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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2018-02-07 21:59:17 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-15 10:56:56 +0100 |
| commit | cbd6bb0e28c9c9772bd818fc7be1bb1452f3cf54 (patch) | |
| tree | 1a7875195ff96c60543e8604650930ebb3f06b14 /net | |
| parent | ec6b058c5431e7e1686c4d7ef42f951473baa78b (diff) | |
| download | linux-cbd6bb0e28c9c9772bd818fc7be1bb1452f3cf54.tar.gz linux-cbd6bb0e28c9c9772bd818fc7be1bb1452f3cf54.tar.bz2 linux-cbd6bb0e28c9c9772bd818fc7be1bb1452f3cf54.zip | |
netfilter: ipt_CLUSTERIP: fix a race condition of proc file creation
commit b3e456fce9f51d6276e576d00271e2813c1b8b67 upstream.
There is a race condition between clusterip_config_entry_put()
and clusterip_config_init(), after we release the spinlock in
clusterip_config_entry_put(), a new proc file with a same IP could
be created immediately since it is already removed from the configs
list, therefore it triggers this warning:
------------[ cut here ]------------
proc_dir_entry 'ipt_CLUSTERIP/172.20.0.170' already registered
WARNING: CPU: 1 PID: 4152 at fs/proc/generic.c:330 proc_register+0x2a4/0x370 fs/proc/generic.c:329
Kernel panic - not syncing: panic_on_warn set ...
As a quick fix, just move the proc_remove() inside the spinlock.
Reported-by: <syzbot+03218bcdba6aa76441a3@syzkaller.appspotmail.com>
Fixes: 6c5d5cfbe3c5 ("netfilter: ipt_CLUSTERIP: check duplicate config when initializing")
Tested-by: Paolo Abeni <pabeni@redhat.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/netfilter/ipt_CLUSTERIP.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 1e4a7209a3d2..77a01c484807 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -107,12 +107,6 @@ clusterip_config_entry_put(struct net *net, struct clusterip_config *c) local_bh_disable(); if (refcount_dec_and_lock(&c->entries, &cn->lock)) { - list_del_rcu(&c->list); - spin_unlock(&cn->lock); - local_bh_enable(); - - unregister_netdevice_notifier(&c->notifier); - /* In case anyone still accesses the file, the open/close * functions are also incrementing the refcount on their own, * so it's safe to remove the entry even if it's in use. */ @@ -120,6 +114,12 @@ clusterip_config_entry_put(struct net *net, struct clusterip_config *c) if (cn->procdir) proc_remove(c->pde); #endif + list_del_rcu(&c->list); + spin_unlock(&cn->lock); + local_bh_enable(); + + unregister_netdevice_notifier(&c->notifier); + return; } local_bh_enable(); |