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brtmr

345 karma · joined March 22, 2015

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brtmr··on Clojure 1.11 is now available
Sweet, variadic maps sound really useful, I am always having to take a moment when mixing functions that take keyword arguments vs. option maps. Also, some of those functions added to core show up in my code as convenience functions - Glad I can now just make use of core.
brtmr··on The hardest program I've ever written (2015)
> The good thing about modern languages is that you don't depend on the location of code in the page for it to work. If you start worrying too much about exact formatting, you throw away this big advantage.

Counterpoint: When using a formatter, I stop worrying about formatting. It's a job for a computer, done by a computer. Humans are bad at consistency and discipline, computers are great at it. I want to concentrate on the things that matter, and formatting isn't one of those.

Especially in larger teams, consistent formatting is just nice. No conflicting styles in the same file, and more meaningful diffs.

brtmr··on Ask stupid questions as a new software developer
Absolutely. There is no magic point in your career where you know everything. Plus, it fosters a culture of asking. And often you’re not the only one in the room who doesn’t know. Often asking a stupid question like „I don’t know that word - Can you explain?“ will prompt further questions from other people.
brtmr··on Nvidia GPUs can break Chrome's incognito mode
It is still possible to inspect previous framebuffers after rebooting.
brtmr··on Nvidia GPUs can break Chrome's incognito mode
This is exactly the reason why the webgl standard strictly forbids allocating buffers without clearing them first. Otherwise anything the user looked at since the last power cycle - including emails, passwords, private keys, ... -could be extracted by visiting a website.
brtmr··on Nvidia GPUs can break Chrome's incognito mode
Previous discussion on the same subject, about a post written by me: https://news.ycombinator.com/item?id=9245980

Basically, this issue is not restricted to NVidia GPUs or specific operating systems - This can be reproduced on Windows, Linux and OSX. Basically the concept of memory safety does not exist in the gpu space - which is the reason why the webgl standard is so strict about always zeroing buffers. The issue of breaking privacy and privilege boundaries on a multiuser system is very real, and there is no workable solution. This seems to be one of those problems where a lot of people are aware, but no one is sure how to fix it and so it just stays how it is.

brtmr··on Hexagonal Langton's Ant 2 – Colors, Gliders and Highways
woa. that looks awesome ;) what am i looking at - whats the rule? and are you also coloring the spaces the ant has already been on, but that reverted to their original state?
brtmr··on Hexagonal Langton's Ant 2 – Colors, Gliders and Highways
Nice! I like how the world grows with the movement of the ant, as opposed to my rather boring static one
brtmr··on Hexagonal Langton's Ant 2 – Colors, Gliders and Highways
Thanks! I have also discovered a pattern that is fully space-filling: BPBBP - will slowly fill the entire screen with a growing green hexagon, with a single yellow dot at the origin.
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
In these tests we were able to recover screenshot-like views of entire websites after viewing them in the newest version of chromium, then running the poc on the local system.
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
Howeverm we did not test on any other browser technologies like flash or java. I cannot guarantee that there is no possibility to access any VRAM from within a browser.
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
i have added your blogpost to the document as prior art.
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
Oracle also discourages the use of 3D acceleration for untrusted hosts. See here: http://www.virtualbox.org/manual/ch04.html#guestadd-3d
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
Yes, this is the same way I found this - In the course of another project I had the same "Huh, this is weird" moment. Then I started experimenting with different setups (Linux, Windows, VMs) and was surprised that I apparently almost always succeeded in recovering stuff.
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
see _wmd's comment below[0]

[0]https://news.ycombinator.com/item?id=9246244

brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
Yes, that is the exact same issue. While searching for any prior art, i did not find your blog post, but the problem seemed far too obvious for me to be the only one to have ever stumbled upon it. I do think this issue needs some exposure, there seem to be a lot of potential security ramifications.
brtmr··on Is Your VirtualBox Reading Your E-Mail? Reconstruction of FrameBuffers from VRAM
The webgl standard has rather strong memory safety considerations:

WebGL resources such as textures and vertex buffer objects (VBOs) must always contain initialized data, even if they were created without initial user data values.[0]

As long as browser vendors implement this (and chrome and firefox seem to), this should not be an issue.

[0] https://www.khronos.org/registry/webgl/specs/1.0.3/