James Morris | 5e6874c | 2006-06-09 00:30:57 -0700 | [diff] [blame] | 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 | |
| 21 | MODULE_LICENSE("GPL"); |
| 22 | MODULE_AUTHOR("James Morris <jmorris@redhat.com>"); |
| 23 | MODULE_DESCRIPTION("ip[6]tables SECMARK modification module"); |
| 24 | MODULE_ALIAS("ipt_SECMARK"); |
| 25 | MODULE_ALIAS("ip6t_SECMARK"); |
| 26 | |
| 27 | #define PFX "SECMARK: " |
| 28 | |
| 29 | static u8 mode; |
| 30 | |
| 31 | static 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, |
Patrick McHardy | fe1cb10 | 2006-08-22 00:35:47 -0700 | [diff] [blame^] | 34 | const void *targinfo) |
James Morris | 5e6874c | 2006-06-09 00:30:57 -0700 | [diff] [blame] | 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 | if ((*pskb)->secmark != secmark) |
| 51 | (*pskb)->secmark = secmark; |
| 52 | |
| 53 | return XT_CONTINUE; |
| 54 | } |
| 55 | |
| 56 | static int checkentry_selinux(struct xt_secmark_target_info *info) |
| 57 | { |
| 58 | int err; |
| 59 | struct xt_secmark_target_selinux_info *sel = &info->u.sel; |
James Morris | a280b89 | 2006-07-30 20:46:38 -0700 | [diff] [blame] | 60 | |
| 61 | sel->selctx[SECMARK_SELCTX_MAX - 1] = '\0'; |
James Morris | 5e6874c | 2006-06-09 00:30:57 -0700 | [diff] [blame] | 62 | |
| 63 | err = selinux_string_to_sid(sel->selctx, &sel->selsid); |
| 64 | if (err) { |
| 65 | if (err == -EINVAL) |
| 66 | printk(KERN_INFO PFX "invalid SELinux context \'%s\'\n", |
| 67 | sel->selctx); |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | if (!sel->selsid) { |
| 72 | printk(KERN_INFO PFX "unable to map SELinux context \'%s\'\n", |
| 73 | sel->selctx); |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | err = selinux_relabel_packet_permission(sel->selsid); |
| 78 | if (err) { |
| 79 | printk(KERN_INFO PFX "unable to obtain relabeling permission\n"); |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | return 1; |
| 84 | } |
| 85 | |
| 86 | static int checkentry(const char *tablename, const void *entry, |
| 87 | const struct xt_target *target, void *targinfo, |
| 88 | unsigned int targinfosize, unsigned int hook_mask) |
| 89 | { |
| 90 | struct xt_secmark_target_info *info = targinfo; |
| 91 | |
| 92 | if (mode && mode != info->mode) { |
| 93 | printk(KERN_INFO PFX "mode already set to %hu cannot mix with " |
| 94 | "rules for mode %hu\n", mode, info->mode); |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | switch (info->mode) { |
| 99 | case SECMARK_MODE_SEL: |
| 100 | if (!checkentry_selinux(info)) |
| 101 | return 0; |
| 102 | break; |
| 103 | |
| 104 | default: |
| 105 | printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode); |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | if (!mode) |
| 110 | mode = info->mode; |
| 111 | return 1; |
| 112 | } |
| 113 | |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 114 | static struct xt_target xt_secmark_target = { |
| 115 | { |
| 116 | .name = "SECMARK", |
| 117 | .family = AF_INET, |
| 118 | .checkentry = checkentry, |
| 119 | .target = target, |
| 120 | .targetsize = sizeof(struct xt_secmark_target_info), |
| 121 | .table = "mangle", |
| 122 | .me = THIS_MODULE, |
| 123 | }, |
| 124 | { |
| 125 | .name = "SECMARK", |
| 126 | .family = AF_INET6, |
| 127 | .checkentry = checkentry, |
| 128 | .target = target, |
| 129 | .targetsize = sizeof(struct xt_secmark_target_info), |
| 130 | .table = "mangle", |
| 131 | .me = THIS_MODULE, |
| 132 | }, |
James Morris | 5e6874c | 2006-06-09 00:30:57 -0700 | [diff] [blame] | 133 | }; |
| 134 | |
| 135 | static int __init xt_secmark_init(void) |
| 136 | { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 137 | return xt_register_targets(xt_secmark_target, |
| 138 | ARRAY_SIZE(xt_secmark_target)); |
James Morris | 5e6874c | 2006-06-09 00:30:57 -0700 | [diff] [blame] | 139 | } |
| 140 | |
| 141 | static void __exit xt_secmark_fini(void) |
| 142 | { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 143 | xt_unregister_targets(xt_secmark_target, ARRAY_SIZE(xt_secmark_target)); |
James Morris | 5e6874c | 2006-06-09 00:30:57 -0700 | [diff] [blame] | 144 | } |
| 145 | |
| 146 | module_init(xt_secmark_init); |
| 147 | module_exit(xt_secmark_fini); |