1828 lines
66 KiB
C++
1828 lines
66 KiB
C++
/* Copyright (C) 2012-2017 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This file is part of the vtable security feature implementation.
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The vtable security feature is designed to detect when a virtual
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call is about to be made through an invalid vtable pointer
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(possibly due to data corruption or malicious attacks). The
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compiler finds every virtual call, and inserts a verification call
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before the virtual call. The verification call takes the actual
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vtable pointer value in the object through which the virtual call
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is being made, and compares the vtable pointer against a set of all
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valid vtable pointers that the object could contain (this set is
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based on the declared type of the object). If the pointer is in
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the valid set, execution is allowed to continue; otherwise the
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program is halted.
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There are several pieces needed in order to make this work: 1. For
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every virtual class in the program (i.e. a class that contains
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virtual methods), we need to build the set of all possible valid
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vtables that an object of that class could point to. This includes
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vtables for any class(es) that inherit from the class under
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consideration. 2. For every such data set we build up, we need a
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way to find and reference the data set. This is complicated by the
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fact that the real vtable addresses are not known until runtime,
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when the program is loaded into memory, but we need to reference the
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sets at compile time when we are inserting verification calls into
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the program. 3. We need to find every virtual call in the program,
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and insert the verification call (with the appropriate arguments)
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before the virtual call. 4. We need some runtime library pieces:
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the code to build up the data sets at runtime; the code to actually
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perform the verification using the data sets; and some code to set
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protections on the data sets, so they themselves do not become
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hacker targets.
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To find and reference the set of valid vtable pointers for any given
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virtual class, we create a special global varible for each virtual
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class. We refer to this as the "vtable map variable" for that
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class. The vtable map variable has the type "void *", and is
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initialized by the compiler to NULL. At runtime when the set of
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valid vtable pointers for a virtual class, e.g. class Foo, is built,
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the vtable map variable for class Foo is made to point to the set.
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During compile time, when the compiler is inserting verification
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calls into the program, it passes the vtable map variable for the
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appropriate class to the verification call, so that at runtime the
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verification call can find the appropriate data set.
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The actual set of valid vtable pointers for a polymorphic class,
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e.g. class Foo, cannot be built until runtime, when the vtables get
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loaded into memory and their addresses are known. But the knowledge
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about which vtables belong in which class' hierarchy is only known
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at compile time. Therefore at compile time we collect class
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hierarchy and vtable information about every virtual class, and we
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generate calls to build up the data sets at runtime. To build the
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data sets, we call one of the functions we add to the runtime
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library, __VLTRegisterPair. __VLTRegisterPair takes two arguments,
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a vtable map variable and the address of a vtable. If the vtable
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map variable is currently NULL, it creates a new data set (hash
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table), makes the vtable map variable point to the new data set, and
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inserts the vtable address into the data set. If the vtable map
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variable is not NULL, it just inserts the vtable address into the
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data set. In order to make sure that our data sets are built before
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any verification calls happen, we create a special constructor
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initialization function for each compilation unit, give it a very
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high initialization priority, and insert all of our calls to
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__VLTRegisterPair into our special constructor initialization
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function. */
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/* This file contains the main externally visible runtime library
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functions for vtable verification: __VLTChangePermission,
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__VLTRegisterPair, and __VLTVerifyVtablePointer. It also contains
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debug versions __VLTRegisterPairDebug and
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__VLTVerifyVtablePointerDebug, which have extra parameters in order
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to make it easier to debug verification failures.
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The final piece of functionality implemented in this file is symbol
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resolution for multiple instances of the same vtable map variable.
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If the same virtual class is used in two different compilation
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units, then each compilation unit will create a vtable map variable
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for the class. We need all instances of the same vtable map
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variable to point to the same (single) set of valid vtable
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pointers for the class, so we wrote our own hashtable-based symbol
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resolution for vtable map variables (with a tiny optimization in
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the case where there is only one instance of the variable).
