6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit f921a58ae20852d188f70842431ce6519c4fdc36 ]
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 <noamr@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
Reviewed-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Link: https://lore.kernel.org/r/20240604181511.769870-1-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 a315748a5e531..418d4a846d04a 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -1186,16 +1186,13 @@ 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) {
--
2.43.0
