[PATCH V2] libc: deal with aux vect inside __uClibc_main only if !SHARED

[Filippo ARCIDIACONO]

On 12/14/2012 11:40 AM, Filippo ARCIDIACONO wrote:
> It's not safe to use the aux vect inside __uClibc_main if we are running
> with shared libraries, because it could have been already modified.
> For example, if some constructor plays with environment variables by
> using unsetenv, the modifications done into the stack to unset an
> environment variable, have impacts on the aux vect due to the extra NULL
> entries added.
> Due to this, __uClibc_main is not able to detect where the aux vect
> starts, so all the entries that are used by __uClibc_main (AT_UID,
> AT_EUID, AT_GID, AT_EGID, AT_PAGESZ and possibly other arch specific)
> are impacted.
>
> Same side effect on the aux vect is caused by the ld.so when running a
> SUID program with some of the unsecure environment variables set, that
> will be unset by the ld.so itself.
>
> In order to fix this issue, it needs to handle aux vect entries into
> __uClibc_main only if SHARED is not defined.
> In SHARED case, libc refers to __dl_secure and _dl_pagesize as initialised
> by the ld.so where the aux vext is still untouched.
>
> Signed-off-by: Filippo Arcidiacono <filippo.arcidiacono at st.com>
> Reviewed-by: Carmelo Amoroso <carmelo.amoroso at st.com>
> ---
>   ldso/ldso/ldso.c                    |    2 +-
>   libc/misc/elf/dl-support.c          |    4 ++++
>   libc/misc/internals/__uClibc_main.c |   22 ++++++++++++++++------
>   3 files changed, 21 insertions(+), 7 deletions(-)
>
[SNIP]

Please consider this version.
It fixes last minute build problem and avoid some compiler warning.

regards,
Filippo.