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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 /net/ipv6/ip6_gre.c
parent8c76e77f9069f10505c08e02646c3ee11ad79038 (diff)
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_gre.c')
-rw-r--r--net/ipv6/ip6_gre.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 229e55c99021..09d0826742f8 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -881,6 +881,9 @@ static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,
struct net_device_stats *stats = &t->dev->stats;
int ret;
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))
goto tx_err;
@@ -923,6 +926,9 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
int nhoff;
int thoff;
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))
goto tx_err;
@@ -995,8 +1001,6 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
goto tx_err;
}
} else {
- struct ipv6hdr *ipv6h = ipv6_hdr(skb);
-
switch (skb->protocol) {
case htons(ETH_P_IP):
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -1004,7 +1008,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
&dsfield, &encap_limit);
break;
case htons(ETH_P_IPV6):
- if (ipv6_addr_equal(&t->parms.raddr, &ipv6h->saddr))
+ if (ipv6_addr_equal(&t->parms.raddr, &ipv6_hdr(skb)->saddr))
goto tx_err;
if (prepare_ip6gre_xmit_ipv6(skb, dev, &fl6,
&dsfield, &encap_limit))