Revision 99f857db8857aff691c51302f93648263ed07eb1 authored by David Woodhouse on 10 January 2013, 14:31:59 UTC, committed by H. Peter Anvin on 28 January 2013, 04:19:37 UTC
We have historically hard-coded entry points in head.S just so it's easy to build the executable/bzImage headers with references to them. Unfortunately, this leads to boot loaders abusing these "known" addresses even when they are *explicitly* told that they "should look at the ELF header to find this address, as it may change in the future". And even when the address in question *has* actually been changed in the past, without fanfare or thought to compatibility. Thus we have bootloaders doing stunningly broken things like jumping to offset 0x200 in the kernel startup code in 64-bit mode, *hoping* that startup_64 is still there (it has moved at least once before). And hoping that it's actually a 64-bit kernel despite the fact that we don't give them any indication of that fact. This patch should hopefully remove the temptation to abuse internal addresses in future, where sternly worded comments have not sufficed. Instead of having hard-coded addresses and saying "please don't abuse these", we actually pull the addresses out of the ELF payload into zoffset.h, and make build.c shove them back into the right places in the bzImage header. Rather than including zoffset.h into build.c and thus having to rebuild the tool for every kernel build, we parse it instead. The parsing code is small and simple. This patch doesn't actually move any of the interesting entry points, so any offending bootloader will still continue to "work" after this patch is applied. For some version of "work" which includes jumping into the compressed payload and crashing, if the bzImage it's given is a 32-bit kernel. No change there then. [ hpa: some of the issues in the description are addressed or retconned by the 2.12 boot protocol. This patch has been edited to only remove fixed addresses that were *not* thus retconned. ] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Matt Fleming <matt.fleming@intel.com>
1 parent b607e21
vlan_core.c
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_vlan.h>
#include <linux/netpoll.h>
#include <linux/export.h>
#include "vlan.h"
bool vlan_do_receive(struct sk_buff **skbp)
{
struct sk_buff *skb = *skbp;
u16 vlan_id = skb->vlan_tci & VLAN_VID_MASK;
struct net_device *vlan_dev;
struct vlan_pcpu_stats *rx_stats;
vlan_dev = vlan_find_dev(skb->dev, vlan_id);
if (!vlan_dev)
return false;
skb = *skbp = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
return false;
skb->dev = vlan_dev;
if (skb->pkt_type == PACKET_OTHERHOST) {
/* Our lower layer thinks this is not local, let's make sure.
* This allows the VLAN to have a different MAC than the
* underlying device, and still route correctly. */
if (ether_addr_equal(eth_hdr(skb)->h_dest, vlan_dev->dev_addr))
skb->pkt_type = PACKET_HOST;
}
if (!(vlan_dev_priv(vlan_dev)->flags & VLAN_FLAG_REORDER_HDR)) {
unsigned int offset = skb->data - skb_mac_header(skb);
/*
* vlan_insert_tag expect skb->data pointing to mac header.
* So change skb->data before calling it and change back to
* original position later
*/
skb_push(skb, offset);
skb = *skbp = vlan_insert_tag(skb, skb->vlan_tci);
if (!skb)
return false;
skb_pull(skb, offset + VLAN_HLEN);
skb_reset_mac_len(skb);
}
skb->priority = vlan_get_ingress_priority(vlan_dev, skb->vlan_tci);
skb->vlan_tci = 0;
rx_stats = this_cpu_ptr(vlan_dev_priv(vlan_dev)->vlan_pcpu_stats);
u64_stats_update_begin(&rx_stats->syncp);
rx_stats->rx_packets++;
rx_stats->rx_bytes += skb->len;
if (skb->pkt_type == PACKET_MULTICAST)
rx_stats->rx_multicast++;
u64_stats_update_end(&rx_stats->syncp);
return true;
}
/* Must be invoked with rcu_read_lock or with RTNL. */
struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
u16 vlan_id)
{
struct vlan_info *vlan_info = rcu_dereference_rtnl(real_dev->vlan_info);
if (vlan_info) {
return vlan_group_get_device(&vlan_info->grp, vlan_id);
} else {
/*
* Bonding slaves do not have grp assigned to themselves.
