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

[Brian Norris]

On Thu, Dec 14, 2023 at 3:38 AM David Lin <yu-hao.lin@xxxxxxx> wrote:
> > From: Francesco Dolcini <francesco@xxxxxxxxxx>
> >
> > On Thu, Dec 14, 2023 at 02:22:57AM +0000, David Lin wrote:
> > > > From: Brian Norris <briannorris@xxxxxxxxxxxx>
> > > > 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.

Right, there's tons of code that could potentially be affected, and
this is definitely a separate patch. (Your feature only adds on to the
existing issue, so these are separate logical changes.)

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

Well, it doesn't really matter than your TLV is "first" -- if there's
an overflow, there's an overflow. Maybe the 8 bytes you're adding here
are the necessary tipping point. I don't know without doing some kind
of informal mathematics/proof.

Brian