[PATCH v3 2/4] elf: Signal la_objopen for the proxy link map in dlmopen (bug 31985)

[Adhemerval Zanella Netto]

Looks good, although maybe extend the commit message a bit to explain that
this adds a new la_objopen event for ld.so in a new namespace.

On 04/09/24 15:50, Florian Weimer wrote:
> ---
>  elf/dl-load.c     | 61 ++++++++++++++++++++++++++---------------------
>  elf/tst-audit23.c | 15 ++++++++++--
>  2 files changed, 47 insertions(+), 29 deletions(-)
> 
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index 8a89b71016..54c9c4d779 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -918,6 +918,37 @@ _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.  */
> @@ -1018,6 +1049,8 @@ _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
> @@ -1442,33 +1475,7 @@ 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;
>  }

Ok.

> diff --git a/elf/tst-audit23.c b/elf/tst-audit23.c
> index 895dab08ea..462548d5ab 100644
> --- a/elf/tst-audit23.c
> +++ b/elf/tst-audit23.c
> @@ -52,6 +52,14 @@ startswith (const char *str, const char *pre)
>    return lenstr >= lenpre && memcmp (pre, str, lenpre) == 0;
>  }
>  
> +static inline bool
> +endswith (const char *str, const char *suf)
> +{
> +  size_t lensuf = strlen (suf);
> +  size_t lenstr = strlen (str);
> +  return lenstr >= lensuf && memcmp (suf, str + lenstr - lensuf, lensuf) == 0;
> +}
> +

Maybe include 'endswith.h' to avoid duplicate this function?

>  static inline bool
>  is_vdso (const char *str)
>  {
> @@ -106,8 +114,9 @@ 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 +245,9 @@ 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);
>      }
>  

Ok.