From c402355dfa7807b8e0adb27c009135a7e2b9f1b0 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 26 Jun 2018 10:24:52 +0200 Subject: libio: Disable vtable validation in case of interposition [BZ #23313] --- libio/vtables.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'libio') diff --git a/libio/vtables.c b/libio/vtables.c index 9fd4ccf642..9df75668c8 100644 --- a/libio/vtables.c +++ b/libio/vtables.c @@ -71,3 +71,19 @@ _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 -- cgit 1.4.1