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authorWillem de Bruijn <willemb@google.com>2018-12-30 17:24:36 -0500
committerDavid S. Miller <davem@davemloft.net>2019-01-01 12:05:02 -0800
commitcb9f1b783850b14cbd7f87d061d784a666dfba1f (patch)
tree652c378230eed5add180c8fec9787db540b32e97 /include/net
parent8c76e77f9069f10505c08e02646c3ee11ad79038 (diff)
downloadlinux-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 'include/net')
-rw-r--r--include/net/ip_tunnels.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index cbcf35ce1b14..34f019650941 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -308,6 +308,26 @@ int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *op,
int ip_tunnel_encap_setup(struct ip_tunnel *t,
struct ip_tunnel_encap *ipencap);
+static inline bool pskb_inet_may_pull(struct sk_buff *skb)
+{
+ int nhlen;
+
+ switch (skb->protocol) {
+#if IS_ENABLED(CONFIG_IPV6)
+ case htons(ETH_P_IPV6):
+ nhlen = sizeof(struct ipv6hdr);
+ break;
+#endif
+ case htons(ETH_P_IP):
+ nhlen = sizeof(struct iphdr);
+ break;
+ default:
+ nhlen = 0;
+ }
+
+ return pskb_network_may_pull(skb, nhlen);
+}
+
static inline int ip_encap_hlen(struct ip_tunnel_encap *e)
{
const struct ip_tunnel_encap_ops *ops;