netdev - [PATCH net v3 1/3] net: Make USO depend on CSUM offload

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240807-udp-gso-egress-from-tunnel-v3-1-8828d93c5b45@cloudflare.com>
Date: Wed, 07 Aug 2024 19:55:03 +0200
From: Jakub Sitnicki <jakub@...udflare.com>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>, 
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, 
 Willem de Bruijn <willemdebruijn.kernel@...il.com>, 
 kernel-team@...udflare.com, Jakub Sitnicki <jakub@...udflare.com>
Subject: [PATCH net v3 1/3] net: Make USO depend on CSUM offload

UDP segmentation offload inherently depends on checksum offload. It should
not be possible to disable checksum offload while leaving USO enabled.
Enforce this dependency in code.

There is a single tx-udp-segmentation feature flag to indicate support for
both IPv4/6, hence the devices wishing to support USO must offer checksum
offload for both IP versions.

Fixes: 83aa025f535f ("udp: add gso support to virtual devices")
Suggested-by: Willem de Bruijn <willemdebruijn.kernel@...il.com>
Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
---
 net/core/dev.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 751d9b70e6ad..dfb12164b35d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9912,6 +9912,16 @@ static void netdev_sync_lower_features(struct net_device *upper,
 	}
 }

+#define IP_CSUM_MASK (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)
+
+static bool has_ip_or_hw_csum(netdev_features_t features)
+{
+	bool ip_csum = (features & IP_CSUM_MASK) == IP_CSUM_MASK;
+	bool hw_csum = features & NETIF_F_HW_CSUM;
+
+	return ip_csum || hw_csum;
+}
+
 static netdev_features_t netdev_fix_features(struct net_device *dev,
 	netdev_features_t features)
 {
@@ -9993,15 +10003,9 @@ static netdev_features_t netdev_fix_features(struct net_device *dev,
 		features &= ~NETIF_F_LRO;
 	}

-	if (features & NETIF_F_HW_TLS_TX) {
-		bool ip_csum = (features & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)) ==
-			(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
-		bool hw_csum = features & NETIF_F_HW_CSUM;
-
-		if (!ip_csum && !hw_csum) {
-			netdev_dbg(dev, "Dropping TLS TX HW offload feature since no CSUM feature.\n");
-			features &= ~NETIF_F_HW_TLS_TX;
-		}
+	if ((features & NETIF_F_HW_TLS_TX) && !has_ip_or_hw_csum(features)) {
+		netdev_dbg(dev, "Dropping TLS TX HW offload feature since no CSUM feature.\n");
+		features &= ~NETIF_F_HW_TLS_TX;
 	}

 	if ((features & NETIF_F_HW_TLS_RX) && !(features & NETIF_F_RXCSUM)) {
@@ -10009,6 +10013,11 @@ static netdev_features_t netdev_fix_features(struct net_device *dev,
 		features &= ~NETIF_F_HW_TLS_RX;
 	}

+	if ((features & NETIF_F_GSO_UDP_L4) && !has_ip_or_hw_csum(features)) {
+		netdev_dbg(dev, "Dropping USO feature since no CSUM feature.\n");
+		features &= ~NETIF_F_GSO_UDP_L4;
+	}
+
 	return features;
 }

-- 
2.40.1