Re: When scrubbing secrets in memory doesn't work

[Michael Zimmermann <zim () vegaa de>]

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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 = false;
>       const size_t cbPwd = 64;
>       char szPwd[cbPwd];
>       if (GetUserPassword(szPwd,cbPwd-1))
>               if (DoSomethingWithPassword(szPwd))
>                       fOK = true;
>
>       memset(szPwd,0,cbPwd);
>
>       return fOK;
> }

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.

- -- 
Michael Zimmermann  (http://vegaa.de)
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