| /* |
| * Module for modifying the secmark field of the skb, for use by |
| * security subsystems. |
| * |
| * Based on the nfmark match by: |
| * (C) 1999-2001 Marc Boucher <marc@mbsi.ca> |
| * |
| * (C) 2006,2008 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| */ |
| #include <linux/module.h> |
| #include <linux/skbuff.h> |
| #include <linux/selinux.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter/xt_SECMARK.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("James Morris <jmorris@redhat.com>"); |
| MODULE_DESCRIPTION("Xtables: packet security mark modification"); |
| MODULE_ALIAS("ipt_SECMARK"); |
| MODULE_ALIAS("ip6t_SECMARK"); |
| |
| #define PFX "SECMARK: " |
| |
| static u8 mode; |
| |
| static unsigned int |
| secmark_tg(struct sk_buff *skb, const struct net_device *in, |
| const struct net_device *out, unsigned int hooknum, |
| const struct xt_target *target, const void *targinfo) |
| { |
| u32 secmark = 0; |
| const struct xt_secmark_target_info *info = targinfo; |
| |
| BUG_ON(info->mode != mode); |
| |
| switch (mode) { |
| case SECMARK_MODE_SEL: |
| secmark = info->u.sel.selsid; |
| break; |
| |
| default: |
| BUG(); |
| } |
| |
| skb->secmark = secmark; |
| return XT_CONTINUE; |
| } |
| |
| static bool checkentry_selinux(struct xt_secmark_target_info *info) |
| { |
| int err; |
| struct xt_secmark_target_selinux_info *sel = &info->u.sel; |
| |
| sel->selctx[SECMARK_SELCTX_MAX - 1] = '\0'; |
| |
| err = selinux_string_to_sid(sel->selctx, &sel->selsid); |
| if (err) { |
| if (err == -EINVAL) |
| printk(KERN_INFO PFX "invalid SELinux context \'%s\'\n", |
| sel->selctx); |
| return false; |
| } |
| |
| if (!sel->selsid) { |
| printk(KERN_INFO PFX "unable to map SELinux context \'%s\'\n", |
| sel->selctx); |
| return false; |
| } |
| |
| err = selinux_secmark_relabel_packet_permission(sel->selsid); |
| if (err) { |
| printk(KERN_INFO PFX "unable to obtain relabeling permission\n"); |
| return false; |
| } |
| |
| selinux_secmark_refcount_inc(); |
| return true; |
| } |
| |
| static bool |
| secmark_tg_check(const char *tablename, const void *entry, |
| const struct xt_target *target, void *targinfo, |
| unsigned int hook_mask) |
| { |
| struct xt_secmark_target_info *info = targinfo; |
| |
| if (strcmp(tablename, "mangle") && strcmp(tablename, "security")) { |
| printk(KERN_INFO PFX "target only valid in the \'mangle\' " |
| "or \'security\' tables, not \'%s\'.\n", tablename); |
| return false; |
| } |
| |
| if (mode && mode != info->mode) { |
| printk(KERN_INFO PFX "mode already set to %hu cannot mix with " |
| "rules for mode %hu\n", mode, info->mode); |
| return false; |
| } |
| |
| switch (info->mode) { |
| case SECMARK_MODE_SEL: |
| if (!checkentry_selinux(info)) |
| return false; |
| break; |
| |
| default: |
| printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode); |
| return false; |
| } |
| |
| if (!mode) |
| mode = info->mode; |
| return true; |
| } |
| |
| static void secmark_tg_destroy(const struct xt_target *target, void *targinfo) |
| { |
| switch (mode) { |
| case SECMARK_MODE_SEL: |
| selinux_secmark_refcount_dec(); |
| } |
| } |
| |
| static struct xt_target secmark_tg_reg __read_mostly = { |
| .name = "SECMARK", |
| .revision = 0, |
| .family = NFPROTO_UNSPEC, |
| .checkentry = secmark_tg_check, |
| .destroy = secmark_tg_destroy, |
| .target = secmark_tg, |
| .targetsize = sizeof(struct xt_secmark_target_info), |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init secmark_tg_init(void) |
| { |
| return xt_register_target(&secmark_tg_reg); |
| } |
| |
| static void __exit secmark_tg_exit(void) |
| { |
| xt_unregister_target(&secmark_tg_reg); |
| } |
| |
| module_init(secmark_tg_init); |
| module_exit(secmark_tg_exit); |