diff options
| author | Willem de Bruijn <willemb@google.com> | 2018-12-30 17:24:36 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-01 12:05:02 -0800 |
| commit | cb9f1b783850b14cbd7f87d061d784a666dfba1f (patch) | |
| tree | 652c378230eed5add180c8fec9787db540b32e97 /net/ipv6/ip6_tunnel.c | |
| parent | 8c76e77f9069f10505c08e02646c3ee11ad79038 (diff) | |
| download | linux-cb9f1b783850b14cbd7f87d061d784a666dfba1f.tar.bz2 | |
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/ipv6/ip6_tunnel.c')
| -rw-r--r-- | net/ipv6/ip6_tunnel.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 99179b9c8384..0c6403cf8b52 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1243,10 +1243,6 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) u8 tproto; int err; - /* ensure we can access the full inner ip header */ - if (!pskb_may_pull(skb, sizeof(struct iphdr))) - return -1; - iph = ip_hdr(skb); memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); @@ -1321,9 +1317,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) u8 tproto; int err; - if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) - return -1; - ipv6h = ipv6_hdr(skb); tproto = READ_ONCE(t->parms.proto); if ((tproto != IPPROTO_IPV6 && tproto != 0) || @@ -1405,6 +1398,9 @@ ip6_tnl_start_xmit(struct sk_buff *skb, struct net_device *dev) struct net_device_stats *stats = &t->dev->stats; int ret; + if (!pskb_inet_may_pull(skb)) + goto tx_err; + switch (skb->protocol) { case htons(ETH_P_IP): ret = ip4ip6_tnl_xmit(skb, dev); |