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Message-ID: <20240215143346.1715054-2-kuba@kernel.org>
Date: Thu, 15 Feb 2024 06:33:46 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org,
edumazet@...gle.com,
pabeni@...hat.com,
Jakub Kicinski <kuba@...nel.org>,
Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>,
jhs@...atatu.com,
xiyou.wangcong@...il.com,
jiri@...nulli.us
Subject: [PATCH net v3 2/2] net/sched: act_mirred: don't override retval if we already lost the skb
If we're redirecting the skb, and haven't called tcf_mirred_forward(),
yet, we need to tell the core to drop the skb by setting the retcode
to SHOT. If we have called tcf_mirred_forward(), however, the skb
is out of our hands and returning SHOT will lead to UaF.
Move the retval override to the error path which actually need it.
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
Fixes: e5cf1baf92cb ("act_mirred: use TC_ACT_REINSERT when possible")
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
CC: jhs@...atatu.com
CC: xiyou.wangcong@...il.com
CC: jiri@...nulli.us
---
net/sched/act_mirred.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 291d47c9eb69..6faa7d00da09 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -266,8 +266,7 @@ static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,
if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {
net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
dev->name);
- err = -ENODEV;
- goto out;
+ goto err_cant_do;
}
/* we could easily avoid the clone only if called by ingress and clsact;
@@ -279,10 +278,8 @@ static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,
tcf_mirred_can_reinsert(retval);
if (!dont_clone) {
skb_to_send = skb_clone(skb, GFP_ATOMIC);
- if (!skb_to_send) {
- err = -ENOMEM;
- goto out;
- }
+ if (!skb_to_send)
+ goto err_cant_do;
}
want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
@@ -319,15 +316,16 @@ static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,
} else {
err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
}
-
- if (err) {
-out:
+ if (err)
tcf_action_inc_overlimit_qstats(&m->common);
- if (is_redirect)
- retval = TC_ACT_SHOT;
- }
return retval;
+
+err_cant_do:
+ if (is_redirect)
+ retval = TC_ACT_SHOT;
+ tcf_action_inc_overlimit_qstats(&m->common);
+ return retval;
}
static int tcf_blockcast_redir(struct sk_buff *skb, struct tcf_mirred *m,
--
2.43.0
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