diff options
Diffstat (limited to 'net/netfilter/xt_multiport.c')
| -rw-r--r-- | net/netfilter/xt_multiport.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/net/netfilter/xt_multiport.c b/net/netfilter/xt_multiport.c new file mode 100644 index 000000000..44a00f5ac --- /dev/null +++ b/net/netfilter/xt_multiport.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Kernel module to match one of a list of TCP/UDP(-Lite)/SCTP/DCCP 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 <coreteam@netfilter.org> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/module.h> +#include <linux/types.h> +#include <linux/udp.h> +#include <linux/skbuff.h> +#include <linux/in.h> + +#include <linux/netfilter/xt_multiport.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv6/ip6_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); +MODULE_DESCRIPTION("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP"); +MODULE_ALIAS("ipt_multiport"); +MODULE_ALIAS("ip6t_multiport"); + +/* Returns 1 if the port is matched by the test, 0 otherwise. */ +static inline bool +ports_match_v1(const struct xt_multiport_v1 *minfo, + u_int16_t src, u_int16_t dst) +{ + unsigned int i; + u_int16_t s, e; + + for (i = 0; i < minfo->count; i++) { + s = minfo->ports[i]; + + if (minfo->pflags[i]) { + /* range port matching */ + e = minfo->ports[++i]; + pr_debug("src or dst matches with %d-%d?\n", s, e); + + switch (minfo->flags) { + case XT_MULTIPORT_SOURCE: + if (src >= s && src <= e) + return true ^ minfo->invert; + break; + case XT_MULTIPORT_DESTINATION: + if (dst >= s && dst <= e) + return true ^ minfo->invert; + break; + case XT_MULTIPORT_EITHER: + if ((dst >= s && dst <= e) || + (src >= s && src <= e)) + return true ^ minfo->invert; + break; + default: + break; + } + } else { + /* exact port matching */ + pr_debug("src or dst matches with %d?\n", s); + + switch (minfo->flags) { + case XT_MULTIPORT_SOURCE: + if (src == s) + return true ^ minfo->invert; + break; + case XT_MULTIPORT_DESTINATION: + if (dst == s) + return true ^ minfo->invert; + break; + case XT_MULTIPORT_EITHER: + if (src == s || dst == s) + return true ^ minfo->invert; + break; + default: + break; + } + } + } + + return minfo->invert; +} + +static bool +multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const __be16 *pptr; + __be16 _ports[2]; + const struct xt_multiport_v1 *multiinfo = par->matchinfo; + + if (par->fragoff != 0) + return false; + + pptr = skb_header_pointer(skb, par->thoff, sizeof(_ports), _ports); + if (pptr == NULL) { + /* We've been asked to examine this packet, and we + * can't. Hence, no choice but to drop. + */ + pr_debug("Dropping evil offset=0 tinygram.\n"); + par->hotdrop = true; + return false; + } + + return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); +} + +static inline bool +check(u_int16_t proto, + u_int8_t ip_invflags, + u_int8_t match_flags, + u_int8_t count) +{ + /* Must specify supported protocol, no unknown flags or bad count */ + return (proto == IPPROTO_TCP || proto == IPPROTO_UDP + || proto == IPPROTO_UDPLITE + || proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) + && !(ip_invflags & XT_INV_PROTO) + && (match_flags == XT_MULTIPORT_SOURCE + || match_flags == XT_MULTIPORT_DESTINATION + || match_flags == XT_MULTIPORT_EITHER) + && count <= XT_MULTI_PORTS; +} + +static int multiport_mt_check(const struct xt_mtchk_param *par) +{ + const struct ipt_ip *ip = par->entryinfo; + const struct xt_multiport_v1 *multiinfo = par->matchinfo; + + return check(ip->proto, ip->invflags, multiinfo->flags, + multiinfo->count) ? 0 : -EINVAL; +} + +static int multiport_mt6_check(const struct xt_mtchk_param *par) +{ + const struct ip6t_ip6 *ip = par->entryinfo; + const struct xt_multiport_v1 *multiinfo = par->matchinfo; + + return check(ip->proto, ip->invflags, multiinfo->flags, + multiinfo->count) ? 0 : -EINVAL; +} + +static struct xt_match multiport_mt_reg[] __read_mostly = { + { + .name = "multiport", + .family = NFPROTO_IPV4, + .revision = 1, + .checkentry = multiport_mt_check, + .match = multiport_mt, + .matchsize = sizeof(struct xt_multiport_v1), + .me = THIS_MODULE, + }, + { + .name = "multiport", + .family = NFPROTO_IPV6, + .revision = 1, + .checkentry = multiport_mt6_check, + .match = multiport_mt, + .matchsize = sizeof(struct xt_multiport_v1), + .me = THIS_MODULE, + }, +}; + +static int __init multiport_mt_init(void) +{ + return xt_register_matches(multiport_mt_reg, + ARRAY_SIZE(multiport_mt_reg)); +} + +static void __exit multiport_mt_exit(void) +{ + xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); +} + +module_init(multiport_mt_init); +module_exit(multiport_mt_exit); |