Skip to content
  • Home Home Home, current page.
  • Moments Moments Moments, current page.

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
RichFelker's profile
Rich Felker
Rich Felker
Rich Felker
@RichFelker

Tweets

Rich Felker

@RichFelker

Yeah, I do @musllibc, FOSS & infosec stuff. But now is not the time for a mostly-/only-tech Twitter feed.

musl-libc.org
Joined March 2014

Tweets

  • © 2018 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Sam Tobin-Hochstadt‏ @samth May 31
      Replying to @filpizlo

      I was thinking about this yesterday, but the hard question is what should out of bounds writes be specified to do? What about UAF? I don't see how to specify this without ruling out genuine optimizations (which is not to say that many of the dumb UB shouldn't be eliminated).

      3 replies 0 retweets 3 likes
    2. John Regehr‏ @johnregehr May 31
      Replying to @samth @filpizlo

      yeah, there are several UBs that are hard to eliminate without changing these languages beyond recognition. this ship sailed long ago. we should focus on new languages but also on C/C++ dialects that don't aim for full back compatibility.

      3 replies 2 retweets 8 likes
    3. Filip Jerzy Pizło‏ @filpizlo May 31
      Replying to @johnregehr @samth

      I don’t think that’s right. The signed math UBs and strict aliasing are just dumb. You don’t need to replace the language to fix those.

      3 replies 0 retweets 1 like
    4. John Regehr‏ @johnregehr May 31
      Replying to @filpizlo @samth

      I'm more talking about things like use of dead stack slots and to a much lesser extent, use of uninitialized storage

      1 reply 0 retweets 0 likes
    5. John Regehr‏ @johnregehr May 31
      Replying to @johnregehr @filpizlo @samth

      since probably >95% of code suffers a negligible performance penalty if you just zero all allocations

      4 replies 0 retweets 0 likes
    6. Filip Jerzy Pizło‏ @filpizlo May 31
      Replying to @johnregehr @samth

      Sounds like you’re saying that this is another UB that is trivial to fix by just specifying that variables get zero-initialized.

      1 reply 0 retweets 1 like
    7. John Regehr‏ @johnregehr May 31
      Replying to @filpizlo @samth

      for most code, yes, but as Sam said it's the UAFs and OOBs that are hard to define sensibly without changing the language too much

      1 reply 0 retweets 0 likes
    8. Filip Jerzy Pizło‏ @filpizlo May 31
      Replying to @johnregehr @samth

      OOB and UAF means you write to some other object or trap. Seems easy to specify to me.

      2 replies 0 retweets 0 likes
    9. Rich Felker‏ @RichFelker May 31
      Replying to @filpizlo @johnregehr @samth

      Writing to "some other object" can have arbitrarily bad effects (full UB) unless you require that freed memory never be usable internally by the implementation (including as heap bookkeeping).

      1 reply 0 retweets 1 like
    10. Filip Jerzy Pizło‏ @filpizlo May 31
      Replying to @RichFelker @johnregehr @samth

      If the malloc is written in C (it is), then there's no problem: the C standard's claim that "any byte in any object would be overwritten by OOB" would capture the effect on malloc.

      1 reply 0 retweets 0 likes
      Rich Felker‏ @RichFelker May 31
      Replying to @filpizlo @johnregehr @samth

      It's not. It's defined formally as part of the language. Typical C implementations would not be permissible under your proposal.

      7:59 PM - 31 May 2018
      2 replies 0 retweets 0 likes
        1. New conversation
        2. Filip Jerzy Pizło‏ @filpizlo May 31
          Replying to @RichFelker @johnregehr @samth

          Typical C implementations implement malloc in C.

          1 reply 0 retweets 0 likes
        3. Rich Felker‏ @RichFelker May 31
          Replying to @filpizlo @johnregehr @samth

          malloc cannot be implemented in C. It can at best be implemented in a mix of C and special constructs or rule-exceptions outside the C language.

          1 reply 0 retweets 0 likes
        4. Filip Jerzy Pizło‏ @filpizlo May 31
          Replying to @RichFelker @johnregehr @samth

          I assure you that I've implemented malloc in C. It was in a .c file and it compiled with a C compiler. Separately, I don't care if the spec in its current form recognizes my malloc as being written in C. That's not relevant to whether or not it's written in C.

          0 replies 0 retweets 0 likes
        5. End of conversation
        1. Rich Felker‏ @RichFelker May 31
          Replying to @RichFelker @filpizlo and

          If you want to throw that formality out and treat all the standard interfaces as implemented in C without constraints that they honor your restrictions on UB, then your restrictions really do nothing.

          0 replies 0 retweets 0 likes
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2018 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Cookies
        • Ads info