[PATCH net-next v4 1/7] ipv6: Check of max HBH or DestOp sysctl is zero and drop if it is
From: Tom Herbert <hidden>
Date: 2026-01-21 21:49:50
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
In IPv6 Destination options processing function check if net->ipv6.sysctl.max_dst_opts_cnt is zero up front. If it is zero then drop the packet since Destination Options processing is disabled. Similarly, in IPv6 hop-by-hop options processing function check if net->ipv6.sysctl.max_hbh_opts_cnt is zero up front. If it is zero then drop the packet since Hop-by-Hop Options processing is disabled. Signed-off-by: Tom Herbert <redacted> --- net/ipv6/exthdrs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 54088fa0c09d..45bbad76f5de 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c@@ -303,7 +303,8 @@ static int ipv6_destopt_rcv(struct sk_buff *skb) struct net *net = dev_net(skb->dev); int extlen; - if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || + if (!net->ipv6.sysctl.max_dst_opts_cnt || + !pskb_may_pull(skb, skb_transport_offset(skb) + 8) || !pskb_may_pull(skb, (skb_transport_offset(skb) + ((skb_transport_header(skb)[1] + 1) << 3)))) { __IP6_INC_STATS(dev_net(dst_dev(dst)), idev,
@@ -1041,7 +1042,8 @@ int ipv6_parse_hopopts(struct sk_buff *skb) * sizeof(struct ipv6hdr) by definition of * hop-by-hop options. */ - if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || + if (!net->ipv6.sysctl.max_hbh_opts_cnt || + !pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + ((skb_transport_header(skb)[1] + 1) << 3)))) { fail_and_free:
--
2.43.0