[PATCH v4 3/5] elf: Signal la_objopen for the proxy link map in dlmopen (bug 31985)

[Adhemerval Zanella Netto]

On 29/11/24 12:40, Florian Weimer wrote:
> Previously, the ld.so link map was silently added to the namespace.
> This change produces an auditing event for it.

Is https://sourceware.org/bugzilla/show_bug.cgi?id=31985#c4 related to this
issue?  The rest looks ok.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> 
> ---
>  elf/dl-load.c     | 61 ++++++++++++++++++++++++++---------------------
>  elf/tst-audit23.c |  8 +++++--
>  2 files changed, 40 insertions(+), 29 deletions(-)
> 
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index e986d7faab..d5725fc714 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -902,6 +902,37 @@ _dl_process_pt_gnu_property (struct link_map *l, int fd, const ElfW(Phdr) *ph)
>      }
>  }
>  
> +static void
> +_dl_notify_new_object (int mode, Lmid_t nsid, struct link_map *l)
> +{
> +  /* Signal that we are going to add new objects.  */
> +  struct r_debug *r = _dl_debug_update (nsid);
> +  if (r->r_state == RT_CONSISTENT)
> +    {
> +#ifdef SHARED
> +      /* Auditing checkpoint: we are going to add new objects.  Since this
> +         is called after _dl_add_to_namespace_list the namespace is guaranteed
> +	 to not be empty.  */
> +      if ((mode & __RTLD_AUDIT) == 0)
> +	_dl_audit_activity_nsid (nsid, LA_ACT_ADD);
> +#endif
> +
> +      /* Notify the debugger we have added some objects.  We need to
> +	 call _dl_debug_initialize in a static program in case dynamic
> +	 linking has not been used before.  */
> +      r->r_state = RT_ADD;
> +      _dl_debug_state ();
> +      LIBC_PROBE (map_start, 2, nsid, r);
> +    }
> +  else
> +    assert (r->r_state == RT_ADD);
> +
> +#ifdef SHARED
> +  /* Auditing checkpoint: we have a new object.  */
> +  if (!GL(dl_ns)[l->l_ns]._ns_loaded->l_auditing)
> +    _dl_audit_objopen (l, nsid);
> +#endif
> +}
>  
>  /* Map in the shared object NAME, actually located in REALNAME, and already
>     opened on FD.  */
> @@ -1002,6 +1033,8 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
>        /* Add the map for the mirrored object to the object list.  */
>        _dl_add_to_namespace_list (l, nsid);
>  
> +      _dl_notify_new_object (mode, nsid, l);
> +
>        return l;
>      }
>  #endif
> @@ -1426,33 +1459,7 @@ cannot enable executable stack as shared object requires");
>    if (mode & __RTLD_SPROF)
>      return l;
>  
> -  /* Signal that we are going to add new objects.  */
> -  struct r_debug *r = _dl_debug_update (nsid);
> -  if (r->r_state == RT_CONSISTENT)
> -    {
> -#ifdef SHARED
> -      /* Auditing checkpoint: we are going to add new objects.  Since this
> -         is called after _dl_add_to_namespace_list the namespace is guaranteed
> -	 to not be empty.  */
> -      if ((mode & __RTLD_AUDIT) == 0)
> -	_dl_audit_activity_nsid (nsid, LA_ACT_ADD);
> -#endif
> -
> -      /* Notify the debugger we have added some objects.  We need to
> -	 call _dl_debug_initialize in a static program in case dynamic
> -	 linking has not been used before.  */
> -      r->r_state = RT_ADD;
> -      _dl_debug_state ();
> -      LIBC_PROBE (map_start, 2, nsid, r);
> -    }
> -  else
> -    assert (r->r_state == RT_ADD);
> -
> -#ifdef SHARED
> -  /* Auditing checkpoint: we have a new object.  */
> -  if (!GL(dl_ns)[l->l_ns]._ns_loaded->l_auditing)
> -    _dl_audit_objopen (l, nsid);
> -#endif
> +  _dl_notify_new_object (mode, nsid, l);
>  
>    return l;
>  }
> diff --git a/elf/tst-audit23.c b/elf/tst-audit23.c
> index 895dab08ea..c8c6553b8f 100644
> --- a/elf/tst-audit23.c
> +++ b/elf/tst-audit23.c
> @@ -17,6 +17,7 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <array_length.h>
> +#include <endswith.h>
>  #include <errno.h>
>  #include <getopt.h>
>  #include <link.h>
> @@ -106,8 +107,9 @@ do_test (int argc, char *argv[])
>       4. libgcc_s.so (one some architectures, for libsupport)
>       5. tst-audit23mod.so
>       6. libc.so (LM_ID_NEWLM).
> +     7. loader (proxy link map in new namespace)
>          vdso (optional and ignored).  */
> -  enum { max_objs = 6 };
> +  enum { max_objs = 7 };
>    struct la_obj_t
>    {
>      char *lname;
> @@ -236,7 +238,9 @@ do_test (int argc, char *argv[])
>  
>    for (size_t i = 0; i < nobjs; i++)
>      {
> -      TEST_COMPARE (objs[i].closed, true);
> +      /* This subtest currently does not pass because of bug 32065.  */
> +      if (! (endswith (objs[i].lname, LD_SO) && objs[i].lmid != LM_ID_BASE))
> +	TEST_COMPARE (objs[i].closed, true);
>        free (objs[i].lname);
>      }
>