Carlos (@00xc1) header
Carlos (@00xc1) profile picture

Carlos

@00xc1

OSdev, Rust, C, Linux, security and so on.

 Spain
00xc.pages.dev/
Joined October 2019
  • Tweets39
  • Following585
  • Followers81
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Photo by Carlos (@00xc1)Photo by Carlos (@00xc1)
Just finished teaching the hypervisor class! Had many good interactions with students and enjoyed it a lot. @hexacon_fr in October is the next opportunity. If you are interested in reading and writing hypervisors, or low-level technologies in general, come to Paris and join us.
Satoshi Tanda (@standa_t) profile pictureSatoshi Tanda@standa_t4 May 2024
I am excited to be back and offer the in-person training course at the awesome conference, @hexacon_fr hexacon.fr/trainer/tanda/ Gain hands-on experience with virtualization and learn real-world applications of it.
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Replying to @00xc1
And you can even enable the panics in release mode as well: doc.rust-lang.org/cargo/refe… :)
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This is the kind of thing that makes you appreciate even more Rust's approach to things. Signed overflow is always well defined: it causes a panic in debug builds and wraps as 2's complement in release builds. Plus `wrapping_add()`, `saturating_add()`, `checked_add()`, etc.
is-eqv.bsky.social (@is_eqv) profile pictureis-eqv.bsky.social@is_eqv13 Mar 2024
Little known fact: this is also true for u16 overflows (due to integer promotions) EVEN THOUGHT the standard SPECIFICALLY says signed integer overflow are 2s complement wrapping. C semantics are absolutely batshit insane.
Image from is-eqv.bsky.social (@is_eqv)
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Together with my session at #OC3 today I am excited to share that COCONUT-SVSM is now public! 🔒🌴 Check out the announcement at suse.com/c/suse-open-sources… or go directly to the GitHub space github.com/coconut-svsm #ConfidentialComputing
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CVE-2022-24986: KCron: Insecure temporary file handling: Posted by Carlos López on Feb 25Hello list, Find below our report for CVE-2022-24986: Insecure temporary file handling in KDE KCron dlvr.it/SKf5rd
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Carlos retweeted
majek04 (@majek04) profile picture
majek04@majek042 Feb 2022
blog.cloudflare.com/how-to-s… "How to stop running out of ephemeral ports and start to love long-lived connections" Or "Userspace Connectx() on Linux" Or "This is why we need kernel-side connectx()" Or "Why you can have tops 28K outbound UDP connections?" Code github.com/cloudflare/cloudf…
How to stop running out of ephemeral ports and start to love long-lived connections

How to stop running out of ephemeral ports and start to love long-lived connections

Often programmers have assumptions that turn out, to their surprise, to be invalid. From my experience this happens a lot. Every API, technology or system can be abused beyond its limits and break in...

blog.cloudflare.com
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I wrote a _very_ simple (and hopefully correct) implementation of hazard pointers in pure C89 using GCC atomic builtins: github.com/00xc/libdanger
GitHub - 00xc/libdanger: A sane and minimal implementation of hazard pointers in pure C89.

GitHub - 00xc/libdanger: A sane and minimal implementation of hazard pointers in pure C89.

A sane and minimal implementation of hazard pointers in pure C89. - 00xc/libdanger

github.com
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A beginner's attempt at optimizing GCC developers.redhat.com/articl…
A beginner's attempt at optimizing GCC | Red Hat Developer

A beginner's attempt at optimizing GCC | Red Hat Developer

Anyone who engages in C/C++ development on a modern GNU/Linux system typically ends up using the GCC or LLVM compiler, to which Red Hat actively contributes. As a member of the toolchain engineering

developers.redhat.com
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Writeup for Cloudinspect, from @hack_lu CTF 2021. My first VM escape! scavengersecurity.com/posts/…

Hack.lu CTF 2021 - Cloudinspect [Pwn]

NOTE: The following is a writeup for the solution we developed independently for this challenge after the end of the competition.

scavengersecurity.com
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Our writeups for ABBR and Beans Talk, from @asisctf. We worked with @ripp3rsCTF for this CTF, great experience overall! scavengersecurity.com/posts/… scavengersecurity.com/posts/…
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Writeup for Flag Checker, from @DownUnderCTF scavengersecurity.com/posts/…

DownUnderCTF 2021 - Flag Checker [Reversing]

flag checker was a reversing challenge during DownUnderCTF 2021 that got 16 solves. We are given a stripped 64 bit binary ELF file for Linux.

scavengersecurity.com
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Writeup for Paas, from GrabCON CTF 2021 (@thecybergrabs). Format string exploitation in the Linux kernel. scavengersecurity.com/posts/…

GrabCON CTF 2021 - Paas [Pwn]

Paas was a kernel exploitation challenge during GrabCON CTF 2021 that only got a single solve (our own). We are given a tarball and SSH access to a remote server. The compressed archive contains a...

scavengersecurity.com
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I’ve recently published my first writeup for “devprivops” bash challenge from #FWordCTF 2021 (by @FwordTeam). Thanks to @ScavengerSec for their support. scavengersecurity.com/posts/…
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Writeup for "Containers?", from FwordCTF 2021. A journey in Linux namespaces. scavengersecurity.com/posts/…

FwordCTF 2021 - Containers? [Bash]

Containers? was a bash challenge during FwordCTF 2021 that got 9 solves. We are given an ELF binary, called sealer, and access to a remote server via SSH.

scavengersecurity.com
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Writeup for optimizeme, from RaRCTF 2021 scavengersecurity.com/posts/…

RaRCTF 2021 - optimizeme [Reversing]

optimize me was a reversing challenge during RaRCTF 2021 that got 16 solves. We are given an ELF binary and the following sentence: rust is fast, but not fast enough.

scavengersecurity.com
Linux Internals: How /proc/self/mem writes to unwritable memory offlinemark.com/2021/05/12/a…
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Writeup for GRUB, from OMH 2021 CTF by @p4_team scavengersecurity.com/posts/…

OMH 2021 CTF - GRUB [Reversing]

GRUB is a reversing challenge that got 20 solves. We are given a bootable GRUB file called grub.iso: 1 2 $ file grub.iso grub.iso: DOS/MBR boot sector; GRand Unified Bootloader, stage1 version 0x79,...

scavengersecurity.com
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You can't stop me anymore @oooverflow
Image from Zach Wade (@zwad3)
Zach Wade (@zwad3) profile pictureZach Wade@zwad330 Apr 2021
👀
Image from Zach Wade (@zwad3)
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The first-quarter of 2021 ended, and the ranking positions got updated just a few hours ago. We are proud to announce that we scored 37th on the global ranking and 1st on the Spanish one on CTFTime. #CTF #CTFTime
Image from Scavenger Security (@ScavengerSec)
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Writeup for Chains (UMassCTF 2021) scavengersecurity.com/posts/…

UMassCTF 2021 - Chains [Reversing]

Chains is a reversing challenge that got 20 solves. We are given a stripped aarch64 (ARM 64 bit) ELF binary called chains:

scavengersecurity.com
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