From: Martin KaFai Lau <kafai@xxxxxx>
commit 4ac30c4b3659efac031818c418beb51e630d512d upstream.
__udp6_lib_err() may be called when handling icmpv6 message. For example,
the icmpv6 toobig(type=2). __udp6_lib_lookup() is then called
which may call reuseport_select_sock(). reuseport_select_sock() will
call into a bpf_prog (if there is one).
reuseport_select_sock() is expecting the skb->data pointing to the
transport header (udphdr in this case). For example, run_bpf_filter()
is pulling the transport header.
However, in the __udp6_lib_err() path, the skb->data is pointing to the
ipv6hdr instead of the udphdr.
One option is to pull and push the ipv6hdr in __udp6_lib_err().
Instead of doing this, this patch follows how the original
commit 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF")
was done in IPv4, which has passed a NULL skb pointer to
reuseport_select_sock().
Fixes: 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF")
Cc: Craig Gallek <kraig@xxxxxxxxxx>
Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
Acked-by: Craig Gallek <kraig@xxxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/udp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -482,7 +482,7 @@ void __udp6_lib_err(struct sk_buff *skb,
struct net *net = dev_net(skb->dev);
sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
- inet6_iif(skb), 0, udptable, skb);
+ inet6_iif(skb), 0, udptable, NULL);
if (!sk) {
__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
ICMP6_MIB_INERRORS);
