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From: Dan Carpenter <dan.carpenter@oracle.com>
To: xiaolinkui <xiaolinkui@gmail.com>
Cc: kvalo@kernel.org, davem@davemloft.net, edumazet@google.com,
	kuba@kernel.org, pabeni@redhat.com, gustavoars@kernel.org,
	quic_jjohnson@quicinc.com, keescook@chromium.org,
	johan@kernel.org, linux-wireless@vger.kernel.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Linkui Xiao <xiaolinkui@kylinos.cn>
Subject: Re: [PATCH] wireless: ath6kl: fix out of bound from length.
Date: Thu, 21 Jul 2022 10:07:07 +0300	[thread overview]
Message-ID: <20220721070707.GF2316@kadam> (raw)
In-Reply-To: <20220721032158.31479-1-xiaolinkui@kylinos.cn>

On Thu, Jul 21, 2022 at 11:21:58AM +0800, xiaolinkui wrote:
> From: Linkui Xiao <xiaolinkui@kylinos.cn>
> 
> If length from debug_buf.length is 4294967293 (0xfffffffd), the result of
> ALIGN(size, 4) will be 0.
> 
> 	length = ALIGN(length, 4);
> 
> In case of length == 4294967293 after four-byte aligned access, length will
> become 0.
> 
> 	ret = ath6kl_diag_read(ar, address, buf, length);
> 
> will fail to read.

It looks like "length" is untrustworthy.  Generally, I kind of distrust
all endian data by default, but I dug a bit deeper and I don't trust it.

Unfortunately, if "length" is larger than ATH6KL_FWLOG_PAYLOAD_SIZE
(1500) then we are screwed.  Can you add a check for that instead?
Please check my work on this because I didn't look *super* carefully.

No need to make any changes to the types, just add the upper bounds
check on ATH6KL_FWLOG_PAYLOAD_SIZE.  The type changes didn't fix the bug
on 32 bit systems anyway...

regards,
dan carpenter


      reply	other threads:[~2022-07-21  7:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-21  3:21 [PATCH] wireless: ath6kl: fix out of bound from length xiaolinkui
2022-07-21  7:07 ` Dan Carpenter [this message]

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