Re: When scrubbing secrets in memory doesn't work

2002-11-05 Thread Perry E. Metzger
"Michael Howard" <[EMAIL PROTECTED]> writes: > On the surface, this looks fine, until you look at the ASM output, and > you see the call to memset has been removed by the optimizer because > szPwd is not read once the function completes. Hence, the secret data is > still floating in memory. Thats

Re: When scrubbing secrets in memory doesn't work

2002-11-07 Thread Gianni Tedesco
On Tue, 2002-11-05 at 22:13, Michael Howard wrote: > On the surface, this looks fine, until you look at the ASM output, and > you see the call to memset has been removed by the optimizer because > szPwd is not read once the function completes. Hence, the secret data is > still floating in memory. >

Re: When scrubbing secrets in memory doesn't work

2002-11-07 Thread Andy Polyakov
> > On the surface, this looks fine, until you look at the ASM output, and > > you see the call to memset has been removed by the optimizer because > > szPwd is not read once the function completes. Hence, the secret data is > > still floating in memory. > > > > This optimization, common in most m

Re: When scrubbing secrets in memory doesn't work

2002-11-08 Thread Valdis . Kletnieks
On Wed, 06 Nov 2002 12:55:26 GMT, Gianni Tedesco <[EMAIL PROTECTED]> said: > FYI: tested on gcc version 2.96 2731 (Red Hat Linux 7.3 2.96-112) > which doesn't seem to do this. What compiler version/flags, if any does > this depend on? gcc 3 and later (3.2 is current) are well able to do this

Re: When scrubbing secrets in memory doesn't work

2002-11-09 Thread Michael Zimmermann
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 At Dienstag, 5. November 2002 23:13 Michael Howard wrote: > During the Windows Security Push in Feb/Mar 2002, we noticed an > 'interesting' anomaly with code to scrub passwords that looks like this: > > bool DoSensitiveStuff() { > bool fOK = fals

RE: When scrubbing secrets in memory doesn't work

2002-11-12 Thread Michael Wojcik
Reposted. > -Original Message- > From: Michael Wojcik > Sent: Wednesday, November 06, 2002 12:25 AM > To: 'Michael Howard' > Cc: [EMAIL PROTECTED] > Subject: RE: When scrubbing secrets in memory doesn't work > > > > From: Michael Howard [mai

Re: When scrubbing secrets in memory doesn't work

2002-11-15 Thread Jan Echternach
On Fri, Nov 08, 2002 at 05:23:34PM +0100, Michael Zimmermann wrote: > Not to declare the intermediate storage for sensitive > data as 'volatile' is a coding flaw. An esily overlooked > one, yes, but nevertheless... Like forgetting to protect > critical code with semaphores. 'volatile' isn't suffic

RE: When scrubbing secrets in memory doesn't work

2002-11-17 Thread Michael Wojcik
> From: Jan Echternach [mailto:[EMAIL PROTECTED]] > Sent: Monday, November 11, 2002 11:47 AM > On Fri, Nov 08, 2002 at 05:23:34PM +0100, Michael Zimmermann wrote: > > Not to declare the intermediate storage for sensitive > > data as 'volatile' is a coding flaw. An esily overlooked > > one, yes, bu

Re: When scrubbing secrets in memory doesn't work

2002-11-18 Thread Nicholas Weaver
On Thu, Nov 14, 2002 at 02:44:58AM -0800, Michael Wojcik composed: > Scrubbing is clearly no more than a best-effort attempt to make it more > difficult to retrieve sensitive data from memory. I think it's of dubious > value, frankly, and this thread has probably prompted more discussion than > it

Re: When scrubbing secrets in memory doesn't work

2002-11-18 Thread Florian Weimer
Richard Moore <[EMAIL PROTECTED]> writes: > It's worth noting that on systems such as linux and solaris, it is > easy to avoid the paging problem by locking the process into > memory. "Locking into memory" does NOT mean "avoid paging". AFAIK, there are operating systems in which memory which has

Re: When scrubbing secrets in memory doesn't work

2002-11-19 Thread Peter Watkins
On Mon, Nov 18, 2002 at 04:36:57PM +, Richard Moore wrote: > Nicholas Weaver wrote: > > On Thu, Nov 14, 2002 at 02:44:58AM -0800, Michael Wojcik composed: > > The bigger concern is when the memory is paged to disk, and that > > record may have a much MUCH longer time window. But scrubbing has

Re: When scrubbing secrets in memory doesn't work

2002-11-20 Thread Richard Moore
Nicholas Weaver wrote: On Thu, Nov 14, 2002 at 02:44:58AM -0800, Michael Wojcik composed: The bigger concern is when the memory is paged to disk, and that record may have a much MUCH longer time window. But scrubbing has no real effect on this, this is an effect of VM memory management and memory