* Grp is assigned to bonding master instead.
*/
if (netif_is_bond_slave(real_dev))
return __vlan_find_dev_deep(real_dev->master, vlan_id);
}
return NULL;
}
EXPORT_SYMBOL(__vlan_find_dev_deep);
struct net_device *vlan_dev_real_dev(const struct net_device *dev)
{
return vlan_dev_priv(dev)->real_dev;
}
EXPORT_SYMBOL(vlan_dev_real_dev);
u16 vlan_dev_vlan_id(const struct net_device *dev)
{
return vlan_dev_priv(dev)->vlan_id;
}
EXPORT_SYMBOL(vlan_dev_vlan_id);
static struct sk_buff *vlan_reorder_header(struct sk_buff *skb)
{
if (skb_cow(skb, skb_headroom(skb)) < 0)
return NULL;
memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
skb->mac_header += VLAN_HLEN;
return skb;
}
struct sk_buff *vlan_untag(struct sk_buff *skb)
{
struct vlan_hdr *vhdr;
u16 vlan_tci;
if (unlikely(vlan_tx_tag_present(skb))) {
/* vlan_tci is already set-up so leave this for another time */
return skb;
}
skb = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
goto err_free;
if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
goto err_free;
vhdr = (struct vlan_hdr *) skb->data;
vlan_tci = ntohs(vhdr->h_vlan_TCI);
__vlan_hwaccel_put_tag(skb, vlan_tci);
skb_pull_rcsum(skb, VLAN_HLEN);
vlan_set_encap_proto(skb, vhdr);
skb = vlan_reorder_header(skb);
if (unlikely(!skb))
goto err_free;
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
skb_reset_mac_len(skb);
return skb;
err_free:
kfree_skb(skb);
return NULL;
}
/*
* vlan info and vid list
*/
static void vlan_group_free(struct vlan_group *grp)
{
int i;
for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++)
kfree(grp->vlan_devices_arrays[i]);
}
static void vlan_info_free(struct vlan_info *vlan_info)
{
vlan_group_free(&vlan_info->grp);
kfree(vlan_info);
}
static void vlan_info_rcu_free(struct rcu_head *rcu)
{
vlan_info_free(container_of(rcu, struct vlan_info, rcu));
}
static struct vlan_info *vlan_info_alloc(struct net_device *dev)
{
struct vlan_info *vlan_info;
vlan_info = kzalloc(sizeof(struct vlan_info), GFP_KERNEL);
if (!vlan_info)
return NULL;
vlan_info->real_dev = dev;
INIT_LIST_HEAD(&vlan_info->vid_list);
return vlan_info;
}
struct vlan_vid_info {
struct list_head list;
unsigned short vid;
int refcount;
};
static struct vlan_vid_info *vlan_vid_info_get(struct vlan_info *vlan_info,
unsigned short vid)
{
struct vlan_vid_info *vid_info;
list_for_each_entry(vid_info, &vlan_info->vid_list, list) {
if (vid_info->vid == vid)
return vid_info;
}
return NULL;
}
static struct vlan_vid_info *vlan_vid_info_alloc(unsigned short vid)
{
struct vlan_vid_info *vid_info;
vid_info = kzalloc(sizeof(struct vlan_vid_info), GFP_KERNEL);
if (!vid_info)
return NULL;
vid_info->vid = vid;
return vid_info;
}
static int __vlan_vid_add(struct vlan_info *vlan_info, unsigned short vid,
struct vlan_vid_info **pvid_info)
{
struct net_device *dev = vlan_info->real_dev;
const struct net_device_ops *ops = dev->netdev_ops;
struct vlan_vid_info *vid_info;
int err;
vid_info = vlan_vid_info_alloc(vid);
if (!vid_info)
return -ENOMEM;
if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
ops->ndo_vlan_rx_add_vid) {
err = ops->ndo_vlan_rx_add_vid(dev, vid);
