APPLIED: [SRU][F/J/O][PATCH 0/1] CVE-2025-21703

[Koichiro Den]

On Tue, Mar 04, 2025 at 11:20:41AM GMT, Tim Whisonant wrote:
> [Impact]
> 
> netem: Update sch->q.qlen before qdisc_tree_reduce_backlog()
> 
> qdisc_tree_reduce_backlog() notifies parent qdisc only if child
> qdisc becomes empty, therefore we need to reduce the backlog of the
> child qdisc before calling it. Otherwise it would miss the opportunity
> to call cops->qlen_notify(), in the case of DRR, it resulted in UAF
> since DRR uses ->qlen_notify() to maintain its active list.
> 
> [Cherry Pick]
> 
> Cherry picked from upstream.
> 
> [Fix]
> 
> Oracular: cherry picked from upstream
> Noble:    not affected
> Jammy:    cherry picked from upstream
> Focal:    cherry picked from upstream
> Bionic:   not affected
> Xenial:   not affected
> Trusty:   not affected
> 
> [Test Plan]
> 
> Compile and boot tested.
> 
> [Where problems could occur]
> 
> The change affects the core network logic. Problems might manifest as
> anomalies in the queuing discipline backlog processing.
> 
> Cong Wang (1):
>   netem: Update sch->q.qlen before qdisc_tree_reduce_backlog()
> 
>  net/sched/sch_netem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Applied to oracular:linux, jammy:linux, focal:linux master-next branches.
Thanks!