linux-kernel - Re: [PATCH] net: tls: fix possible info leak in tls_set_device

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Message-ID: <310391ea-7c71-395e-5dcb-b0a983e6fc93@gmail.com>
Date:   Fri, 24 Feb 2023 11:07:54 +0800
From:   Hangyu Hua <hbh25y@...il.com>
To:     Sabrina Dubroca <sd@...asysnail.net>
Cc:     borisp@...dia.com, john.fastabend@...il.com, kuba@...nel.org,
        davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: tls: fix possible info leak in
 tls_set_device_offload()

On 23/2/2023 19:15, Sabrina Dubroca wrote:
> 2023-02-23, 17:05:08 +0800, Hangyu Hua wrote:
>> After tls_set_device_offload() fails, we enter tls_set_sw_offload(). But
>> tls_set_sw_offload can't set cctx->iv and cctx->rec_seq to NULL if it fails
>> before kmalloc cctx->iv. This may cause info leak when we call
>> do_tls_getsockopt_conf().
> 
> Is there really an issue here?
> 
> If both tls_set_device_offload and tls_set_sw_offload fail,
> do_tls_setsockopt_conf will clear crypto_{send,recv} from the context.
> Then the TLS_CRYPTO_INFO_READY in do_tls_getsockopt_conf will fail, so
> we won't try to access iv or rec_seq.
> 

My bad. I forget memzero_explicit. Then this is harmless. But I still 
think it is better to set them to NULL like tls_set_sw_offload's error 
path because we don't know there are another way to do this(I will 
change the commit log). What do you think?