Commit 3b8377dc authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'variable-length-ll-headers' 



Willem de Bruijn says:

====================
net: validate variable length ll headers

Allow device-specific validation of link layer headers. Existing
checks drop all packets shorter than hard_header_len. For variable
length protocols, such packets can be valid.

patch 1 adds header_ops.validate and dev_validate_header
patch 2 implements the protocol specific callback for AX25
patch 3 replaces ll_header_truncated with dev_validate_header
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 9531ab65 9ed988cd

include/linux/netdevice.h

+20 −2
Original line number Diff line number Diff line
@@ -268,6 +268,7 @@ struct header_ops { 
	void	(*cache_update)(struct hh_cache *hh,

				const struct net_device *dev,

				const unsigned char *haddr);

	bool	(*validate)(const char *ll_header, unsigned int len);

};



/* These flag bits are private to the generic network queueing
@@ -1459,8 +1460,7 @@ enum netdev_priv_flags { 
 *	@dma:		DMA channel

 *	@mtu:		Interface MTU value

 *	@type:		Interface hardware type

 *	@hard_header_len: Hardware header length, which means that this is the

 *			  minimum size of a packet.

 *	@hard_header_len: Maximum hardware header length.

 *

 *	@needed_headroom: Extra headroom the hardware may need, but not in all

 *			  cases can this be guaranteed
@@ -2687,6 +2687,24 @@ static inline int dev_parse_header(const struct sk_buff *skb, 
	return dev->header_ops->parse(skb, haddr);

}



/* ll_header must have at least hard_header_len allocated */

static inline bool dev_validate_header(const struct net_device *dev,

				       char *ll_header, int len)

{

	if (likely(len >= dev->hard_header_len))

		return true;



	if (capable(CAP_SYS_RAWIO)) {

		memset(ll_header + len, 0, dev->hard_header_len - len);

		return true;

	}



	if (dev->header_ops && dev->header_ops->validate)

		return dev->header_ops->validate(ll_header, len);



	return false;

}



typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);

int register_gifconf(unsigned int family, gifconf_func_t *gifconf);

static inline int unregister_gifconf(unsigned int family)

net/ax25/ax25_ip.c

+15 −0
Original line number Diff line number Diff line
@@ -228,8 +228,23 @@ netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) 
}

#endif



static bool ax25_validate_header(const char *header, unsigned int len)

{

	ax25_digi digi;



	if (!len)

		return false;



	if (header[0])

		return true;



	return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL,

			       NULL);

}



const struct header_ops ax25_header_ops = {

	.create = ax25_hard_header,

	.validate = ax25_validate_header,

};



EXPORT_SYMBOL(ax25_header_ops);

net/packet/af_packet.c

+18 −25
Original line number Diff line number Diff line
@@ -1915,6 +1915,10 @@ retry: 
		goto retry;

	}



	if (!dev_validate_header(dev, skb->data, len)) {

		err = -EINVAL;

		goto out_unlock;

	}

	if (len > (dev->mtu + dev->hard_header_len + extra_len) &&

	    !packet_extra_vlan_len_allowed(dev, skb)) {

		err = -EMSGSIZE;
@@ -2393,18 +2397,6 @@ static void tpacket_destruct_skb(struct sk_buff *skb) 
	sock_wfree(skb);

}



static bool ll_header_truncated(const struct net_device *dev, int len)

{

	/* net device doesn't like empty head */

	if (unlikely(len < dev->hard_header_len)) {

		net_warn_ratelimited("%s: packet size is too short (%d < %d)\n",

				     current->comm, len, dev->hard_header_len);

		return true;

	}



	return false;

}



static void tpacket_set_protocol(const struct net_device *dev,

				 struct sk_buff *skb)

{
@@ -2522,16 +2514,20 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, 
		if (unlikely(err < 0))

			return -EINVAL;

	} else if (copylen) {

		int hdrlen = min_t(int, copylen, tp_len);



		skb_push(skb, dev->hard_header_len);

		skb_put(skb, copylen - dev->hard_header_len);

		err = skb_store_bits(skb, 0, data, copylen);

		err = skb_store_bits(skb, 0, data, hdrlen);

		if (unlikely(err))

			return err;

		if (!dev_validate_header(dev, skb->data, hdrlen))

			return -EINVAL;

		if (!skb->protocol)

			tpacket_set_protocol(dev, skb);



		data += copylen;

		to_write -= copylen;

		data += hdrlen;

		to_write -= hdrlen;

	}



	offset = offset_in_page(data);
@@ -2703,13 +2699,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) 
			copylen = __virtio16_to_cpu(vio_le(),

						    vnet_hdr->hdr_len);

		}

		if (dev->hard_header_len) {

			if (ll_header_truncated(dev, tp_len)) {

				tp_len = -EINVAL;

				goto tpacket_error;

			}

		copylen = max_t(int, copylen, dev->hard_header_len);

		}

		skb = sock_alloc_send_skb(&po->sk,

				hlen + tlen + sizeof(struct sockaddr_ll) +

				(copylen - dev->hard_header_len),
@@ -2905,9 +2895,6 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
		offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len);

		if (unlikely(offset < 0))

			goto out_free;

	} else {

		if (ll_header_truncated(dev, len))

			goto out_free;

	}



	/* Returns -EFAULT on error */
@@ -2915,6 +2902,12 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
	if (err)

		goto out_free;



	if (sock->type == SOCK_RAW &&

	    !dev_validate_header(dev, skb->data, len)) {

		err = -EINVAL;

		goto out_free;

	}



	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);



	if (!vnet_hdr.gso_type && (len > dev->mtu + reserve + extra_len) &&

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