| 1 | /* Kernel module to match one of a list of TCP/UDP(-Lite)/SCTP/DCCP ports: |
| 2 | ports are in the same place so we can treat them as equal. */ |
| 3 | |
| 4 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 5 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
| 11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <linux/udp.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | #include <linux/in.h> |
| 17 | |
| 18 | #include <linux/netfilter/xt_multiport.h> |
| 19 | #include <linux/netfilter/x_tables.h> |
| 20 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 21 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| 22 | |
| 23 | MODULE_LICENSE("GPL"); |
| 24 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| 25 | MODULE_DESCRIPTION("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP"); |
| 26 | MODULE_ALIAS("ipt_multiport"); |
| 27 | MODULE_ALIAS("ip6t_multiport"); |
| 28 | |
| 29 | /* Returns 1 if the port is matched by the test, 0 otherwise. */ |
| 30 | static inline bool |
| 31 | ports_match_v1(const struct xt_multiport_v1 *minfo, |
| 32 | u_int16_t src, u_int16_t dst) |
| 33 | { |
| 34 | unsigned int i; |
| 35 | u_int16_t s, e; |
| 36 | |
| 37 | for (i = 0; i < minfo->count; i++) { |
| 38 | s = minfo->ports[i]; |
| 39 | |
| 40 | if (minfo->pflags[i]) { |
| 41 | /* range port matching */ |
| 42 | e = minfo->ports[++i]; |
| 43 | pr_debug("src or dst matches with %d-%d?\n", s, e); |
| 44 | |
| 45 | switch (minfo->flags) { |
| 46 | case XT_MULTIPORT_SOURCE: |
| 47 | if (src >= s && src <= e) |
| 48 | return true ^ minfo->invert; |
| 49 | break; |
| 50 | case XT_MULTIPORT_DESTINATION: |
| 51 | if (dst >= s && dst <= e) |
| 52 | return true ^ minfo->invert; |
| 53 | break; |
| 54 | case XT_MULTIPORT_EITHER: |
| 55 | if ((dst >= s && dst <= e) || |
| 56 | (src >= s && src <= e)) |
| 57 | return true ^ minfo->invert; |
| 58 | break; |
| 59 | default: |
| 60 | break; |
| 61 | } |
| 62 | } else { |
| 63 | /* exact port matching */ |
| 64 | pr_debug("src or dst matches with %d?\n", s); |
| 65 | |
| 66 | switch (minfo->flags) { |
| 67 | case XT_MULTIPORT_SOURCE: |
| 68 | if (src == s) |
| 69 | return true ^ minfo->invert; |
| 70 | break; |
| 71 | case XT_MULTIPORT_DESTINATION: |
| 72 | if (dst == s) |
| 73 | return true ^ minfo->invert; |
| 74 | break; |
| 75 | case XT_MULTIPORT_EITHER: |
| 76 | if (src == s || dst == s) |
| 77 | return true ^ minfo->invert; |
| 78 | break; |
| 79 | default: |
| 80 | break; |
| 81 | } |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | return minfo->invert; |
| 86 | } |
| 87 | |
| 88 | static bool |
| 89 | multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) |
| 90 | { |
| 91 | const __be16 *pptr; |
| 92 | __be16 _ports[2]; |
| 93 | const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
| 94 | |
| 95 | if (par->fragoff != 0) |
| 96 | return false; |
| 97 | |
| 98 | pptr = skb_header_pointer(skb, par->thoff, sizeof(_ports), _ports); |
| 99 | if (pptr == NULL) { |
| 100 | /* We've been asked to examine this packet, and we |
| 101 | * can't. Hence, no choice but to drop. |
| 102 | */ |
| 103 | pr_debug("Dropping evil offset=0 tinygram.\n"); |
| 104 | par->hotdrop = true; |
| 105 | return false; |
| 106 | } |
| 107 | |
| 108 | return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); |
| 109 | } |
| 110 | |
| 111 | static inline bool |
| 112 | check(u_int16_t proto, |
| 113 | u_int8_t ip_invflags, |
| 114 | u_int8_t match_flags, |
| 115 | u_int8_t count) |
| 116 | { |
| 117 | /* Must specify supported protocol, no unknown flags or bad count */ |
| 118 | return (proto == IPPROTO_TCP || proto == IPPROTO_UDP |
| 119 | || proto == IPPROTO_UDPLITE |
| 120 | || proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) |
| 121 | && !(ip_invflags & XT_INV_PROTO) |
| 122 | && (match_flags == XT_MULTIPORT_SOURCE |
| 123 | || match_flags == XT_MULTIPORT_DESTINATION |
| 124 | || match_flags == XT_MULTIPORT_EITHER) |
| 125 | && count <= XT_MULTI_PORTS; |
| 126 | } |
| 127 | |
| 128 | static int multiport_mt_check(const struct xt_mtchk_param *par) |
| 129 | { |
| 130 | const struct ipt_ip *ip = par->entryinfo; |
| 131 | const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
| 132 | |
| 133 | return check(ip->proto, ip->invflags, multiinfo->flags, |
| 134 | multiinfo->count) ? 0 : -EINVAL; |
| 135 | } |
| 136 | |
| 137 | static int multiport_mt6_check(const struct xt_mtchk_param *par) |
| 138 | { |
| 139 | const struct ip6t_ip6 *ip = par->entryinfo; |
| 140 | const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
| 141 | |
| 142 | return check(ip->proto, ip->invflags, multiinfo->flags, |
| 143 | multiinfo->count) ? 0 : -EINVAL; |
| 144 | } |
| 145 | |
| 146 | static struct xt_match multiport_mt_reg[] __read_mostly = { |
| 147 | { |
| 148 | .name = "multiport", |
| 149 | .family = NFPROTO_IPV4, |
| 150 | .revision = 1, |
| 151 | .checkentry = multiport_mt_check, |
| 152 | .match = multiport_mt, |
| 153 | .matchsize = sizeof(struct xt_multiport_v1), |
| 154 | .me = THIS_MODULE, |
| 155 | }, |
| 156 | { |
| 157 | .name = "multiport", |
| 158 | .family = NFPROTO_IPV6, |
| 159 | .revision = 1, |
| 160 | .checkentry = multiport_mt6_check, |
| 161 | .match = multiport_mt, |
| 162 | .matchsize = sizeof(struct xt_multiport_v1), |
| 163 | .me = THIS_MODULE, |
| 164 | }, |
| 165 | }; |
| 166 | |
| 167 | static int __init multiport_mt_init(void) |
| 168 | { |
| 169 | return xt_register_matches(multiport_mt_reg, |
| 170 | ARRAY_SIZE(multiport_mt_reg)); |
| 171 | } |
| 172 | |
| 173 | static void __exit multiport_mt_exit(void) |
| 174 | { |
| 175 | xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); |
| 176 | } |
| 177 | |
| 178 | module_init(multiport_mt_init); |
| 179 | module_exit(multiport_mt_exit); |