From: Eric Dumazet edumazet@google.com

stable inclusion from stable-v6.6.35 commit 724050ae4b76e4fae05a923cb54101d792cf4404 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6H2M CVE: CVE-2024-36974

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ 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 Signed-off-by: Liu Jian liujian56@huawei.com --- 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 87d8070fffbe..118473e5dea7 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) {