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

Commit c402355dfa ("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 db3476aff1
("libio: Implement vtable verification [BZ #20191]").

Change-Id: Ief6f9f17e91d1f7263421c56a7dc018f4f595c21
(cherry picked from commit cb61630ed7)
This commit is contained in:
Florian Weimer 2019-11-28 14:42:11 +01:00
parent 7966ce07e8
commit f55e312bcd
2 changed files with 6 additions and 0 deletions

1
NEWS
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@ -69,6 +69,7 @@ The following bugs are resolved with this release:
[24228] old x86 applications that use legacy libio crash on exit
[24476] dlfcn: Guard __dlerror_main_freeres with __libc_once_get (once)
[24744] io: Remove the copy_file_range emulation.
[25203] libio: Disable vtable validation for pre-2.1 interposed handles
[25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs
Security related changes:

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@ -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);
}
}