* Re: [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP
2024-06-04 18:15 [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP Eric Dumazet
@ 2024-06-04 19:11 ` Vladimir Oltean
2024-06-04 21:12 ` Vinicius Costa Gomes
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Vladimir Oltean @ 2024-06-04 19:11 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim,
Cong Wang, Jiri Pirko, netdev, eric.dumazet, Noam Rathaus,
Vinicius Costa Gomes
On Tue, Jun 04, 2024 at 06:15:11PM +0000, Eric Dumazet wrote:
> 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>
> Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Cc: Vladimir Oltean <vladimir.oltean@nxp.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 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) {
> --
> 2.45.2.505.gda0bf45e8d-goog
>
Correct, the mqprio qopt structure should be validated whenever passed,
not just if dev->num_tc == 0.
But... what bad things can happen?
Whenever I try to trick the kernel into doing something with the second
mqprio, I get:
"Changing the traffic mapping of a running schedule is not supported."
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP
2024-06-04 18:15 [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP Eric Dumazet
2024-06-04 19:11 ` Vladimir Oltean
@ 2024-06-04 21:12 ` Vinicius Costa Gomes
2024-06-04 21:31 ` Vladimir Oltean
2024-06-05 23:10 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 5+ messages in thread
From: Vinicius Costa Gomes @ 2024-06-04 21:12 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Jamal Hadi Salim, Cong Wang, Jiri Pirko, netdev, eric.dumazet,
Eric Dumazet, Noam Rathaus, Vladimir Oltean
Eric Dumazet <edumazet@google.com> writes:
> 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>
> Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Cc: Vladimir Oltean <vladimir.oltean@nxp.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 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;
> + }
Nice one. I think I have an idea of what's going on here.
Validating the priomap even if we are not going to install it is good:
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cheers,
--
Vinicius
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP
2024-06-04 18:15 [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP Eric Dumazet
2024-06-04 19:11 ` Vladimir Oltean
2024-06-04 21:12 ` Vinicius Costa Gomes
@ 2024-06-04 21:31 ` Vladimir Oltean
2024-06-05 23:10 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 5+ messages in thread
From: Vladimir Oltean @ 2024-06-04 21:31 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim,
Cong Wang, Jiri Pirko, netdev, eric.dumazet, Noam Rathaus,
Vinicius Costa Gomes
On Tue, Jun 04, 2024 at 06:15:11PM +0000, Eric Dumazet wrote:
> 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>
> Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
> ---
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP
2024-06-04 18:15 [PATCH net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP Eric Dumazet
` (2 preceding siblings ...)
2024-06-04 21:31 ` Vladimir Oltean
@ 2024-06-05 23:10 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-06-05 23:10 UTC (permalink / raw)
To: Eric Dumazet
Cc: davem, kuba, pabeni, jhs, xiyou.wangcong, jiri, netdev,
eric.dumazet, noamr, vinicius.gomes, vladimir.oltean
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Tue, 4 Jun 2024 18:15:11 +0000 you wrote:
> 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.
>
> [...]
Here is the summary with links:
- [net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP
https://git.kernel.org/netdev/net/c/f921a58ae208
You are awesome, thank you!
--
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^ permalink raw reply [flat|nested] 5+ messages in thread