![Jan Engelhardt](/assets/img/avatar_default.png)
Commit 784544739a
(netfilter: iptables:
lock free counters) broke a number of modules whose rule data referenced
itself. A reallocation would not reestablish the correct references, so
it is best to use a separate struct that does not fall under RCU.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
90 lines
1.9 KiB
C
90 lines
1.9 KiB
C
/*
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* netfilter module to enforce network quotas
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*
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* Sam Johnston <samj@samj.net>
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*/
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#include <linux/skbuff.h>
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#include <linux/spinlock.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_quota.h>
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struct xt_quota_priv {
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uint64_t quota;
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};
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
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MODULE_DESCRIPTION("Xtables: countdown quota match");
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MODULE_ALIAS("ipt_quota");
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MODULE_ALIAS("ip6t_quota");
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static DEFINE_SPINLOCK(quota_lock);
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static bool
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quota_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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struct xt_quota_info *q = (void *)par->matchinfo;
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struct xt_quota_priv *priv = q->master;
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bool ret = q->flags & XT_QUOTA_INVERT;
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spin_lock_bh("a_lock);
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if (priv->quota >= skb->len) {
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priv->quota -= skb->len;
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ret = !ret;
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} else {
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/* we do not allow even small packets from now on */
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priv->quota = 0;
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}
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/* Copy quota back to matchinfo so that iptables can display it */
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q->quota = priv->quota;
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spin_unlock_bh("a_lock);
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return ret;
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}
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static bool quota_mt_check(const struct xt_mtchk_param *par)
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{
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struct xt_quota_info *q = par->matchinfo;
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if (q->flags & ~XT_QUOTA_MASK)
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return false;
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q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
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if (q->master == NULL)
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return -ENOMEM;
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return true;
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}
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static void quota_mt_destroy(const struct xt_mtdtor_param *par)
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{
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const struct xt_quota_info *q = par->matchinfo;
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kfree(q->master);
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}
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static struct xt_match quota_mt_reg __read_mostly = {
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.name = "quota",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.match = quota_mt,
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.checkentry = quota_mt_check,
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.destroy = quota_mt_destroy,
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.matchsize = sizeof(struct xt_quota_info),
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.me = THIS_MODULE,
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};
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static int __init quota_mt_init(void)
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{
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return xt_register_match("a_mt_reg);
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}
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static void __exit quota_mt_exit(void)
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{
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xt_unregister_match("a_mt_reg);
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}
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module_init(quota_mt_init);
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module_exit(quota_mt_exit);
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