[PATCH 6.1 0888/1146] net: macsec: fix net device access prior to holding a lock

Greg Kroah-Hartman
2022-12-28T16:44:58Z

From: Emeel Hakim <ehakim@nvidia.com>

[ Upstream commit f3b4a00f0f62da252c598310698dfc82ef2f2e2e ]

Currently macsec offload selection update routine accesses
the net device prior to holding the relevant lock.
Fix by holding the lock prior to the device access.

Fixes: dcb780fb2795 ("net: macsec: add nla support for changing the offloading selection")
Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Emeel Hakim <ehakim@nvidia.com>
Link: https://lore.kernel.org/r/20221211075532.28099-1-ehakim@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/macsec.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 2fbac51b9b19..038a78794392 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -2593,7 +2593,7 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
const struct macsec_ops *ops;
struct macsec_context ctx;
struct macsec_dev *macsec;
- int ret;
+ int ret = 0;

if (!attrs[MACSEC_ATTR_IFINDEX])
return -EINVAL;
@@ -2606,28 +2606,36 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
macsec_genl_offload_policy, NULL))
return -EINVAL;

+ rtnl_lock();
+
dev = get_dev_from_nl(genl_info_net(info), attrs);
- if (IS_ERR(dev))
- return PTR_ERR(dev);
+ if (IS_ERR(dev)) {
+ ret = PTR_ERR(dev);
+ goto out;
+ }
macsec = macsec_priv(dev);

- if (!tb_offload[MACSEC_OFFLOAD_ATTR_TYPE])
- return -EINVAL;
+ if (!tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]) {
+ ret = -EINVAL;
+ goto out;
+ }

offload = nla_get_u8(tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]);
if (macsec->offload == offload)
- return 0;
+ goto out;

/* Check if the offloading mode is supported by the underlying layers */
if (offload != MACSEC_OFFLOAD_OFF &&
- !macsec_check_offload(offload, macsec))
- return -EOPNOTSUPP;
+ !macsec_check_offload(offload, macsec)) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }

/* Check if the net device is busy. */
- if (netif_running(dev))
- return -EBUSY;
-
- rtnl_lock();
+ if (netif_running(dev)) {
+ ret = -EBUSY;
+ goto out;
+ }

prev_offload = macsec->offload;
macsec->offload = offload;
@@ -2662,7 +2670,7 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)

rollback:
macsec->offload = prev_offload;
-
+out:
rtnl_unlock();
return ret;
}
--
2.35.1