oss-security - Re: CVE request: Kernel MSM - Memory leak in drivers/base/genlock.c

Follow @Openwall on Twitter for new release announcements and other news

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

Date: Mon, 25 Nov 2013 17:20:17 -0800
From: Seth Arnold <seth.arnold@...onical.com>
To: "Christey, Steven M." <coley@...re.org>
Cc: "oss-security@...ts.openwall.com" <oss-security@...ts.openwall.com>
Subject: Re: CVE request: Kernel MSM - Memory leak in
 drivers/base/genlock.c

On Tue, Nov 26, 2013 at 12:57:23AM +0000, Christey, Steven M. wrote:
> Kurt said:
> 
> >> The Genlock driver does not properly initialize all members of a
> >> structure before copying it to user space. This allows a local
> >> attacker to obtain potentially sensitive information from kernel
> >> stack memory via ioctl system calls.
> >
> >This should be classified as CWE-200 Information Disclosure, "memory
> >leak" refers to memory being used and not released properly, resulting
> >in out of memory conditions.
> 
> In CWE, we discourage the "memory leak" term because it has multiple
> meanings and interpretations: (1) that memory is allocated but never
> released, or (2) that sensitive portions of memory are accidentally
> disclosed to untrusted parties.
> 
> This request sounds like variant (2) of the varying uses of the "memory
> leak" term, although Kurt's interpretation seems to be that it's about
> variant (1), which further reinforces my personal desire to see that
> term go away forever.

I wrote a response to Kurt, suggesting that he had mis-diagnosed the
problem but did not send my response when I found that his message said
the same thing mine said once you replace his first ',' with a ';'. Try
this instead:

> >This should be classified as CWE-200 Information Disclosure; "memory
> >leak" refers to memory being used and not released properly, resulting
> >in out of memory conditions.

[Kurt's words with the first comma replaced with a semicolon.]

It's amazing what a difference two pixels can make. :)

> Anyway... Note that, as this issue is described, "information
> disclosure" actually results from a root cause in which certain
> locations are not properly initialized.  Thus CWE-665: Improper
> Initialization (or its child CWE-457 Use of Uninitialized Variable) are
> probably more appropriate characterizations of the core issue; in this
> case, it happens to lead to memory disclosure, but in other cases, it
> might lead to privilege escalation or other consequences (depending on
> how the uninitialized data is used.)

I came up with CWE 212 before I properly parsed Kurt's mail:
CWE-212: Improper Cross-boundary Removal of Sensitive Data

With so much to chose from it's surprising the fix is one line of code. :)


Thanks

Download attachment "signature.asc" of type "application/pgp-signature" (491 bytes)

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.