Segfault when calling pm3 from Lua (experimental_lib)

[doegox]

Quick notes not to forget:

$ cd client/experimental_lib
$ ./01make_lib.sh
$ cd example_lua
$ ./01link_lib.sh
$ ./02run_test.sh
[=] Session log /home/phil/.proxmark3/logs/log_20241027110937.txt
[+] Using UART port /dev/ttyACM0
[+] Communicating with PM3 over USB-CDC
Segmentation fault

Problem appeared somewhere when Lua got migrated from 5.2 to 5.4:

but to test these old commits, one has to add the missing line ${PM3_ROOT}/client/src/lua_bitlib.c in client/experimental_lib/CMakeLists.txt as done later with 50d9042a5cd5415dce0c54ad077529f12cbee108

[doegox]

@jmichelp could you have a look please?

[jmichelp]

Just had a go at testing. Works for me after a few tweaks due to OSX:

• had to enforce SKIPQT=1 in the build script otherwise compilation fails (probably some missing CFLAGS as the pre-processor complains about c++17 standard being required)
• had to manually symlink pm3.so because the build library is .dylib on OSX
• had to change the path to the USB serial
• had to also symlink dkjson.lua to run the second test in the example otherwise the Lua module wasn't found.

No segfault.

Will test on a Linux next.

[jmichelp]

Same behavior on Linux after an extra ln -sf ../../lualibs/dkjson.lua . to run the tests until the end

[jmichelp]

Considering that the example relies on the system lua binary, my current assumption would be that client and libraries were compiled against the bundled lua5.4 library but you're trying to run the script using your system lua.5.2 interpreter.

I could confirm this behavior on my Linux machine by running:

$ sudo apt remove lua5.4
$ sudo apt install lua5.2
$ ./02run_test.sh
[...]
[+] Communicating with PM3 over USB-CDC
./02run_test.sh: line 8: 2957012 Segmentation fault      ./test.lua

[doegox]

😮🤦‍♂️ that makes totally sense, thanks! I pushed a fix to call lua5.4 in the shebang and added the dkjson symlink