if (err) {
kfree(vid_info);
return err;
}
}
list_add(&vid_info->list, &vlan_info->vid_list);
vlan_info->nr_vids++;
*pvid_info = vid_info;
return 0;
}
int vlan_vid_add(struct net_device *dev, unsigned short vid)
{
struct vlan_info *vlan_info;
struct vlan_vid_info *vid_info;
bool vlan_info_created = false;
int err;
ASSERT_RTNL();
vlan_info = rtnl_dereference(dev->vlan_info);
if (!vlan_info) {
vlan_info = vlan_info_alloc(dev);
if (!vlan_info)
return -ENOMEM;
vlan_info_created = true;
}
vid_info = vlan_vid_info_get(vlan_info, vid);
if (!vid_info) {
err = __vlan_vid_add(vlan_info, vid, &vid_info);
if (err)
goto out_free_vlan_info;
}
vid_info->refcount++;
if (vlan_info_created)
rcu_assign_pointer(dev->vlan_info, vlan_info);
return 0;
out_free_vlan_info:
if (vlan_info_created)
kfree(vlan_info);
return err;
}
EXPORT_SYMBOL(vlan_vid_add);
static void __vlan_vid_del(struct vlan_info *vlan_info,
struct vlan_vid_info *vid_info)
{
struct net_device *dev = vlan_info->real_dev;
const struct net_device_ops *ops = dev->netdev_ops;
unsigned short vid = vid_info->vid;
int err;
if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
ops->ndo_vlan_rx_kill_vid) {
err = ops->ndo_vlan_rx_kill_vid(dev, vid);
if (err) {
pr_warn("failed to kill vid %d for device %s\n",
vid, dev->name);
}
}
list_del(&vid_info->list);
kfree(vid_info);
vlan_info->nr_vids--;
}
void vlan_vid_del(struct net_device *dev, unsigned short vid)
{
struct vlan_info *vlan_info;
struct vlan_vid_info *vid_info;
ASSERT_RTNL();
vlan_info = rtnl_dereference(dev->vlan_info);
if (!vlan_info)
return;
vid_info = vlan_vid_info_get(vlan_info, vid);
if (!vid_info)
return;
vid_info->refcount--;
if (vid_info->refcount == 0) {
__vlan_vid_del(vlan_info, vid_info);
if (vlan_info->nr_vids == 0) {
RCU_INIT_POINTER(dev->vlan_info, NULL);
call_rcu(&vlan_info->rcu, vlan_info_rcu_free);
}
}
}
EXPORT_SYMBOL(vlan_vid_del);
int vlan_vids_add_by_dev(struct net_device *dev,
const struct net_device *by_dev)
{
struct vlan_vid_info *vid_info;
struct vlan_info *vlan_info;
int err;
ASSERT_RTNL();
vlan_info = rtnl_dereference(by_dev->vlan_info);
if (!vlan_info)
return 0;
list_for_each_entry(vid_info, &vlan_info->vid_list, list) {
err = vlan_vid_add(dev, vid_info->vid);
if (err)
goto unwind;
}
return 0;
unwind:
list_for_each_entry_continue_reverse(vid_info,
&vlan_info->vid_list,
list) {
vlan_vid_del(dev, vid_info->vid);
}
return err;
}
EXPORT_SYMBOL(vlan_vids_add_by_dev);
void vlan_vids_del_by_dev(struct net_device *dev,
const struct net_device *by_dev)
{
struct vlan_vid_info *vid_info;
struct vlan_info *vlan_info;
ASSERT_RTNL();
vlan_info = rtnl_dereference(by_dev->vlan_info);
if (!vlan_info)
return;
list_for_each_entry(vid_info, &vlan_info->vid_list, list)
vlan_vid_del(dev, vid_info->vid);
}
EXPORT_SYMBOL(vlan_vids_del_by_dev);
bool vlan_uses_dev(const struct net_device *dev)
{
struct vlan_info *vlan_info;
ASSERT_RTNL();
vlan_info = rtnl_dereference(dev->vlan_info);
if (!vlan_info)
return false;
return vlan_info->grp.nr_vlan_devs ? true : false;
}
EXPORT_SYMBOL(vlan_uses_dev);
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