Re: [GIT PULL] execve updates for v6.13-rc1 (take 2)

[Al Viro]

On Thu, Nov 28, 2024 at 06:43:31PM -0800, Linus Torvalds wrote:
> A sane setup has lots of options
> 
>  - just use execve() with the actual name of the executable
> 
>  - use hardlinks and use execveat()
> 
>  - use open() on a symlink and then execveat() of that file, and get
> the actual name of the executable behind the symlink
> 
>  - disagree about comm[] being relevant at all, and don't use it, and
> don't use tools that do
> 
> and none of those are wrong decisions.

Just one thing - IMO we want to use the relative pathname when it's
not empty.  Even in execveat().  Because some wanker *will* decide
that newer is better and make libc use execveat() to implement execve().
Which won't be spotted for about a year, and when it does we'll get
seriously stuck.

I agree that for fexecve() the only sane approach is to go by whatever
that opened file refers to; I'm not sold on the _usefulness_ of
fexecve() to start with, but if we want that thing, that's the way
to go.