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There are two other important pieces to the runtime for vtable
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verification besides the main pieces that go into libstdc++.so: two
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special tiny shared libraries, libvtv_init.so and libvtv_stubs.so.
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libvtv_init.so is built from vtv_init.cc. It is designed to help
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minimize the calls made to mprotect (see the comments in
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vtv_init.cc for more details). Anything compiled with
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"-fvtable-verify=std" must be linked with libvtv_init.so (the gcc
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driver has been modified to do this). vtv_stubs.so is built from
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vtv_stubs.cc. It replaces the main runtime functions
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(__VLTChangePermissino, __VLTRegisterPair and
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__VLTVerifyVtablePointer) with stub functions that do nothing. If
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a programmer has a library that was built with verification, but
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wishes to not have verification turned on, the programmer can link
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in the vtv_stubs.so library. */
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#if defined (__CYGWIN__) || defined (__MINGW32__)
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#include <windows.h>
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#include <winternl.h>
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#include <psapi.h>
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#else
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#include <execinfo.h>
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#endif
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#include <unistd.h>
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#if !defined (__CYGWIN__) && !defined (__MINGW32__)
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#include <sys/mman.h>
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#include <link.h>
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#endif
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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/* For gthreads suppport */
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#include <bits/c++config.h>
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#include <ext/concurrence.h>
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#include "vtv_utils.h"
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#include "vtv_malloc.h"
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#include "vtv_set.h"
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#include "vtv_map.h"
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#include "vtv_rts.h"
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#include "vtv_fail.h"
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#include "vtv-change-permission.h"
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#ifdef HAVE_GETEXECNAME
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const char *program_invocation_name;
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#endif
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#ifdef HAVE___FORTIFY_FAIL
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extern "C" {
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/* __fortify_fail is a function in glibc that calls __libc_message,
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causing it to print out a program termination error message
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(including the name of the binary being terminated), a stack
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trace where the error occurred, and a memory map dump. Ideally
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we would have called __libc_message directly, but that function
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does not appear to be accessible to functions outside glibc,
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whereas __fortify_fail is. We call __fortify_fail from
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__vtv_really_fail. We looked at calling __libc_fatal, which is
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externally accessible, but it does not do the back trace and
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memory dump. */
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extern void __fortify_fail (const char *) __attribute__((noreturn));
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} /* extern "C" */
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#else
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#if defined (__CYGWIN__) || defined (__MINGW32__)
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// porting: fix link error to libc
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void __fortify_fail (const char * msg){
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OutputDebugString(msg);
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abort();
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}
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#else
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// FIXME: Provide backtrace via libbacktrace?
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void __fortify_fail (const char *msg) {
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write (2, msg, strlen (msg));
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abort ();
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}
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#endif
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#endif
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/* The following variables are used only for debugging and performance
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tuning purposes. Therefore they do not need to be "protected".
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They cannot be used to attack the vtable verification system and if
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they become corrupted it will not affect the correctness or
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security of any of the rest of the vtable verification feature. */
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unsigned int num_calls_to_regset = 0;
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unsigned int num_calls_to_regpair = 0;
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unsigned int num_calls_to_verify_vtable = 0;
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unsigned long long regset_cycles = 0;
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unsigned long long regpair_cycles = 0;
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unsigned long long verify_vtable_cycles = 0;
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/* Be careful about initialization of statics in this file. Some of
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the routines below are called before any runtime initialization for
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statics in this file will be done. For example, dont try to
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initialize any of these statics with a runtime call (for ex:
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sysconf). The initialization will happen after calls to the routines
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to protect/unprotec the vtabla_map variables */
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/* No need to mark the following variables with VTV_PROTECTED_VAR.
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These are either const or are only used for debugging/tracing.
