From: Davide Caratti Date: Thu, 3 Dec 2020 09:46:06 +0000 (+0100) Subject: net: openvswitch: ensure LSE is pullable before reading it X-Git-Tag: v5.9.13~13 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=44a0f9f84d690d0c06e9a4c0c44d1f3760f00a61;p=thirdparty%2Fkernel%2Fstable.git net: openvswitch: ensure LSE is pullable before reading it [ Upstream commit 43c13605bad44b8abbc9776d6e63f62ccb7a47d6 ] 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index b41698d5cf332..90bebf685aaa3 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -200,6 +200,9 @@ 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);