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Subject[PATCH] netfilter: nat: Do not use ARRAY_SIZE() on spinlocks to fix zero div
Date
If no spinlock debugging options (CONFIG_GENERIC_LOCKBREAK,
CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_LOCK_ALLOC) are enabled on a UP
platform (e.g. m68k defconfig), arch_spinlock_t is an empty struct,
hence using ARRAY_SIZE(nf_nat_locks) causes a division by zero:

net/netfilter/nf_nat_core.c: In function ‘nf_nat_setup_info’:
net/netfilter/nf_nat_core.c:432: warning: division by zero
net/netfilter/nf_nat_core.c: In function ‘__nf_nat_cleanup_conntrack’:
net/netfilter/nf_nat_core.c:535: warning: division by zero
net/netfilter/nf_nat_core.c:537: warning: division by zero
net/netfilter/nf_nat_core.c: In function ‘nf_nat_init’:
net/netfilter/nf_nat_core.c:810: warning: division by zero
net/netfilter/nf_nat_core.c:811: warning: division by zero
net/netfilter/nf_nat_core.c:824: warning: division by zero

Fix this by using the CONNTRACK_LOCKS definition instead.

Suggested-by: Florian Westphal <fw@strlen.de>
Fixes: 8073e960a03bf7b5 ("netfilter: nat: use keyed locks")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
net/netfilter/nf_nat_core.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index f393a7086025f6c5..af8345fc4fbde30a 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -429,7 +429,7 @@ nf_nat_setup_info(struct nf_conn *ct,

srchash = hash_by_src(net,
&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
- lock = &nf_nat_locks[srchash % ARRAY_SIZE(nf_nat_locks)];
+ lock = &nf_nat_locks[srchash % CONNTRACK_LOCKS];
spin_lock_bh(lock);
hlist_add_head_rcu(&ct->nat_bysource,
&nf_nat_bysource[srchash]);
@@ -532,9 +532,9 @@ static void __nf_nat_cleanup_conntrack(struct nf_conn *ct)
unsigned int h;

h = hash_by_src(nf_ct_net(ct), &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
- spin_lock_bh(&nf_nat_locks[h % ARRAY_SIZE(nf_nat_locks)]);
+ spin_lock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
hlist_del_rcu(&ct->nat_bysource);
- spin_unlock_bh(&nf_nat_locks[h % ARRAY_SIZE(nf_nat_locks)]);
+ spin_unlock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
}

static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
@@ -807,8 +807,8 @@ static int __init nf_nat_init(void)

/* Leave them the same for the moment. */
nf_nat_htable_size = nf_conntrack_htable_size;
- if (nf_nat_htable_size < ARRAY_SIZE(nf_nat_locks))
- nf_nat_htable_size = ARRAY_SIZE(nf_nat_locks);
+ if (nf_nat_htable_size < CONNTRACK_LOCKS)
+ nf_nat_htable_size = CONNTRACK_LOCKS;

nf_nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, 0);
if (!nf_nat_bysource)
@@ -821,7 +821,7 @@ static int __init nf_nat_init(void)
return ret;
}

- for (i = 0; i < ARRAY_SIZE(nf_nat_locks); i++)
+ for (i = 0; i < CONNTRACK_LOCKS; i++)
spin_lock_init(&nf_nat_locks[i]);

nf_ct_helper_expectfn_register(&follow_master_nat);
--
2.7.4
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