Re: AT_EXECPATH aux_info vector contains path of interpreter when directly exec'ing rtld

From: Conrad Meyer <cem_at_freebsd.org>
Date: Fri, 20 Dec 2019 14:02:14 -0800
Isn’t rtld’s behavior here correct? It’s really Clang which is doing
something quite odd.

On Fri, Dec 20, 2019 at 13:27 Ryan Stone <rysto32_at_gmail.com> wrote:

> I've noticed that on head, if I directly execute rtld to run an
> executable, AT_EXECPATH contains the path to rtld on head (on
> 12.0-RELEASE it will contain nothing).  This is causing me a problem
> because clang uses AT_EXECPATH to preferentially locate where it's
> installed, which it uses to locate its driver programs.
>
> The end result is that clang can no longer successfully be executed
> from a process in capability mode, whereas before I could fexecve rtld
> and give it a pre-opened file descriptor to /usr/bin/clang.
>
> I've put together a quick test program demonstrating the problem:
>
> https://people.freebsd.org/~rstone/getprogname.c
>
> On 12.0-RELEASE, directly executing rtld to run this program gives this
> output:
> $ /libexec/ld-elf.so.1 -- ./progname
> progname: progname
> argv[0]:  ./progname
> elf_aux_info failed: No such file or directory
>
> On head, I get this instead:
> /libexec/ld-elf.so.1 -- ./progname
> progname: progname
> argv[0]:  ./progname
> AT_EXECPATH: /libexec/ld-elf.so.1
> _______________________________________________
> freebsd-current_at_freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-current
> To unsubscribe, send any mail to "freebsd-current-unsubscribe_at_freebsd.org"
>
Received on Fri Dec 20 2019 - 21:02:28 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:41:22 UTC