commit acc738fec03bdaa5b77340c32a82fbfedaaabef0
Author: Jan Engelhardt <jengelh@xxxxxxxxxx>
Date: Mon Mar 16 15:35:29 2009 +0100
netfilter: xtables: avoid pointer to self
Commit 784544739a25c30637397ace5489eeb6e15d7d49 (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@xxxxxxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
diff --git a/include/linux/netfilter/xt_limit.h b/include/linux/netfilter/xt_limit.h
index b3ce653..fda222c 100644
--- a/include/linux/netfilter/xt_limit.h
+++ b/include/linux/netfilter/xt_limit.h
@@ -4,6 +4,8 @@
/* timings are in milliseconds. */
#define XT_LIMIT_SCALE 10000
+struct xt_limit_priv;
+
/* 1/10,000 sec period => max of 10,000/sec. Min rate is then 429490
seconds, or one every 59 hours. */
struct xt_rateinfo {
@@ -11,11 +13,10 @@ struct xt_rateinfo {
u_int32_t burst; /* Period multiplier for upper limit. */
/* Used internally by the kernel */
- unsigned long prev;
- u_int32_t credit;
+ unsigned long prev; /* moved to xt_limit_priv */
+ u_int32_t credit; /* moved to xt_limit_priv */
u_int32_t credit_cap, cost;
- /* Ugly, ugly fucker. */
- struct xt_rateinfo *master;
+ struct xt_limit_priv *master;
};
#endif /*_XT_RATE_H*/
diff --git a/include/linux/netfilter/xt_quota.h b/include/linux/netfilter/xt_quota.h
index 4c8368d..8dc89df 100644
--- a/include/linux/netfilter/xt_quota.h
+++ b/include/linux/netfilter/xt_quota.h
@@ -6,13 +6,15 @@ enum xt_quota_flags {
};
#define XT_QUOTA_MASK 0x1
+struct xt_quota_priv;
+
struct xt_quota_info {
u_int32_t flags;
u_int32_t pad;
/* Used internally by the kernel */
aligned_u64 quota;
- struct xt_quota_info *master;
+ struct xt_quota_priv *master;
};
#endif /* _XT_QUOTA_H */
diff --git a/include/linux/netfilter/xt_statistic.h b/include/linux/netfilter/xt_statistic.h
index 3d38bc9..8f521ab 100644
--- a/include/linux/netfilter/xt_statistic.h
+++ b/include/linux/netfilter/xt_statistic.h
@@ -13,6 +13,8 @@ enum xt_statistic_flags {
};
#define XT_STATISTIC_MASK 0x1
+struct xt_statistic_priv;
+
struct xt_statistic_info {
u_int16_t mode;
u_int16_t flags;
@@ -23,11 +25,10 @@ struct xt_statistic_info {
struct {
u_int32_t every;
u_int32_t packet;
- /* Used internally by the kernel */
- u_int32_t count;
+ u_int32_t count; /* unused */
} nth;
} u;
- struct xt_statistic_info *master __attribute__((aligned(8)));
+ struct xt_statistic_priv *master __attribute__((aligned(8)));
};
#endif /* _XT_STATISTIC_H */
diff --git a/net/netfilter/xt_limit.c b/net/netfilter/xt_limit.c
index c908d69..2e8089e 100644
--- a/net/netfilter/xt_limit.c
+++ b/net/netfilter/xt_limit.c
@@ -14,6 +14,11 @@
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_limit.h>
+struct xt_limit_priv {
+ unsigned long prev;
+ uint32_t credit;
+};
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Herve Eychenne <rv@xxxxxxxxxxxx>");
MODULE_DESCRIPTION("Xtables: rate-limit match");
@@ -60,18 +65,18 @@ static DEFINE_SPINLOCK(limit_lock);
static bool
limit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
- struct xt_rateinfo *r =
- ((const struct xt_rateinfo *)par->matchinfo)->master;
+ const struct xt_rateinfo *r = par->matchinfo;
+ struct xt_limit_priv *priv = r->master;
unsigned long now = jiffies;
spin_lock_bh(&limit_lock);
- r->credit += (now - xchg(&r->prev, now)) * CREDITS_PER_JIFFY;
- if (r->credit > r->credit_cap)
- r->credit = r->credit_cap;
+ priv->credit += (now - xchg(&priv->prev, now)) * CREDITS_PER_JIFFY;
+ if (priv->credit > r->credit_cap)
+ priv->credit = r->credit_cap;
- if (r->credit >= r->cost) {
+ if (priv->credit >= r->cost) {
/* We're not limited. */
- r->credit -= r->cost;
+ priv->credit -= r->cost;
spin_unlock_bh(&limit_lock);
return true;
}
@@ -95,6 +100,7 @@ user2credits(u_int32_t user)
static bool limit_mt_check(const struct xt_mtchk_param *par)
{
struct xt_rateinfo *r = par->matchinfo;
+ struct xt_limit_priv *priv;
/* Check for overflow. */
if (r->burst == 0
@@ -104,19 +110,30 @@ static bool limit_mt_check(const struct xt_mtchk_param *par)
return false;
}
- /* For SMP, we only want to use one set of counters. */
- r->master = r;
+ priv = kmalloc(sizeof(*priv), GFP_KERNEL);
+ if (priv == NULL)
+ return -ENOMEM;
+
+ /* For SMP, we only want to use one set of state. */
+ r->master = priv;
if (r->cost == 0) {
/* User avg in seconds * XT_LIMIT_SCALE: convert to jiffies *
128. */
- r->prev = jiffies;
- r->credit = user2credits(r->avg * r->burst); /* Credits full. */
+ priv->prev = jiffies;
+ priv->credit = user2credits(r->avg * r->burst); /* Credits full. */
