From 4dcb31d4649df36297296b819437709f5407059c Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 14 Mar 2018 09:04:16 -0700
Subject: net: use skb_to_full_sk() in skb_update_prio()
Andrei Vagin reported a KASAN: slab-out-of-bounds error in
skb_update_prio()
Since SYNACK might be attached to a request socket, we need to
get back to the listener socket.
Since this listener is manipulated without locks, add const
qualifiers to sock_cgroup_prioidx() so that the const can also
be used in skb_update_prio()
Also add the const qualifier to sock_cgroup_classid() for consistency.
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/dev.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
(limited to 'net/core/dev.c')
diff --git a/net/core/dev.c b/net/core/dev.c
index 2cedf520cb28..12be20535714 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3278,15 +3278,23 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
static void skb_update_prio(struct sk_buff *skb)
{
- struct netprio_map *map = rcu_dereference_bh(skb->dev->priomap);
+ const struct netprio_map *map;
+ const struct sock *sk;
+ unsigned int prioidx;
- if (!skb->priority && skb->sk && map) {
- unsigned int prioidx =
- sock_cgroup_prioidx(&skb->sk->sk_cgrp_data);
+ if (skb->priority)
+ return;
+ map = rcu_dereference_bh(skb->dev->priomap);
+ if (!map)
+ return;
+ sk = skb_to_full_sk(skb);
+ if (!sk)
+ return;
- if (prioidx < map->priomap_len)
- skb->priority = map->priomap[prioidx];
- }
+ prioidx = sock_cgroup_prioidx(&sk->sk_cgrp_data);
+
+ if (prioidx < map->priomap_len)
+ skb->priority = map->priomap[prioidx];
}
#else
#define skb_update_prio(skb)
--
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