Re: [PATCHv10 man-pages 5/5] execveat.2: initial man page for execveat(2)

[Eric W. Biederman]

Rich Felker <dalias@xxxxxxxxxx> writes:

> On Fri, Jan 09, 2015 at 09:09:41PM +0000, Al Viro wrote:

> The "magic open-once magic symlink" approach is really the cleanest
> solution I can find. In the case where the interpreter does not open
> the script, nothing terribly bad happens; the magic symlink just
> sticks around until _exit or exec. In the case where the interpreter
> opens it more than once, you get a failure, but as far as I know
> existing interpreters don't do this, and it's arguably bad design. In
> any case it's a caught error.

And it doesn't work without introducing security vulnerabilities into
the kernel, because it breaks close-on-exec semantics.

All you have to do is pick a file descriptor, good canidates are 0 and
255 and make it a convention that that file descriptor is used for
fexecve.  At least when you want to support scripts.  Otherwise you can
set close-on-exec.

That results in no accumulation of file descriptors  because everyone
always uses the same file descriptor.

Regardless you don't have a patch and you aren't proposing code and the
code isn't actually broken so please go away.

Eric
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