From f921a58ae20852d188f70842431ce6519c4fdc36 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 4 Jun 2024 18:15:11 +0000 Subject: [PATCH] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP If one TCA_TAPRIO_ATTR_PRIOMAP attribute has been provided, taprio_parse_mqprio_opt() must validate it, or userspace can inject arbitrary data to the kernel, the second time taprio_change() is called. First call (with valid attributes) sets dev->num_tc to a non zero value. Second call (with arbitrary mqprio attributes) returns early from taprio_parse_mqprio_opt() and bad things can happen. Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule") Reported-by: Noam Rathaus Signed-off-by: Eric Dumazet Acked-by: Vinicius Costa Gomes Reviewed-by: Vladimir Oltean Link: https://lore.kernel.org/r/20240604181511.769870-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/sched/sch_taprio.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 937a0c513c17..b284a06b5a75 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1176,16 +1176,13 @@ static int taprio_parse_mqprio_opt(struct net_device *dev, { bool allow_overlapping_txqs = TXTIME_ASSIST_IS_ENABLED(taprio_flags); - if (!qopt && !dev->num_tc) { - NL_SET_ERR_MSG(extack, "'mqprio' configuration is necessary"); - return -EINVAL; - } - - /* If num_tc is already set, it means that the user already - * configured the mqprio part - */ - if (dev->num_tc) + if (!qopt) { + if (!dev->num_tc) { + NL_SET_ERR_MSG(extack, "'mqprio' configuration is necessary"); + return -EINVAL; + } return 0; + } /* taprio imposes that traffic classes map 1:n to tx queues */ if (qopt->num_tc > dev->num_tx_queues) { -- 2.20.1