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[NETFILTER] nf_conntrack: fix possibility of infinite loop while evicting nf_ct_frag6_queue

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This synchronizes nf_ct_reasm with ipv6 reassembly, and fixes a possibility
of an infinite loop if CPUs evict and create nf_ct_frag6_queue in parallel.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yasuyuki Kozakai 2005-11-14 15:28:18 -08:00 committed by David S. Miller
parent 7686a02c0e
commit 1ba430bc3e
1 changed files with 26 additions and 16 deletions
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42
net/ipv6/netfilter/nf_conntrack_reasm.c
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@ -190,8 +190,10 @@ static void nf_ct_frag6_secret_rebuild(unsigned long dummy)
atomic_t nf_ct_frag6_mem = ATOMIC_INIT(0);
/* Memory Tracking Functions. */
static inline void frag_kfree_skb(struct sk_buff *skb)
static inline void frag_kfree_skb(struct sk_buff *skb, unsigned int *work)
{
if (work)
*work -= skb->truesize;
atomic_sub(skb->truesize, &nf_ct_frag6_mem);
if (NFCT_FRAG6_CB(skb)->orig)
kfree_skb(NFCT_FRAG6_CB(skb)->orig);
@ -199,8 +201,11 @@ static inline void frag_kfree_skb(struct sk_buff *skb)
kfree_skb(skb);
}
static inline void frag_free_queue(struct nf_ct_frag6_queue *fq)
static inline void frag_free_queue(struct nf_ct_frag6_queue *fq,
unsigned int *work)
{
if (work)
*work -= sizeof(struct nf_ct_frag6_queue);
atomic_sub(sizeof(struct nf_ct_frag6_queue), &nf_ct_frag6_mem);
kfree(fq);
}
@ -218,7 +223,8 @@ static inline struct nf_ct_frag6_queue *frag_alloc_queue(void)
/* Destruction primitives. */
/* Complete destruction of fq. */
static void nf_ct_frag6_destroy(struct nf_ct_frag6_queue *fq)
static void nf_ct_frag6_destroy(struct nf_ct_frag6_queue *fq,
unsigned int *work)
{
struct sk_buff *fp;
@ -230,17 +236,17 @@ static void nf_ct_frag6_destroy(struct nf_ct_frag6_queue *fq)
while (fp) {
struct sk_buff *xp = fp->next;
frag_kfree_skb(fp);
frag_kfree_skb(fp, work);
fp = xp;
}
frag_free_queue(fq);
frag_free_queue(fq, work);
}
static __inline__ void fq_put(struct nf_ct_frag6_queue *fq)
static __inline__ void fq_put(struct nf_ct_frag6_queue *fq, unsigned int *work)
{
if (atomic_dec_and_test(&fq->refcnt))
nf_ct_frag6_destroy(fq);
nf_ct_frag6_destroy(fq, work);
}
/* Kill fq entry. It is not destroyed immediately,
@ -262,10 +268,14 @@ static void nf_ct_frag6_evictor(void)
{
struct nf_ct_frag6_queue *fq;
struct list_head *tmp;
unsigned int work;
for (;;) {
if (atomic_read(&nf_ct_frag6_mem) <= nf_ct_frag6_low_thresh)
return;
work = atomic_read(&nf_ct_frag6_mem);
if (work <= nf_ct_frag6_low_thresh)
return;
work -= nf_ct_frag6_low_thresh;
while (work > 0) {
read_lock(&nf_ct_frag6_lock);
if (list_empty(&nf_ct_frag6_lru_list)) {
read_unlock(&nf_ct_frag6_lock);
@ -281,7 +291,7 @@ static void nf_ct_frag6_evictor(void)
fq_kill(fq);
spin_unlock(&fq->lock);
fq_put(fq);
fq_put(fq, &work);
}
}
@ -298,7 +308,7 @@ static void nf_ct_frag6_expire(unsigned long data)
out:
spin_unlock(&fq->lock);
fq_put(fq);
fq_put(fq, NULL);
}
/* Creation primitives. */
@ -318,7 +328,7 @@ static struct nf_ct_frag6_queue *nf_ct_frag6_intern(unsigned int hash,
atomic_inc(&fq->refcnt);
write_unlock(&nf_ct_frag6_lock);
fq_in->last_in |= COMPLETE;
fq_put(fq_in);
fq_put(fq_in, NULL);
return fq;
}
}
@ -535,7 +545,7 @@ static int nf_ct_frag6_queue(struct nf_ct_frag6_queue *fq, struct sk_buff *skb,
fq->fragments = next;
fq->meat -= free_it->len;
frag_kfree_skb(free_it);
frag_kfree_skb(free_it, NULL);
}
}
@ -811,7 +821,7 @@ struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb)
if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
spin_unlock(&fq->lock);
DEBUGP("Can't insert skb to queue\n");
fq_put(fq);
fq_put(fq, NULL);
goto ret_orig;
}
@ -822,7 +832,7 @@ struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb)
}
spin_unlock(&fq->lock);
fq_put(fq);
fq_put(fq, NULL);
return ret_skb;
ret_orig: