| Message ID | 20240604181511.769870-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f921a58ae20852d188f70842431ce6519c4fdc36 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net/sched: taprio: always validate TCA_TAPRIO_ATTR_PRIOMAP | expand |
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."
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,
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>
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!
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) {
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(-)