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authorGuillaume Nault <gnault@redhat.com>2020-10-02 21:53:08 +0200
committerDavid S. Miller <davem@davemloft.net>2020-10-04 15:09:26 -0700
commit4296adc3e32f5d544a95061160fe7e127be1b9ff (patch)
tree2f43479d747def5e6782893e35dbf998b6e2a4ea /net
parentf4544e5361da5050ff5c0330ceea095cb5dbdd72 (diff)
net/core: check length before updating Ethertype in skb_mpls_{push,pop}
Openvswitch allows to drop a packet's Ethernet header, therefore skb_mpls_push() and skb_mpls_pop() might be called with ethernet=true and mac_len=0. In that case the pointer passed to skb_mod_eth_type() doesn't point to an Ethernet header and the new Ethertype is written at unexpected locations. Fix this by verifying that mac_len is big enough to contain an Ethernet header. Fixes: fa4e0f8855fc ("net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions") Signed-off-by: Guillaume Nault <gnault@redhat.com> Acked-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 6faf73d6a0f7..2b48cb0cc684 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5622,7 +5622,7 @@ int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
lse->label_stack_entry = mpls_lse;
skb_postpush_rcsum(skb, lse, MPLS_HLEN);
- if (ethernet)
+ if (ethernet && mac_len >= ETH_HLEN)
skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);
skb->protocol = mpls_proto;
@@ -5662,7 +5662,7 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
skb_reset_mac_header(skb);
skb_set_network_header(skb, mac_len);
- if (ethernet) {
+ if (ethernet && mac_len >= ETH_HLEN) {
struct ethhdr *hdr;
/* use mpls_hdr() to get ethertype to account for VLANs. */