6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jakub Kicinski kuba@kernel.org
[ Upstream commit 166c2c8a6a4dc2e4ceba9e10cfe81c3e469e3210 ]
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@linux.intel.com Fixes: e5cf1baf92cb ("act_mirred: use TC_ACT_REINSERT when possible") Signed-off-by: Jakub Kicinski kuba@kernel.org Acked-by: Jamal Hadi Salim jhs@mojatatu.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 bab090bb5e80a..674f7ae356ca2 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -240,8 +240,7 @@ 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; @@ -253,10 +252,8 @@ 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); @@ -293,15 +290,16 @@ 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; }
TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,