Jan Engelhardt | 0265ab4 | 2007-12-04 23:27:38 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Kernel module to match various things tied to sockets associated with |
| 3 | * locally generated outgoing packets. |
| 4 | * |
| 5 | * (C) 2000 Marc Boucher <marc@mbsi.ca> |
| 6 | * |
Jan Engelhardt | edc26f7 | 2008-01-31 04:06:38 -0800 | [diff] [blame] | 7 | * Copyright © CC Computer Consultants GmbH, 2007 - 2008 |
| 8 | * <jengelh@computergmbh.de> |
Jan Engelhardt | 0265ab4 | 2007-12-04 23:27:38 -0800 | [diff] [blame] | 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License version 2 as |
| 12 | * published by the Free Software Foundation. |
| 13 | */ |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | #include <linux/file.h> |
| 17 | #include <net/sock.h> |
| 18 | #include <linux/netfilter/x_tables.h> |
| 19 | #include <linux/netfilter/xt_owner.h> |
| 20 | #include <linux/netfilter_ipv4/ipt_owner.h> |
| 21 | #include <linux/netfilter_ipv6/ip6t_owner.h> |
| 22 | |
| 23 | static bool |
| 24 | owner_mt_v0(const struct sk_buff *skb, const struct net_device *in, |
| 25 | const struct net_device *out, const struct xt_match *match, |
| 26 | const void *matchinfo, int offset, unsigned int protoff, |
| 27 | bool *hotdrop) |
| 28 | { |
| 29 | const struct ipt_owner_info *info = matchinfo; |
| 30 | const struct file *filp; |
| 31 | |
| 32 | if (skb->sk == NULL || skb->sk->sk_socket == NULL) |
| 33 | return false; |
| 34 | |
| 35 | filp = skb->sk->sk_socket->file; |
| 36 | if (filp == NULL) |
| 37 | return false; |
| 38 | |
| 39 | if (info->match & IPT_OWNER_UID) |
| 40 | if ((filp->f_uid != info->uid) ^ |
| 41 | !!(info->invert & IPT_OWNER_UID)) |
| 42 | return false; |
| 43 | |
| 44 | if (info->match & IPT_OWNER_GID) |
| 45 | if ((filp->f_gid != info->gid) ^ |
| 46 | !!(info->invert & IPT_OWNER_GID)) |
| 47 | return false; |
| 48 | |
| 49 | return true; |
| 50 | } |
| 51 | |
| 52 | static bool |
| 53 | owner_mt6_v0(const struct sk_buff *skb, const struct net_device *in, |
| 54 | const struct net_device *out, const struct xt_match *match, |
| 55 | const void *matchinfo, int offset, unsigned int protoff, |
| 56 | bool *hotdrop) |
| 57 | { |
| 58 | const struct ip6t_owner_info *info = matchinfo; |
| 59 | const struct file *filp; |
| 60 | |
| 61 | if (skb->sk == NULL || skb->sk->sk_socket == NULL) |
| 62 | return false; |
| 63 | |
| 64 | filp = skb->sk->sk_socket->file; |
| 65 | if (filp == NULL) |
| 66 | return false; |
| 67 | |
| 68 | if (info->match & IP6T_OWNER_UID) |
| 69 | if ((filp->f_uid != info->uid) ^ |
| 70 | !!(info->invert & IP6T_OWNER_UID)) |
| 71 | return false; |
| 72 | |
| 73 | if (info->match & IP6T_OWNER_GID) |
| 74 | if ((filp->f_gid != info->gid) ^ |
| 75 | !!(info->invert & IP6T_OWNER_GID)) |
| 76 | return false; |
| 77 | |
| 78 | return true; |
| 79 | } |
| 80 | |
| 81 | static bool |
| 82 | owner_mt(const struct sk_buff *skb, const struct net_device *in, |
| 83 | const struct net_device *out, const struct xt_match *match, |
| 84 | const void *matchinfo, int offset, unsigned int protoff, |
| 85 | bool *hotdrop) |
| 86 | { |
| 87 | const struct xt_owner_match_info *info = matchinfo; |
| 88 | const struct file *filp; |
| 89 | |
| 90 | if (skb->sk == NULL || skb->sk->sk_socket == NULL) |
| 91 | return (info->match ^ info->invert) == 0; |
| 92 | else if (info->match & info->invert & XT_OWNER_SOCKET) |
| 93 | /* |
| 94 | * Socket exists but user wanted ! --socket-exists. |
| 95 | * (Single ampersands intended.) |
| 96 | */ |
| 97 | return false; |
| 98 | |
| 99 | filp = skb->sk->sk_socket->file; |
| 100 | if (filp == NULL) |
| 101 | return ((info->match ^ info->invert) & |
| 102 | (XT_OWNER_UID | XT_OWNER_GID)) == 0; |
| 103 | |
| 104 | if (info->match & XT_OWNER_UID) |
Jan Engelhardt | edc26f7 | 2008-01-31 04:06:38 -0800 | [diff] [blame] | 105 | if ((filp->f_uid >= info->uid_min && |
