[PATCH v2 net-next 5/9] net: ethtool: mm: sanitize some UAPI configurations

[Vladimir Oltean]

The verify-enabled boolean (ETHTOOL_A_MM_VERIFY_ENABLED) was intended to
be a sub-setting of tx-enabled (ETHTOOL_A_MM_TX_ENABLED). IOW, MAC Merge
TX can be enabled with or without verification, but verification with TX
disabled makes no sense.

The pmac-enabled boolean (ETHTOOL_A_MM_PMAC_ENABLED) was intended to be
a global toggle from an API perspective, whereas tx-enabled just handles
the TX direction. IOW, the pMAC can be enabled with or without TX, but
it doesn't make sense to enable TX if the pMAC is not enabled.

Add two checks which sanitize and reject these invalid cases.

Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
v1->v2: add missing "Verification requires TX enabled" check which was
        only mentioned in the commit message

 net/ethtool/mm.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/net/ethtool/mm.c b/net/ethtool/mm.c
index e00d7d5cea7e..4058a557b5a4 100644
--- a/net/ethtool/mm.c
+++ b/net/ethtool/mm.c
@@ -214,6 +214,16 @@ static int ethnl_set_mm(struct ethnl_req_info *req_info, struct genl_info *info)
 		return -ERANGE;
 	}
 
+	if (cfg.verify_enabled && !cfg.tx_enabled) {
+		NL_SET_ERR_MSG(extack, "Verification requires TX enabled");
+		return -EINVAL;
+	}
+
+	if (cfg.tx_enabled && !cfg.pmac_enabled) {
+		NL_SET_ERR_MSG(extack, "TX enabled requires pMAC enabled");
+		return -EINVAL;
+	}
+
 	ret = dev->ethtool_ops->set_mm(dev, &cfg, extack);
 	return ret < 0 ? ret : 1;
 }
-- 
2.34.1