Hey Willy, On Sun, Apr 9, 2017 at 3:25 PM, Willy Tarreau <w...@1wt.eu> wrote: > > Hi Jason, > > On Sun, Apr 09, 2017 at 02:59:53PM +0200, Jason A. Donenfeld wrote: > > Hey Willy, > > > > Linux 3.10 is inexplicably missing crypto_memneq, making all crypto > > mac comparisons use non constant-time comparisons. Bad news bears. > > > > 3.12 got these backported with > > d68e944a8fcb2c6212b38064771c9f5af7b0b92c, > > afe5a791d374e50a06ada7f4eda4e921e1b77996, and possibly others. I'd > > suggest following suit, since many people are relying on this kernel > > to do safe crypto. > > Interesting. I remembered seeing some crypto_memneq stuff in the past, > and in fact there was one patch talking about this but trimmed down to > only affect other parts since crypto_memneq is indeed not part of 3.10. > > I'll check if the 3.12 patches above can be safely backported, and I'll > have to re-apply the missing part of the one that was trimmed down > (commit 620c411 ("crypto: more robust crypto_memneq")).
I'm vaguely wondering if you ever decided on backporting this. After I reported the issue to Ubiquiti -- a random vendor doing ipsec with 3.10 -- they actually released a backport of these functions in a security update for their stuff. So I imagine others might want this sort of thing too. Jason