From 1ba430bc3e243d38c0bb2b185bea664b04fc59df Mon Sep 17 00:00:00 2001 From: Yasuyuki Kozakai Date: Mon, 14 Nov 2005 15:28:18 -0800 Subject: [PATCH] [NETFILTER] nf_conntrack: fix possibility of infinite loop while evicting nf_ct_frag6_queue 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 Signed-off-by: Harald Welte Signed-off-by: David S. Miller --- net/ipv6/netfilter/nf_conntrack_reasm.c | 42 ++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c index ed7603f..1b68d71 100644 --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -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: -- 2.7.4