knweiss

Joined 17 years ago

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Jan 3

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Comment · 3 years ago

I can’t believe you’re the only one mentioning this.

Comment · 4 years ago

Feedback and bug reports (exception: security) should be public and users should be able to vote. Apple then could prioritize much better.

Also, take a look at their user forums: They are full of bug reports with hundreds of users having the same problems - and nothing happens. I really wish they would react much better with official acknowledgments, references to open bugs, workarounds, etc. It is depressing how much collective time is wasted.

Comment · 4 years ago

Interactive PFSA map for the US: https://www.ewg.org/interactive-maps/pfas_contamination/map/

Comment · 7 years ago

FWIW: AMD offers this: https://developer.amd.com/amd-aocl/blas-library/

The source code is available on GitHub.

Comment · 8 years ago

IMHO it's worth mentioning that this discussion is about Spectre variant 1 (as is the original article). I.e. we should not write "Spectre" when we talk about a specific Spectre variant.

I'm mentioning this because (at least to my understanding) in Spectre variant 2 the entire address space of the victim process can be used to find the "gadget" i.e. an usable target for the indirect branch. This means that making only your input validation code "spectre-free" is not good enough for variant 2. (This is why e.g. OpenSSH recently started using the (Spectre variant 2!) retpoline compiler flags of GCC/LLVM if available. See this thread for details: https://lists.mindrot.org/pipermail/openssh-unix-dev/2018-Fe...)

Comment · 9 years ago

There are better cryptographic hash functions (e.g. Blake2) than SHA1 that are even faster. Check out the "results" slide of this slide deck for the cycles per byte table: https://blake2.net/acns/slides.html

Comment · 10 years ago

From the OpenSSH moduli(5) man page:

  "When performing Diffie-Hellman Group Exchange, sshd(8)
  first estimates the size of the modulus required to
  produce enough Diffie-Hellman output to sufficiently
  key the selected symmetric cipher. sshd(8) then randomly
  selects a modulus from /etc/ssh/moduli that best meets
  the size requirement."

The problem is

a) OS distributions ship pre-computed moduli in the /etc/ssh/moduli file. I.e. most users don't change these moduli. This facilitates pre-computation attacks.

b) These moduli are often too short (<2048 bit).

You can create your own moduli with ssh-keygen (see the "MODULI GENERATION" section in the ssh-keygen manpage).

FWIW: Here's my open bug for RHEL7 where I try to convince Red Hat to improve the situation (including more details and references):