So obviously claiming that there's no good reason for process to read argv[0] is either demonstrating the author's ignorance or needs a much stronger defense; I'd be fascinated to hear how they think busybox should work on an OpenWrt box with a 16MB root filesystem.
However, I am willing to consider the discussion about whether there could be merit to restricting the ability to write that value; I could imagine a system that populated it only from the actual file name and did not allow it to be written by the parent process or the child process at runtime. The obvious place this still falls apart is that an attacker could just
ln /bin/curl ./some\ other\ name
but there are sometimes security measures that we use even though they're less than 100% effective so it at least conceivable that this might be a trade off worth making.
However, I am willing to consider the discussion about whether there could be merit to restricting the ability to write that value; I could imagine a system that populated it only from the actual file name and did not allow it to be written by the parent process or the child process at runtime. The obvious place this still falls apart is that an attacker could just
but there are sometimes security measures that we use even though they're less than 100% effective so it at least conceivable that this might be a trade off worth making.