netdev - Re: [Patch net v2] sit: update dev->needed_headroom in ipip6_tunnel_bind

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: <20230427171013.9911-1-kuniyu@amazon.com>
Date:   Thu, 27 Apr 2023 10:10:13 -0700
From:   Kuniyuki Iwashima <kuniyu@...zon.com>
To:     <xiyou.wangcong@...il.com>
CC:     <cong.wang@...edance.com>, <edumazet@...gle.com>,
        <kuniyu@...zon.com>, <netdev@...r.kernel.org>,
        <oswalpalash@...il.com>
Subject: Re: [Patch net v2] sit: update dev->needed_headroom in ipip6_tunnel_bind_dev()

From:   Cong Wang <xiyou.wangcong@...il.com>
Date:   Wed, 26 Apr 2023 23:00:06 -0700
> From: Cong Wang <cong.wang@...edance.com>
> 
> When a tunnel device is bound with the underlying device, its
> dev->needed_headroom needs to be updated properly. IPv4 tunnels
> already do the same in ip_tunnel_bind_dev(). Otherwise we may
> not have enough header room for skb, especially after commit
> b17f709a2401 ("gue: TX support for using remote checksum offload option").
> 
> Fixes: 32b8a8e59c9c ("sit: add IPv4 over IPv4 support")
> Reported-by: Palash Oswal <oswalpalash@...il.com>
> Link: https://lore.kernel.org/netdev/CAGyP=7fDcSPKu6nttbGwt7RXzE3uyYxLjCSE97J64pRxJP8jPA@mail.gmail.com/
> Cc: Kuniyuki Iwashima <kuniyu@...zon.com>
> Cc: Eric Dumazet <edumazet@...gle.com>
> Signed-off-by: Cong Wang <cong.wang@...edance.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@...zon.com>


> ---
> v2: follow reverse Christmas tree style

nit: less changes needed if we put t_hlen init down.

---8<---
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 70d81bba5093..dce9efba24a9 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1095,6 +1095,7 @@ static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
 
 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 {
+	int t_hlen, hlen = LL_MAX_HEADER;
 	struct net_device *tdev = NULL;
 	struct ip_tunnel *tunnel;
 	const struct iphdr *iph;
@@ -1122,15 +1123,18 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 	if (!tdev && tunnel->parms.link)
 		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
 
+	t_hlen = tunnel->hlen + sizeof(struct iphdr);
+
 	if (tdev && !netif_is_l3_master(tdev)) {
-		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 		int mtu;
 
 		mtu = tdev->mtu - t_hlen;
 		if (mtu < IPV6_MIN_MTU)
 			mtu = IPV6_MIN_MTU;
 		WRITE_ONCE(dev->mtu, mtu);
+		hlen = tdev->hard_header_len + tdev->needed_headroom;
 	}
+	dev->needed_headroom = hlen + t_hlen;
 }
 
 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
---8<---

Thanks,
Kuniyuki


> 
> Note, this is targeting for -net and -table, so I'd keep the fix
> small. We can refactor and reuse ip_tunnel_bind_dev() for -net-next.
> 
>  net/ipv6/sit.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
> index 70d81bba5093..3ffb6a5b1f82 100644
> --- a/net/ipv6/sit.c
> +++ b/net/ipv6/sit.c
> @@ -1095,12 +1095,13 @@ static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
>  
>  static void ipip6_tunnel_bind_dev(struct net_device *dev)
>  {
> +	struct ip_tunnel *tunnel = netdev_priv(dev);
> +	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
>  	struct net_device *tdev = NULL;
> -	struct ip_tunnel *tunnel;
> +	int hlen = LL_MAX_HEADER;
>  	const struct iphdr *iph;
>  	struct flowi4 fl4;
>  
> -	tunnel = netdev_priv(dev);
>  	iph = &tunnel->parms.iph;
>  
>  	if (iph->daddr) {
> @@ -1123,14 +1124,15 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
>  		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
>  
>  	if (tdev && !netif_is_l3_master(tdev)) {
> -		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
>  		int mtu;
>  
>  		mtu = tdev->mtu - t_hlen;
>  		if (mtu < IPV6_MIN_MTU)
>  			mtu = IPV6_MIN_MTU;
>  		WRITE_ONCE(dev->mtu, mtu);
> +		hlen = tdev->hard_header_len + tdev->needed_headroom;
>  	}
> +	dev->needed_headroom = t_hlen + hlen;
>  }
>  
>  static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
> -- 
> 2.34.1