DNS aggregation over TLS

computer dns network internet tls

In a previous post, I tried different solutions for tunnelling DNS over TLS. One of those solutions was using a dedicated DNS-over-UDP fake service replying to all queries with the truncate flag set: this was causing the stub resolvers to retry the query using a TCP-based virtual-circuit. This solution is interesting because it is dead simple (it fits in a few line of codes) but it is clearly a hack. Here, I'm using a dedicated DNS forwarder aggregating all the incoming DNS-over-UDP requests over a single persistent TCP virtual-circuit.

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Debugging use-after-free with RR reverse execution

computer debug gdb rr simgrid

RR is a very useful tool for debugging. It can record the execution of a program and then replay the exact same execution at will inside a debugger. One very useful extra power available since 4.0 is the support for efficient reverse execution which can be used to find the root cause of a bug in your program by rewinding time. In this example, we reverse-execute a program from a case of use-after-free in order to find where the block of memory was freed.

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Private PostgreSQL instance

computer sql

How to create a private on-demand PostgreSQL instance accessible only for the local user over UNIX socket.

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SimGridMC: The Big Split (and Cleanup)

computer simgrid system

In my previous SimGrid post, I talked about different solutions for a better isolation between the model-checked application and the model-checker. We chose to avoid the (hackery) solution based multiple dynamic-linker namespaces in the same process and use a more conventional process-based isolation.

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FTL data file

computer video-game ftl reverse-engineering

FTL is a very nice (and quite difficult) rogue-like-ish game with space battles, teleporters, management of the energy of your ship, asteroid fields, alien species, droids (drones), etc. It is quite cheap, DRM-free and available natively on Intel-based GNU/Linux. These are notes taken while trying to find out the format of the .dat files of the game containing the game assets, ships statistics, events, etc. when I had not access to the internet to find the solution. There's a companion C program, ftldat, for extracting the files within the archives and generating archives. Unsurprisingly, similar tools with the same name already exists. However, the description of the process of reverse-engineering a (very simple) binary format might be interesting for someone out there.

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I can has systray?

computer gui kde

In Plasma 5, support for the XEmbed-based “legacy” systray protocol was removed: only the new SNI protocol is handled. However, in the real worl a lot of applications do not handle the new protocol: Qt4 and Qt5 applications can be fixed by installing the sni-qt (currently in experimental) and libdbusmenu-qt5 respectively but other applications (such as GTK ones) must be patched/recompiled with SNI support. Without this, windows disappear into oblivion 😿. You can have a seamless systray-enabled Plasma panel with a single (OK, two) line of shell 😼.

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