Subject: [PATCH AUTOSEL 4.19 417/671] bpf: fix the check that forwarding is enabled in bpf_ipv6_fib_lookup

From: Sasha Levin <[email-masked]>
Date: Thu, 16 Jan 2020 12:00:55 -0500

From: Anton Protopopov <[email-masked]>

[ Upstream commit 56f0f84e69c7a7f229dfa524b13b0ceb6ce9b09e ]

The bpf_ipv6_fib_lookup function should return BPF_FIB_LKUP_RET_FWD_DISABLED
when forwarding is disabled for the input device.  However instead of checking
if forwarding is enabled on the input device, it checked the global
net->ipv6.devconf_all->forwarding flag.  Change it to behave as expected.

Fixes: 87f5fc7e48dd ("bpf: Provide helper to do forwarding lookups in kernel FIB table")
Signed-off-by: Anton Protopopov <[email-masked]>
Acked-by: Toke Høiland-Jørgensen <[email-masked]>
Reviewed-by: David Ahern <[email-masked]>
Signed-off-by: Daniel Borkmann <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/core/filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 91b950261975..9daf1a4118b5 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4367,7 +4367,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 		return -ENODEV;
 
 	idev = __in6_dev_get_safely(dev);
-	if (unlikely(!idev || !net->ipv6.devconf_all->forwarding))
+	if (unlikely(!idev || !idev->cnf.forwarding))
 		return BPF_FIB_LKUP_RET_FWD_DISABLED;
 
 	if (flags & BPF_FIB_LOOKUP_OUTPUT) {
-- 
2.20.1