Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH] net: sched: sch: Bounds check priority | Date | Fri, 27 Jan 2023 14:40:37 -0800 |
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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> --- 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 f46643850df8..cc28e41fb745 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) -- 2.34.1
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