[PATCH net v3 2/2] net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0
From: Balazs Nemeth <hidden>
Date: 2021-03-09 11:32:40
Also in:
lkml
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
A packet with skb_inner_network_header(skb) == skb_network_header(skb) and ETH_P_MPLS_UC will prevent mpls_gso_segment from pulling any headers from the packet. Subsequently, the call to skb_mac_gso_segment will again call mpls_gso_segment with the same packet leading to an infinite loop. In addition, ensure that the header length is a multiple of four, which should hold irrespective of the number of stacked labels. Signed-off-by: Balazs Nemeth <redacted> --- net/mpls/mpls_gso.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c
index b1690149b6fa..1482259de9b5 100644
--- a/net/mpls/mpls_gso.c
+++ b/net/mpls/mpls_gso.c@@ -14,6 +14,7 @@ #include <linux/netdev_features.h> #include <linux/netdevice.h> #include <linux/skbuff.h> +#include <net/mpls.h> static struct sk_buff *mpls_gso_segment(struct sk_buff *skb, netdev_features_t features)
@@ -27,6 +28,8 @@ static struct sk_buff *mpls_gso_segment(struct sk_buff *skb, skb_reset_network_header(skb); mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb); + if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN)) + goto out; if (unlikely(!pskb_may_pull(skb, mpls_hlen))) goto out;
--
2.29.2