[BUG] Null pointer dereference vulnerability in classifier.c

[shiyujunz]

I have found a potential null pointer dereference bug in classifier.c and would like to report it to the maintainers. This vulnerability has the potential to cause unexpected application behavior, crashes. Can you please help me check it? Thank you for your effort and patience!

Below is the execution sequence of the program that may produce null pointer dereference bug .
First, in file classifier.c, function get_regression_values calls strchr on line 23, which may return null. p is assigned to null.
Second, p is dereferenced on line 24, which leads to a null pointer dereference vulnerability.

In addition, in other places where the strchr function is used in this project, there are judgments about whether the function's return value is null or not. For example, in the file getopt.c, on line 169, the return value of the function strchr is judged.

Thank you very much for reading and I look forward to hearing from you!