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authorDavid Ahern <dsa@cumulusnetworks.com>2017-03-06 19:53:04 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-09 10:10:02 +0300
commitf7887d40e541f74402df0684a1463c0a0bb68c68 (patch)
treeadeec7423b3f7fe0793164a91e463ad4d0c36f65 /drivers/net/vrf.c
parent3331aa378e9bcbd0d16de9034b0c20f4050e26b4 (diff)
downloadlinux-f7887d40e541f74402df0684a1463c0a0bb68c68.tar.xz
vrf: Fix use-after-free in vrf_xmit
KASAN detected a use-after-free: [ 269.467067] BUG: KASAN: use-after-free in vrf_xmit+0x7f1/0x827 [vrf] at addr ffff8800350a21c0 [ 269.467067] Read of size 4 by task ssh/1879 [ 269.467067] CPU: 1 PID: 1879 Comm: ssh Not tainted 4.10.0+ #249 [ 269.467067] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 269.467067] Call Trace: [ 269.467067] dump_stack+0x81/0xb6 [ 269.467067] kasan_object_err+0x21/0x78 [ 269.467067] kasan_report+0x2f7/0x450 [ 269.467067] ? vrf_xmit+0x7f1/0x827 [vrf] [ 269.467067] ? ip_output+0xa4/0xdb [ 269.467067] __asan_load4+0x6b/0x6d [ 269.467067] vrf_xmit+0x7f1/0x827 [vrf] ... Which corresponds to the skb access after xmit handling. Fix by saving skb->len and using the saved value to update stats. Fixes: 193125dbd8eb2 ("net: Introduce VRF device driver") Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/vrf.c')
-rw-r--r--drivers/net/vrf.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 22379da63400..fea687f35b5a 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -340,6 +340,7 @@ static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev)
static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
{
+ int len = skb->len;
netdev_tx_t ret = is_ip_tx_frame(skb, dev);
if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
@@ -347,7 +348,7 @@ static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
u64_stats_update_begin(&dstats->syncp);
dstats->tx_pkts++;
- dstats->tx_bytes += skb->len;
+ dstats->tx_bytes += len;
u64_stats_update_end(&dstats->syncp);
} else {
this_cpu_inc(dev->dstats->tx_drps);