[PATCH] elf: ldconfig should skip temporary files created by package managers

[Guillem Jover]

Hi!

[ Hope the reply works, had to construct it from the web archive. ]

On Fri Oct 20 12:29:50 GMT 2023 Florian Weimer wrote:
> diff --git a/elf/ldconfig.c b/elf/ldconfig.c
> index d26eef1fb4..02387a169c 100644
> --- a/elf/ldconfig.c
> +++ b/elf/ldconfig.c
> @@ -661,6 +661,31 @@ struct dlib_entry
>    struct dlib_entry *next;
>  };
> 
> +/* Skip some temporary DSO files.  These files may be partially written
> +   and lead to ldconfig crashes when examined.  */
> +static bool
> +skip_dso_based_on_name (const char *name, size_t len)
> +{
> +  /* Skip temporary files created by the prelink program.  Files with
> +     names like these are never really DSOs we want to look at.  */
> +  if (len >= sizeof (".#prelink#") - 1)
> +    {
> +      if (strcmp (name + len - sizeof (".#prelink#") + 1,
> +		  ".#prelink#") == 0)
> +	return true;
> +      if (len >= sizeof (".#prelink#.XXXXXX") - 1
> +	  && memcmp (name + len - sizeof (".#prelink#.XXXXXX")
> +		     + 1, ".#prelink#.", sizeof (".#prelink#.") - 1) == 0)
> +	return true;
> +    }
> +  /* Skip temporary files created by RPM.  */
> +  if (memchr (name, len, ';') != NULL)
> +    return true;
> +  /* Skip temporary files created by dpkg.  */
> +  if (len > 4 && memcmp (name + len - 4, ".tmp", 4) == 0)
> +    return true;

If this refers to files dpkg creates during an unpack, then for
regular files, it might end up creating ones ending with «.dpkg-new»
and «.dpkg-tmp» (for conffiles there are other extensions used, but
those would not seem relevant here).

(And, hmm, I should probably try to document that somewhere in the
dpkg manual pages or docs.)

> +  return false;
> +}
> 
>  static void
>  search_dir (const struct dir_entry *entry)

Thanks,
Guillem