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| author | Willem de Bruijn <willemb@google.com> | 2018-12-30 23:24:36 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-01 21:05:02 +0100 |
| commit | cb9f1b783850b14cbd7f87d061d784a666dfba1f (patch) | |
| tree | 652c378230eed5add180c8fec9787db540b32e97 /net/ipv4/ip_vti.c | |
| parent | tap: call skb_probe_transport_header after setting skb->dev (diff) | |
| download | linux-cb9f1b783850b14cbd7f87d061d784a666dfba1f.tar.xz linux-cb9f1b783850b14cbd7f87d061d784a666dfba1f.zip | |
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_vti.c')
| -rw-r--r-- | net/ipv4/ip_vti.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c index de31b302d69c..d7b43e700023 100644 --- a/net/ipv4/ip_vti.c +++ b/net/ipv4/ip_vti.c @@ -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) |