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authorEric Dumazet <edumazet@google.com>2017-10-08 21:44:52 -0700
committerDavid S. Miller <davem@davemloft.net>2017-10-09 20:55:01 -0700
commitfbb1fb4ad415cb31ce944f65a5ca700aaf73a227 (patch)
treea7b1d3fddab2353229b73daaa103904ce539414d /net/core
parent9f1c2674b328a69ab5a9b5a1c52405795ee4163f (diff)
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 <edumazet@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/sock.c3
1 files changed, 1 insertions, 2 deletions
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)