Re: [PATCH] tools/nolibc: getopt: Fix potential out of bounds access

[Thomas Weißschuh]

Hi Daniel,

On 2026-05-20 20:19:31+0900, Daniel Palmer wrote:
> Running clang-tidy on a program that uses getopt() from nolibc
> this warning appears:
> 
> getopt.h:80:6: warning: Out of bound access to memory after the end of the string literal [clang-analyzer-security.ArrayBound]
> 80 |         if (optstring[i] == ':') {
> 
> Claude was asked for a reproducer and the human fixed up version
> looks like this:

Thanks for the report and patch!

(...)

> Claude suggests using `-fsanitize=address` to detect the issue
> but that doesn't work for nolibc so lets do it manually with
> gdb:

It works fine to copy the nolibc getopt() implementation into a new
normal source file and compile it with asan there.
That reproduces the issue and confirms the fix.

I'll apply your fix with a trimmed commit message.

(...)


Thomas