netdev - Re: [PATCH] net/handshake: Fix memory leak in tls_handshake

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Message-ID: <aQ3HJRwkz6j512o7@horms.kernel.org>
Date: Fri, 7 Nov 2025 10:17:09 +0000
From: Simon Horman <horms@...nel.org>
To: Zilin Guan <zilin@....edu.cn>
Cc: chuck.lever@...cle.com, davem@...emloft.net, edumazet@...gle.com,
	kuba@...nel.org, pabeni@...hat.com,
	kernel-tls-handshake@...ts.linux.dev, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, jianhao.xu@....edu.cn
Subject: Re: [PATCH] net/handshake: Fix memory leak in tls_handshake_accept()

On Thu, Nov 06, 2025 at 02:45:11PM +0000, Zilin Guan wrote:
> In tls_handshake_accept(), a netlink message is allocated using
> genlmsg_new(). In the error handling path, genlmsg_cancel() is called
> to cancel the message construction, but the message itself is not freed.
> This leads to a memory leak.
> 
> Fix this by calling nlmsg_free() in the error path after genlmsg_cancel()
> to release the allocated memory.
> 
> Fixes: 2fd5532044a89 ("net/handshake: Add a kernel API for requesting a TLSv1.3 handshake")
> Signed-off-by: Zilin Guan <zilin@....edu.cn>
> ---
>  net/handshake/tlshd.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
> index 081093dfd553..8f9532a15f43 100644
> --- a/net/handshake/tlshd.c
> +++ b/net/handshake/tlshd.c
> @@ -259,6 +259,7 @@ static int tls_handshake_accept(struct handshake_req *req,
>  
>  out_cancel:
>  	genlmsg_cancel(msg, hdr);

Hi Zilin Guan,

I don't think genlmsg_cancel() is necessary if msg is freed on the next line.
If so, I suggest removing it, and renaming out_cancel accordingly.

> +	nlmsg_free(msg);
>  out:
>  	return ret;
>  }
> -- 
> 2.34.1
>