From: Kees Cook keescook@chromium.org
[ Upstream commit de5ca4c3852f896cacac2bf259597aab5e17d9e3 ]
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 jhs@mojatatu.com Cc: Cong Wang xiyou.wangcong@gmail.com Cc: Jiri Pirko jiri@resnulli.us Cc: "David S. Miller" davem@davemloft.net Cc: Eric Dumazet edumazet@google.com Cc: Jakub Kicinski kuba@kernel.org Cc: Paolo Abeni pabeni@redhat.com Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org Reviewed-by: Simon Horman simon.horman@corigine.com Reviewed-by: Cong Wang cong.wang@bytedance.com Link: https://lore.kernel.org/r/20230127224036.never.561-kees@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 45b92e40082ef..7ea8c73ddeff0 100644 --- a/net/sched/sch_htb.c +++ b/net/sched/sch_htb.c @@ -427,7 +427,10 @@ 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)