From: Christian Eggers <ceggers@arri.de>
To: Andrew Lunn <andrew@lunn.ch>,
Florian Fainelli <f.fainelli@gmail.com>,
Vladimir Oltean <olteanv@gmail.com>
Cc: Vivien Didelot <vivien.didelot@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Christian Eggers <ceggers@arri.de>
Subject: [PATCH net-next] net: dsa: avoid potential use-after-free error
Date: Wed, 18 Nov 2020 16:43:35 +0100 [thread overview]
Message-ID: <20201118154335.1189-1-ceggers@arri.de> (raw)
If dsa_switch_ops::port_txtstamp() returns false, clone will be freed
immediately. Storing the pointer in DSA_SKB_CB(skb)->clone anyway,
supports annoying use-after-free bugs.
Signed-off-by: Christian Eggers <ceggers@arri.de>
Fixes 146d442c2357 ("net: dsa: Keep a pointer to the skb clone for TX timestamping")
---
net/dsa/slave.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index ff2266d2b998..7efc753e4d9d 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -522,10 +522,10 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
if (!clone)
return;
- DSA_SKB_CB(skb)->clone = clone;
-
- if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type))
+ if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type)) {
+ DSA_SKB_CB(skb)->clone = clone;
return;
+ }
kfree_skb(clone);
}
--
Christian Eggers
Embedded software developer
Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler
next reply other threads:[~2020-11-18 15:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 15:43 Christian Eggers [this message]
2020-11-18 23:33 ` [PATCH net-next] net: dsa: avoid potential use-after-free error Vladimir Oltean
2020-11-19 5:27 ` Christian Eggers
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