[alsa-devel] [PATCH] hda: add bounds checking for the codec command fields v2

Guo, Chaohong chaohong.guo at intel.com
Mon Jul 20 04:13:48 CEST 2009


>Cc: Guo, Chaohong; alsa-devel at alsa-project.org; Jaroslav 
>Kysela; John Villalovos
>Subject: Re: [PATCH] hda: add bounds checking for the codec 
>command fields v2
>On Fri, Jul 17, 2009 at 06:46:01PM +0800, Takashi Iwai wrote:
>> At Fri, 17 Jul 2009 18:41:05 +0800,
>> Guo, Chaohong wrote:
>> > 
>> > Although it does address this issue, I am not comfortable 
>with this fixing. 
>> > It seems more like a workaround than fix.
>> No, it's rather for catching a bug.  This is definitely neither
>> "workaround" nor "fix".
>Yes, I wrote this mainly for catching unknown bugs.

Oh, I misunderstood your intention.  So, we still need to  investigate
the bug which occurs on RH i386 version  :)

>> >  Moreover, if long format node
>> > ID is used in the future,  the code will cause little 
>trouble for maintaining.
>> Well, the current code doesn't support the long id (as the 
>> of HD-audio controller side), so we'd need major changes in anyway.
>> Thus this check is no big issue for maintenance, at least to me :)
>Does the HDA spec define cmd format that accept long form NID?
>If so, can you point me to the specific location please? Thanks.

No.  AFAIK,  HDA doesn't specifiy long NID verb yet,  I said "In the
feature".   but who knows why hardware vendors want to use long
NID in the future,  seems 128 is enough.


>> > what I want is to fix it during parsing connection list, 
>and verify the node
>> > id is valid there .  
>> Heh, this was already fixed :)
>AFAIK, snd_hda_get_connections() won't return NIDs bigger than
>0x7f(short) or 0x7ffff(long).

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