From fbb1fb4ad415cb31ce944f65a5ca700aaf73a227 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 8 Oct 2017 21:44:52 -0700 Subject: net: defer call to cgroup_sk_alloc() sk_clone_lock() might run while TCP/DCCP listener already vanished. In order to prevent use after free, it is better to defer cgroup_sk_alloc() to the point we know both parent and child exist, and from process context. Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Signed-off-by: Eric Dumazet Cc: Johannes Weiner Cc: Tejun Heo Signed-off-by: David S. Miller --- net/core/sock.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'net/core') diff --git a/net/core/sock.c b/net/core/sock.c index 70c6ccbdf49f..4499e3153813 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1680,6 +1680,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) /* sk->sk_memcg will be populated at accept() time */ newsk->sk_memcg = NULL; + memset(&newsk->sk_cgrp_data, 0, sizeof(newsk->sk_cgrp_data)); atomic_set(&newsk->sk_drops, 0); newsk->sk_send_head = NULL; @@ -1718,8 +1719,6 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) newsk->sk_incoming_cpu = raw_smp_processor_id(); atomic64_set(&newsk->sk_cookie, 0); - cgroup_sk_alloc(&newsk->sk_cgrp_data); - /* * Before updating sk_refcnt, we must commit prior changes to memory * (Documentation/RCU/rculist_nulls.txt for details) -- cgit v1.2.3