[patch 34/37] appletalk: Fix skb leak when ipddp interface is not loaded

Greg KH
2009-10-09T23:42:55Z

[-- Attachment #1: appletalk-fix-skb-leak-when-ipddp-interface-is-not-loaded.patch --]
[-- Type: text/plain, Size: 6105 bytes --]

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

------------------
From: Arnaldo Carvalho de Melo <acme@redhat.com>

[ Upstream commit ffcfb8db540ff879c2a85bf7e404954281443414 ]

And also do a better job of returning proper NET_{RX,XMIT}_ values.

Based on a patch by Mark Smith.

This fixes CVE-2009-2903

Reported-by: Mark Smith <lk-netdev@lk-netdev.nosense.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/net/appletalk/ipddp.c | 3 --
net/appletalk/aarp.c | 16 +++++++----
net/appletalk/ddp.c | 58 ++++++++++++++++++++++--------------------
3 files changed, 43 insertions(+), 34 deletions(-)

--- a/drivers/net/appletalk/ipddp.c
+++ b/drivers/net/appletalk/ipddp.c
@@ -176,8 +176,7 @@ static int ipddp_xmit(struct sk_buff *sk
dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;

- if(aarp_send_ddp(rt->dev, skb, &rt->at, NULL) < 0)
- dev_kfree_skb(skb);
+ aarp_send_ddp(rt->dev, skb, &rt->at, NULL);

spin_unlock(&ipddp_route_lock);

--- a/net/appletalk/aarp.c
+++ b/net/appletalk/aarp.c
@@ -599,7 +599,7 @@ int aarp_send_ddp(struct net_device *dev

/* Non ELAP we cannot do. */
if (dev->type != ARPHRD_ETHER)
- return -1;
+ goto free_it;

skb->dev = dev;
skb->protocol = htons(ETH_P_ATALK);
@@ -634,7 +634,7 @@ int aarp_send_ddp(struct net_device *dev
if (!a) {
/* Whoops slipped... good job it's an unreliable protocol 8) */
write_unlock_bh(&aarp_lock);
- return -1;
+ goto free_it;
}

/* Set up the queue */
@@ -663,15 +663,21 @@ out_unlock:
write_unlock_bh(&aarp_lock);

/* Tell the ddp layer we have taken over for this frame. */
- return 0;
+ goto sent;

sendit:
if (skb->sk)
skb->priority = skb->sk->sk_priority;
- dev_queue_xmit(skb);
+ if (dev_queue_xmit(skb))
+ goto drop;
sent:
- return 1;
+ return NET_XMIT_SUCCESS;
+free_it:
+ kfree_skb(skb);
+drop:
+ return NET_XMIT_DROP;
}
+EXPORT_SYMBOL(aarp_send_ddp);

/*
* An entry in the aarp unresolved queue has become resolved. Send
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1270,8 +1270,10 @@ static int handle_ip_over_ddp(struct sk_
struct net_device_stats *stats;

/* This needs to be able to handle ipddp"N" devices */
- if (!dev)
- return -ENODEV;
+ if (!dev) {
+ kfree_skb(skb);
+ return NET_RX_DROP;
+ }

skb->protocol = htons(ETH_P_IP);
skb_pull(skb, 13);
@@ -1281,8 +1283,7 @@ static int handle_ip_over_ddp(struct sk_
stats = netdev_priv(dev);
stats->rx_packets++;
stats->rx_bytes += skb->len + 13;
- netif_rx(skb); /* Send the SKB up to a higher place. */
- return 0;
+ return netif_rx(skb); /* Send the SKB up to a higher place. */
}
#else
/* make it easy for gcc to optimize this test out, i.e. kill the code */
@@ -1290,9 +1291,8 @@ static int handle_ip_over_ddp(struct sk_
#define handle_ip_over_ddp(skb) 0
#endif

-static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
- struct ddpehdr *ddp, __u16 len_hops,
- int origlen)
+static int atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
+ struct ddpehdr *ddp, __u16 len_hops, int origlen)
{
struct atalk_route *rt;
struct atalk_addr ta;
@@ -1359,8 +1359,6 @@ static void atalk_route_packet(struct sk
/* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
kfree_skb(skb);
- if (!nskb)
- goto out;
skb = nskb;
} else
skb = skb_unshare(skb, GFP_ATOMIC);
@@ -1369,12 +1367,18 @@ static void atalk_route_packet(struct sk
* If the buffer didn't vanish into the lack of space bitbucket we can
* send it.
*/
- if (skb && aarp_send_ddp(rt->dev, skb, &ta, NULL) == -1)
- goto free_it;
-out:
- return;
+ if (skb == NULL)
+ goto drop;
+
+ /*
+ * It is OK, NET_XMIT_SUCCESS == NET_RX_SUCCESS and
+ * NET_XMIT_DROP == NET_RX_DROP
+ */
+ return aarp_send_ddp(rt->dev, skb, &ta, NULL);
free_it:
kfree_skb(skb);
+drop:
+ return NET_RX_DROP;
}

/**
@@ -1404,7 +1408,7 @@ static int atalk_rcv(struct sk_buff *skb

/* Don't mangle buffer if shared */
if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
- goto out;
+ goto drop;

/* Size check and make sure header is contiguous */
if (!pskb_may_pull(skb, sizeof(*ddp)))
@@ -1448,8 +1452,7 @@ static int atalk_rcv(struct sk_buff *skb
/* Not ours, so we route the packet via the correct
* AppleTalk iface
*/
- atalk_route_packet(skb, dev, ddp, len_hops, origlen);
- goto out;
+ return atalk_route_packet(skb, dev, ddp, len_hops, origlen);
}

/* if IP over DDP is not selected this code will be optimized out */
@@ -1472,11 +1475,12 @@ static int atalk_rcv(struct sk_buff *skb

if (sock_queue_rcv_skb(sock, skb) < 0)
goto freeit;
-out:
- return 0;
+
+ return NET_RX_SUCCESS;
freeit:
kfree_skb(skb);
- goto out;
+drop:
+ return NET_RX_DROP;
}

/*
@@ -1652,10 +1656,10 @@ static int atalk_sendmsg(struct kiocb *i
if (skb2) {
loopback = 1;
SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
- if (aarp_send_ddp(dev, skb2,
- &usat->sat_addr, NULL) == -1)
- kfree_skb(skb2);
- /* else queued/sent above in the aarp queue */
+ /*
+ * If it fails it is queued/sent above in the aarp queue
+ */
+ aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL);
}
}

@@ -1685,9 +1689,10 @@ static int atalk_sendmsg(struct kiocb *i
usat = &gsat;
}

- if (aarp_send_ddp(dev, skb, &usat->sat_addr, NULL) == -1)
- kfree_skb(skb);
- /* else queued/sent above in the aarp queue */
+ /*
+ * If it fails it is queued/sent above in the aarp queue
+ */
+ aarp_send_ddp(dev, skb, &usat->sat_addr, NULL);
}
SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);

@@ -1865,7 +1870,6 @@ static struct packet_type ppptalk_packet
static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };

/* Export symbols for use by drivers when AppleTalk is a module */
-EXPORT_SYMBOL(aarp_send_ddp);
EXPORT_SYMBOL(atrtr_get_dev);
EXPORT_SYMBOL(atalk_find_dev_addr);