[patch 14/31] Fix IFB net driver input device crashes

Greg KH
2007-04-11T23:03:48Z

[-- Attachment #1: fix-ifb-net-driver-input-device-crashes.patch --]
[-- Type: text/plain, Size: 4653 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------
From: Patrick McHardy <kaber@trash.net>

[IFB]: Fix crash on input device removal

The input_device pointer is not refcounted, which means the device may
disappear while packets are queued, causing a crash when ifb passes packets
with a stale skb->dev pointer to netif_rx().

Fix by storing the interface index instead and do a lookup where neccessary.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/net/ifb.c | 35 +++++++++++++----------------------
include/linux/skbuff.h | 5 +++--
include/net/pkt_cls.h | 7 +++++--
net/core/dev.c | 8 ++++----
net/core/skbuff.c | 2 +-
net/sched/act_mirred.c | 2 +-
6 files changed, 27 insertions(+), 32 deletions(-)

--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -96,17 +96,24 @@ static void ri_tasklet(unsigned long dev
skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
stats->tx_packets++;
stats->tx_bytes +=skb->len;
+
+ skb->dev = __dev_get_by_index(skb->iif);
+ if (!skb->dev) {
+ dev_kfree_skb(skb);
+ stats->tx_dropped++;
+ break;
+ }
+ skb->iif = _dev->ifindex;
+
if (from & AT_EGRESS) {
dp->st_rx_frm_egr++;
dev_queue_xmit(skb);
} else if (from & AT_INGRESS) {
-
dp->st_rx_frm_ing++;
+ skb_pull(skb, skb->dev->hard_header_len);
netif_rx(skb);
- } else {
- dev_kfree_skb(skb);
- stats->tx_dropped++;
- }
+ } else
+ BUG();
}

if (netif_tx_trylock(_dev)) {
@@ -157,26 +164,10 @@ static int ifb_xmit(struct sk_buff *skb,
stats->rx_packets++;
stats->rx_bytes+=skb->len;

- if (!from || !skb->input_dev) {
-dropped:
+ if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
dev_kfree_skb(skb);
stats->rx_dropped++;
return ret;
- } else {
- /*
- * note we could be going
- * ingress -> egress or
- * egress -> ingress
- */
- skb->dev = skb->input_dev;
- skb->input_dev = dev;
- if (from & AT_INGRESS) {
- skb_pull(skb, skb->dev->hard_header_len);
- } else {
- if (!(from & AT_EGRESS)) {
- goto dropped;
- }
- }
}

if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -188,7 +188,7 @@ enum {
* @sk: Socket we are owned by
* @tstamp: Time we arrived
* @dev: Device we arrived on/are leaving by
- * @input_dev: Device we arrived on
+ * @iif: ifindex of device we arrived on
* @h: Transport layer header
* @nh: Network layer header
* @mac: Link layer header
@@ -235,7 +235,8 @@ struct sk_buff {
struct sock *sk;
struct skb_timeval tstamp;
struct net_device *dev;
- struct net_device *input_dev;
+ int iif;
+ /* 4 byte hole on 64 bit*/

union {
struct tcphdr *th;
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -352,10 +352,13 @@ tcf_change_indev(struct tcf_proto *tp, c
static inline int
tcf_match_indev(struct sk_buff *skb, char *indev)
{
+ struct net_device *dev;
+
if (indev[0]) {
- if (!skb->input_dev)
+ if (!skb->iif)
return 0;
- if (strcmp(indev, skb->input_dev->name))
+ dev = __dev_get_by_index(skb->iif);
+ if (!dev || strcmp(indev, dev->name))
return 0;
}

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1741,8 +1741,8 @@ static int ing_filter(struct sk_buff *sk
if (dev->qdisc_ingress) {
__u32 ttl = (__u32) G_TC_RTTL(skb->tc_verd);
if (MAX_RED_LOOP < ttl++) {
- printk(KERN_WARNING "Redir loop detected Dropping packet (%s->%s)\n",
- skb->input_dev->name, skb->dev->name);
+ printk(KERN_WARNING "Redir loop detected Dropping packet (%d->%d)\n",
+ skb->iif, skb->dev->ifindex);
return TC_ACT_SHOT;
}

@@ -1775,8 +1775,8 @@ int netif_receive_skb(struct sk_buff *sk
if (!skb->tstamp.off_sec)
net_timestamp(skb);

- if (!skb->input_dev)
- skb->input_dev = skb->dev;
+ if (!skb->iif)
+ skb->iif = skb->dev->ifindex;

orig_dev = skb_bond(skb);

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -497,7 +497,7 @@ struct sk_buff *skb_clone(struct sk_buff
n->tc_verd = SET_TC_VERD(skb->tc_verd,0);
n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
- C(input_dev);
+ C(iif);
#endif
skb_copy_secmark(n, skb);
#endif
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -199,7 +199,7 @@ bad_mirred:
skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);

skb2->dev = dev;
- skb2->input_dev = skb->dev;
+ skb2->iif = skb->dev->ifindex;
dev_queue_xmit(skb2);
spin_unlock(&m->tcf_lock);
return m->tcf_action;

--