net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache, and the lwtunnel state will never be freed. Discovered by the ioam6.sh test, kmemleak was recently fixed to catch per-cpu memory leaks. I'm not sure if rpl and seg6 can actually hit this, but in principle I don't see why not.

References

• https://git.kernel.org/stable/c/5ab11a4e219e93b8b31a27f8ec98d42afadd8b7a
• https://git.kernel.org/stable/c/4c0f200c7d06fedddde82209c099014d63f4a6c0
• https://git.kernel.org/stable/c/92191dd1073088753821b862b791dcc83e558e07