blob: 23b2d6c486b573927dcefd00b575546b35376bfa [file] [log] [blame]
James Morris5e6874cd2006-06-09 00:30:57 -07001/*
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 *
James Morris560ee652008-06-09 15:57:24 -07008 * (C) 2006,2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
James Morris5e6874cd2006-06-09 00:30:57 -07009 *
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 */
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +010015#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
James Morris5e6874cd2006-06-09 00:30:57 -070016#include <linux/module.h>
17#include <linux/skbuff.h>
18#include <linux/selinux.h>
19#include <linux/netfilter/x_tables.h>
20#include <linux/netfilter/xt_SECMARK.h>
21
22MODULE_LICENSE("GPL");
23MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
Jan Engelhardt2ae15b62008-01-14 23:42:28 -080024MODULE_DESCRIPTION("Xtables: packet security mark modification");
James Morris5e6874cd2006-06-09 00:30:57 -070025MODULE_ALIAS("ipt_SECMARK");
26MODULE_ALIAS("ip6t_SECMARK");
27
28#define PFX "SECMARK: "
29
30static u8 mode;
31
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -080032static unsigned int
Jan Engelhardt4b560b42009-07-05 19:43:26 +020033secmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
James Morris5e6874cd2006-06-09 00:30:57 -070034{
35 u32 secmark = 0;
Jan Engelhardt7eb35582008-10-08 11:35:19 +020036 const struct xt_secmark_target_info *info = par->targinfo;
James Morris5e6874cd2006-06-09 00:30:57 -070037
38 BUG_ON(info->mode != mode);
39
40 switch (mode) {
41 case SECMARK_MODE_SEL:
42 secmark = info->u.sel.selsid;
43 break;
44
45 default:
46 BUG();
47 }
48
Herbert Xu3db05fe2007-10-15 00:53:15 -070049 skb->secmark = secmark;
James Morris5e6874cd2006-06-09 00:30:57 -070050 return XT_CONTINUE;
51}
52
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +010053static int checkentry_selinux(struct xt_secmark_target_info *info)
James Morris5e6874cd2006-06-09 00:30:57 -070054{
55 int err;
56 struct xt_secmark_target_selinux_info *sel = &info->u.sel;
YOSHIFUJI Hideaki601e68e2007-02-12 11:15:49 -080057
James Morrisa280b892006-07-30 20:46:38 -070058 sel->selctx[SECMARK_SELCTX_MAX - 1] = '\0';
James Morris5e6874cd2006-06-09 00:30:57 -070059
60 err = selinux_string_to_sid(sel->selctx, &sel->selsid);
61 if (err) {
62 if (err == -EINVAL)
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +010063 pr_info("invalid SELinux context \'%s\'\n",
64 sel->selctx);
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +010065 return err;
James Morris5e6874cd2006-06-09 00:30:57 -070066 }
67
68 if (!sel->selsid) {
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +010069 pr_info("unable to map SELinux context \'%s\'\n", sel->selctx);
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +010070 return -ENOENT;
James Morris5e6874cd2006-06-09 00:30:57 -070071 }
72
Paul Moored621d352008-01-29 08:43:36 -050073 err = selinux_secmark_relabel_packet_permission(sel->selsid);
James Morris5e6874cd2006-06-09 00:30:57 -070074 if (err) {
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +010075 pr_info("unable to obtain relabeling permission\n");
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +010076 return err;
James Morris5e6874cd2006-06-09 00:30:57 -070077 }
78
Paul Moored621d352008-01-29 08:43:36 -050079 selinux_secmark_refcount_inc();
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +010080 return 0;
James Morris5e6874cd2006-06-09 00:30:57 -070081}
82
Jan Engelhardt135367b2010-03-19 17:16:42 +010083static int secmark_tg_check(const struct xt_tgchk_param *par)
James Morris5e6874cd2006-06-09 00:30:57 -070084{
Jan Engelhardtaf5d6dc2008-10-08 11:35:19 +020085 struct xt_secmark_target_info *info = par->targinfo;
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +010086 int err;
James Morris5e6874cd2006-06-09 00:30:57 -070087
Jan Engelhardtaf5d6dc2008-10-08 11:35:19 +020088 if (strcmp(par->table, "mangle") != 0 &&
89 strcmp(par->table, "security") != 0) {
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +010090 pr_info("target only valid in the \'mangle\' "
91 "or \'security\' tables, not \'%s\'.\n", par->table);
Jan Engelhardtd6b00a52010-03-25 16:34:45 +010092 return -EINVAL;
James Morris560ee652008-06-09 15:57:24 -070093 }
94
James Morris5e6874cd2006-06-09 00:30:57 -070095 if (mode && mode != info->mode) {
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +010096 pr_info("mode already set to %hu cannot mix with "
97 "rules for mode %hu\n", mode, info->mode);
Jan Engelhardtd6b00a52010-03-25 16:34:45 +010098 return -EINVAL;
James Morris5e6874cd2006-06-09 00:30:57 -070099 }
100
101 switch (info->mode) {
102 case SECMARK_MODE_SEL:
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +0100103 err = checkentry_selinux(info);
104 if (err <= 0)
105 return err;
James Morris5e6874cd2006-06-09 00:30:57 -0700106 break;
107
108 default:
Jan Engelhardt8bee4ba2010-03-17 16:04:40 +0100109 pr_info("invalid mode: %hu\n", info->mode);
Jan Engelhardtd6b00a52010-03-25 16:34:45 +0100110 return -EINVAL;
James Morris5e6874cd2006-06-09 00:30:57 -0700111 }
112
113 if (!mode)
114 mode = info->mode;
Jan Engelhardtd6b00a52010-03-25 16:34:45 +0100115 return 0;
James Morris5e6874cd2006-06-09 00:30:57 -0700116}
117
Jan Engelhardta2df1642008-10-08 11:35:19 +0200118static void secmark_tg_destroy(const struct xt_tgdtor_param *par)
Paul Moored621d352008-01-29 08:43:36 -0500119{
120 switch (mode) {
121 case SECMARK_MODE_SEL:
122 selinux_secmark_refcount_dec();
123 }
124}
125
Jan Engelhardt55b69e92008-10-08 11:35:01 +0200126static struct xt_target secmark_tg_reg __read_mostly = {
127 .name = "SECMARK",
128 .revision = 0,
129 .family = NFPROTO_UNSPEC,
130 .checkentry = secmark_tg_check,
131 .destroy = secmark_tg_destroy,
132 .target = secmark_tg,
133 .targetsize = sizeof(struct xt_secmark_target_info),
134 .me = THIS_MODULE,
James Morris5e6874cd2006-06-09 00:30:57 -0700135};
136
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -0800137static int __init secmark_tg_init(void)
James Morris5e6874cd2006-06-09 00:30:57 -0700138{
Jan Engelhardt55b69e92008-10-08 11:35:01 +0200139 return xt_register_target(&secmark_tg_reg);
James Morris5e6874cd2006-06-09 00:30:57 -0700140}
141
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -0800142static void __exit secmark_tg_exit(void)
James Morris5e6874cd2006-06-09 00:30:57 -0700143{
Jan Engelhardt55b69e92008-10-08 11:35:01 +0200144 xt_unregister_target(&secmark_tg_reg);
James Morris5e6874cd2006-06-09 00:30:57 -0700145}
146
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -0800147module_init(secmark_tg_init);
148module_exit(secmark_tg_exit);