[net,v2] ipv4: fix wildcard search with inet_confirm_addr()

Help of this function says: "in_dev: only on this interface, 0=any interface",
but since commit 39a6d0630012 ("[NETNS]: Process inet_confirm_addr in the
correct namespace."), the code supposes that it will never be NULL. This
function is never called with in_dev == NULL, but it's exported and may be used
by an external module.

Because this patch restore the ability to call inet_confirm_addr() with in_dev
== NULL, I partially revert the above commit, as suggested by Julian.

CC: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---

This bug was spotted by code review.

v2: fix change in bond_confirm_addr()
    partially revert 39a6d0630012 ("[NETNS]: Process inet_confirm_addr in the
    correct namespace.")
    fix API desc of inet_confirm_addr()

 drivers/net/bonding/bonding.h | 4 ++--
 include/linux/inetdevice.h    | 3 ++-
 net/ipv4/arp.c                | 4 +++-
 net/ipv4/devinet.c            | 9 ++++-----
 4 files changed, 11 insertions(+), 9 deletions(-)

Hello,

On Wed, 13 Nov 2013, Nicolas Dichtel wrote:

> Help of this function says: "in_dev: only on this interface, 0=any interface",
> but since commit 39a6d0630012 ("[NETNS]: Process inet_confirm_addr in the
> correct namespace."), the code supposes that it will never be NULL. This
> function is never called with in_dev == NULL, but it's exported and may be used
> by an external module.
> 
> Because this patch restore the ability to call inet_confirm_addr() with in_dev
> == NULL, I partially revert the above commit, as suggested by Julian.
> 
> CC: Julian Anastasov <ja@ssi.bg>
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>

	This patch looks ok to me, thanks!

Reviewed-by: Julian Anastasov <ja@ssi.bg>

	Still, I think this is a net-next material
and you have to wait some days... The net tree that
you are using is missing the changes that remove
'extern', so I think you have to port it to net-next
tree to avoid the conflict in include/linux/inetdevice.h.

> ---
> 
> This bug was spotted by code review.
> 
> v2: fix change in bond_confirm_addr()
>     partially revert 39a6d0630012 ("[NETNS]: Process inet_confirm_addr in the
>     correct namespace.")
>     fix API desc of inet_confirm_addr()
> 
>  drivers/net/bonding/bonding.h | 4 ++--
>  include/linux/inetdevice.h    | 3 ++-
>  net/ipv4/arp.c                | 4 +++-
>  net/ipv4/devinet.c            | 9 ++++-----
>  4 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
> index 03cf3fd14490..0ad3f4bd99c0 100644
> --- a/drivers/net/bonding/bonding.h
> +++ b/drivers/net/bonding/bonding.h
> @@ -414,8 +414,8 @@ static inline __be32 bond_confirm_addr(struct net_device *dev, __be32 dst, __be3
>  	in_dev = __in_dev_get_rcu(dev);
>  
>  	if (in_dev)
> -		addr = inet_confirm_addr(in_dev, dst, local, RT_SCOPE_HOST);
> -
> +		addr = inet_confirm_addr(dev_net(dev), in_dev, dst, local,
> +					 RT_SCOPE_HOST);
>  	rcu_read_unlock();
>  	return addr;
>  }
> diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
> index 79640e015a86..5870f7060917 100644
> --- a/include/linux/inetdevice.h
> +++ b/include/linux/inetdevice.h
> @@ -164,7 +164,8 @@ extern int		devinet_ioctl(struct net *net, unsigned int cmd, void __user *);
>  extern void		devinet_init(void);
>  extern struct in_device	*inetdev_by_index(struct net *, int);
>  extern __be32		inet_select_addr(const struct net_device *dev, __be32 dst, int scope);
> -extern __be32		inet_confirm_addr(struct in_device *in_dev, __be32 dst, __be32 local, int scope);
> +__be32 inet_confirm_addr(struct net *net, struct in_device *in_dev, __be32 dst,
> +			 __be32 local, int scope);
>  extern struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix, __be32 mask);
>  
>  static __inline__ int inet_ifa_match(__be32 addr, struct in_ifaddr *ifa)
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 7808093cede6..46c7b4483bcf 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -379,6 +379,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  
>  static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
>  {
> +	struct net *net = dev_net(in_dev->dev);
>  	int scope;
>  
>  	switch (IN_DEV_ARP_IGNORE(in_dev)) {
> @@ -397,6 +398,7 @@ static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
>  	case 3:	/* Do not reply for scope host addresses */
>  		sip = 0;
>  		scope = RT_SCOPE_LINK;
> +		in_dev = NULL;
>  		break;
>  	case 4:	/* Reserved */
>  	case 5:
> @@ -408,7 +410,7 @@ static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
>  	default:
>  		return 0;
>  	}
> -	return !inet_confirm_addr(in_dev, sip, tip, scope);
> +	return !inet_confirm_addr(net, in_dev, sip, tip, scope);
>  }
>  
>  static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
> diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
> index a1b5bcbd04ae..19426e4b232c 100644
> --- a/net/ipv4/devinet.c
> +++ b/net/ipv4/devinet.c
> @@ -1236,22 +1236,21 @@ static __be32 confirm_addr_indev(struct in_device *in_dev, __be32 dst,
>  
>  /*
>   * Confirm that local IP address exists using wildcards:
> - * - in_dev: only on this interface, 0=any interface
> + * - net: netns to check, cannot be NULL
> + * - in_dev: only on this interface, NULL=any interface
>   * - dst: only in the same subnet as dst, 0=any dst
>   * - local: address, 0=autoselect the local address
>   * - scope: maximum allowed scope value for the local address
>   */
> -__be32 inet_confirm_addr(struct in_device *in_dev,
> +__be32 inet_confirm_addr(struct net *net, struct in_device *in_dev,
>  			 __be32 dst, __be32 local, int scope)
>  {
>  	__be32 addr = 0;
>  	struct net_device *dev;
> -	struct net *net;
>  
> -	if (scope != RT_SCOPE_LINK)
> +	if (in_dev != NULL)
>  		return confirm_addr_indev(in_dev, dst, local, scope);
>  
> -	net = dev_net(in_dev->dev);
>  	rcu_read_lock();
>  	for_each_netdev_rcu(net, dev) {
>  		in_dev = __in_dev_get_rcu(dev);
> -- 
> 1.8.4.1

Regards

--
Julian Anastasov <ja@ssi.bg>
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Le 13/11/2013 22:27, Julian Anastasov a écrit :
>
> 	Hello,
>
> On Wed, 13 Nov 2013, Nicolas Dichtel wrote:
>
>> Help of this function says: "in_dev: only on this interface, 0=any interface",
>> but since commit 39a6d0630012 ("[NETNS]: Process inet_confirm_addr in the
>> correct namespace."), the code supposes that it will never be NULL. This
>> function is never called with in_dev == NULL, but it's exported and may be used
>> by an external module.
>>
>> Because this patch restore the ability to call inet_confirm_addr() with in_dev
>> == NULL, I partially revert the above commit, as suggested by Julian.
>>
>> CC: Julian Anastasov <ja@ssi.bg>
>> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
>
> 	This patch looks ok to me, thanks!
>
> Reviewed-by: Julian Anastasov <ja@ssi.bg>
>
> 	Still, I think this is a net-next material
> and you have to wait some days... The net tree that
Ok.

> you are using is missing the changes that remove
> 'extern', so I think you have to port it to net-next
> tree to avoid the conflict in include/linux/inetdevice.h.
Yes, checkpatch already warns about this extern kerword.

Thank you,
Nicolas
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