From 43c13605bad44b8abbc9776d6e63f62ccb7a47d6 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 3 Dec 2020 10:46:06 +0100 Subject: [PATCH] net: openvswitch: ensure LSE is pullable before reading it when openvswitch is configured to mangle the LSE, the current value is read from the packet dereferencing 4 bytes at mpls_hdr(): ensure that the label is contained in the skb "linear" area. Found by code inspection. Fixes: d27cf5c59a12 ("net: core: add MPLS update core helper and use in OvS") Signed-off-by: Davide Caratti Link: https://lore.kernel.org/r/aa099f245d93218b84b5c056b67b6058ccf81a66.1606987185.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski --- net/openvswitch/actions.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 5829a020b81c..c3a664871cb5 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -199,6 +199,9 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key, __be32 lse; int err; + if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN)) + return -ENOMEM; + stack = mpls_hdr(skb); lse = OVS_MASKED(stack->label_stack_entry, *mpls_lse, *mask); err = skb_mpls_update_lse(skb, lse);