From 1154cb63e725a579def2d7ba8383fd950931342b Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 26 Jun 2018 10:24:52 +0200 Subject: [PATCH] libio: Disable vtable validation in case of interposition [BZ #23313] (cherry picked from commit c402355dfa7807b8e0adb27c009135a7e2b9f1b0) --- ChangeLog | 5 +++++ libio/vtables.c | 16 ++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/ChangeLog b/ChangeLog index 3ca1f72be0..3eba7630c6 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2018-06-26 Florian Weimer + + [BZ #23313] + * libio/vtables.c (check_stdfiles_vtables): New ELF constructor. + 2019-11-01 Dragan Mladjenovic * sysdeps/unix/sysv/linux/mips/Makefile diff --git a/libio/vtables.c b/libio/vtables.c index b361f44e91..722a090790 100644 --- a/libio/vtables.c +++ b/libio/vtables.c @@ -70,3 +70,19 @@ _IO_vtable_check (void) __libc_fatal ("Fatal error: glibc detected an invalid stdio handle\n"); } + +/* Some variants of libstdc++ interpose _IO_2_1_stdin_ etc. and + install their own vtables directly, without calling _IO_init or + other functions. Detect this by looking at the vtables values + during startup, and disable vtable validation in this case. */ +#ifdef SHARED +__attribute__ ((constructor)) +static void +check_stdfiles_vtables (void) +{ + if (_IO_2_1_stdin_.vtable != &_IO_file_jumps + || _IO_2_1_stdout_.vtable != &_IO_file_jumps + || _IO_2_1_stderr_.vtable != &_IO_file_jumps) + IO_set_accept_foreign_vtables (&_IO_vtable_check); +} +#endif