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debugging/tracing will not be ON on production environments */
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static const bool debug_hash = HASHTABLE_STATS;
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#ifdef VTV_DEBUG
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static const int debug_functions = 1;
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static const int debug_init = 1;
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static const int debug_verify_vtable = 1;
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#else
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static const int debug_functions = 0;
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static const int debug_init = 0;
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static const int debug_verify_vtable = 0;
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#endif
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/* Global file descriptor variables for logging, tracing and debugging. */
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static int init_log_fd = -1;
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static int verify_vtable_log_fd = -1;
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/* This holds a formatted error logging message, to be written to the
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vtable verify failures log. */
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static char debug_log_message[1024];
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#ifdef __GTHREAD_MUTEX_INIT
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static __gthread_mutex_t change_permissions_lock = __GTHREAD_MUTEX_INIT;
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#else
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static __gthread_mutex_t change_permissions_lock;
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#endif
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#ifndef VTV_STATS
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#define VTV_STATS 0
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#endif
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#if VTV_STATS
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static inline unsigned long long
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get_cycle_count (void)
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{
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return rdtsc();
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}
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static inline void
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accumulate_cycle_count (unsigned long long *sum, unsigned long long start)
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{
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unsigned long long end = rdtsc();
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*sum = *sum + (end - start);
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}
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static inline void
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increment_num_calls (unsigned int *num_calls)
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{
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*num_calls = *num_calls + 1;
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}
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#else
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static inline unsigned long long
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get_cycle_count (void)
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{
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return (unsigned long long) 0;
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}
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static inline void
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accumulate_cycle_count (unsigned long long *sum __attribute__((__unused__)),
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unsigned long long start __attribute__((__unused__)))
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{
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/* Do nothing. */
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}
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static inline void
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increment_num_calls (unsigned int *num_calls __attribute__((__unused__)))
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{
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/* Do nothing. */
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}
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#endif
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/* Types needed by insert_only_hash_sets. */
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typedef uintptr_t int_vptr;
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/* The set of valid vtable pointers for each virtual class is stored
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in a hash table. This is the hashing function used for the hash
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table. For more information on the implementation of the hash
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table, see the class insert_only_hash_sets in vtv_set.h. */
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struct vptr_hash
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{
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/* Hash function, used to convert vtable pointer, V, (a memory
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address) into an index into the hash table. */
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size_t
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operator() (int_vptr v) const
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{
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const uint32_t x = 0x7a35e4d9;
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const int shift = (sizeof (v) == 8) ? 23 : 21;
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v = x * v;
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return v ^ (v >> shift);
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}
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};
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/* This is the memory allocator used to create the hash table data
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sets of valid vtable pointers. We use VTV_malloc in order to keep
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track of which pages have been allocated, so we can update the
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protections on those pages appropriately. See the class
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insert_only_hash_sets in vtv_set.h for more information. */
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struct vptr_set_alloc
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{
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/* Memory allocator operator. N is the number of bytes to be
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allocated. */
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void *
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operator() (size_t n) const
