RE: [EXT] Re: [PATCH v2] wifi: mwifiex: fix STA cannot connect to AP

[David Lin]

> From: Francesco Dolcini <francesco@xxxxxxxxxx>
> Sent: Thursday, December 14, 2023 3:35 PM
> To: David Lin <yu-hao.lin@xxxxxxx>
> Cc: Brian Norris <briannorris@xxxxxxxxxxxx>;
> linux-wireless@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> kvalo@xxxxxxxxxx; francesco@xxxxxxxxxx; Pete Hsieh
> <tsung-hsien.hsieh@xxxxxxx>; stable@xxxxxxxxxxxxxxx
> Subject: Re: [EXT] Re: [PATCH v2] wifi: mwifiex: fix STA cannot connect to AP
> 
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> 
> Hello David,
> 
> On Thu, Dec 14, 2023 at 02:22:57AM +0000, David Lin wrote:
> > > From: Brian Norris <briannorris@xxxxxxxxxxxx>
> ...
> > > Nitpick: "fix STA cannot connect to AP" isn't the best commit
> > > message; that could describe an enormous number of fixes. Maybe
> > > something more like "Configure BSSID consistently when starting AP"?
> >
> > Thanks for your suggestion. I will change commit message as you
> > suggested. Does it mean I should create another patch from v1?
> 
> Just create `[PATCH v3] wifi: mwifiex: fix STA cannot connect to AP`
> 
> Add the change suggested by Brian and the tags you received on this v2:
> 
>  - Reviewed-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
>  - Tested-by: Rafael Beims <rafael.beims@xxxxxxxxxxx> # Verdin iMX8MP /
> SD8997 SD
>  - Acked-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> 

O.K. Thanks.

> > > Not directly related to this patch, but while you're expanding the
> > > size of this command buffer: it always felt like a
> > > security-hole-in-waiting that none of these command producers do any
> kinds of bounds checking.
> > > We're just "lucky" that these function only generate contents of
> > > ~100 bytes at max, while MWIFIEX_SIZE_OF_CMD_BUFFER=2048. But, just
> > > add a few more user-space controlled TLV params, and boom, we'll
> > > have ourselves a nice little CVE.
> > >
> > > It probably wouldn't hurt to significantly write much of this
> > > driver, but at a minimum, we could probably use a few checks like this:
> > >
> > >         cmd_size += sizeof(struct host_cmd_tlv_mac_addr);
> > >         if (cmd_size > MWIFIEX_SIZE_OF_CMD_BUFFER)
> > >                 return -1;
> > >         // Only touch tlv *after* the bounds check.
> > >
> > > That doesn't need to block this patch, of course.
> > >
> > > Brian
> > >
> >
> > I will modify the code for next patch.
> 
> I would suggest not modify this in this patch, we should fix all the code that
> is subjected to this potential issue.
> 
> I would personally do a follow-up patch just to add the check to avoid
> overflowing the cmd buffer everywhere it is used.
> 
> Francesco


O.K. I will only change commit message. In fact, this TLV command is added as the first one command.