Re: [net-2.6 PATCH] af_packet: move strict addr_len check right

[Jiri Pirko <jpirko () redhat com>]

Wed, Mar 03, 2010 at 07:40:01AM CET, jpirko () redhat com wrote:
> Subject: [net-2.6 PATCH] af_packet: move strict addr_len check right before dev_[mc/unicast]_[add/del]

Dave please apply this against net-next-2.6. I see that 914c8ad2d18b is still not in
net-2.6.

Thanks a lot

Jirka

> My previous patch 914c8ad2d18b62ad1420f518c0cab0b0b90ab308 incorrectly changed
> the length check in packet_mc_add to be more strict. The problem is that
> userspace is not filling this field (and it stays zeroed) in case of setting
> PACKET_MR_PROMISC or PACKET_MR_ALLMULTI. So move the strict check to the point
> in path where the addr_len must be set correctly.
>
> Signed-off-by: Jiri Pirko <jpirko () redhat com>
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 031a5e6..1612d41 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1688,6 +1688,8 @@ static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
> {
>       switch (i->type) {
>       case PACKET_MR_MULTICAST:
> +              if (i->alen != dev->addr_len)
> +                      return -EINVAL;
>               if (what > 0)
>                       return dev_mc_add(dev, i->addr, i->alen, 0);
>               else
> @@ -1700,6 +1702,8 @@ static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
>               return dev_set_allmulti(dev, what);
>               break;
>       case PACKET_MR_UNICAST:
> +              if (i->alen != dev->addr_len)
> +                      return -EINVAL;
>               if (what > 0)
>                       return dev_unicast_add(dev, i->addr);
>               else
> @@ -1734,7 +1738,7 @@ static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
>               goto done;
>
>       err = -EINVAL;
> -      if (mreq->mr_alen != dev->addr_len)
> +      if (mreq->mr_alen > dev->addr_len)
>               goto done;
>
>       err = -ENOBUFS;
-
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