yara -r trapped in endless loop on symlink to current directory

[ruppde]

Describe the bug If yara -r runs into a symlink to .. it's trapped in a endless loop. A common example of this is the Debian package of llvm which creates in /lib/llvm-11/build/ the following symlink:

lrwxrwxrwx 1 root root    2 Jan 27  2022 Debug+Asserts -> ../

To Reproduce

$ mkdir -p /tmp/d1/d2
$ cd /tmp/d1/d2
$ ln -s .. d3
$ ln -s .. d4
$ echo "rule test { condition: filesize > 1MB }" > test.yar
$ $ yara -rn test.yar .
test ./test.yar
test ./d4/d2/test.yar
test ./d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
test ./d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/d4/d2/test.yar
...

Expected behavior Don't follow symlinks to ..

Please complete the following information:

• OS: Linux
• YARA version: 4.3.2

Additional context This fixes to problem but there are probably more elegant solutions (I'm not a C coder ;)