net/bridge/netfilter/ebt_ip6.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  ebt_ip6
   4  *
   5  *      Authors:
   6  *      Manohar Castelino <[email protected]>
   7  *      Kuo-Lang Tseng <[email protected]>
   8  *      Jan Engelhardt <[email protected]>
   9  *
  10  * Summary:
  11  * This is just a modification of the IPv4 code written by
  12  * Bart De Schuymer <[email protected]>
  13  * with the changes required to support IPv6
  14  *
  15  *  Jan, 2008
  16  */
  17 #include <linux/ipv6.h>
  18 #include <net/ipv6.h>
  19 #include <linux/in.h>
  20 #include <linux/module.h>
  21 #include <net/dsfield.h>
  22 #include <linux/netfilter/x_tables.h>
  23 #include <linux/netfilter_bridge/ebtables.h>
  24 #include <linux/netfilter_bridge/ebt_ip6.h>
  25
  26 union pkthdr {
  27         struct {
  28                 __be16 src;
  29                 __be16 dst;
  30         } tcpudphdr;
  31         struct {
  32                 u8 type;
  33                 u8 code;
  34         } icmphdr;
  35 };
  36
  37 static bool
  38 ebt_ip6_mt(const struct sk_buff *skb, struct xt_action_param *par)
  39 {
  40         const struct ebt_ip6_info *info = par->matchinfo;
  41         const struct ipv6hdr *ih6;
  42         struct ipv6hdr _ip6h;
  43         const union pkthdr *pptr;
  44         union pkthdr _pkthdr;
  45
  46         ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
  47         if (ih6 == NULL)
  48                 return false;
  49         if ((info->bitmask & EBT_IP6_TCLASS) &&
  50             NF_INVF(info, EBT_IP6_TCLASS,
  51                     info->tclass != ipv6_get_dsfield(ih6)))
  52                 return false;
  53         if (((info->bitmask & EBT_IP6_SOURCE) &&
  54              NF_INVF(info, EBT_IP6_SOURCE,
  55                      ipv6_masked_addr_cmp(&ih6->saddr, &info->smsk,
  56                                           &info->saddr))) ||
  57             ((info->bitmask & EBT_IP6_DEST) &&
  58              NF_INVF(info, EBT_IP6_DEST,
  59                      ipv6_masked_addr_cmp(&ih6->daddr, &info->dmsk,
  60                                           &info->daddr))))
  61                 return false;
  62         if (info->bitmask & EBT_IP6_PROTO) {
  63                 uint8_t nexthdr = ih6->nexthdr;
  64                 __be16 frag_off;
  65                 int offset_ph;
  66
  67                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr, &frag_off);
  68                 if (offset_ph == -1)
  69                         return false;
  70                 if (NF_INVF(info, EBT_IP6_PROTO, info->protocol != nexthdr))
  71                         return false;
  72                 if (!(info->bitmask & (EBT_IP6_DPORT |
  73                                        EBT_IP6_SPORT | EBT_IP6_ICMP6)))
  74                         return true;
  75
  76                 /* min icmpv6 headersize is 4, so sizeof(_pkthdr) is ok. */
  77                 pptr = skb_header_pointer(skb, offset_ph, sizeof(_pkthdr),
  78                                           &_pkthdr);
  79                 if (pptr == NULL)
  80                         return false;
  81                 if (info->bitmask & EBT_IP6_DPORT) {
  82                         u16 dst = ntohs(pptr->tcpudphdr.dst);
  83                         if (NF_INVF(info, EBT_IP6_DPORT,
  84                                     dst < info->dport[0] ||
  85                                     dst > info->dport[1]))
  86                                 return false;
  87                 }
  88                 if (info->bitmask & EBT_IP6_SPORT) {
  89                         u16 src = ntohs(pptr->tcpudphdr.src);
  90                         if (NF_INVF(info, EBT_IP6_SPORT,
  91                                     src < info->sport[0] ||
  92                                     src > info->sport[1]))
  93                                 return false;
  94                 }
  95                 if ((info->bitmask & EBT_IP6_ICMP6) &&
  96                     NF_INVF(info, EBT_IP6_ICMP6,
  97                             pptr->icmphdr.type < info->icmpv6_type[0] ||
  98                             pptr->icmphdr.type > info->icmpv6_type[1] ||
  99                             pptr->icmphdr.code < info->icmpv6_code[0] ||
 100                             pptr->icmphdr.code > info->icmpv6_code[1]))
 101                         return false;
 102         }
 103         return true;
 104 }
 105
 106 static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
 107 {
 108         const struct ebt_entry *e = par->entryinfo;
 109         struct ebt_ip6_info *info = par->matchinfo;
 110
 111         if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
 112                 return -EINVAL;
 113         if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
 114                 return -EINVAL;
 115         if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
 116                 if (info->invflags & EBT_IP6_PROTO)
 117                         return -EINVAL;
 118                 if (info->protocol != IPPROTO_TCP &&
 119                     info->protocol != IPPROTO_UDP &&
 120                     info->protocol != IPPROTO_UDPLITE &&
 121                     info->protocol != IPPROTO_SCTP &&
 122                     info->protocol != IPPROTO_DCCP)
 123                         return -EINVAL;
 124         }
 125         if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
 126                 return -EINVAL;
 127         if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
 128                 return -EINVAL;
 129         if (info->bitmask & EBT_IP6_ICMP6) {
 130                 if ((info->invflags & EBT_IP6_PROTO) ||
 131                      info->protocol != IPPROTO_ICMPV6)
 132                         return -EINVAL;
 133                 if (info->icmpv6_type[0] > info->icmpv6_type[1] ||
 134                     info->icmpv6_code[0] > info->icmpv6_code[1])
 135                         return -EINVAL;
 136         }
 137         return 0;
 138 }
 139
 140 static struct xt_match ebt_ip6_mt_reg __read_mostly = {
 141         .name           = "ip6",
 142         .revision       = 0,
 143         .family         = NFPROTO_BRIDGE,
 144         .match          = ebt_ip6_mt,
 145         .checkentry     = ebt_ip6_mt_check,
 146         .matchsize      = sizeof(struct ebt_ip6_info),
 147         .me             = THIS_MODULE,
 148 };
 149
 150 static int __init ebt_ip6_init(void)
 151 {
 152         return xt_register_match(&ebt_ip6_mt_reg);
 153 }
 154
 155 static void __exit ebt_ip6_fini(void)
 156 {
 157         xt_unregister_match(&ebt_ip6_mt_reg);
 158 }
 159
 160 module_init(ebt_ip6_init);
 161 module_exit(ebt_ip6_fini);
 162 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 163 MODULE_AUTHOR("Kuo-Lang Tseng <[email protected]>");
 164 MODULE_LICENSE("GPL");