diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2019-09-28 02:00:31 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-10-01 03:13:43 +0300 |
| commit | 8c7138b33e5c690c308b2a7085f6313fdcb3f616 (patch) | |
| tree | 7b75bde03bddc203db1a1b91f90f0b09fdf5ccd1 /net | |
| parent | 0e141f757b2c78c983df893e9993313e2dc21e38 (diff) | |
| download | linux-8c7138b33e5c690c308b2a7085f6313fdcb3f616.tar.xz | |
net: Unpublish sk from sk_reuseport_cb before call_rcu
The "reuse->sock[]" array is shared by multiple sockets. The going away
sk must unpublish itself from "reuse->sock[]" before making call_rcu()
call. However, this unpublish-action is currently done after a grace
period and it may cause use-after-free.
The fix is to move reuseport_detach_sock() to sk_destruct().
Due to the above reason, any socket with sk_reuseport_cb has
to go through the rcu grace period before freeing it.
It is a rather old bug (~3 yrs). The Fixes tag is not necessary
the right commit but it is the one that introduced the SOCK_RCU_FREE
logic and this fix is depending on it.
Fixes: a4298e4522d6 ("net: add SOCK_RCU_FREE socket flag")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/sock.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index 07863edbe6fc..e23ec80a67bf 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1700,8 +1700,6 @@ static void __sk_destruct(struct rcu_head *head) sk_filter_uncharge(sk, filter); RCU_INIT_POINTER(sk->sk_filter, NULL); } - if (rcu_access_pointer(sk->sk_reuseport_cb)) - reuseport_detach_sock(sk); sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP); @@ -1728,7 +1726,14 @@ static void __sk_destruct(struct rcu_head *head) void sk_destruct(struct sock *sk) { - if (sock_flag(sk, SOCK_RCU_FREE)) + bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE); + + if (rcu_access_pointer(sk->sk_reuseport_cb)) { + reuseport_detach_sock(sk); + use_call_rcu = true; + } + + if (use_call_rcu) call_rcu(&sk->sk_rcu, __sk_destruct); else __sk_destruct(&sk->sk_rcu); |