6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Justin Iurman justin.iurman@uliege.be
[ Upstream commit 3e7a60b368eadf6c30a4a79dea1eb8f88b6d620d ]
Fix the lwtunnel_output() reentry loop in ioam6_iptunnel when the destination is the same after transformation. Note that a check on the destination address was already performed, but it was not enough. This is the example of a lwtunnel user taking care of loops without relying only on the last resort detection offered by lwtunnel.
Fixes: 8cb3bf8bff3c ("ipv6: ioam: Add support for the ip6ip6 encapsulation") Signed-off-by: Justin Iurman justin.iurman@uliege.be Link: https://patch.msgid.link/20250314120048.12569-3-justin.iurman@uliege.be Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv6/ioam6_iptunnel.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c index 4215cebe7d85a..647dd8417c6cf 100644 --- a/net/ipv6/ioam6_iptunnel.c +++ b/net/ipv6/ioam6_iptunnel.c @@ -339,7 +339,6 @@ static int ioam6_do_encap(struct net *net, struct sk_buff *skb, static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) { struct dst_entry *dst = skb_dst(skb), *cache_dst = NULL; - struct in6_addr orig_daddr; struct ioam6_lwt *ilwt; int err = -EINVAL; u32 pkt_cnt; @@ -354,8 +353,6 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) if (pkt_cnt % ilwt->freq.n >= ilwt->freq.k) goto out;
- orig_daddr = ipv6_hdr(skb)->daddr; - local_bh_disable(); cache_dst = dst_cache_get(&ilwt->cache); local_bh_enable(); @@ -424,7 +421,10 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) goto drop; }
- if (!ipv6_addr_equal(&orig_daddr, &ipv6_hdr(skb)->daddr)) { + /* avoid lwtunnel_output() reentry loop when destination is the same + * after transformation (e.g., with the inline mode) + */ + if (dst->lwtstate != cache_dst->lwtstate) { skb_dst_drop(skb); skb_dst_set(skb, cache_dst); return dst_output(net, sk, skb);