Skip to content

[lts8_6] CVE-2025-38000 and its bfs #801

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
roxanan1996 merged 8 commits into from
Jan 13, 2026
+35 −38
Merged

[lts8_6] CVE-2025-38000 and its bfs #801

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
ccb65ca
sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()
roxanan1996 Dec 5, 2025
d7dfc52
net/sched: Always pass notifications when child class becomes empty
roxanan1996 Dec 9, 2025
0a7465a
net_sched: sch_ets: implement lockless ets_dump()
roxanan1996 Dec 9, 2025
d82b055
sch_ets: make est_qlen_notify() idempotent
roxanan1996 Dec 9, 2025
f2faedf
net: sched: tbf: don't call qdisc_put() while holding tree lock
roxanan1996 Dec 9, 2025
d8a3091
net_sched: tbf: fix a race in tbf_change()
roxanan1996 Dec 9, 2025
5c6a24d
net_sched: ets: fix a race in ets_qdisc_change()
roxanan1996 Dec 9, 2025
8cb9852
net/sched: ets: use old 'nbands' while purging unused classes
roxanan1996 Dec 9, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 5 additions & 14 deletions net/sched/sch_api.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -767,15 +767,12 @@ static u32 qdisc_alloc_handle(struct net_device *dev)

void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
{
bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
const struct Qdisc_class_ops *cops;
unsigned long cl;
u32 parentid;
bool notify;
int drops;

if (n == 0 && len == 0)
return;
drops = max_t(int, n, 0);
rcu_read_lock();
while ((parentid = sch->parent)) {
Expand All @@ -784,17 +781,8 @@ void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)

if (sch->flags & TCQ_F_NOPARENT)
break;
/* Notify parent qdisc only if child qdisc becomes empty.
*
* If child was empty even before update then backlog
* counter is screwed and we skip notification because
* parent class is already passive.
*
* If the original child was offloaded then it is allowed
* to be seem as empty, so the parent is notified anyway.
*/
notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
!qdisc_is_offloaded);
/* Notify parent qdisc only if child qdisc becomes empty. */
notify = !sch->q.qlen;
/* TODO: perform the search on a per txq basis */
sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
if (sch == NULL) {
Expand All @@ -803,6 +791,9 @@ void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
}
cops = sch->ops->cl_ops;
if (notify && cops->qlen_notify) {
/* Note that qlen_notify must be idempotent as it may get called
* multiple times.
*/
cl = cops->find(sch, parentid);
cops->qlen_notify(sch, cl);
}
Expand Down
42 changes: 23 additions & 19 deletions net/sched/sch_ets.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -296,7 +296,7 @@ static void ets_class_qlen_notify(struct Qdisc *sch, unsigned long arg)
* to remove them.
*/
if (!ets_class_is_strict(q, cl) && sch->q.qlen)
list_del(&cl->alist);
list_del_init(&cl->alist);
}

static int ets_class_dump(struct Qdisc *sch, unsigned long arg,
Expand Down Expand Up @@ -497,7 +497,7 @@ static struct sk_buff *ets_qdisc_dequeue(struct Qdisc *sch)
if (unlikely(!skb))
goto out;
if (cl->qdisc->q.qlen == 0)
list_del(&cl->alist);
list_del_init(&cl->alist);
return ets_qdisc_dequeue_skb(sch, skb);
}

Expand Down Expand Up @@ -662,23 +662,24 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,

sch_tree_lock(sch);

q->nbands = nbands;
for (i = nbands; i < oldbands; i++) {
if (i >= q->nstrict && q->classes[i].qdisc->q.qlen)
list_del_init(&q->classes[i].alist);
qdisc_purge_queue(q->classes[i].qdisc);
}

WRITE_ONCE(q->nbands, nbands);
for (i = nstrict; i < q->nstrict; i++) {
if (q->classes[i].qdisc->q.qlen) {
list_add_tail(&q->classes[i].alist, &q->active);
q->classes[i].deficit = quanta[i];
}
}
for (i = q->nbands; i < oldbands; i++) {
if (i >= q->nstrict && q->classes[i].qdisc->q.qlen)
list_del(&q->classes[i].alist);
qdisc_tree_flush_backlog(q->classes[i].qdisc);
}
q->nstrict = nstrict;
WRITE_ONCE(q->nstrict, nstrict);
memcpy(q->prio2band, priomap, sizeof(priomap));

