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Erster Outdoor Homeoffice Tag

Posted Fri 17 Mar 2023 11:22:49 AM CET Florian Lohoff in

Es ist soweit. Es ist draussen warm genug. Homeoffice draussen.

c++ symbol mangling

Posted Sat 18 Mar 2023 12:05:06 PM CET Florian Lohoff in

Rebuilding Debian/Stretch for MIPSel with --march=mips2 caused some packages to fail with symbol changes. Which at first puzzled me a bit but i just built the packages with ignoring the symbols.

Now we are at the last 10% of packages and i thought to dig into this a bit deeper.

So i found that some symbols simply changed. They did not disappear but changes in some subtle issue that i did not understand. So i dug into dpkg-gensymbols and how it actually did the decoding - and - Oh boy ... i wish i had not have a look.

I saw the c++ symbols from binaries for at least 15 years and had no clue on what that actually was, but now it was time to find out. Basically the c++ compiler mangles the complete function/method declaration into the c++ symbol.

Consider you have this little c++ snippet:

#include <string>

typedef std::basic_string<char> bstring;

int bar(bstring& foo) {

If you compile this into a shared object the symbol for bar gets:


So how does one decode this, or how is this constructed? So c++filt comes to help to decode:

root@stretch:~# c++filt -n _Z3barRNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE
bar(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)

So you can decode the full symbol to the functions declaration.

Now - after staring at the Debian/Mipsel symbol issues i found something to be missing. Compiling the same test code, with the same compiler on Mipsel and on amd64 caused the __cxx11 to be dropped from the symbol on Mipsel. So i have a broken c++ compiler on Mipsel. I transitioned from Jessies gcc 4.9 to gcc 5.1.1-23 (Which had c++11) to gcc 6.1.1 to gcc 6.3.0 and now i am generating broken symbols. So some libstdc++ abi transition has failed.

Microsoft AD DS - Encoding msDFS-TargetListv2

Posted Mon 27 Mar 2023 11:21:14 AM CEST Florian Lohoff in

When looking for exporting the DFS targets from an AD DS dump created with ldifde you stumple upon tons of issues with bullshit microsoft creates.

First they create an .xml file with information, put this into the AD attribute msDFS-TargetListv2 and fuck up the base64 encoding beyond repair in ldifde:

See this?


Okay - this looks like base64 except the "\" at the beginning. Removing the \ breaks the base64 so you'll need them

After playing around a bit Microsoft fucked this up by replacing the needed "//" with "\".

I guess they simply pushed stuff after the base64 encoder through the filepath decoder or something.

Fucked up beyond repair