4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Tobias Brunner <[email protected]> commit 6916fb3b10b3cbe3b1f9f5b680675f53e4e299eb upstream. Whenever thresholds are changed the hash tables are rebuilt. This is done by enumerating all policies and hashing and inserting them into the right table according to the thresholds and direction. Because socket policies are also contained in net->xfrm.policy_all but no hash tables are defined for their direction (dir + XFRM_POLICY_MAX) this causes a NULL or invalid pointer dereference after returning from policy_hash_bysel() if the rebuild is done while any socket policies are installed. Since the rebuild after changing thresholds is scheduled this crash could even occur if the userland sets thresholds seemingly before installing any socket policies. Fixes: 53c2e285f970 ("xfrm: Do not hash socket policies") Signed-off-by: Tobias Brunner <[email protected]> Acked-by: Herbert Xu <[email protected]> Signed-off-by: Steffen Klassert <[email protected]> Cc: Zubin Mithra <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/xfrm/xfrm_policy.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -626,6 +626,10 @@ static void xfrm_hash_rebuild(struct wor /* re-insert all policies by order of creation */ list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) { + if (xfrm_policy_id2dir(policy->index) >= XFRM_POLICY_MAX) { + /* skip socket policies */ + continue; + } newpos = NULL; chain = policy_hash_bysel(net, &policy->selector, policy->family,
