gcc/libgcc/vtv_start.c

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/* Copyright (C) 2012-2015 Free Software Foundation, Inc.
Commit the vtable verification feature. Commit the vtable verification feature. This feature is designed to detect, at run time, if/when the vtable pointer in a C++ object has been corrupted, before allowing virtual calls through that pointer. If pointer corruption is detected, execution of the program is halted. libstdc++-v3 ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> * fragment.am: Add XTEMPLATE_FLAGS. * configure.ac: Add definitions for --enable-vtable-verify. * acinclude.m4: Add --enable-vtable-verify and --disable-vtable-verify; define --enable-vtable-verify; define VTV_CXXFLAGS, VTV_PCH_CXXFLAGS and VTV_CXXLINKFLAGS. * config/abi/pre/gnu.ver: Export symbols for vtable verification. * libsupc++/Makefile.am: Define vtv_sources and add it to libsupc___la_SOURCES and libsupc__convenience_la_SOURCES. * libsupc++/vtv_stubs.cc: New file. * include/Makefile.am: Add VTV_PCH_CXXFLAGS to PCHFLAGS. * src/Makefile.am: Add VTV_CXXFLAGS to AM_CXXFLAGS; add VTV_CXXLINKFLAGS to CXXLINK. * src/c++98/Makefile.am: Comment out XTEMPLATE_FLAGS; add VTV_CXXFLAGS to AM_CXXFLAGS; add VTV_CXXXLINKFLAGS to CXXLINK. * src/C++11/Makefile.am: Ditto. * doc/xml/manual/configure.xml: Add entry for --enable-vtable-verify. * scripts/testsuite_flags.in: Add cxxvtvflags to Usage; cause cxxvtvflags to use VTV_CXXFLAGS and VTV_CXXLINKFLAGS. * testsuite/lib/libstdc++.exp: Add cxxvtvflags; add code to locate libvtv if --enable-vtable-verify was used; set cxxvtvflags; add cxxvtvflags to cxx_final. * testsuite/18_support/bad_exception/23591_thread-1.c: Add -fvtable-verify=none to compiler flags. * testsuite/17_intro/freestanding.cc: Add -fvtable-verify=none to compiler flags. * configure: Regenerated. * Makefile.in: Regenerated. * python/Makefile.in: Regenerated. * include/Makefile.in: Regenerated. * libsupc++/Makefile.in: Regenerated. * config.h.in: Regenerated. * po/Makefile.in: Regenerated. * src/Makefile.in: Regenerated. * src/c++98/Makefile.in: Regenerated. * src/c++11/Makefile.in: Regenerated. * doc/Makefile.in: Regenerated. * testsuite/Makefile.in: Regenerated. top level ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> * configure.ac: Add target-libvtv to target_libraries; disable libvtv on non-linux systems; add target-libvtv to noconfigdirs; add libsupc++/.libs to C++ library search paths. * configure: Regenerated. * Makefile.def: Add libvtv to target_modules; make libvtv depend on libstdc++ and libgcc. * Makefile.in: Regenerated. include/ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> * vtv-change-permission.h: New file. contrib/ChangeLog: 2013-08-06 Caroline Tice4 <cmtice@google.com> * gcc_update: Add libvtv files. libgcc/ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> config.host (extra_parts): Add vtv_start.o, vtv_end.o vtv_start_preinit.o and vtv_end_preinit.o. configure.ac: Add code to check/set enable_vtable_verify. Makefile.in: Add rules to build vtv_*.o, if enable_vtable_verify is true. vtv_start_preinit.c: New file. vtv_end_preinit.c: New file. vtv_start.c: New file. vtv_end.c: New file. configure: Regenerated. gcc/ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> * gcc.c (VTABLE_VERIFICATION_SPEC): New definition. (LINK_COMMAND_SPEC): Add VTABLE_VERIFICATION_SPEC. * tree-pass.h: Add pass_vtable_verify. * varasm.c (assemble_variable): Add code to properly set the comdat section and name for the .vtable_map_vars section. (assemble_vtyv_preinit_initializer): New function. (default_sectin_type_flags): Make sure .vtable_map_vars section has LINK_ONCE flag. * output.h: Add function decl for assemble_vtv_preinit_initializer. * vtable-verify.c: New file. * vtable-verify.h: New file. * flag-types.h (enum vtv_priority): Defintions for flag_vtable_verify initialiation levels. * timevar.def (TV_VTABLE_VERIFICATION): New definition. * passes.def: Insert pass_vtable_verify. * aclocal.m4: Reorder includes. * doc/invoke.texi: Add documentation for the flags -fvtable-verify=, -fvtv-debug and -fvtv-counts. * config/gnu-user.h (GNU_USER_TARGET_STARTFILE_SPEC): Add vtv_start*.o, as appropriate, if -fvtable-verify=... is used. (GNU_USER_TARGET_ENDFILE_SPEC): Add vtv_end*.o as appropriate, if -fvtable-verify=... is used. * Makefile.in (OBJS): Add vtable-verify.o to list. (vtable-verify.o): Add new build rule. (GTFILES): Add vtable-verify.c to list. * common.opt (fvtable-verify=): New flag. (vtv_priority): Values for fvtable-verify= flag. (fvtv-counts): New flag. (fvtv-debug): New flag. * tree.h (save_vtable_map_decl): New extern function decl. gcc/cp/ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> * Make-lang.in (*CXX_AND_OBJCXX_OBJS): Add vtable-class-hierarchy.o to list. (vtable-class-hierarchy.o): Add build rule. * cp-tree.h (vtv_start_verification_constructor_init_function): New extern function decl. (vtv_finish_verification_constructor_init_function): New extern function decl. (build_vtbl_address): New extern function decl. (get_mangled_vtable_map_var_name): New extern function decl. (vtv_compute_class_hierarchy_transitive_closure): New extern function decl. (vtv_generate_init_routine): New extern function decl. (vtv_save_class_info): New extern function decl. (vtv_recover_class_info): New extern function