From de5ca4c3852f896cacac2bf259597aab5e17d9e3 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 27 Jan 2023 14:40:37 -0800 Subject: [PATCH] net: sched: sch: Bounds check priority Nothing was explicitly bounds checking the priority index used to access clpriop[]. WARN and bail out early if it's pathological. Seen with GCC 13: ../net/sched/sch_htb.c: In function 'htb_activate_prios': ../net/sched/sch_htb.c:437:44: warning: array subscript [0, 31] is outside array bounds of 'struct htb_prio[8]' [-Warray-bounds=] 437 | if (p->inner.clprio[prio].feed.rb_node) | ~~~~~~~~~~~~~~~^~~~~~ ../net/sched/sch_htb.c:131:41: note: while referencing 'clprio' 131 | struct htb_prio clprio[TC_HTB_NUMPRIO]; | ^~~~~~ Cc: Jamal Hadi Salim Cc: Cong Wang Cc: Jiri Pirko Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Simon Horman Reviewed-by: Cong Wang Link: https://lore.kernel.org/r/20230127224036.never.561-kees@kernel.org Signed-off-by: Paolo Abeni --- net/sched/sch_htb.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c index f466438..cc28e41 100644 --- a/net/sched/sch_htb.c +++ b/net/sched/sch_htb.c @@ -431,7 +431,10 @@ static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl) while (cl->cmode == HTB_MAY_BORROW && p && mask) { m = mask; while (m) { - int prio = ffz(~m); + unsigned int prio = ffz(~m); + + if (WARN_ON_ONCE(prio > ARRAY_SIZE(p->inner.clprio))) + break; m &= ~(1 << prio); if (p->inner.clprio[prio].feed.rb_node) -- 2.7.4