mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
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127 lines
3.4 KiB
Diff
127 lines
3.4 KiB
Diff
From d199fab63c11998a602205f7ee7ff7c05c97164b Mon Sep 17 00:00:00 2001
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From: Eric Dumazet <edumazet@google.com>
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Date: Tue, 14 Feb 2017 09:03:51 -0800
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Subject: packet: fix races in fanout_add()
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Multiple threads can call fanout_add() at the same time.
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We need to grab fanout_mutex earlier to avoid races that could
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lead to one thread freeing po->rollover that was set by another thread.
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Do the same in fanout_release(), for peace of mind, and to help us
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finding lockdep issues earlier.
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Fixes: dc99f600698d ("packet: Add fanout support.")
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Fixes: 0648ab70afe6 ("packet: rollover prepare: per-socket state")
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Signed-off-by: Eric Dumazet <edumazet@google.com>
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Cc: Willem de Bruijn <willemb@google.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/packet/af_packet.c | 55 +++++++++++++++++++++++++++-----------------------
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1 file changed, 30 insertions(+), 25 deletions(-)
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diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
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index d56ee46..0f03f6a 100644
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--- a/net/packet/af_packet.c
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+++ b/net/packet/af_packet.c
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@@ -1619,6 +1619,7 @@ static void fanout_release_data(struct packet_fanout *f)
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static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
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{
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+ struct packet_rollover *rollover = NULL;
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struct packet_sock *po = pkt_sk(sk);
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struct packet_fanout *f, *match;
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u8 type = type_flags & 0xff;
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@@ -1641,23 +1642,28 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
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return -EINVAL;
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}
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+ mutex_lock(&fanout_mutex);
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+
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+ err = -EINVAL;
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if (!po->running)
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- return -EINVAL;
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+ goto out;
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+ err = -EALREADY;
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if (po->fanout)
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- return -EALREADY;
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+ goto out;
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if (type == PACKET_FANOUT_ROLLOVER ||
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(type_flags & PACKET_FANOUT_FLAG_ROLLOVER)) {
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- po->rollover = kzalloc(sizeof(*po->rollover), GFP_KERNEL);
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- if (!po->rollover)
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- return -ENOMEM;
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- atomic_long_set(&po->rollover->num, 0);
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- atomic_long_set(&po->rollover->num_huge, 0);
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- atomic_long_set(&po->rollover->num_failed, 0);
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+ err = -ENOMEM;
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+ rollover = kzalloc(sizeof(*rollover), GFP_KERNEL);
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+ if (!rollover)
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+ goto out;
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+ atomic_long_set(&rollover->num, 0);
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+ atomic_long_set(&rollover->num_huge, 0);
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+ atomic_long_set(&rollover->num_failed, 0);
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+ po->rollover = rollover;
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}
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- mutex_lock(&fanout_mutex);
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match = NULL;
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list_for_each_entry(f, &fanout_list, list) {
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if (f->id == id &&
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@@ -1704,11 +1710,11 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
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}
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}
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out:
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- mutex_unlock(&fanout_mutex);
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- if (err) {
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- kfree(po->rollover);
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+ if (err && rollover) {
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+ kfree(rollover);
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po->rollover = NULL;
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}
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+ mutex_unlock(&fanout_mutex);
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return err;
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}
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@@ -1717,23 +1723,22 @@ static void fanout_release(struct sock *sk)
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struct packet_sock *po = pkt_sk(sk);
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struct packet_fanout *f;
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- f = po->fanout;
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- if (!f)
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- return;
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-
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mutex_lock(&fanout_mutex);
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- po->fanout = NULL;
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+ f = po->fanout;
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+ if (f) {
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+ po->fanout = NULL;
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+
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+ if (atomic_dec_and_test(&f->sk_ref)) {
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+ list_del(&f->list);
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+ dev_remove_pack(&f->prot_hook);
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+ fanout_release_data(f);
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+ kfree(f);
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+ }
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- if (atomic_dec_and_test(&f->sk_ref)) {
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- list_del(&f->list);
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- dev_remove_pack(&f->prot_hook);
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- fanout_release_data(f);
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- kfree(f);
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+ if (po->rollover)
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+ kfree_rcu(po->rollover, rcu);
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}
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mutex_unlock(&fanout_mutex);
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-
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- if (po->rollover)
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- kfree_rcu(po->rollover, rcu);
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}
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static bool packet_extra_vlan_len_allowed(const struct net_device *dev,
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--
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cgit v1.1
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