linux-kernel - Re: [PATCH] usb: host: ehci-sched: avoid possible NULL dereference

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]

Date:   Mon, 5 Oct 2020 21:25:44 -0400
From:   "stern@...land.harvard.edu" <stern@...land.harvard.edu>
To:     "Harley A.W. Lorenzo" <hl1998@...tonmail.com>
Cc:     Sudip Mukherjee <sudipm.mukherjee@...il.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-safety@...ts.elisa.tech" <linux-safety@...ts.elisa.tech>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Subject: Re: [PATCH] usb: host: ehci-sched: avoid possible NULL dereference

On Mon, Oct 05, 2020 at 11:19:02PM +0000, Harley A.W. Lorenzo wrote:
> On Monday, October 5, 2020 5:31 PM, Sudip Mukherjee <sudipm.mukherjee@...il.com> wrote:
> 
> > find_tt() can return NULL or the error value in ERR_PTR() and
> > dereferencing the return value without checking for the error can
> > lead to a possible dereference of NULL pointer or ERR_PTR().
> 
> Looks fine to me. There is in fact no checks of the return value
> before a dereference here, and this solves that.
> 
> Reviewed-by: Harley A.W. Lorenzo <hl1998@...tonmail.com

No, this patch is wrong.  In fact, these calls to find_tt() cannot 
return NULL or an ERR_PTR value.

Alan Stern