From: Pedro Tammela <pctammela@xxxxxxxxxxxx> commit 158810b261d02fc7dd92ca9c392d8f8a211a2401 upstream. 25369891fcef deletes a check for the case where no 'lmax' is specified which 3037933448f6 previously fixed as 'lmax' could be set to the device's MTU without any bound checking for QFQ_LMAX_MIN and QFQ_LMAX_MAX. Therefore, reintroduce the check. Fixes: 25369891fcef ("net/sched: sch_qfq: refactor parsing of netlink parameters") Acked-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Pedro Tammela <pctammela@xxxxxxxxxxxx> Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/sch_qfq.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/net/sched/sch_qfq.c +++ b/net/sched/sch_qfq.c @@ -428,10 +428,17 @@ static int qfq_change_class(struct Qdisc else weight = 1; - if (tb[TCA_QFQ_LMAX]) + if (tb[TCA_QFQ_LMAX]) { lmax = nla_get_u32(tb[TCA_QFQ_LMAX]); - else + } else { + /* MTU size is user controlled */ lmax = psched_mtu(qdisc_dev(sch)); + if (lmax < QFQ_MIN_LMAX || lmax > QFQ_MAX_LMAX) { + NL_SET_ERR_MSG_MOD(extack, + "MTU size out of bounds for qfq"); + return -EINVAL; + } + } inv_w = ONE_FP / weight; weight = ONE_FP / inv_w;