1/* 2 * Module for modifying the secmark field of the skb, for use by 3 * security subsystems. 4 * 5 * Based on the nfmark match by: 6 * (C) 1999-2001 Marc Boucher <marc@mbsi.ca> 7 * 8 * (C) 2006 Red Hat, Inc., James Morris <jmorris@redhat.com> 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 */ 15#include <linux/module.h> 16#include <linux/skbuff.h> 17#include <linux/selinux.h> 18#include <linux/netfilter/x_tables.h> 19#include <linux/netfilter/xt_SECMARK.h> 20 21MODULE_LICENSE("GPL"); 22MODULE_AUTHOR("James Morris <jmorris@redhat.com>"); 23MODULE_DESCRIPTION("ip[6]tables SECMARK modification module"); 24MODULE_ALIAS("ipt_SECMARK"); 25MODULE_ALIAS("ip6t_SECMARK"); 26 27#define PFX "SECMARK: " 28 29static u8 mode; 30 31static unsigned int target(struct sk_buff **pskb, const struct net_device *in, 32 const struct net_device *out, unsigned int hooknum, 33 const struct xt_target *target, 34 const void *targinfo) 35{ 36 u32 secmark = 0; 37 const struct xt_secmark_target_info *info = targinfo; 38 39 BUG_ON(info->mode != mode); 40 41 switch (mode) { 42 case SECMARK_MODE_SEL: 43 secmark = info->u.sel.selsid; 44 break; 45 46 default: 47 BUG(); 48 } 49 50 (*pskb)->secmark = secmark; 51 return XT_CONTINUE; 52} 53 54static int checkentry_selinux(struct xt_secmark_target_info *info) 55{ 56 int err; 57 struct xt_secmark_target_selinux_info *sel = &info->u.sel; 58 59 sel->selctx[SECMARK_SELCTX_MAX - 1] = '\0'; 60 61 err = selinux_string_to_sid(sel->selctx, &sel->selsid); 62 if (err) { 63 if (err == -EINVAL) 64 printk(KERN_INFO PFX "invalid SELinux context \'%s\'\n", 65 sel->selctx); 66 return 0; 67 } 68 69 if (!sel->selsid) { 70 printk(KERN_INFO PFX "unable to map SELinux context \'%s\'\n", 71 sel->selctx); 72 return 0; 73 } 74 75 err = selinux_relabel_packet_permission(sel->selsid); 76 if (err) { 77 printk(KERN_INFO PFX "unable to obtain relabeling permission\n"); 78 return 0; 79 } 80 81 return 1; 82} 83 84static int checkentry(const char *tablename, const void *entry, 85 const struct xt_target *target, void *targinfo, 86 unsigned int hook_mask) 87{ 88 struct xt_secmark_target_info *info = targinfo; 89 90 if (mode && mode != info->mode) { 91 printk(KERN_INFO PFX "mode already set to %hu cannot mix with " 92 "rules for mode %hu\n", mode, info->mode); 93 return 0; 94 } 95 96 switch (info->mode) { 97 case SECMARK_MODE_SEL: 98 if (!checkentry_selinux(info)) 99 return 0; 100 break; 101 102 default: 103 printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode); 104 return 0; 105 } 106 107 if (!mode) 108 mode = info->mode; 109 return 1; 110} 111 112static struct xt_target xt_secmark_target[] = { 113 { 114 .name = "SECMARK", 115 .family = AF_INET, 116 .checkentry = checkentry, 117 .target = target, 118 .targetsize = sizeof(struct xt_secmark_target_info), 119 .table = "mangle", 120 .me = THIS_MODULE, 121 }, 122 { 123 .name = "SECMARK", 124 .family = AF_INET6, 125 .checkentry = checkentry, 126 .target = target, 127 .targetsize = sizeof(struct xt_secmark_target_info), 128 .table = "mangle", 129 .me = THIS_MODULE, 130 }, 131}; 132 133static int __init xt_secmark_init(void) 134{ 135 return xt_register_targets(xt_secmark_target, 136 ARRAY_SIZE(xt_secmark_target)); 137} 138 139static void __exit xt_secmark_fini(void) 140{ 141 xt_unregister_targets(xt_secmark_target, ARRAY_SIZE(xt_secmark_target)); 142} 143 144module_init(xt_secmark_init); 145module_exit(xt_secmark_fini); 146