commit cb61630ed712d033f54295f776967532d3f4b46a

Author: Florian Weimer <fweimer@redhat.com>

Date:   Fri Nov 22 22:10:42 2019 +0100

    libio: Disable vtable validation for pre-2.1 interposed handles [BZ #25203]

    Commit c402355dfa7807b8e0adb27c009135a7e2b9f1b0 ("libio: Disable

    vtable validation in case of interposition [BZ #23313]") only covered

    the interposable glibc 2.1 handles, in libio/stdfiles.c.  The

    parallel code in libio/oldstdfiles.c needs similar detection logic.

    Fixes (again) commit db3476aff19b75c4fdefbe65fcd5f0a90588ba51

    ("libio: Implement vtable verification [BZ #20191]").

    Change-Id: Ief6f9f17e91d1f7263421c56a7dc018f4f595c21

diff --git a/libio/oldstdfiles.c b/libio/oldstdfiles.c

index 870cb0536c52024f..54d3e354fcbf257e 100644

--- a/libio/oldstdfiles.c

+++ b/libio/oldstdfiles.c

@@ -87,6 +87,11 @@ _IO_check_libio (void)

 	stdout->_vtable_offset = stderr->_vtable_offset =

 	((int) sizeof (struct _IO_FILE)

 	 - (int) sizeof (struct _IO_FILE_complete));

+

+      if (_IO_stdin_.vtable != &_IO_old_file_jumps

+	  || _IO_stdout_.vtable != &_IO_old_file_jumps

+	  || _IO_stderr_.vtable != &_IO_old_file_jumps)

+	IO_set_accept_foreign_vtables (&_IO_vtable_check);

     }

 }