// SPDX-License-Identifier: GPL-2.0-only
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/*
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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) 2006,2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/security.h>
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#include <linux/skbuff.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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static u8 mode;
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static unsigned int
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secmark_tg(struct sk_buff *skb, const struct xt_secmark_target_info_v1 *info)
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{
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u32 secmark = 0;
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switch (mode) {
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case SECMARK_MODE_SEL:
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secmark = info->secid;
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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 int checkentry_lsm(struct xt_secmark_target_info_v1 *info)
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{
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int err;
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info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
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info->secid = 0;
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err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
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&info->secid);
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if (err) {
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if (err == -EINVAL)
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pr_info_ratelimited("invalid security context \'%s\'\n",
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info->secctx);
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return err;
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}
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if (!info->secid) {
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pr_info_ratelimited("unable to map security context \'%s\'\n",
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info->secctx);
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return -ENOENT;
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}
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err = security_secmark_relabel_packet(info->secid);
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if (err) {
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pr_info_ratelimited("unable to obtain relabeling permission\n");
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return err;
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}
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security_secmark_refcount_inc();
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return 0;
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}
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static int
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secmark_tg_check(const char *table, struct xt_secmark_target_info_v1 *info)
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{
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int err;
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if (strcmp(table, "mangle") != 0 &&
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strcmp(table, "security") != 0) {
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pr_info_ratelimited("only valid in \'mangle\' or \'security\' table, not \'%s\'\n",
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table);
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return -EINVAL;
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}
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if (mode && mode != info->mode) {
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pr_info_ratelimited("mode already set to %hu cannot mix with rules for mode %hu\n",
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mode, info->mode);
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return -EINVAL;
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}
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switch (info->mode) {
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case SECMARK_MODE_SEL:
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break;
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default:
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pr_info_ratelimited("invalid mode: %hu\n", info->mode);
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return -EINVAL;
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}
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err = checkentry_lsm(info);
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if (err)
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return err;
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if (!mode)
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mode = info->mode;
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return 0;
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}
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static void secmark_tg_destroy(const struct xt_tgdtor_param *par)
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{
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switch (mode) {
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case SECMARK_MODE_SEL:
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security_secmark_refcount_dec();
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}
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}
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static int secmark_tg_check_v0(const struct xt_tgchk_param *par)
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{
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struct xt_secmark_target_info *info = par->targinfo;
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struct xt_secmark_target_info_v1 newinfo = {
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.mode = info->mode,
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};
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int ret;
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memcpy(newinfo.secctx, info->secctx, SECMARK_SECCTX_MAX);
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ret = secmark_tg_check(par->table, &newinfo);
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info->secid = newinfo.secid;
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return ret;
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}
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static unsigned int
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secmark_tg_v0(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_secmark_target_info *info = par->targinfo;
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struct xt_secmark_target_info_v1 newinfo = {
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.secid = info->secid,
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};
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return secmark_tg(skb, &newinfo);
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}
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static int secmark_tg_check_v1(const struct xt_tgchk_param *par)
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{
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return secmark_tg_check(par->table, par->targinfo);
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}
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static unsigned int
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secmark_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
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{
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return secmark_tg(skb, par->targinfo);
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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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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.checkentry = secmark_tg_check_v0,
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.destroy = secmark_tg_destroy,
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.target = secmark_tg_v0,
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.targetsize = sizeof(struct xt_secmark_target_info),
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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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.revision = 1,
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.family = NFPROTO_UNSPEC,
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.checkentry = secmark_tg_check_v1,
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.destroy = secmark_tg_destroy,
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.target = secmark_tg_v1,
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.targetsize = sizeof(struct xt_secmark_target_info_v1),
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.usersize = offsetof(struct xt_secmark_target_info_v1, secid),
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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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