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Subject: Re: [PATCH] brcmfmac: buffer overflow in brcmf_cfg80211_mgmt_tx()
To: Dan Carpenter <dan.carpenter@oracle.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
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        Wright Feng <Wright.Feng@cypress.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>,
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From: Arend van Spriel <arend.vanspriel@broadcom.com>
Message-ID: <a2496a2e-9258-7cc9-3c04-87886f0029cd@broadcom.com> (sfid-20170707_112420_534443_B25C5223)
Date: Fri, 7 Jul 2017 11:24:11 +0200
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On 7/7/2017 10:46 AM, Dan Carpenter wrote:
> On Thu, Jul 06, 2017 at 03:32:42PM -0700, Linus Torvalds wrote:
>> On Thu, Jul 6, 2017 at 10:11 AM, Arend van Spriel
>> <arend.vanspriel@broadcom.com> wrote:
>>>
>>> Looks fine to me so ...
>>
>> I really think that if we can't trust 'len', then we have to check
>> against the lower bound of DOT11_MGMT_HDR_LEN too, because otherwise
>> we'll just have a big 16-bit number instead.
> 
> There is already a check in cfg80211_mlme_mgmt_tx().
> 
> 	if (params->len < 24 + 1)
> 		return -EINVAL;
> 
> It probably should be using DOT11_MGMT_HDR_LEN instead of a magic 24.

Missed that check when I looked yesterday evening. Must have been the 
time ;-)

Regards,
Arend