Compiler support for erasure of sensitive data

[Zack Weinberg]

On 09/09/2015 12:52 PM, Paul_Koning@Dell.com wrote:
> Then again, suppose all you had is explicit_bzero, and an annotation
> on the data saying it's sensitive.  Can static code analyzers take
> care of the rest?  If so, this sort of thing doesn't need to be in
> the compiler.

The thing that absolutely has to be implemented in the compiler (AFAICT)
is register clearing.  I'm undecided as to how *necessary* that is.
There certainly can be a lot of sensitive data in registers (e.g. AESNI
puts an entire AES key schedule in xmm registers).  I don't know of any
exploits that depended on salvaging such data from registers, but I
don't follow exploit research closely.

zw