Messages in this thread | | | Date | Mon, 5 Jan 2015 10:36:37 +1100 | From | Herbert Xu <> | Subject | Re: [PATCH] Use memzero_explicit to clear local buffers |
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On Sun, Jan 04, 2015 at 11:49:09PM +0100, Giel van Schijndel wrote: > > > sctx does not point to stack memory so this is bogus. > > > > Only stack memory cleared just before it goes out of scope needs > > memzero_explicit. > > Is that because the compiler can't safely optimize memset(0) away for a > variable with greater-than-local scope?
Exactly. memzero_explicit is not a marker for sensitive data. Its only purpose is to prevent the compiler from optimising away zeroing that occurs at the end of a scope.
Daniel, we should add a comment so that people stop sending bogus patches with memzero_explicit.
Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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