netfilter: xtables: avoid pointer to self
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>
This commit is contained in:
parent
95ba434f89
commit
acc738fec0
6 changed files with 88 additions and 31 deletions
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@ -4,6 +4,8 @@
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/* timings are in milliseconds. */
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#define XT_LIMIT_SCALE 10000
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struct xt_limit_priv;
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/* 1/10,000 sec period => max of 10,000/sec. Min rate is then 429490
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seconds, or one every 59 hours. */
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struct xt_rateinfo {
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@ -11,11 +13,10 @@ struct xt_rateinfo {
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u_int32_t burst; /* Period multiplier for upper limit. */
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/* Used internally by the kernel */
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unsigned long prev;
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u_int32_t credit;
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unsigned long prev; /* moved to xt_limit_priv */
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u_int32_t credit; /* moved to xt_limit_priv */
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u_int32_t credit_cap, cost;
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/* Ugly, ugly fucker. */
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struct xt_rateinfo *master;
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struct xt_limit_priv *master;
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};
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#endif /*_XT_RATE_H*/
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@ -6,13 +6,15 @@ enum xt_quota_flags {
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};
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#define XT_QUOTA_MASK 0x1
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struct xt_quota_priv;
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struct xt_quota_info {
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u_int32_t flags;
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u_int32_t pad;
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/* Used internally by the kernel */
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aligned_u64 quota;
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struct xt_quota_info *master;
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struct xt_quota_priv *master;
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};
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#endif /* _XT_QUOTA_H */
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@ -13,6 +13,8 @@ enum xt_statistic_flags {
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};
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#define XT_STATISTIC_MASK 0x1
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struct xt_statistic_priv;
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struct xt_statistic_info {
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u_int16_t mode;
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u_int16_t flags;
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@ -23,11 +25,10 @@ struct xt_statistic_info {
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struct {
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u_int32_t every;
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u_int32_t packet;
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/* Used internally by the kernel */
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u_int32_t count;
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u_int32_t count; /* unused */
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} nth;
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} u;
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struct xt_statistic_info *master __attribute__((aligned(8)));
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struct xt_statistic_priv *master __attribute__((aligned(8)));
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};
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#endif /* _XT_STATISTIC_H */
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@ -14,6 +14,11 @@
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_limit.h>
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struct xt_limit_priv {
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unsigned long prev;
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uint32_t credit;
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};
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Herve Eychenne <rv@wallfire.org>");
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MODULE_DESCRIPTION("Xtables: rate-limit match");
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@ -60,18 +65,18 @@ static DEFINE_SPINLOCK(limit_lock);
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static bool
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limit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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struct xt_rateinfo *r =
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((const struct xt_rateinfo *)par->matchinfo)->master;
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const struct xt_rateinfo *r = par->matchinfo;
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struct xt_limit_priv *priv = r->master;
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unsigned long now = jiffies;
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spin_lock_bh(&limit_lock);
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r->credit += (now - xchg(&r->prev, now)) * CREDITS_PER_JIFFY;
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if (r->credit > r->credit_cap)
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r->credit = r->credit_cap;
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priv->credit += (now - xchg(&priv->prev, now)) * CREDITS_PER_JIFFY;
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if (priv->credit > r->credit_cap)
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priv->credit = r->credit_cap;
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if (r->credit >= r->cost) {
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if (priv->credit >= r->cost) {
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/* We're not limited. */
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r->credit -= r->cost;
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priv->credit -= r->cost;
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spin_unlock_bh(&limit_lock);
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return true;
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}
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@ -95,6 +100,7 @@ user2credits(u_int32_t user)
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static bool limit_mt_check(const struct xt_mtchk_param *par)
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{
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struct xt_rateinfo *r = par->matchinfo;
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struct xt_limit_priv *priv;
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/* Check for overflow. */
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if (r->burst == 0
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@ -104,19 +110,30 @@ static bool limit_mt_check(const struct xt_mtchk_param *par)
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return false;
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}
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/* For SMP, we only want to use one set of counters. */
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r->master = r;
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priv = kmalloc(sizeof(*priv), GFP_KERNEL);
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if (priv == NULL)
