[patch net-next v3] net: ethtool: fix unheld rtnl lock

From: Diogo Jahchan Koike
Date: Mon Aug 26 2024 - 13:39:49 EST


ethnl_req_get_phydev should be called with rtnl lock held.

Reported-by: syzbot+ec369e6d58e210135f71@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=ec369e6d58e210135f71
Fixes: 31748765bed3 ("net: ethtool: pse-pd: Target the command to the requested PHY")
Signed-off-by: Diogo Jahchan Koike <djahchankoike@xxxxxxxxx>
---
net/ethtool/pse-pd.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/net/ethtool/pse-pd.c b/net/ethtool/pse-pd.c
index 507cb21d6bf0..290edbfd47d2 100644
--- a/net/ethtool/pse-pd.c
+++ b/net/ethtool/pse-pd.c
@@ -226,17 +226,21 @@ ethnl_set_pse_validate(struct ethnl_req_info *req_info, struct genl_info *info)
{
struct nlattr **tb = info->attrs;
struct phy_device *phydev;
+ int ret = 1;

+ rtnl_lock();
phydev = ethnl_req_get_phydev(req_info, tb[ETHTOOL_A_PSE_HEADER],
info->extack);
if (IS_ERR_OR_NULL(phydev)) {
NL_SET_ERR_MSG(info->extack, "No PHY is attached");
- return -EOPNOTSUPP;
+ ret = -EOPNOTSUPP;
+ goto out;
}

if (!phydev->psec) {
NL_SET_ERR_MSG(info->extack, "No PSE is attached");
- return -EOPNOTSUPP;
+ ret = -EOPNOTSUPP;
+ goto out;
}

if (tb[ETHTOOL_A_PODL_PSE_ADMIN_CONTROL] &&
@@ -244,17 +248,21 @@ ethnl_set_pse_validate(struct ethnl_req_info *req_info, struct genl_info *info)
NL_SET_ERR_MSG_ATTR(info->extack,
tb[ETHTOOL_A_PODL_PSE_ADMIN_CONTROL],
"setting PoDL PSE admin control not supported");
- return -EOPNOTSUPP;
+ ret = -EOPNOTSUPP;
+ goto out;
}
if (tb[ETHTOOL_A_C33_PSE_ADMIN_CONTROL] &&
!pse_has_c33(phydev->psec)) {
NL_SET_ERR_MSG_ATTR(info->extack,
tb[ETHTOOL_A_C33_PSE_ADMIN_CONTROL],
"setting C33 PSE admin control not supported");
- return -EOPNOTSUPP;
+ ret = -EOPNOTSUPP;
+ goto out;
}

- return 1;
+out:
+ rtnl_unlock();
+ return ret;
}

static int
--
2.43.0