diff options
| author | David S. Miller <davem@sunset.davemloft.net> | 2006-04-09 22:43:55 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-04-09 22:43:55 -0700 |
| commit | 55c0022e53452360064ea264c41410c70565d9f8 (patch) | |
| tree | cca5e75b12dfaaadf5620b59c7121a017a799117 | |
| parent | 19910d1aec0b2b96ff4b4a93e2aed0d32643e850 (diff) | |
[IPV4] ip_fragment: Always compute hash with ipfrag_lock held.
Otherwise we could compute an inaccurate hash due to the
random seed changing.
Noticed by Zach Brown and patch is based upon some feedback
from Herbert Xu.
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/ip_fragment.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index 2a8adda15e1..da734c43917 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -304,13 +304,17 @@ out: /* Creation primitives. */ -static struct ipq *ip_frag_intern(unsigned int hash, struct ipq *qp_in) +static struct ipq *ip_frag_intern(struct ipq *qp_in) { struct ipq *qp; #ifdef CONFIG_SMP struct hlist_node *n; #endif + unsigned int hash; + write_lock(&ipfrag_lock); + hash = ipqhashfn(qp_in->id, qp_in->saddr, qp_in->daddr, + qp_in->protocol); #ifdef CONFIG_SMP /* With SMP race we have to recheck hash table, because * such entry could be created on other cpu, while we @@ -345,7 +349,7 @@ static struct ipq *ip_frag_intern(unsigned int hash, struct ipq *qp_in) } /* Add an entry to the 'ipq' queue for a newly received IP datagram. */ -static struct ipq *ip_frag_create(unsigned hash, struct iphdr *iph, u32 user) +static struct ipq *ip_frag_create(struct iphdr *iph, u32 user) { struct ipq *qp; @@ -371,7 +375,7 @@ static struct ipq *ip_frag_create(unsigned hash, struct iphdr *iph, u32 user) spin_lock_init(&qp->lock); atomic_set(&qp->refcnt, 1); - return ip_frag_intern(hash, qp); + return ip_frag_intern(qp); out_nomem: LIMIT_NETDEBUG(KERN_ERR "ip_frag_create: no memory left !\n"); @@ -387,11 +391,12 @@ static inline struct ipq *ip_find(struct iphdr *iph, u32 user) __u32 saddr = iph->saddr; __u32 daddr = iph->daddr; __u8 protocol = iph->protocol; - unsigned int hash = ipqhashfn(id, saddr, daddr, protocol); + unsigned int hash; struct ipq *qp; struct hlist_node *n; read_lock(&ipfrag_lock); + hash = ipqhashfn(id, saddr, daddr, protocol); hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { if(qp->id == id && qp->saddr == saddr && @@ -405,7 +410,7 @@ static inline struct ipq *ip_find(struct iphdr *iph, u32 user) } read_unlock(&ipfrag_lock); - return ip_frag_create(hash, iph, user); + return ip_frag_create(iph, user); } /* Is the fragment too far ahead to be part of ipq? */ |