rmalmain
commented
1 month ago Thank you for the report. I think we don't really have a choice other than reimplementing in that case, indeed. I don't mind including it in the library.
However, your implementation doesn't seem right to me, I think we should stick to the tolower signature and documentation.
Also, I can see a loop in your code that should not be there IMHO.
You can have a look to newlib implementation for example, it should be a good inspiration. The closer it is to a well-tested code, the less likely it will be a problem in the future.
domenukk
Zofyan
string.c of libqasan calls the tolower function which later tries to call
__ctype_tolowerfrom libc. This function does not always exist in firmware however; one firmware that does not contain it is this one for example https://archive.org/details/Linksys_EA6300_1.1.40_e2ec7 Instead, a function named__ctype_tolower_locis found.For my own project, I have created a fork in which I created a custom tolower function and call that instead. I would assume that this not the desired long-term solution, but this is the commit: https://github.com/Zofyan/LibAFL-bzero-patch/commit/439a3e29b2c1c6e9ae5a4f6e99c6435c056e4859
If this happens to be an acceptable solution, In will create a PR.
PS: this problem is probably caused by me picking the wrong cross-compiler, but tracking down the right one can be tricky for (older) firmware with limited information. Hence, making libqasan more compiler agnostic might make it easier to use in such cases.