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{
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return __vtv_malloc (n);
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}
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};
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/* Instantiate the template classes (in vtv_set.h) for our particular
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hash table needs. */
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typedef insert_only_hash_sets<int_vptr, vptr_hash, vptr_set_alloc> vtv_sets;
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typedef vtv_sets::insert_only_hash_set vtv_set;
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typedef vtv_set * vtv_set_handle;
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typedef vtv_set_handle * vtv_set_handle_handle;
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/* Records for caching the section header information that we have
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read out of the file(s) on disk (in dl_iterate_phdr_callback), to
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avoid having to re-open and re-read the same file multiple
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times. */
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struct sect_hdr_data
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{
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#if defined (__CYGWIN__) || defined (__MINGW32__)
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uintptr_t dlpi_addr; /* The header address in the INFO record,
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passed in from dl_iterate_phdr. */
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uintptr_t mp_low; /* Start address of the .vtable_map_vars
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section in memory. */
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#else
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ElfW (Addr) dlpi_addr; /* The header address in the INFO record,
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passed in from dl_iterate_phdr. */
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ElfW (Addr) mp_low; /* Start address of the .vtable_map_vars
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section in memory. */
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#endif
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size_t mp_size; /* Size of the .vtable_map_vars section in
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memory. */
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};
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/* Array for caching the section header information, read from file,
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to avoid re-opening and re-reading the same file over-and-over
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again. */
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#define MAX_ENTRIES 250
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static struct sect_hdr_data vtv_sect_info_cache[MAX_ENTRIES] VTV_PROTECTED_VAR;
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unsigned int num_cache_entries VTV_PROTECTED_VAR = 0;
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/* This function takes the LOAD_ADDR for an object opened by the
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dynamic loader, and checks the array of cached file data to see if
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there is an entry with the same addres. If it finds such an entry,
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it returns the record for that entry; otherwise it returns
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NULL. */
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#if defined (__CYGWIN__) || defined (__MINGW32__)
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struct sect_hdr_data *
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search_cached_file_data (uintptr_t load_addr)
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#else
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struct sect_hdr_data *
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search_cached_file_data (ElfW (Addr) load_addr)
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#endif
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{
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unsigned int i;
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for (i = 0; i < num_cache_entries; ++i)
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{
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if (vtv_sect_info_cache[i].dlpi_addr == load_addr)
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return &(vtv_sect_info_cache[i]);
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}
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return NULL;
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}
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/* This function tries to read COUNT bytes out of the file referred to
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by FD into the buffer BUF. It returns the actual number of bytes
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it succeeded in reading. */
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static size_t
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ReadPersistent (int fd, void *buf, size_t count)
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{
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char *buf0 = (char *) buf;
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size_t num_bytes = 0;
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while (num_bytes < count)
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{
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int len;
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len = read (fd, buf0 + num_bytes, count - num_bytes);
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if (len < 0)
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return -1;
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if (len == 0)
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break;
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num_bytes += len;
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}
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return num_bytes;
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}
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/* This function tries to read COUNT bytes, starting at OFFSET from
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the file referred to by FD, and put them into BUF. It calls
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ReadPersistent to help it do so. It returns the actual number of
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bytes read, or -1 if it fails altogether. */
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static size_t
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ReadFromOffset (int fd, void *buf, const size_t count, const off_t offset)
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{
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off_t off = lseek (fd, offset, SEEK_SET);
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if (off != (off_t) -1)
