net/sched: act_mirred: don't override retval if we already lost the skb
commit 166c2c8a6a4dc2e4ceba9e10cfe81c3e469e3210 upstream.
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.
BUG=b/388468765
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-26739 in the Linux kernel.
cos-patch: security-high
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Fixes: e5cf1baf92cb ("act_mirred: use TC_ACT_REINSERT when possible")
Change-Id: I90196ae07bd418fabc95f98c74259938e577fb01
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>
[Minor conflict resolved due to code context change.]
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/101547
Reviewed-by: Michael Kochera <kochera@google.com>
Reviewed-by: Anil Altinay <aaltinay@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 36395e5..bbc3498 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -255,31 +255,31 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
m_eaction = READ_ONCE(m->tcfm_eaction);
+ is_redirect = tcf_mirred_is_act_redirect(m_eaction);
retval = READ_ONCE(m->tcf_action);
dev = rcu_dereference_bh(m->tcfm_dev);
if (unlikely(!dev)) {
pr_notice_once("tc mirred: target device is gone\n");
- goto out;
+ goto err_cant_do;
}
if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {
net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
dev->name);
- goto out;
+ goto err_cant_do;
}
/* we could easily avoid the clone only if called by ingress and clsact;
* since we can't easily detect the clsact caller, skip clone only for
* ingress - that covers the TC S/W datapath.
*/
- is_redirect = tcf_mirred_is_act_redirect(m_eaction);
at_ingress = skb_at_tc_ingress(skb);
use_reinsert = at_ingress && is_redirect &&
tcf_mirred_can_reinsert(retval);
if (!use_reinsert) {
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
- goto out;
+ goto err_cant_do;
}
want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
@@ -321,12 +321,16 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
}
err = tcf_mirred_forward(want_ingress, skb2);
- if (err) {
-out:
+ if (err)
tcf_action_inc_overlimit_qstats(&m->common);
- if (tcf_mirred_is_act_redirect(m_eaction))
- retval = TC_ACT_SHOT;
- }
+ __this_cpu_dec(mirred_nest_level);
+
+ return retval;
+
+err_cant_do:
+ if (is_redirect)
+ retval = TC_ACT_SHOT;
+ tcf_action_inc_overlimit_qstats(&m->common);
__this_cpu_dec(mirred_nest_level);
return retval;
