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A comment on SSH gets protection against side-channel attacks. Parent comment

Re:SSH gets protection against side-channel attacks by cesarb on Friday June 21, 2019 @10:15AM (#20242664)
> Compilers these days are very good at detecting "dummy" memsets to memory that's never read afterwards and optimize them away. You have to use some dirty tricks to get the compiler to do what you want (copious amounts of volatile helps).

Or you can use explicit_bzero(), which is designed for that use case.

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Re:SSH gets protection against side-channel attacks by loeg on Friday June 21, 2019 @10:45AM (#20242906)
Sure, although this is a non-standard and potentially non-portable extension. memset_s in Annex K is standard, but all of Annex K is optional, and like the rest of Annex K, it has an awful interface.
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Re:SSH gets protection against side-channel attacks by rurban on Saturday June 22, 2019 @10:08AM (#20249618)
explicit_bzero or SecureZeroMemory are all insecure against those new sidechannel attacks we are talking about here. Only memset_s is.

You really need a mfence (full memory barrier), not just a compiler barrier, maybe even a clflush.

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