r->credit_cap = user2credits(r->avg * r->burst); /* Credits full. */
r->cost = user2credits(r->avg);
}
return true;
}
+static void limit_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_rateinfo *info = par->matchinfo;
+
+ kfree(info->master);
+}
+
#ifdef CONFIG_COMPAT
struct compat_xt_rateinfo {
u_int32_t avg;
@@ -167,6 +184,7 @@ static struct xt_match limit_mt_reg __read_mostly = {
.family = NFPROTO_UNSPEC,
.match = limit_mt,
.checkentry = limit_mt_check,
+ .destroy = limit_mt_destroy,
.matchsize = sizeof(struct xt_rateinfo),
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_rateinfo),
diff --git a/net/netfilter/xt_quota.c b/net/netfilter/xt_quota.c
index c84fce5..01dd07b 100644
--- a/net/netfilter/xt_quota.c
+++ b/net/netfilter/xt_quota.c
@@ -9,6 +9,10 @@
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_quota.h>
+struct xt_quota_priv {
+ uint64_t quota;
+};
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sam Johnston <samj@xxxxxxxx>");
MODULE_DESCRIPTION("Xtables: countdown quota match");
@@ -20,18 +24,20 @@ static DEFINE_SPINLOCK(quota_lock);
static bool
quota_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
- struct xt_quota_info *q =
- ((const struct xt_quota_info *)par->matchinfo)->master;
+ struct xt_quota_info *q = (void *)par->matchinfo;
+ struct xt_quota_priv *priv = q->master;
bool ret = q->flags & XT_QUOTA_INVERT;
spin_lock_bh("a_lock);
- if (q->quota >= skb->len) {
- q->quota -= skb->len;
+ if (priv->quota >= skb->len) {
+ priv->quota -= skb->len;
ret = !ret;
} else {
/* we do not allow even small packets from now on */
- q->quota = 0;
+ priv->quota = 0;
}
+ /* Copy quota back to matchinfo so that iptables can display it */
+ q->quota = priv->quota;
spin_unlock_bh("a_lock);
return ret;
@@ -43,17 +49,28 @@ static bool quota_mt_check(const struct xt_mtchk_param *par)
if (q->flags & ~XT_QUOTA_MASK)
return false;
- /* For SMP, we only want to use one set of counters. */
- q->master = q;
+
+ q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
+ if (q->master == NULL)
+ return -ENOMEM;
+
return true;
}
+static void quota_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_quota_info *q = par->matchinfo;
+
+ kfree(q->master);
+}
+
static struct xt_match quota_mt_reg __read_mostly = {
.name = "quota",
.revision = 0,
.family = NFPROTO_UNSPEC,
.match = quota_mt,
.checkentry = quota_mt_check,
+ .destroy = quota_mt_destroy,
.matchsize = sizeof(struct xt_quota_info),
.me = THIS_MODULE,
};
diff --git a/net/netfilter/xt_statistic.c b/net/netfilter/xt_statistic.c
index 0d75141..d8c0f8f 100644
--- a/net/netfilter/xt_statistic.c
+++ b/net/netfilter/xt_statistic.c
@@ -16,6 +16,10 @@
#include <linux/netfilter/xt_statistic.h>
#include <linux/netfilter/x_tables.h>
+struct xt_statistic_priv {
+ uint32_t count;
+};
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@xxxxxxxxx>");
MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
@@ -27,7 +31,7 @@ static DEFINE_SPINLOCK(nth_lock);
static bool
statistic_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
- struct xt_statistic_info *info = (void *)par->matchinfo;
+ const struct xt_statistic_info *info = par->matchinfo;
bool ret = info->flags & XT_STATISTIC_INVERT;
switch (info->mode) {
@@ -36,10 +40,9 @@ statistic_mt(const struct sk_buff *skb, const struct xt_match_param *par)
ret = !ret;
break;
case XT_STATISTIC_MODE_NTH:
- info = info->master;
spin_lock_bh(&nth_lock);
- if (info->u.nth.count++ == info->u.nth.every) {
- info->u.nth.count = 0;
+ if (info->master->count++ == info->u.nth.every) {
+ info->master->count = 0;
ret = !ret;
}
spin_unlock_bh(&nth_lock);
@@ -56,16 +59,31 @@ static bool statistic_mt_check(const struct xt_mtchk_param *par)
if (info->mode > XT_STATISTIC_MODE_MAX ||
info->flags & ~XT_STATISTIC_MASK)
return false;
- info->master = info;
+
+ info->master = kzalloc(sizeof(*info->master), GFP_KERNEL);
+ if (info->master == NULL) {
+ printk(KERN_ERR KBUILD_MODNAME ": Out of memory\n");
+ return false;
+ }
+ info->master->count = info->u.nth.count;
+
return true;
}
+static void statistic_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_statistic_info *info = par->matchinfo;
+
+ kfree(info->master);
+}
+
static struct xt_match xt_statistic_mt_reg __read_mostly = {
.name = "statistic",
.revision = 0,
.family = NFPROTO_UNSPEC,
.match = statistic_mt,
.checkentry = statistic_mt_check,
+ .destroy = statistic_mt_destroy,
.matchsize = sizeof(struct xt_statistic_info),
.me = THIS_MODULE,
};
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