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Date: Mon, 21 Sep 2026 15:23:05 +0100
From: Simon Horman <horms@kernel.org>
To: Weiming Shi <bestswngs@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	Marc Dionne <marc.dionne@auristor.com>,
	"David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	linux-afs@lists.infradead.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, Xiang Mei <xmei5@asu.edu>,
	stable@vger.kernel.org, co+c09f7e87f6209a56@bugs.sh
Subject: Re: [PATCH net] rxrpc: rxgk: Initialize challenge control message
Message-ID: <20260921142305.GT13925@horms.kernel.org>
References: <20260918145705.1511737-3-bestswngs@gmail.com>
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In-Reply-To: <20260918145705.1511737-3-bestswngs@gmail.com>

On Fri, Sep 18, 2026 at 10:57:07PM +0800, Weiming Shi wrote:
> rxgk_challenge_to_recvmsg() copies the complete rxgk_challenge structure
> into an RXRPC_CHALLENGED control message.  The pad member of the embedded
> rxrpc_challenge is not assigned, so the copy can disclose one byte of
> kernel stack memory to userspace.
> 
> Initialize the whole structure before filling its meaningful fields so
> that the reserved byte is always zero.
> 
> Cc: stable@vger.kernel.org
> Fixes: 9d1d2b59341f ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)")
> Reported-by: <co+c09f7e87f6209a56@bugs.sh>
> Assisted-by: LLM
> Signed-off-by: Weiming Shi <bestswngs@gmail.com>

Reviewed-by: Simon Horman <horms@kernel.org>

...