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From: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com>
To: davem@davemloft.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org,
	kuba@kernel.org, pshelar@nicira.com,
	willemdebruijn.kernel@gmail.com
Cc: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzbot+ff8e1b9f2f36481e2efc@syzkaller.appspotmail.com
Subject: [PATCH 1/2 net] ip_gre: add validation for csum_start
Date: Sat, 21 Aug 2021 12:44:24 +0530	[thread overview]
Message-ID: <20210821071425.512834-1-chouhan.shreyansh630@gmail.com> (raw)
In-Reply-To: <20210819100447.00201b26@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>

Validate csum_start in gre_handle_offloads before we call _gre_xmit so
that we do not crash later when the csum_start value is used in the
lco_csum function call.

This patch deals with ipv4 code.

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Reported-by: syzbot+ff8e1b9f2f36481e2efc@syzkaller.appspotmail.com
Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com>
---
 net/ipv4/ip_gre.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 12dca0c85f3c..95419b7adf5c 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -473,6 +473,8 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 
 static int gre_handle_offloads(struct sk_buff *skb, bool csum)
 {
+	if (csum && skb_checksum_start(skb) < skb->data)
+		return -EINVAL;
 	return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 }
 
-- 
2.31.1


  reply	other threads:[~2021-08-21  7:14 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19 14:34 [PATCH] ip_gre/ip6_gre: add check for invalid csum_start Shreyansh Chouhan
2021-08-19 16:56 ` Willem de Bruijn
2021-08-19 17:04   ` Jakub Kicinski
2021-08-21  7:14     ` Shreyansh Chouhan [this message]
2021-08-21 13:41       ` [PATCH 1/2 net] ip_gre: add validation for csum_start Willem de Bruijn
2021-09-01 11:53         ` Ido Schimmel
2021-09-01 13:46           ` Willem de Bruijn
2021-09-01 15:53             ` Ido Schimmel
2021-09-01 21:39               ` Willem de Bruijn
2021-08-22 20:30       ` patchwork-bot+netdevbpf
2021-08-21  7:14     ` [PATCH 2/2 net] ip6_gre: " Shreyansh Chouhan
2021-08-21 13:42       ` Willem de Bruijn
2021-08-21  7:18     ` [PATCH] ip_gre/ip6_gre: add check for invalid csum_start Shreyansh Chouhan
2021-08-21 13:44       ` Willem de Bruijn

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