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authorSabrina Dubroca <sd@queasysnail.net>2020-07-03 16:57:09 +0200
committerSteffen Klassert <steffen.klassert@secunet.com>2020-07-07 08:19:46 +0200
commit17175d1a27c618e214555b91eca8a0be4cf07f45 (patch)
treee59787c4d3b5ff06dda4f562cc5d0530b71cc26c /net/ipv6/esp6.c
parent4f47e8ab6ab796b5380f74866fa5287aca4dcc58 (diff)
xfrm: esp6: fix encapsulation header offset computation
In commit 0146dca70b87, I incorrectly adapted the code that computes the location of the UDP or TCP encapsulation header from IPv4 to IPv6. In esp6_input_done2, skb->transport_header points to the ESP header, so by adding skb_network_header_len, uh and th will point to the ESP header, not the encapsulation header that's in front of it. Since the TCP header's size can change with options, we have to start from the IPv6 header and walk past possible extensions. Fixes: 0146dca70b87 ("xfrm: add support for UDPv6 encapsulation of ESP") Fixes: 26333c37fc28 ("xfrm: add IPv6 support for espintcp") Reported-by: Tobias Brunner <tobias@strongswan.org> Tested-by: Tobias Brunner <tobias@strongswan.org> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/ipv6/esp6.c')
-rw-r--r--net/ipv6/esp6.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index c43592771126..55ae70be91b3 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -805,10 +805,16 @@ int esp6_input_done2(struct sk_buff *skb, int err)
if (x->encap) {
const struct ipv6hdr *ip6h = ipv6_hdr(skb);
+ int offset = skb_network_offset(skb) + sizeof(*ip6h);
struct xfrm_encap_tmpl *encap = x->encap;
- struct udphdr *uh = (void *)(skb_network_header(skb) + hdr_len);
- struct tcphdr *th = (void *)(skb_network_header(skb) + hdr_len);
- __be16 source;
+ u8 nexthdr = ip6h->nexthdr;
+ __be16 frag_off, source;
+ struct udphdr *uh;
+ struct tcphdr *th;
+
+ offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
+ uh = (void *)(skb->data + offset);
+ th = (void *)(skb->data + offset);
switch (x->encap->encap_type) {
case TCP_ENCAP_ESPINTCP: