--- a/include/linux/netfilter_ipv4/ipt_multiport.h +++ b/include/linux/netfilter_ipv4/ipt_multiport.h @@ -11,11 +11,12 @@ enum ipt_multiport_flags #define IPT_MULTI_PORTS 15 -/* Must fit inside union ipt_matchinfo: 16 bytes */ -struct ipt_multiport +struct ipt_multiport_v1 { u_int8_t flags; /* Type of comparison */ u_int8_t count; /* Number of ports */ u_int16_t ports[IPT_MULTI_PORTS]; /* Ports */ + u_int8_t pflags[IPT_MULTI_PORTS]; /* Port flags */ + u_int8_t invert; /* Invert flag */ }; #endif /*_IPT_MULTIPORT_H*/ --- a/net/ipv4/netfilter/ipt_multiport.c +++ b/net/ipv4/netfilter/ipt_multiport.c @@ -1,5 +1,14 @@ /* Kernel module to match one of a list of TCP/UDP ports: ports are in the same place so we can treat them as equal. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2004 Netfilter Core Team + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + #include #include #include @@ -8,97 +17,136 @@ #include #include +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Netfilter Core Team "); +MODULE_DESCRIPTION("iptables multiple port match module"); + #if 0 #define duprintf(format, args...) printk(format , ## args) #else #define duprintf(format, args...) #endif +/* from linux 2.6 skbuff.h */ +static inline void *skb_header_pointer(const struct sk_buff *skb, int offset, + int len, void *buffer) +{ + int hlen = skb_headlen(skb); + + if (hlen - offset >= len) + return skb->data + offset; + + if (skb_copy_bits(skb, offset, buffer, len) < 0) + return NULL; + + return buffer; +} + + /* Returns 1 if the port is matched by the test, 0 otherwise. */ static inline int -ports_match(const u_int16_t *portlist, enum ipt_multiport_flags flags, - u_int8_t count, u_int16_t src, u_int16_t dst) +ports_match_v1(const struct ipt_multiport_v1 *minfo, + u_int16_t src, u_int16_t dst) { unsigned int i; - for (i=0; icount; i++) { + s = minfo->ports[i]; + + if (minfo->pflags[i]) { + /* range port matching */ + e = minfo->ports[++i]; + duprintf("src or dst matches with %d-%d?\n", s, e); + + if (minfo->flags == IPT_MULTIPORT_SOURCE + && src >= s && src <= e) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_DESTINATION + && dst >= s && dst <= e) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_EITHER + && ((dst >= s && dst <= e) + || (src >= s && src <= e))) + return 1 ^ minfo->invert; + } else { + /* exact port matching */ + duprintf("src or dst matches with %d?\n", s); + + if (minfo->flags == IPT_MULTIPORT_SOURCE + && src == s) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_DESTINATION + && dst == s) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_EITHER + && (src == s || dst == s)) + return 1 ^ minfo->invert; + } + } + + return minfo->invert; } static int -match(const struct sk_buff *skb, - const struct net_device *in, - const struct net_device *out, - const void *matchinfo, - int offset, - const void *hdr, - u_int16_t datalen, - int *hotdrop) +match_v1(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + int *hotdrop) { - const struct udphdr *udp = hdr; - const struct ipt_multiport *multiinfo = matchinfo; + u16 _ports[2], *pptr; + const struct ipt_multiport_v1 *multiinfo = matchinfo; + + if (offset) + return 0; - /* Must be big enough to read ports. */ - if (offset == 0 && datalen < sizeof(struct udphdr)) { + pptr = skb_header_pointer(skb, skb->nh.iph->ihl * 4, + sizeof(_ports), _ports); + if (pptr == NULL) { /* We've been asked to examine this packet, and we - can't. Hence, no choice but to drop. */ - duprintf("ipt_multiport:" - " Dropping evil offset=0 tinygram.\n"); - *hotdrop = 1; - return 0; + * can't. Hence, no choice but to drop. + */ + duprintf("ipt_multiport:" + " Dropping evil offset=0 tinygram.\n"); + *hotdrop = 1; + return 0; } - /* Must not be a fragment. */ - return !offset - && ports_match(multiinfo->ports, - multiinfo->flags, multiinfo->count, - ntohs(udp->source), ntohs(udp->dest)); + return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); } -/* Called when user tries to insert an entry of this type. */ static int -checkentry(const char *tablename, - const struct ipt_ip *ip, - void *matchinfo, - unsigned int matchsize, - unsigned int hook_mask) +checkentry_v1(const char *tablename, + const struct ipt_ip *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) { - const struct ipt_multiport *multiinfo = matchinfo; - - if (matchsize != IPT_ALIGN(sizeof(struct ipt_multiport))) - return 0; - - /* Must specify proto == TCP/UDP, no unknown flags or bad count */ - return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP) - && !(ip->invflags & IPT_INV_PROTO) - && matchsize == IPT_ALIGN(sizeof(struct ipt_multiport)) - && (multiinfo->flags == IPT_MULTIPORT_SOURCE - || multiinfo->flags == IPT_MULTIPORT_DESTINATION - || multiinfo->flags == IPT_MULTIPORT_EITHER) - && multiinfo->count <= IPT_MULTI_PORTS; + return (matchsize == IPT_ALIGN(sizeof(struct ipt_multiport_v1))); } -static struct ipt_match multiport_match -= { { NULL, NULL }, "multiport", &match, &checkentry, NULL, THIS_MODULE }; +static struct ipt_match multiport_match_v1 = { + .name = "multiport", + .match = &match_v1, + .checkentry = &checkentry_v1, + .me = THIS_MODULE, +}; static int __init init(void) { - return ipt_register_match(&multiport_match); + int err; + + err = ipt_register_match(&multiport_match_v1); + + return err; } static void __exit fini(void) { - ipt_unregister_match(&multiport_match); + ipt_unregister_match(&multiport_match_v1); } module_init(init); module_exit(fini); -MODULE_LICENSE("GPL");