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authorWillem de Bruijn <willemb@google.com>2018-12-31 01:24:36 +0300
committerDavid S. Miller <davem@davemloft.net>2019-01-01 23:05:02 +0300
commitcb9f1b783850b14cbd7f87d061d784a666dfba1f (patch)
tree652c378230eed5add180c8fec9787db540b32e97 /net/ipv4/ip_gre.c
parent8c76e77f9069f10505c08e02646c3ee11ad79038 (diff)
downloadlinux-cb9f1b783850b14cbd7f87d061d784a666dfba1f.tar.xz
ip: validate header length on virtual device xmit
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 76c0ddd8c3a6 ("ip6_tunnel: be careful when accessing the inner header") and commit ccfec9e5cb2d ("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>
Diffstat (limited to 'net/ipv4/ip_gre.c')
-rw-r--r--net/ipv4/ip_gre.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index c7a7bd58a23c..d1d09f3e5f9e 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -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;