diff options
| author | Guillaume Nault <gnault@redhat.com> | 2020-10-02 22:53:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-14 11:33:06 +0300 |
| commit | a42dbd059ef6616e009d3f9d7e6c92e93d9eb27b (patch) | |
| tree | f29cc0dd57dd043e8cfe1afd67ea2cfe96ef2403 | |
| parent | e39c9eba9bef0e1dd01d744360660873c10d9d3c (diff) | |
| download | linux-a42dbd059ef6616e009d3f9d7e6c92e93d9eb27b.tar.xz | |
net/core: check length before updating Ethertype in skb_mpls_{push,pop}
commit 4296adc3e32f5d544a95061160fe7e127be1b9ff upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/core/skbuff.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 08d9915d50c0..466d6273da9f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5515,7 +5515,7 @@ 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; @@ -5555,7 +5555,7 @@ 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. */ |