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![Paul Moore](/assets/img/avatar_default.png)
This patch introduces a mechanism for checking when labeled IPsec or SECMARK are in use by keeping introducing a configuration reference counter for each subsystem. In the case of labeled IPsec, whenever a labeled SA or SPD entry is created the labeled IPsec/XFRM reference count is increased and when the entry is removed it is decreased. In the case of SECMARK, when a SECMARK target is created the reference count is increased and later decreased when the target is removed. These reference counters allow SELinux to quickly determine if either of these subsystems are enabled. NetLabel already has a similar mechanism which provides the netlbl_enabled() function. This patch also renames the selinux_relabel_packet_permission() function to selinux_secmark_relabel_packet_permission() as the original name and description were misleading in that they referenced a single packet label which is not the case. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: James Morris <jmorris@namei.org>
156 lines
3.6 KiB
C
156 lines
3.6 KiB
C
/*
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* Module for modifying the secmark field of the skb, for use by
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* security subsystems.
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*
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* Based on the nfmark match by:
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* (C) 1999-2001 Marc Boucher <marc@mbsi.ca>
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*
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* (C) 2006 Red Hat, Inc., James Morris <jmorris@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/selinux.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_SECMARK.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
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MODULE_DESCRIPTION("Xtables: packet security mark modification");
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MODULE_ALIAS("ipt_SECMARK");
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MODULE_ALIAS("ip6t_SECMARK");
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#define PFX "SECMARK: "
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static u8 mode;
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static unsigned int
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secmark_tg(struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, unsigned int hooknum,
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const struct xt_target *target, const void *targinfo)
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{
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u32 secmark = 0;
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const struct xt_secmark_target_info *info = targinfo;
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BUG_ON(info->mode != mode);
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switch (mode) {
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case SECMARK_MODE_SEL:
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secmark = info->u.sel.selsid;
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break;
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default:
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BUG();
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}
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skb->secmark = secmark;
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return XT_CONTINUE;
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}
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static bool checkentry_selinux(struct xt_secmark_target_info *info)
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{
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int err;
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struct xt_secmark_target_selinux_info *sel = &info->u.sel;
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sel->selctx[SECMARK_SELCTX_MAX - 1] = '\0';
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err = selinux_string_to_sid(sel->selctx, &sel->selsid);
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if (err) {
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if (err == -EINVAL)
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printk(KERN_INFO PFX "invalid SELinux context \'%s\'\n",
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sel->selctx);
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return false;
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}
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if (!sel->selsid) {
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printk(KERN_INFO PFX "unable to map SELinux context \'%s\'\n",
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sel->selctx);
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return false;
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}
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err = selinux_secmark_relabel_packet_permission(sel->selsid);
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if (err) {
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printk(KERN_INFO PFX "unable to obtain relabeling permission\n");
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return false;
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}
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selinux_secmark_refcount_inc();
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return true;
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}
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static bool
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secmark_tg_check(const char *tablename, const void *entry,
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const struct xt_target *target, void *targinfo,
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unsigned int hook_mask)
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{
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struct xt_secmark_target_info *info = targinfo;
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if (mode && mode != info->mode) {
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printk(KERN_INFO PFX "mode already set to %hu cannot mix with "
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"rules for mode %hu\n", mode, info->mode);
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return false;
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}
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switch (info->mode) {
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case SECMARK_MODE_SEL:
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if (!checkentry_selinux(info))
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return false;
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break;
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default:
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printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
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return false;
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}
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if (!mode)
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mode = info->mode;
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return true;
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}
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void secmark_tg_destroy(const struct xt_target *target, void *targinfo)
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{
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switch (mode) {
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case SECMARK_MODE_SEL:
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selinux_secmark_refcount_dec();
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}
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}
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static struct xt_target secmark_tg_reg[] __read_mostly = {
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{
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.name = "SECMARK",
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.family = AF_INET,
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.checkentry = secmark_tg_check,
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.destroy = secmark_tg_destroy,
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.target = secmark_tg,
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.targetsize = sizeof(struct xt_secmark_target_info),
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.table = "mangle",
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.me = THIS_MODULE,
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},
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{
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.name = "SECMARK",
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.family = AF_INET6,
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.checkentry = secmark_tg_check,
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.destroy = secmark_tg_destroy,
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.target = secmark_tg,
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.targetsize = sizeof(struct xt_secmark_target_info),
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.table = "mangle",
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.me = THIS_MODULE,
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},
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};
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static int __init secmark_tg_init(void)
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{
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return xt_register_targets(secmark_tg_reg, ARRAY_SIZE(secmark_tg_reg));
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}
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static void __exit secmark_tg_exit(void)
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{
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xt_unregister_targets(secmark_tg_reg, ARRAY_SIZE(secmark_tg_reg));
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}
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module_init(secmark_tg_init);
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module_exit(secmark_tg_exit);
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