for (i = 0; i < q->nbands; i++)
q->classes[i].quantum = quanta[i];
WRITE_ONCE(q->classes[i].quantum, quanta[i]);

for (i = oldbands; i < q->nbands; i++) {
q->classes[i].qdisc = queues[i];
Expand All @@ -692,7 +693,7 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
for (i = q->nbands; i < oldbands; i++) {
qdisc_put(q->classes[i].qdisc);
q->classes[i].qdisc = NULL;
q->classes[i].quantum = 0;
WRITE_ONCE(q->classes[i].quantum, 0);
q->classes[i].deficit = 0;
memset(&q->classes[i].bstats, 0, sizeof(q->classes[i].bstats));
memset(&q->classes[i].qstats, 0, sizeof(q->classes[i].qstats));
Expand Down Expand Up @@ -727,7 +728,7 @@ static void ets_qdisc_reset(struct Qdisc *sch)

for (band = q->nstrict; band < q->nbands; band++) {
if (q->classes[band].qdisc->q.qlen)
list_del(&q->classes[band].alist);
list_del_init(&q->classes[band].alist);
}
for (band = 0; band < q->nbands; band++)
qdisc_reset(q->classes[band].qdisc);
Expand All @@ -749,6 +750,7 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
struct ets_sched *q = qdisc_priv(sch);
struct nlattr *opts;
struct nlattr *nest;
u8 nbands, nstrict;
int band;
int prio;
int err;
Expand All @@ -761,21 +763,22 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
if (!opts)
goto nla_err;

if (nla_put_u8(skb, TCA_ETS_NBANDS, q->nbands))
nbands = READ_ONCE(q->nbands);
if (nla_put_u8(skb, TCA_ETS_NBANDS, nbands))
goto nla_err;

if (q->nstrict &&
nla_put_u8(skb, TCA_ETS_NSTRICT, q->nstrict))
nstrict = READ_ONCE(q->nstrict);
if (nstrict && nla_put_u8(skb, TCA_ETS_NSTRICT, nstrict))
goto nla_err;

if (q->nbands > q->nstrict) {
if (nbands > nstrict) {
nest = nla_nest_start(skb, TCA_ETS_QUANTA);
if (!nest)
goto nla_err;

for (band = q->nstrict; band < q->nbands; band++) {
for (band = nstrict; band < nbands; band++) {
if (nla_put_u32(skb, TCA_ETS_QUANTA_BAND,
q->classes[band].quantum))
READ_ONCE(q->classes[band].quantum)))
goto nla_err;
}

Expand All @@ -787,7 +790,8 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
goto nla_err;

for (prio = 0; prio <= TC_PRIO_MAX; prio++) {
if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND, q->prio2band[prio]))
if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND,
READ_ONCE(q->prio2band[prio])))
goto nla_err;
}

Expand Down
6 changes: 3 additions & 3 deletions net/sched/sch_hfsc.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1579,6 +1579,9 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
return err;
}

sch->qstats.backlog += len;
sch->q.qlen++;

if (first && !cl_in_el_or_vttree(cl)) {
if (cl->cl_flags & HFSC_RSC)
init_ed(cl, len);
Expand All @@ -1594,9 +1597,6 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)

}

sch->qstats.backlog += len;
sch->q.qlen++;

return NET_XMIT_SUCCESS;
}

Expand Down
6 changes: 4 additions & 2 deletions net/sched/sch_tbf.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -345,6 +345,7 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt,
struct nlattr *tb[TCA_TBF_MAX + 1];
struct tc_tbf_qopt *qopt;
struct Qdisc *child = NULL;
struct Qdisc *old = NULL;
struct psched_ratecfg rate;
struct psched_ratecfg peak;
u64 max_size;
Expand Down Expand Up @@ -435,8 +436,8 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt,

sch_tree_lock(sch);
if (child) {
qdisc_tree_flush_backlog(q->qdisc);
qdisc_put(q->qdisc);
qdisc_purge_queue(q->qdisc);
old = q->qdisc;
q->qdisc = child;
}
q->limit = qopt->limit;
Expand All @@ -456,6 +457,7 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt,
memcpy(&q->peak, &peak, sizeof(struct psched_ratecfg));

sch_tree_unlock(sch);
qdisc_put(old);
err = 0;

tbf_offload_change(sch);
Expand Down