2021-04-11 11:37:41

by Phillip Potter

Subject: [PATCH] net: geneve: check skb is large enough for IPv4/IPv6 header

Check within geneve_xmit_skb/geneve6_xmit_skb that sk_buff structure
is large enough to include IPv4 or IPv6 header, and reject if not. The
geneve_xmit_skb portion and overall idea was contributed by Eric Dumazet.
Fixes a KMSAN-found uninit-value bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=abe95dc3e3e9667fc23b8d81f29ecad95c6f106f

Suggested-by: Eric Dumazet <[email protected]>
Reported-by: [email protected]
Signed-off-by: Phillip Potter <[email protected]>
---
drivers/net/geneve.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 5523f069b9a5..adfceb60f7f8 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -891,6 +891,9 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
__be16 sport;
int err;

+ if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
+ return -EINVAL;
+
sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
rt = geneve_get_v4_rt(skb, dev, gs4, &fl4, info,
geneve->cfg.info.key.tp_dst, sport);
@@ -977,6 +980,9 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
__be16 sport;
int err;

+ if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
+ return -EINVAL;
+
sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
dst = geneve_get_v6_dst(skb, dev, gs6, &fl6, info,
geneve->cfg.info.key.tp_dst, sport);
--
2.30.2

2021-04-11 17:34:49

by Eric Dumazet

Subject: Re: [PATCH] net: geneve: check skb is large enough for IPv4/IPv6 header

On Sun, Apr 11, 2021 at 1:28 PM Phillip Potter <[email protected]> wrote:
>
> Check within geneve_xmit_skb/geneve6_xmit_skb that sk_buff structure
> is large enough to include IPv4 or IPv6 header, and reject if not. The
> geneve_xmit_skb portion and overall idea was contributed by Eric Dumazet.
> Fixes a KMSAN-found uninit-value bug reported by syzbot at:
> https://syzkaller.appspot.com/bug?id=abe95dc3e3e9667fc23b8d81f29ecad95c6f106f
>
> Suggested-by: Eric Dumazet <[email protected]>
> Reported-by: [email protected]
> Signed-off-by: Phillip Potter <[email protected]>

Signed-off-by: Eric Dumazet <[email protected]>

Thanks !

2021-04-12 00:19:40

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] net: geneve: check skb is large enough for IPv4/IPv6 header

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Sun, 11 Apr 2021 12:28:24 +0100 you wrote:
> Check within geneve_xmit_skb/geneve6_xmit_skb that sk_buff structure
> is large enough to include IPv4 or IPv6 header, and reject if not. The
> geneve_xmit_skb portion and overall idea was contributed by Eric Dumazet.
> Fixes a KMSAN-found uninit-value bug reported by syzbot at:
> https://syzkaller.appspot.com/bug?id=abe95dc3e3e9667fc23b8d81f29ecad95c6f106f
>
> Suggested-by: Eric Dumazet <[email protected]>
> Reported-by: [email protected]
> Signed-off-by: Phillip Potter <[email protected]>
>
> [...]

Here is the summary with links:
- net: geneve: check skb is large enough for IPv4/IPv6 header
https://git.kernel.org/netdev/net/c/6628ddfec758

You are awesome, thank you!
--
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