5.15-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ 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@ssd-disclosure.com Signed-off-by: Eric Dumazet edumazet@google.com Acked-by: Vinicius Costa Gomes vinicius.gomes@intel.com Reviewed-by: Vladimir Oltean vladimir.oltean@nxp.com Link: https://lore.kernel.org/r/20240604181511.769870-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 e40b4425eb6b5..4a0986843fb5d 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -947,16 +947,13 @@ static int taprio_parse_mqprio_opt(struct net_device *dev, { int i, j;
- 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; + }
/* Verify num_tc is not out of max range */ if (qopt->num_tc > TC_MAX_QUEUE) {