[PATCH 4.19 152/421] ipv6: exthdrs: do not blindly use init_net

Greg Kroah-Hartman
2021-07-19T16:17:43Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit bcc3f2a829b9edbe3da5fb117ee5a63686d31834 ]

I see no reason why max_dst_opts_cnt and max_hbh_opts_cnt
are fetched from the initial net namespace.

The other sysctls (max_dst_opts_len & max_hbh_opts_len)
are in fact already using the current ns.

Note: it is not clear why ipv6_destopt_rcv() use two ways to
get to the netns :

1) dev_net(dst->dev)
Originally used to increment IPSTATS_MIB_INHDRERRORS

2) dev_net(skb->dev)
Tom used this variant in his patch.

Maybe this calls to use ipv6_skb_net() instead ?

Fixes: 47d3d7ac656a ("ipv6: Implement limits on Hop-by-Hop and Destination options")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@quantonium.net>
Cc: Coco Li <lixiaoyan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv6/exthdrs.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 20291c2036fc..68b8084da83a 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -309,7 +309,7 @@ fail_and_free:
#endif

if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
- init_net.ipv6.sysctl.max_dst_opts_cnt)) {
+ net->ipv6.sysctl.max_dst_opts_cnt)) {
skb->transport_header += extlen;
opt = IP6CB(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
@@ -848,7 +848,7 @@ fail_and_free:

opt->flags |= IP6SKB_HOPBYHOP;
if (ip6_parse_tlv(tlvprochopopt_lst, skb,
- init_net.ipv6.sysctl.max_hbh_opts_cnt)) {
+ net->ipv6.sysctl.max_hbh_opts_cnt)) {
skb->transport_header += extlen;
opt = IP6CB(skb);
opt->nhoff = sizeof(struct ipv6hdr);
--
2.30.2