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From: Christoph Hellwig <hch@lst•de>
To: Kevin Brodsky <kevin.brodsky@arm•com>
Cc: netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
	Christoph Hellwig <hch@lst•de>,
	Eric Dumazet <edumazet@google•com>,
	"David S. Miller" <davem@davemloft•net>,
	Jakub Kicinski <kuba@kernel•org>
Subject: Re: [PATCH] net: Finish up ->msg_control{,_user} split
Date: Wed, 12 Apr 2023 17:25:48 +0200	[thread overview]
Message-ID: <20230412152548.GA26786@lst.de> (raw)
In-Reply-To: <20230411122625.3902339-1-kevin.brodsky@arm.com>

On Tue, Apr 11, 2023 at 01:26:25PM +0100, Kevin Brodsky wrote:
> This patch is attempting to complete the split. Most issues are about
> msg_control being used when in fact a user pointer is stored in the
> union; msg_control_user is now used instead. An exception is made
> for null checks, as it should be safe to use msg_control
> unconditionally for that purpose.

So all of the fixes looks good to me.

> Additionally, a special situation in
> cmsghdr_from_user_compat_to_kern() is addressed. There the input
> struct msghdr holds a user pointer (msg_control_user), but a kernel
> pointer is stored in msg_control when returning. msg_control_is_user
> is now updated accordingly.

But this is a small isolated real bugfix.  So I'd suggest to split
this into a simple and easily backportable patch, and do the rest
in another.

> diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
> index 2917dd8d198c..ae818ff46224 100644
> --- a/net/ipv6/ipv6_sockglue.c
> +++ b/net/ipv6/ipv6_sockglue.c
> @@ -716,6 +716,7 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
>  			goto done;
>  
>  		msg.msg_controllen = optlen;
> +		msg.msg_control_is_user = false;

And this is another one that has a real effect.

  reply	other threads:[~2023-04-12 15:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-11 12:26 [PATCH] net: Finish up ->msg_control{,_user} split Kevin Brodsky
2023-04-12 15:25 ` Christoph Hellwig [this message]
2023-04-13  8:34   ` Kevin Brodsky

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