linux-kernel - Re: [PATCH] [RFC] net: dsa: mv88e6xxx: Pre-initialize err in mv88e6xxx_port_bridge

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: <87vb35a942.fsf@ketchup.mtl.sfl>
Date:	Mon, 25 Apr 2016 13:31:09 -0400
From:	Vivien Didelot <vivien.didelot@...oirfairelinux.com>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:	"David S. Miller" <davem@...emloft.net>,
	"netdev\@vger.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [RFC] net: dsa: mv88e6xxx: Pre-initialize err in mv88e6xxx_port_bridge_join()

Hi Geert,

Geert Uytterhoeven <geert@...ux-m68k.org> writes:

> On Mon, Apr 25, 2016 at 5:03 PM, Vivien Didelot
> <vivien.didelot@...oirfairelinux.com> wrote:
>> Geert Uytterhoeven <geert@...ux-m68k.org> writes:
>>> drivers/net/dsa/mv88e6xxx.c: In function ‘mv88e6xxx_port_bridge_join’:
>>> drivers/net/dsa/mv88e6xxx.c:2184: warning: ‘err’ may be used uninitialized in this function
>>
>> Interesting, I don't have those warnings on 207afda1b5036009...
>
> It depends on the compiler version (still using 4.1.2) and options.
>
>>> If netdev_notifier_changeupper_info.upper_dev is ever NULL, the bridge
>>> parameter will be NULL too, and the function will return an
>>> uninitialized value.
>>>
>>> Pre-initialize err to zero to fix this.
>>>
>>> Fixes: 207afda1b5036009 ("net: dsa: mv88e6xxx: share the same default FDB")
>>> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
>>> ---
>>> Can this actually happen?
>>
>> bridge cannot be NULL here. Also ps->ports[port].bridge_dev is assigned
>> to it before entering the for loop, so _mv88e6xxx_port_based_vlan_map
>> will be called at least for this port.
>
> But there's no way the compiler can know that...

Or maybe it can in new configurations. Anyway, this fix doesn't hurt,
with a relevant commit message, I'd ack it.

Thanks,

        Vivien