xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ip: validate header length on virtual device xmit

Browse Source 
KMSAN detected read beyond end of buffer in vti and sit devices when
passing truncated packets with PF_PACKET. The issue affects additional
ip tunnel devices.

Extend commit 76c0ddd8c3 ("ip6_tunnel: be careful when accessing the
inner header") and commit ccfec9e5cb ("ip_tunnel: be careful when
accessing the inner header").

Move the check to a separate helper and call at the start of each
ndo_start_xmit function in net/ipv4 and net/ipv6.

Minor changes:
- convert dev_kfree_skb to kfree_skb on error path,
  as dev_kfree_skb calls consume_skb which is not for error paths.
- use pskb_network_may_pull even though that is pedantic here,
  as the same as pskb_may_pull for devices without llheaders.
- do not cache ipv6 hdrs if used only once
  (unsafe across pskb_may_pull, was more relevant to earlier patch)

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Willem de Bruijn
2018-12-30 17:24:36 -05:00
committed by David S. Miller
parent 8c76e77f90
commit cb9f1b7838
9 changed files with 66 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
net/ipv4/ip_gre.c
View File

@@ -676,6 +676,9 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
struct ip_tunnel *tunnel = netdev_priv(dev);
const struct iphdr *tnl_params;
if (!pskb_inet_may_pull(skb))
goto free_skb;
if (tunnel->collect_md) {
gre_fb_xmit(skb, dev, skb->protocol);
return NETDEV_TX_OK;
@@ -719,6 +722,9 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
struct ip_tunnel *tunnel = netdev_priv(dev);
bool truncate = false;
if (!pskb_inet_may_pull(skb))
goto free_skb;
if (tunnel->collect_md) {
erspan_fb_xmit(skb, dev, skb->protocol);
return NETDEV_TX_OK;
@@ -762,6 +768,9 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
{
struct ip_tunnel *tunnel = netdev_priv(dev);
if (!pskb_inet_may_pull(skb))
goto free_skb;
if (tunnel->collect_md) {
gre_fb_xmit(skb, dev, htons(ETH_P_TEB));
return NETDEV_TX_OK;

9
net/ipv4/ip_tunnel.c
View File

@@ -627,7 +627,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const struct iphdr *tnl_params, u8 protocol)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
unsigned int inner_nhdr_len = 0;
const struct iphdr *inner_iph;
struct flowi4 fl4;
u8 tos, ttl;
@@ -637,14 +636,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
__be32 dst;
bool connected;
/* ensure we can access the inner net header, for several users below */
if (skb->protocol == htons(ETH_P_IP))
inner_nhdr_len = sizeof(struct iphdr);
else if (skb->protocol == htons(ETH_P_IPV6))
inner_nhdr_len = sizeof(struct ipv6hdr);
if (unlikely(!pskb_may_pull(skb, inner_nhdr_len)))
goto tx_error;
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
connected = (tunnel->parms.iph.daddr != 0);

12
net/ipv4/ip_vti.c
View File

@@ -241,6 +241,9 @@ static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
struct ip_tunnel *tunnel = netdev_priv(dev);
struct flowi fl;
if (!pskb_inet_may_pull(skb))
goto tx_err;
memset(&fl, 0, sizeof(fl));
switch (skb->protocol) {
@@ -253,15 +256,18 @@ static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
break;
default:
dev->stats.tx_errors++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
goto tx_err;
}
/* override mark with tunnel output key */
fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
return vti_xmit(skb, dev, &fl);
tx_err:
dev->stats.tx_errors++;
kfree_skb(skb);
return NETDEV_TX_OK;
}
static int vti4_err(struct sk_buff *skb, u32 info)