netdev - Re: [PATCH] net: usb: pegasus: fix improper read if get

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: <20190731191446.o2ae53krxcpa4qfb@carbon>
Date:   Wed, 31 Jul 2019 22:14:46 +0300
From:   Petko Manolov <petkan@...leusys.com>
To:     Denis Kirjanov <kda@...ux-powerpc.org>
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [PATCH] net: usb: pegasus: fix improper read if get_registers()
 fail

On 19-07-31 22:10:39, Petko Manolov wrote:
> On 19-07-30 15:13:57, Denis Kirjanov wrote:
> > get_registers() may fail with -ENOMEM and in this
> > case we can read a garbage from the status variable tmp.
> > 
> > Reported-by: syzbot+3499a83b2d062ae409d4@...kaller.appspotmail.com
> > Signed-off-by: Denis Kirjanov <kda@...ux-powerpc.org>
> > ---
> >  drivers/net/usb/pegasus.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
> > index 6d25dea5ad4b..f7d117d80cfb 100644
> > --- a/drivers/net/usb/pegasus.c
> > +++ b/drivers/net/usb/pegasus.c
> > @@ -282,7 +282,7 @@ static void mdio_write(struct net_device *dev, int phy_id, int loc, int val)
> >  static int read_eprom_word(pegasus_t *pegasus, __u8 index, __u16 *retdata)
> >  {
> >  	int i;
> > -	__u8 tmp;
> > +	__u8 tmp = 0;
> >  	__le16 retdatai;
> >  	int ret;
> 
> Unfortunately this patch does not fix anything.  Even if get_registers() fail 
> with -ENOMEM the "for" loop will cover for it and will exit only if the 
> operation was successful or the device got disconnected.  Please read the code 
> carefully.
> 
> So while the patch is harmless it isn't solving a problem.

Actually i am wrong - if "tmp" contains a random value it may accidentally have 
the EPROM_DONE bit set.

Dave, please apply the patch.


thanks,
Petko