wh_dst, *wh_src;
137         __be32 dip = 0, sip = 0;
138 
139         wh_dst = ebt_among_wh_dst(info);
140         wh_src = ebt_among_wh_src(info);
141 
142         if (wh_src) {
143                 smac = eth_hdr(skb)->h_source;
144                 if (get_ip_src(skb, &sip))
145                         return false;
146                 if (!(info->bitmask & EBT_AMONG_SRC_NEG)) {
147                         /* we match only if it contains */
148                         if (!ebt_mac_wormhash_contains(wh_src, smac, sip))
149                                 return false;
150                 } else {
151                         /* we match only if it DOES NOT contain */
152                         if (ebt_mac_wormhash_contains(wh_src, smac, sip))
153                                 return false;
154                 }
155         }
156 
157         if (wh_dst) {
158                 dmac = eth_hdr(skb)->h_dest;
159                 if (get_ip_dst(skb, &dip))
160                         return false;
161                 if (!(info->bitmask & EBT_AMONG_DST_NEG)) {
162                         /* we match only if it contains */
163                         if (!ebt_mac_wormhash_contains(wh_dst, dmac, dip))
164                                 return false;
165                 } else {
166                         /* we match only if it DOES NOT contain */
167                         if (ebt_mac_wormhash_contains(wh_dst, dmac, dip))
168                                 return false;
169                 }
170         }
171 
172         return true;
173 }
174 
175 static bool poolsize_invalid(const struct ebt_mac_wormhash *w)
176 {
177         return w && w->poolsize >= (INT_MAX / sizeof(struct ebt_mac_wormhash_tuple));
178 }
179 
180 static bool wormhash_offset_invalid(int off, unsigned int len)
181 {
182         if (off == 0) /* not present */
183                 return false;
184 
185         if (off < (int)sizeof(struct ebt_among_info) ||
186             off % __alignof__(struct ebt_mac_wormhash))
187                 return true;
188 
189         off += sizeof(struct ebt_mac_wormhash);
190 
191         return off > len;
192 }
193 
194 static bool wormhash_sizes_valid(const struct ebt_mac_wormhash *wh, int a, int b)
195 {
196         if (a == 0)
197                 a = sizeof(struct ebt_among_info);
198 
199         return ebt_mac_wormhash_size(wh) + a == b;
200 }
201 
202 static int ebt_among_mt_check(const struct xt_mtchk_param *par)
203 {
204         const struct ebt_among_info *info = par->matchinfo;
205         const struct ebt_entry_match *em =
206                 container_of(par->matchinfo, const struct ebt_entry_match, data);
207         unsigned int expected_length = sizeof(struct ebt_among_info);
208         const struct ebt_mac_wormhash *wh_dst, *wh_src;
209         int err;
210 
211         if (expected_length > em->match_size)
212                 return -EINVAL;
213 
214         if (wormhash_offset_invalid(info->wh_dst_ofs, em->match_size) ||
215             wormhash_offset_invalid(info->wh_src_ofs, em->match_size))
216                 return -EINVAL;
217 
218         wh_dst = ebt_among_wh_dst(info);
219         if (poolsize_invalid(wh_dst))
220                 return -EINVAL;
221 
222         expected_length += ebt_mac_wormhash_size(wh_dst);
223         if (expected_length > em->match_size)
224                 return -EINVAL;
225 
226         wh_src = ebt_among_wh_src(info);
227         if (poolsize_invalid(wh_src))
228                 return -EINVAL;
229 
230         if (info->wh_src_ofs < info->wh_dst_ofs) {
231                 if (!wormhash_sizes_valid(wh_src, info->wh_src_ofs, info->wh_dst_ofs))
232                         return -EINVAL;
233         } else {
234                 if (!wormhash_sizes_valid(wh_dst, info->wh_dst_ofs, info->wh_src_ofs))
235                         return -EINVAL;
236         }
237 
238         expected_length += ebt_mac_wormhash_size(wh_src);
239 
240         if (em->match_size != EBT_ALIGN(expected_length)) {
241                 pr_err_ratelimited("wrong size: %d against expected %d, rounded to %zd\n",
242                                    em->match_size, expected_length,
243                                    EBT_ALIGN(expected_length));
244                 return -EINVAL;
245         }
246         if (wh_dst && (err = ebt_mac_wormhash_check_integrity(wh_dst))) {
247                 pr_err_ratelimited("dst integrity fail: %x\n", -err);
248                 return -EINVAL;
249         }
250         if (wh_src && (err = ebt_mac_wormhash_check_integrity(wh_src))) {
251                 pr_err_ratelimited("src integrity fail: %x\n", -err);
252                 return -EINVAL;
253         }
254         return 0;
255 }
256 
257 static struct xt_match ebt_among_mt_reg __read_mostly = {
258         .name           = "among",
259         .revision       = 0,
260         .family         = NFPROTO_BRIDGE,
261         .match          = ebt_among_mt,
262         .checkentry     = ebt_among_mt_check,
263         .matchsize      = -1, /* special case */
264         .me             = THIS_MODULE,
265 };
266 
267 static int __init ebt_among_init(void)
268 {
269         return xt_register_match(&ebt_among_mt_reg);
270 }
271 
272 static void __exit ebt_among_fini(void)
273 {
274         xt_unregister_match(&ebt_among_mt_reg);
275 }
276 
277 module_init(ebt_among_init);
278 module_exit(ebt_among_fini);
279 MODULE_DESCRIPTION("Ebtables: Combined MAC/IP address list matching");
280 MODULE_LICENSE("GPL");
281 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp