projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 6a649f33 | 2 | /* Kernel module to match IPComp parameters for IPv4 and IPv6 |
| 3 | * | |
| 4 | * Copyright (C) 2013 WindRiver | |
| 5 | * | |
| 6 | * Author: | |
| 7 | * Fan Du <[email protected]> | |
| 8 | * | |
| 9 | * Based on: | |
| 10 | * net/netfilter/xt_esp.c | |
| 6a649f33 | 11 | */ |
| 12 | ||
| 13 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
| 14 | #include <linux/in.h> | |
| 15 | #include <linux/module.h> | |
| 16 | #include <linux/skbuff.h> | |
| 17 | #include <linux/ip.h> | |
| 18 | ||
| 19 | #include <linux/netfilter/xt_ipcomp.h> | |
| 20 | #include <linux/netfilter/x_tables.h> | |
| 21 | ||
| 22 | MODULE_LICENSE("GPL"); | |
| 23 | MODULE_AUTHOR("Fan Du <[email protected]>"); | |
| 24 | MODULE_DESCRIPTION("Xtables: IPv4/6 IPsec-IPComp SPI match"); | |
| f434ed0a LZ |
25 | MODULE_ALIAS("ipt_ipcomp"); |
| 26 | MODULE_ALIAS("ip6t_ipcomp"); | |
| 6a649f33 | 27 | |
| 28 | /* Returns 1 if the spi is matched by the range, 0 otherwise */ | |
| 29 | static inline bool | |
| 30 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) | |
| 31 | { | |
| 32 | bool r; | |
| 33 | pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n", | |
| 34 | invert ? '!' : ' ', min, spi, max); | |
| 35 | r = (spi >= min && spi <= max) ^ invert; | |
| 36 | pr_debug(" result %s\n", r ? "PASS" : "FAILED"); | |
| 37 | return r; | |
| 38 | } | |
| 39 | ||
| 40 | static bool comp_mt(const struct sk_buff *skb, struct xt_action_param *par) | |
| 41 | { | |
| 42 | struct ip_comp_hdr _comphdr; | |
| 43 | const struct ip_comp_hdr *chdr; | |
| 44 | const struct xt_ipcomp *compinfo = par->matchinfo; | |
| 45 | ||
| 46 | /* Must not be a fragment. */ | |
| 47 | if (par->fragoff != 0) | |
| 48 | return false; | |
| 49 | ||
| 50 | chdr = skb_header_pointer(skb, par->thoff, sizeof(_comphdr), &_comphdr); | |
| 51 | if (chdr == NULL) { | |
| 52 | /* We've been asked to examine this packet, and we | |
| 53 | * can't. Hence, no choice but to drop. | |
| 54 | */ | |
| 55 | pr_debug("Dropping evil IPComp tinygram.\n"); | |
| 56 | par->hotdrop = true; | |
| d384e65f | 57 | return false; |
| 6a649f33 | 58 | } |
| 59 | ||
| 60 | return spi_match(compinfo->spis[0], compinfo->spis[1], | |
| 2ba436fc | 61 | ntohs(chdr->cpi), |
| 6a649f33 | 62 | !!(compinfo->invflags & XT_IPCOMP_INV_SPI)); |
| 63 | } | |
| 64 | ||
| 65 | static int comp_mt_check(const struct xt_mtchk_param *par) | |
| 66 | { | |
| 67 | const struct xt_ipcomp *compinfo = par->matchinfo; | |
| 68 | ||
| 69 | /* Must specify no unknown invflags */ | |
| 70 | if (compinfo->invflags & ~XT_IPCOMP_INV_MASK) { | |
| b2606644 | 71 | pr_info_ratelimited("unknown flags %X\n", compinfo->invflags); |
| 6a649f33 | 72 | return -EINVAL; |
| 73 | } | |
| 74 | return 0; | |
| 75 | } | |
| 76 | ||
| 77 | static struct xt_match comp_mt_reg[] __read_mostly = { | |
| 78 | { | |
| 79 | .name = "ipcomp", | |
| 80 | .family = NFPROTO_IPV4, | |
| 81 | .match = comp_mt, | |
| 82 | .matchsize = sizeof(struct xt_ipcomp), | |
| 83 | .proto = IPPROTO_COMP, | |
| 84 | .checkentry = comp_mt_check, | |
| 85 | .me = THIS_MODULE, | |
| 86 | }, | |
| 87 | { | |
| 88 | .name = "ipcomp", | |
| 89 | .family = NFPROTO_IPV6, | |
| 90 | .match = comp_mt, | |
| 91 | .matchsize = sizeof(struct xt_ipcomp), | |
| 92 | .proto = IPPROTO_COMP, | |
| 93 | .checkentry = comp_mt_check, | |
| 94 | .me = THIS_MODULE, | |
| 95 | }, | |
| 96 | }; | |
| 97 | ||
| 98 | static int __init comp_mt_init(void) | |
| 99 | { | |
| 100 | return xt_register_matches(comp_mt_reg, ARRAY_SIZE(comp_mt_reg)); | |
| 101 | } | |
| 102 | ||
| 103 | static void __exit comp_mt_exit(void) | |
| 104 | { | |
| 105 | xt_unregister_matches(comp_mt_reg, ARRAY_SIZE(comp_mt_reg)); | |
| 106 | } | |
| 107 | ||
| 108 | module_init(comp_mt_init); | |
| 109 | module_exit(comp_mt_exit); |