Now we will force to do garbage collection if any policy removed in
xfrm_policy_flush(). But during xfrm_net_exit(). We call flow_cache_fini()
first and set set fc->percpu to NULL. Then after we call xfrm_policy_fini()
-> frxm_policy_flush() -> flow_cache_flush(), we will get NULL pointer
dereference when check percpu_empty. The code path looks like:
flow_cache_fini()
- fc->percpu = NULL
xfrm_policy_fini()
- xfrm_policy_flush()
- xfrm_garbage_collect()
- flow_cache_flush()
- flow_cache_percpu_empty()
- fcp = per_cpu_ptr(fc->percpu, cpu)
To reproduce, just add ipsec in netns and then remove the netns.
v2:
As Xin Long suggested, since only two other places need to call it. move
xfrm_garbage_collect() outside xfrm_policy_flush().
v3:
Fix subject mismatch after v2 fix.
Fixes: 35db069121 ("xfrm: do the garbage collection after flushing policy")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
138437f591