From: Davide Caratti dcaratti@redhat.com
[ Upstream commit 9608fa653059c3f72faab0c148ac8773c46e7314 ]
when 'act_mpls' is used 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.
v2: - use MPLS_HLEN instead of sizeof(new_lse), thanks to Jakub Kicinski
Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC") Signed-off-by: Davide Caratti dcaratti@redhat.com Acked-by: Guillaume Nault gnault@redhat.com Link: https://lore.kernel.org/r/3243506cba43d14858f3bd21ee0994160e44d64a.160698705... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_mpls.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/net/sched/act_mpls.c +++ b/net/sched/act_mpls.c @@ -88,6 +88,9 @@ static int tcf_mpls_act(struct sk_buff * goto drop; break; case TCA_MPLS_ACT_MODIFY: + if (!pskb_may_pull(skb, + skb_network_offset(skb) + MPLS_HLEN)) + goto drop; new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false); if (skb_mpls_update_lse(skb, new_lse)) goto drop;