[PATCH net-next] ipv6: set msg_control_is_user in do_ipv6_getsockopt

[PATCH net-next] ipv6: set msg_control_is_user in do_ipv6_getsockopt

[Christoph Hellwig]

While do_ipv6_getsockopt does not call the high-level recvmsg helper,
the msghdr eventually ends up being passed to put_cmsg anyway, and thus
needs msg_control_is_user set to the proper value.

Fixes: 1f466e1f15cf ("net: cleanly handle kernel vs user buffers for ->msg_control")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 net/ipv6/ipv6_sockglue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 18d05403d3b52..a0e50cc57e545 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1075,6 +1075,7 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 		msg.msg_control = optval;
 		msg.msg_controllen = len;
 		msg.msg_flags = flags;
+		msg.msg_control_is_user = true;
 
 		lock_sock(sk);
 		skb = np->pktoptions;
-- 
2.26.2

Re: [PATCH net-next] ipv6: set msg_control_is_user in do_ipv6_getsockopt

[David Miller]

From: Christoph Hellwig <hch@lst.de>
Date: Wed, 13 May 2020 21:36:41 +0200

> While do_ipv6_getsockopt does not call the high-level recvmsg helper,
> the msghdr eventually ends up being passed to put_cmsg anyway, and thus
> needs msg_control_is_user set to the proper value.
> 
> Fixes: 1f466e1f15cf ("net: cleanly handle kernel vs user buffers for ->msg_control")
> Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Applied, thanks.