2005-04-16 22:20:36 +00:00
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/* Kernel module to match AH parameters. */
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/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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2005-12-27 04:43:12 +00:00
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#include <linux/ip.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/ipv6.h>
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#include <linux/types.h>
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#include <net/checksum.h>
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#include <net/ipv6.h>
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2007-02-07 23:11:19 +00:00
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#include <linux/netfilter/x_tables.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter_ipv6/ip6t_ah.h>
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("IPv6 AH match");
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MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(format, args...)
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#endif
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/* Returns 1 if the spi is matched by the range, 0 otherwise */
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static inline int
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spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
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{
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int r=0;
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DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
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min,spi,max);
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r = (spi >= min && spi <= max) ^ invert;
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DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
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return r;
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}
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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2006-03-21 02:02:56 +00:00
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const struct xt_match *match,
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2005-04-16 22:20:36 +00:00
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const void *matchinfo,
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int offset,
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unsigned int protoff,
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int *hotdrop)
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{
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2005-09-19 22:34:40 +00:00
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struct ip_auth_hdr *ah, _ah;
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2005-04-16 22:20:36 +00:00
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const struct ip6t_ah *ahinfo = matchinfo;
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unsigned int ptr;
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unsigned int hdrlen = 0;
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2006-10-24 23:15:10 +00:00
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int err;
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2005-04-16 22:20:36 +00:00
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2006-10-24 23:15:10 +00:00
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err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
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if (err < 0) {
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if (err != -ENOENT)
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*hotdrop = 1;
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2005-04-16 22:20:36 +00:00
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return 0;
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2006-10-24 23:15:10 +00:00
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}
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2005-04-16 22:20:36 +00:00
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2005-09-19 22:34:40 +00:00
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ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
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if (ah == NULL) {
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2005-04-16 22:20:36 +00:00
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*hotdrop = 1;
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return 0;
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}
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2005-09-19 22:34:40 +00:00
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hdrlen = (ah->hdrlen + 2) << 2;
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2005-04-16 22:20:36 +00:00
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DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
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DEBUGP("RES %04X ", ah->reserved);
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DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
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DEBUGP("IPv6 AH spi %02X ",
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(spi_match(ahinfo->spis[0], ahinfo->spis[1],
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2007-02-09 14:24:49 +00:00
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ntohl(ah->spi),
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!!(ahinfo->invflags & IP6T_AH_INV_SPI))));
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2005-04-16 22:20:36 +00:00
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DEBUGP("len %02X %04X %02X ",
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ahinfo->hdrlen, hdrlen,
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(!ahinfo->hdrlen ||
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2007-02-09 14:24:49 +00:00
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(ahinfo->hdrlen == hdrlen) ^
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!!(ahinfo->invflags & IP6T_AH_INV_LEN)));
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2005-04-16 22:20:36 +00:00
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DEBUGP("res %02X %04X %02X\n",
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ahinfo->hdrres, ah->reserved,
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!(ahinfo->hdrres && ah->reserved));
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return (ah != NULL)
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&&
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(spi_match(ahinfo->spis[0], ahinfo->spis[1],
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2007-02-09 14:24:49 +00:00
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ntohl(ah->spi),
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!!(ahinfo->invflags & IP6T_AH_INV_SPI)))
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2005-04-16 22:20:36 +00:00
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&&
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(!ahinfo->hdrlen ||
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2007-02-09 14:24:49 +00:00
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(ahinfo->hdrlen == hdrlen) ^
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!!(ahinfo->invflags & IP6T_AH_INV_LEN))
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2005-04-16 22:20:36 +00:00
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&&
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!(ahinfo->hdrres && ah->reserved);
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}
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/* Called when user tries to insert an entry of this type. */
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static int
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checkentry(const char *tablename,
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2007-02-09 14:24:49 +00:00
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const void *entry,
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2006-03-21 02:02:56 +00:00
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const struct xt_match *match,
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2007-02-09 14:24:49 +00:00
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void *matchinfo,
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unsigned int hook_mask)
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2005-04-16 22:20:36 +00:00
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{
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const struct ip6t_ah *ahinfo = matchinfo;
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if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
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DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
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return 0;
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}
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return 1;
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}
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2007-02-07 23:11:19 +00:00
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static struct xt_match ah_match = {
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2005-04-16 22:20:36 +00:00
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.name = "ah",
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2007-02-07 23:11:19 +00:00
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.family = AF_INET6,
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2006-03-21 02:01:43 +00:00
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.match = match,
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.matchsize = sizeof(struct ip6t_ah),
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.checkentry = checkentry,
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2005-04-16 22:20:36 +00:00
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.me = THIS_MODULE,
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};
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2006-03-29 00:37:06 +00:00
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static int __init ip6t_ah_init(void)
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2005-04-16 22:20:36 +00:00
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{
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2007-02-07 23:11:19 +00:00
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return xt_register_match(&ah_match);
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2005-04-16 22:20:36 +00:00
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}
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2006-03-29 00:37:06 +00:00
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static void __exit ip6t_ah_fini(void)
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2005-04-16 22:20:36 +00:00
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{
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2007-02-07 23:11:19 +00:00
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xt_unregister_match(&ah_match);
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2005-04-16 22:20:36 +00:00
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}
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2006-03-29 00:37:06 +00:00
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module_init(ip6t_ah_init);
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module_exit(ip6t_ah_fini);
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