netdev - 回覆: 回覆: [PATCH net-next] net: ftgmac100: Fix potential NULL dereference in error handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:
 <SEYPR06MB5134C7E0E578CB8AB92AA76F9D9A2@SEYPR06MB5134.apcprd06.prod.outlook.com>
Date: Tue, 10 Sep 2024 06:19:54 +0000
From: Jacky Chou <jacky_chou@...eedtech.com>
To: Dan Carpenter <dan.carpenter@...aro.org>, Andrew Lunn <andrew@...n.ch>
CC: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>, Uwe Kleine-König
	<u.kleine-koenig@...gutronix.de>, Jacob Keller <jacob.e.keller@...el.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject:
 回覆: 回覆: [PATCH net-next] net: ftgmac100: Fix potential NULL dereference in error handling

Hello, Dan

> On Mon, Sep 09, 2024 at 02:03:32PM +0200, Andrew Lunn wrote:
> > > > Are you actually saying:
> > > >
> > > >         if (netdev->phydev) {
> > > >                 /* If we have a PHY, start polling */
> > > >                 phy_start(netdev->phydev);
> > > >         }
> > > >
> > > > is wrong, it is guaranteed there is always a phydev?
> > > >
> > > This patch is focus on error handling when using NC-SI at open stage.
> > >
> > >          if (netdev->phydev) {
> > >                  /* If we have a PHY, start polling */
> > >                  phy_start(netdev->phydev);
> > >          }
> > >
> > > This code is used to check the other cases.
> > > Perhaps, phy-handle or fixed-link property are not added in DTS.
> >
> > I'm guessing, but i think the static analysers see this condition, and
> > deducing that phydev might be a NULL. Hence when phy_stop() is called,
> > it needs the check.
> >
> > You say the static analyser is wrong, probably because it cannot check
> > the bigger context. It can be NULL for phy_start() but not for
> > phy_stop(). Maybe you can give it some more hints?
> >
> > Dan, is this Smatch? Is it possible to dump the paths through the code
> > where it thinks it might be NULL?
> 
> Adding a check here is the correct thing.  The current code works because we
> only have the one goto after the call to phy_start(netdev->phydev), but as soon
> as we add a second goto then it will crash.

Could you share more detail about the crash is happening when you add a second goto?
I'm wondering if there are other things I missed.
Thank you.

> 
> Silencing this warning means tying the information from probe() into it.  It's a
> fun problem but not something I'm going to do this year.
> 

Jacky