Re: [PATCH] libsemanage: treat module data as bytes in the Python bindings

On Mon, Aug 17, 2026 at 10:35 AM James Carter <[email protected]> wrote:
>
> On Thu, Aug 13, 2026 at 2:41 PM Stephen Smalley
> <[email protected]> wrote:
> >
> > semanage_module_install() / semanage_module_install_info() take a
> > (char *data, size_t data_len) pair, and semanage_module_extract()
> > returns (void **mapped_data, size_t *data_len). In both directions
> > the payload is an opaque module blob (.pp / bzip2 / CIL / HLL), not a
> > NUL-terminated C string.
> >
> > On Python 3 the current SWIG bindings get this wrong on both sides:
> >
> > - install()/install_info(): the SWIG default for a bare "char *"
> >   only accepts str objects and UTF-8-encodes them, so a .pp blob
> >   cannot be passed at all, and even for CIL text the separately
> >   supplied data_len is wrong for any non-ASCII content since
> >   Python len(str) counts code points, not UTF-8 bytes.
> >
> > - extract(): %cstring_output_allocate_size turns the mapped buffer
> >   into a str via UTF-8 decoding, which for a binary module either
> >   raises UnicodeDecodeError or (with surrogateescape) yields a str
> >   that cannot be fed straight back into install().
> >
> > Add a (char *module_data, size_t data_len) input typemap that
> > accepts any object exposing the buffer protocol (bytes, bytearray,
> > mmap, ...) as a single argument and derives the length from it, and
> > apply it to the (char *data, size_t data_len) pair of
> > semanage_module_install_info() as well.
> >
> > Replace the extract() output typemap with an explicit multi-argument
> > typemap that returns a bytes object built from the mapped buffer and
> > then unmaps it, so extract() -> install() round-trips.  Drop the
> > now-unused <cstring.i> include.
> >
> > The Python signatures become
> >   semanage_module_install(sh, data, name, ext_lang)
> >   semanage_module_install_info(sh, modinfo, data)
> > There are no in-tree Python callers.
> >
> > Fixes: https://github.com/SELinuxProject/selinux/issues/502
> > Signed-off-by: Stephen Smalley <[email protected]>
>
> Acked-by: James Carter <[email protected]>

Thanks, merged.