| 106 | filp->f_uid <= info->uid_max) ^ |
| 107 | !(info->invert & XT_OWNER_UID)) |
Jan Engelhardt | 0265ab4 | 2007-12-04 23:27:38 -0800 | [diff] [blame] | 108 | return false; |
| 109 | |
| 110 | if (info->match & XT_OWNER_GID) |
Jan Engelhardt | edc26f7 | 2008-01-31 04:06:38 -0800 | [diff] [blame] | 111 | if ((filp->f_gid >= info->gid_min && |
| 112 | filp->f_gid <= info->gid_max) ^ |
| 113 | !(info->invert & XT_OWNER_GID)) |
Jan Engelhardt | 0265ab4 | 2007-12-04 23:27:38 -0800 | [diff] [blame] | 114 | return false; |
| 115 | |
| 116 | return true; |
| 117 | } |
| 118 | |
| 119 | static bool |
| 120 | owner_mt_check_v0(const char *tablename, const void *ip, |
| 121 | const struct xt_match *match, void *matchinfo, |
| 122 | unsigned int hook_mask) |
| 123 | { |
| 124 | const struct ipt_owner_info *info = matchinfo; |
| 125 | |
| 126 | if (info->match & (IPT_OWNER_PID | IPT_OWNER_SID | IPT_OWNER_COMM)) { |
| 127 | printk(KERN_WARNING KBUILD_MODNAME |
| 128 | ": PID, SID and command matching is not " |
| 129 | "supported anymore\n"); |
| 130 | return false; |
| 131 | } |
| 132 | |
| 133 | return true; |
| 134 | } |
| 135 | |
| 136 | static bool |
| 137 | owner_mt6_check_v0(const char *tablename, const void *ip, |
| 138 | const struct xt_match *match, void *matchinfo, |
| 139 | unsigned int hook_mask) |
| 140 | { |
| 141 | const struct ip6t_owner_info *info = matchinfo; |
| 142 | |
| 143 | if (info->match & (IP6T_OWNER_PID | IP6T_OWNER_SID)) { |
| 144 | printk(KERN_WARNING KBUILD_MODNAME |
| 145 | ": PID and SID matching is not supported anymore\n"); |
| 146 | return false; |
| 147 | } |
| 148 | |
| 149 | return true; |
| 150 | } |
| 151 | |
| 152 | static struct xt_match owner_mt_reg[] __read_mostly = { |
| 153 | { |
| 154 | .name = "owner", |
| 155 | .revision = 0, |
| 156 | .family = AF_INET, |
| 157 | .match = owner_mt_v0, |
| 158 | .matchsize = sizeof(struct ipt_owner_info), |
| 159 | .checkentry = owner_mt_check_v0, |
| 160 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
| 161 | (1 << NF_INET_POST_ROUTING), |
| 162 | .me = THIS_MODULE, |
| 163 | }, |
| 164 | { |
| 165 | .name = "owner", |
| 166 | .revision = 0, |
| 167 | .family = AF_INET6, |
| 168 | .match = owner_mt6_v0, |
| 169 | .matchsize = sizeof(struct ip6t_owner_info), |
| 170 | .checkentry = owner_mt6_check_v0, |
| 171 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
| 172 | (1 << NF_INET_POST_ROUTING), |
| 173 | .me = THIS_MODULE, |
| 174 | }, |
| 175 | { |
| 176 | .name = "owner", |
| 177 | .revision = 1, |
| 178 | .family = AF_INET, |
| 179 | .match = owner_mt, |
| 180 | .matchsize = sizeof(struct xt_owner_match_info), |
| 181 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
| 182 | (1 << NF_INET_POST_ROUTING), |
| 183 | .me = THIS_MODULE, |
| 184 | }, |
| 185 | { |
| 186 | .name = "owner", |
| 187 | .revision = 1, |
| 188 | .family = AF_INET6, |
| 189 | .match = owner_mt, |
| 190 | .matchsize = sizeof(struct xt_owner_match_info), |
| 191 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
| 192 | (1 << NF_INET_POST_ROUTING), |
| 193 | .me = THIS_MODULE, |
| 194 | }, |
| 195 | }; |
| 196 | |
| 197 | static int __init owner_mt_init(void) |
| 198 | { |
| 199 | return xt_register_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg)); |
| 200 | } |
| 201 | |
| 202 | static void __exit owner_mt_exit(void) |
| 203 | { |
| 204 | xt_unregister_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg)); |
| 205 | } |
| 206 | |
| 207 | module_init(owner_mt_init); |
| 208 | module_exit(owner_mt_exit); |
| 209 | MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 210 | MODULE_DESCRIPTION("Xtables: socket owner matching"); |
Jan Engelhardt | 0265ab4 | 2007-12-04 23:27:38 -0800 | [diff] [blame] | 211 | MODULE_LICENSE("GPL"); |
| 212 | MODULE_ALIAS("ipt_owner"); |
| 213 | MODULE_ALIAS("ip6t_owner"); |