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return -ENOMEM;
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/* For SMP, we only want to use one set of state. */
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r->master = priv;
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if (r->cost == 0) {
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/* User avg in seconds * XT_LIMIT_SCALE: convert to jiffies *
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128. */
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r->prev = jiffies;
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r->credit = user2credits(r->avg * r->burst); /* Credits full. */
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priv->prev = jiffies;
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priv->credit = user2credits(r->avg * r->burst); /* Credits full. */
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r->credit_cap = user2credits(r->avg * r->burst); /* Credits full. */
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r->cost = user2credits(r->avg);
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}
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return true;
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}
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static void limit_mt_destroy(const struct xt_mtdtor_param *par)
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{
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const struct xt_rateinfo *info = par->matchinfo;
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kfree(info->master);
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}
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#ifdef CONFIG_COMPAT
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struct compat_xt_rateinfo {
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u_int32_t avg;
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@ -167,6 +184,7 @@ static struct xt_match limit_mt_reg __read_mostly = {
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.family = NFPROTO_UNSPEC,
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.match = limit_mt,
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.checkentry = limit_mt_check,
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.destroy = limit_mt_destroy,
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.matchsize = sizeof(struct xt_rateinfo),
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#ifdef CONFIG_COMPAT
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.compatsize = sizeof(struct compat_xt_rateinfo),
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@ -9,6 +9,10 @@
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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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@ -20,18 +24,20 @@ 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 =
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((const struct xt_quota_info *)par->matchinfo)->master;
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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 (q->quota >= skb->len) {
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q->quota -= skb->len;
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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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q->quota = 0;
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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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@ -43,17 +49,28 @@ static bool quota_mt_check(const struct xt_mtchk_param *par)
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if (q->flags & ~XT_QUOTA_MASK)
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return false;
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/* For SMP, we only want to use one set of counters. */
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q->master = q;
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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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@ -16,6 +16,10 @@
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#include <linux/netfilter/xt_statistic.h>
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#include <linux/netfilter/x_tables.h>
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struct xt_statistic_priv {
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uint32_t count;
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};
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
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@ -27,7 +31,7 @@ static DEFINE_SPINLOCK(nth_lock);
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static bool
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statistic_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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struct xt_statistic_info *info = (void *)par->matchinfo;
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const struct xt_statistic_info *info = par->matchinfo;
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bool ret = info->flags & XT_STATISTIC_INVERT;
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switch (info->mode) {
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ret = !ret;
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break;
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case XT_STATISTIC_MODE_NTH:
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info = info->master;
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spin_lock_bh(&nth_lock);
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if (info->u.nth.count++ == info->u.nth.every) {
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info->u.nth.count = 0;
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if (info->master->count++ == info->u.nth.every) {
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info->master->count = 0;
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ret = !ret;
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}
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spin_unlock_bh(&nth_lock);
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if (info->mode > XT_STATISTIC_MODE_MAX ||
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info->flags & ~XT_STATISTIC_MASK)
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return false;
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info->master = info;
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info->master = kzalloc(sizeof(*info->master), GFP_KERNEL);
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if (info->master == NULL) {
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printk(KERN_ERR KBUILD_MODNAME ": Out of memory\n");
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return false;
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}
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info->master->count = info->u.nth.count;
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return true;
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}
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static void statistic_mt_destroy(const struct xt_mtdtor_param *par)
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{
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const struct xt_statistic_info *info = par->matchinfo;
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kfree(info->master);
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}
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static struct xt_match xt_statistic_mt_reg __read_mostly = {
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.name = "statistic",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.match = statistic_mt,
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.checkentry = statistic_mt_check,
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.destroy = statistic_mt_destroy,
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.matchsize = sizeof(struct xt_statistic_info),
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.me = THIS_MODULE,
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};
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