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 if (minfo->flags == XT_MULTIPORT_SOURCE 46 && src >= s && src <= e) 47 return true ^ minfo->invert; 48 if (minfo->flags == XT_MULTIPORT_DESTINATION 49 && dst >= s && dst <= e) 50 return true ^ minfo->invert; 51 if (minfo->flags == XT_MULTIPORT_EITHER 52 && ((dst >= s && dst <= e) 53 || (src >= s && src <= e))) 54 return true ^ minfo->invert; 55 } else { 56 /* exact port matching */ 57 pr_debug("src or dst matches with %d?\n", s); 58 59 if (minfo->flags == XT_MULTIPORT_SOURCE 60 && src == s) 61 return true ^ minfo->invert; 62 if (minfo->flags == XT_MULTIPORT_DESTINATION 63 && dst == s) 64 return true ^ minfo->invert; 65 if (minfo->flags == XT_MULTIPORT_EITHER 66 && (src == s || dst == s)) 67 return true ^ minfo->invert; 68 } 69 } 70 71 return minfo->invert; 72 } 73 74 static bool 75 multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) 76 { 77 const __be16 *pptr; 78 __be16 _ports[2]; 79 const struct xt_multiport_v1 *multiinfo = par->matchinfo; 80 81 if (par->fragoff != 0) 82 return false; 83 84 pptr = skb_header_pointer(skb, par->thoff, sizeof(_ports), _ports); 85 if (pptr == NULL) { 86 /* We've been asked to examine this packet, and we 87 * can't. Hence, no choice but to drop. 88 */ 89 pr_debug("Dropping evil offset=0 tinygram.\n"); 90 par->hotdrop = true; 91 return false; 92 } 93 94 return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); 95 } 96 97 static inline bool 98 check(u_int16_t proto, 99 u_int8_t ip_invflags, 100 u_int8_t match_flags, 101 u_int8_t count) 102 { 103 /* Must specify supported protocol, no unknown flags or bad count */ 104 return (proto == IPPROTO_TCP || proto == IPPROTO_UDP 105 || proto == IPPROTO_UDPLITE 106 || proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) 107 && !(ip_invflags & XT_INV_PROTO) 108 && (match_flags == XT_MULTIPORT_SOURCE 109 || match_flags == XT_MULTIPORT_DESTINATION 110 || match_flags == XT_MULTIPORT_EITHER) 111 && count <= XT_MULTI_PORTS; 112 } 113 114 static int multiport_mt_check(const struct xt_mtchk_param *par) 115 { 116 const struct ipt_ip *ip = par->entryinfo; 117 const struct xt_multiport_v1 *multiinfo = par->matchinfo; 118 119 return check(ip->proto, ip->invflags, multiinfo->flags, 120 multiinfo->count) ? 0 : -EINVAL; 121 } 122 123 static int multiport_mt6_check(const struct xt_mtchk_param *par) 124 { 125 const struct ip6t_ip6 *ip = par->entryinfo; 126 const struct xt_multiport_v1 *multiinfo = par->matchinfo; 127 128 return check(ip->proto, ip->invflags, multiinfo->flags, 129 multiinfo->count) ? 0 : -EINVAL; 130 } 131 132 static struct xt_match multiport_mt_reg[] __read_mostly = { 133 { 134 .name = "multiport", 135 .family = NFPROTO_IPV4, 136 .revision = 1, 137 .checkentry = multiport_mt_check, 138 .match = multiport_mt, 139 .matchsize = sizeof(struct xt_multiport_v1), 140 .me = THIS_MODULE, 141 }, 142 { 143 .name = "multiport", 144 .family = NFPROTO_IPV6, 145 .revision = 1, 146 .checkentry = multiport_mt6_check, 147 .match = multiport_mt, 148 .matchsize = sizeof(struct xt_multiport_v1), 149 .me = THIS_MODULE, 150 }, 151 }; 152 153 static int __init multiport_mt_init(void) 154 { 155 return xt_register_matches(multiport_mt_reg, 156 ARRAY_SIZE(multiport_mt_reg)); 157 } 158 159 static void __exit multiport_mt_exit(void) 160 { 161 xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); 162 } 163 164 module_init(multiport_mt_init); 165 module_exit(multiport_mt_exit); 166