decl. (vtv_build_vtable_verify_fndecl): New extern function decl. * class.c (finish_struct_1): Add call to vtv_save_class_info if flag_vtable_verify is true. * config-lang.in: Add vtable-class-hierarchy.c to gtfiles list. * vtable-class-hierarchy.c: New file. * mangle.c (get_mangled_vtable_map_var_name): New function. * decl2.c (start_objects): Update function comment. (cp_write_global_declarations): Call vtv_recover_class_info, vtv_compute_class_hierarchy_transitive_closure and vtv_build_vtable_verify_fndecl, before calling finalize_compilation_unit, and call vtv_generate_init_rount after, IFF flag_vtable_verify is true. (vtv_start_verification_constructor_init_function): New function. (vtv_finish_verification_constructor_init_function): New function. * init.c (build_vtbl_address): Remove static qualifier from function. libvtv/ChangeLog: 2013-08-06 Caroline Tice <cmtice@google.com> Initial check-in of new vtable verification feature. * configure.ac : New file. * acinclude.m4 : New file. * Makefile.am : New file. * aclocal.m4 : New file. * configure.tgt : New file. * configure: New file (generated). * Makefile.in: New file (generated). * vtv_set.h : New file. * vtv_utils.cc : New file. * vtv_utils.h : New file. * vtv_malloc.cc : New file. * vtv_rts.cc : New file. * vtv_malloc.h : New file. * vtv_rts.h : New file. * vtv_fail.cc : New file. * vtv_fail.h : New file. * vtv_map.h : New file. * scripts/run-testsuite.sh : New file. * scripts/sum-vtv-counts.c : New file. * testsuite/parts-test-main.h : New file. * testusite/dataentry.cc : New file. * testsuite/temp_deriv.cc : New file. * testsuite/register_pair.cc : New file. * testsuite/virtual_inheritance.cc : New file. * testsuite/field-test.cc : New file. * testsuite/nested_vcall_test.cc : New file. * testsuite/template-list-iostream.cc : New file. * testsuite/register_pair_inserts.cc : New file. * testsuite/register_pair_inserts_mt.cc : New file. * testsuite/event.list : New file. * testsuite/parts-test-extra-parts-views.cc : New file. * testsuite/parts-test-extra-parts-views.h : New file. * testsuite/environment-fail-32.s : New file. * testsuite/parts-test-extra-parts.h : New file. * testsuite/temp_deriv2.cc : New file. * testsuite/dlopen_mt.cc : New file. * testsuite/event.h : New file. * testsuite/template-list.cc : New file. * testsuite/replace-fail.cc : New file. * testsuite/Makefile.am : New file. * testsuite/Makefile.in: New file (generated). * testsuite/mempool_negative.c : New file. * testsuite/parts-test-main.cc : New file. * testsuite/event-private.cc : New file. * testsuite/thunk.cc : New file. * testsuite/event-defintiions.cc : New file. * testsuite/event-private.h : New file. * testsuite/parts-test.list : New file. * testusite/register_pair_mt.cc : New file. * testsuite/povray-derived.cc : New file. * testsuite/event-main.cc : New file. * testsuite/environment.cc : New file. * testsuite/template-list2.cc : New file. * testsuite/thunk_vtable_map_attack.cc : New file. * testsuite/parts-test-extra-parts.cc : New file. * testsuite/environment-fail-64.s : New file. * testsuite/dlopen.cc : New file. * testsuite/so.cc : New file. * testsuite/temp_deriv3.cc : New file. * testsuite/const_vtable.cc : New file. * testsuite/mempool_positive.c : New file. * testsuite/dup_name.cc : New file. From-SVN: r201555
2013-08-07 05:38:59 +02:00
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
/* This file is part of the vtable verification feature (for a
detailed description of the feature, see comments in
vtable-verify.c). The vtable verification feature creates
certain global symbols that need to be read-write sometimes during
program execution, and read-only at others. It uses 'mprotect' to
change the memory protections of the pages on which these variables
are stored. In order to not affect the protections of other
program variables, these variables are put into a special named
section, ".vtable_map_vars", which is page-aligned at the start,
and which is padded with a page-sized amount of zeros at the end.
To make this section page aligned, we create a special symbol,
"_vtable_map_vars_start" which we make the very first thing that
goes into the section. This file defines that symbol (and only
that symbol). GCC compiles this file into vtv_start.o, and
inserts vtv_start.o into the link line immediately after
crtbegin.o, if the program is compiled with -fvtable.verify.
In order to pad the ".vtable_map_vars" section with a page-sized
amount of zeros at the end, there is a second symbol,
_vtable_map_vars_end, which is defined in another file, vtv_end.c.
This second symbol is a page-sized array of chars, zero-filled, and
is the very last thing to go into the section. When the GCC driver
inserts vtv_start.o into the link line (just after crtbegin.o) it
also inserts vtv_end.o into the link line, just before crtend.o.
This has the desired effect of making our section page-aligned and
page-size paded, ensuring that no other program data lands on our
pages. */
#include "vtv-change-permission.h"
__attribute__ ((constructor(98))) void
__VLTunprotect (void)
{
__VLTChangePermission (__VLTP_READ_WRITE);
}
/* Page-aligned symbol to mark beginning of .vtable_map_vars section. */
char _vtable_map_vars_start []
__attribute__ ((__visibility__ ("protected"), used, aligned(VTV_PAGE_SIZE),
section(".vtable_map_vars")))
= { };