[PATCH 6.0 154/157] net: mvneta: Fix an out of bounds check

Greg Kroah-Hartman
2022-12-12T13:47:30Z

From: Dan Carpenter <error27@gmail.com>

[ Upstream commit cdd97383e19d4afe29adc3376025a15ae3bab3a3 ]

In an earlier commit, I added a bounds check to prevent an out of bounds
read and a WARN(). On further discussion and consideration that check
was probably too aggressive. Instead of returning -EINVAL, a better fix
would be to just prevent the out of bounds read but continue the process.

Background: The value of "pp->rxq_def" is a number between 0-7 by default,
or even higher depending on the value of "rxq_number", which is a module
parameter. If the value is more than the number of available CPUs then
it will trigger the WARN() in cpu_max_bits_warn().

Fixes: e8b4fc13900b ("net: mvneta: Prevent out of bounds read in mvneta_config_rss()")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/Y5A7d1E5ccwHTYPf@kadam
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/marvell/mvneta.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 3805b61b9263..85c93ba6a82b 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -4271,7 +4271,7 @@ static void mvneta_percpu_elect(struct mvneta_port *pp)
/* Use the cpu associated to the rxq when it is online, in all
* the other cases, use the cpu 0 which can't be offline.
*/
- if (cpu_online(pp->rxq_def))
+ if (pp->rxq_def < nr_cpu_ids && cpu_online(pp->rxq_def))
elected_cpu = pp->rxq_def;

max_cpu = num_present_cpus();
@@ -4927,9 +4927,6 @@ static int mvneta_config_rss(struct mvneta_port *pp)
napi_disable(&pp->napi);
}

- if (pp->indir[0] >= nr_cpu_ids)
- return -EINVAL;
-
pp->rxq_def = pp->indir[0];

/* Update unicast mapping */
--
2.35.1