Re: New function: consttime_memcmp(3)

[Taylor R Campbell <campbell+netbsd-tech-userlevel%mumble.net@localhost>]

   Date: Mon, 16 Mar 2015 08:54:17 +0100
   From: "Kamil Rytarowski" <n54%gmx.com@localhost>

   Taylor R Campbell wrote:
   >
   >    Date: Mon, 16 Mar 2015 01:58:19 +0100
   >    From: "Kamil Rytarowski" <n54%gmx.com@localhost>
   > 
   >    I'm attaching a patch against current adding a new libc and
   >    kernel function: consttime_memcmp(3). The code is borrowed
   >    from OpenBSD timingsafe_memcmp(3) [1].
   > 
   > Why?  What do you want to use this for?
   > 

   My personal use-case is playing with the code from src/lib/libssl (applies for LibreSSL), which comes from OpenBSD.

   grep -r timingsafe_memcmp src/lib/libssl

In every one of those cases, `timingsafe_memcmp' can be correctly
(and safely) replaced by `!consttime_memequal'.