From: Greg Kroah-Hartman Date: Mon, 2 Jun 2025 09:51:52 +0000 (+0200) Subject: 5.4-stable patches X-Git-Tag: v5.4.294~31 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=79f3d482347d7470d49f80caca7f68a1b5f1a11b;p=thirdparty%2Fkernel%2Fstable-queue.git 5.4-stable patches added patches: net_sched-hfsc-address-reentrant-enqueue-adding-class-to-eltree-twice.patch --- diff --git a/queue-5.4/net_sched-hfsc-address-reentrant-enqueue-adding-class-to-eltree-twice.patch b/queue-5.4/net_sched-hfsc-address-reentrant-enqueue-adding-class-to-eltree-twice.patch new file mode 100644 index 0000000000..42dabecb5d --- /dev/null +++ b/queue-5.4/net_sched-hfsc-address-reentrant-enqueue-adding-class-to-eltree-twice.patch @@ -0,0 +1,85 @@ +From ac9fe7dd8e730a103ae4481147395cc73492d786 Mon Sep 17 00:00:00 2001 +From: Pedro Tammela +Date: Thu, 22 May 2025 15:14:47 -0300 +Subject: net_sched: hfsc: Address reentrant enqueue adding class to eltree twice + +From: Pedro Tammela + +commit ac9fe7dd8e730a103ae4481147395cc73492d786 upstream. + +Savino says: + "We are writing to report that this recent patch + (141d34391abbb315d68556b7c67ad97885407547) [1] + can be bypassed, and a UAF can still occur when HFSC is utilized with + NETEM. + + The patch only checks the cl->cl_nactive field to determine whether + it is the first insertion or not [2], but this field is only + incremented by init_vf [3]. + + By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the + check and insert the class twice in the eltree. + Under normal conditions, this would lead to an infinite loop in + hfsc_dequeue for the reasons we already explained in this report [5]. + + However, if TBF is added as root qdisc and it is configured with a + very low rate, + it can be utilized to prevent packets from being dequeued. + This behavior can be exploited to perform subsequent insertions in the + HFSC eltree and cause a UAF." + +To fix both the UAF and the infinite loop, with netem as an hfsc child, +check explicitly in hfsc_enqueue whether the class is already in the eltree +whenever the HFSC_RSC flag is set. + +[1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547 +[2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572 +[3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677 +[4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574 +[5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u + +Fixes: 37d9cf1a3ce3 ("sched: Fix detection of empty queues in child qdiscs") +Reported-by: Savino Dicanosa +Reported-by: William Liu +Acked-by: Jamal Hadi Salim +Tested-by: Victor Nogueira +Signed-off-by: Pedro Tammela +Link: https://patch.msgid.link/20250522181448.1439717-2-pctammela@mojatatu.com +Signed-off-by: Paolo Abeni +Signed-off-by: Greg Kroah-Hartman +--- + net/sched/sch_hfsc.c | 9 ++++++++- + 1 file changed, 8 insertions(+), 1 deletion(-) + +--- a/net/sched/sch_hfsc.c ++++ b/net/sched/sch_hfsc.c +@@ -176,6 +176,11 @@ struct hfsc_sched { + + #define HT_INFINITY 0xffffffffffffffffULL /* infinite time value */ + ++static bool cl_in_el_or_vttree(struct hfsc_class *cl) ++{ ++ return ((cl->cl_flags & HFSC_FSC) && cl->cl_nactive) || ++ ((cl->cl_flags & HFSC_RSC) && !RB_EMPTY_NODE(&cl->el_node)); ++} + + /* + * eligible tree holds backlogged classes being sorted by their eligible times. +@@ -1038,6 +1043,8 @@ hfsc_change_class(struct Qdisc *sch, u32 + if (cl == NULL) + return -ENOBUFS; + ++ RB_CLEAR_NODE(&cl->el_node); ++ + err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack); + if (err) { + kfree(cl); +@@ -1576,7 +1583,7 @@ hfsc_enqueue(struct sk_buff *skb, struct + sch->qstats.backlog += len; + sch->q.qlen++; + +- if (first && !cl->cl_nactive) { ++ if (first && !cl_in_el_or_vttree(cl)) { + if (cl->cl_flags & HFSC_RSC) + init_ed(cl, len); + if (cl->cl_flags & HFSC_FSC) diff --git a/queue-5.4/series b/queue-5.4/series index 4f23ab5a05..eeb5536eba 100644 --- a/queue-5.4/series +++ b/queue-5.4/series @@ -188,3 +188,4 @@ netfilter-nf_tables-do-not-defer-rule-destruction-via-call_rcu.patch drm-i915-gvt-fix-unterminated-string-initialization-warning.patch smb-client-fix-use-after-free-in-cifs_fill_dirent.patch smb-client-reset-all-search-buffer-pointers-when-releasing-buffer.patch +net_sched-hfsc-address-reentrant-enqueue-adding-class-to-eltree-twice.patch