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return ReadPersistent (fd, buf, count);
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return -1;
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}
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/* The function takes a MESSAGE and attempts to write it to the vtable
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memory protection log (for debugging purposes). If the file is not
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open, it attempts to open the file first. */
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static void
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log_memory_protection_data (char *message)
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{
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static int log_fd = -1;
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if (log_fd == -1)
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log_fd = __vtv_open_log ("vtv_memory_protection_data.log");
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__vtv_add_to_log (log_fd, "%s", message);
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}
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#if defined (__CYGWIN__) || defined (__MINGW32__)
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static void
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read_section_offset_and_length (char *name,
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uintptr_t addr,
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const char *sect_name,
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int mprotect_flags,
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off_t *sect_offset,
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WORD *sect_len)
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{
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bool found = false;
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struct sect_hdr_data *cached_data = NULL;
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/* Check to see if we already have the data for this file. */
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cached_data = search_cached_file_data (addr);
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if (cached_data)
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{
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*sect_offset = cached_data->mp_low;
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*sect_len = cached_data->mp_size;
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return;
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}
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// check for DOS Header magic bytes
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if (*(WORD *)addr == 0x5A4D)
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{
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int name_len = strlen (sect_name);
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int fd = -1;
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/* Attempt to open the binary file on disk. */
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if (strlen (name) == 0)
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{
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return;
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}
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else
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fd = open (name, O_RDONLY | O_BINARY);
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if (fd != -1)
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{
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/* Find the section header information in memory. */
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PIMAGE_DOS_HEADER pDosHeader = (PIMAGE_DOS_HEADER)addr;
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PIMAGE_NT_HEADERS pNtHeaders = (PIMAGE_NT_HEADERS)((char *)addr
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+ pDosHeader->e_lfanew);
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PIMAGE_FILE_HEADER pFileHeader = &pNtHeaders->FileHeader;
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DWORD PointerToStringTable = pFileHeader->PointerToSymbolTable
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+ (pFileHeader->NumberOfSymbols*0x12);
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PIMAGE_SECTION_HEADER sect_hdr =
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(PIMAGE_SECTION_HEADER)((char *)&pNtHeaders->OptionalHeader
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+ pFileHeader->SizeOfOptionalHeader);
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|
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/* Loop through all the section headers, looking for one whose
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name is ".vtable_map_vars". */
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|
|
for (int i = 0; i < pFileHeader->NumberOfSections && !found; ++i)
|
|
{
|
|
char header_name[64];
|
|
|
|
/* Check if we have to get the section name from the COFF string
|
|
table. */
|
|
if (sect_hdr[i].Name[0] == '/')
|
|
{
|
|
if (atoi((const char*)sect_hdr[i].Name+1) == 0)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
off_t name_offset = PointerToStringTable
|
|
+ atoi((const char*)sect_hdr[i].Name+1);
|
|
|
|
size_t bytes_read = ReadFromOffset (fd, &header_name, 64,
|
|
name_offset);
|
|
|
|
VTV_ASSERT (bytes_read > 0);
|
|
}
|
|
else
|
|
{
|
|
memcpy (&header_name, sect_hdr[i].Name,
|
|
sizeof (sect_hdr[i].Name));
|
|
}
|
|
|
|
if (memcmp (header_name, sect_name, name_len) == 0)
|
|
{
|
|
/* We found the section; get its load offset and
|
|
size. */
|
|
*sect_offset = sect_hdr[i].VirtualAddress;
|
|
if (sect_hdr[i].Misc.VirtualSize % VTV_PAGE_SIZE != 0)
|
|
*sect_len = sect_hdr[i].Misc.VirtualSize + VTV_PAGE_SIZE
|
|
- (sect_hdr[i].Misc.VirtualSize % VTV_PAGE_SIZE);
|
|
else
|
|
*sect_len = sect_hdr[i].Misc.VirtualSize;
|
|
found = true;
|
|
}
|
|
}
|
|
close (fd);
|
|
}
|
|
}
|
|
|
|
if (*sect_offset != 0 && *sect_len != 0)
|
|
{
|
|
/* Calculate the page location in memory, making sure the
|
|
address is page-aligned. */
|
|
uintptr_t start_addr = addr + *sect_offset;
|
|
*sect_offset = start_addr & ~(VTV_PAGE_SIZE - 1);
|
|
*sect_len = *sect_len - 1;
|
|
|
|
/* Since we got this far, we must not have found these pages in
|
|
the cache, so add them to it. NOTE: We could get here either
|
|
while making everything read-only or while making everything
|
|
read-write. We will only update the cache if we get here on
|
|
a read-write (to make absolutely sure the cache is writable
|
|
-- also the read-write pass should come before the read-only
|
|
pass). */
|
|
if ((mprotect_flags & PROT_WRITE)
|
|
&& num_cache_entries < MAX_ENTRIES)
|
|
{
|
|
vtv_sect_info_cache[num_cache_entries].dlpi_addr = addr;
|
|
vtv_sect_info_cache[num_cache_entries].mp_low = *sect_offset;
|
|
vtv_sect_info_cache[num_cache_entries].mp_size = *sect_len;
|
|
num_cache_entries++;
|
|
}
|
|
}
|
|
}
|
|
#else
|
|
static void
|
|
read_section_offset_and_length (struct dl_phdr_info *info,
|
|
const char *sect_name,
|
|
int mprotect_flags,
|
|
off_t *sect_offset,
|
|
ElfW (Word) *sect_len)
|
|
{
|
|
char program_name[PATH_MAX];
|
|
char *cptr;
|
|
bool found = false;
|
|
struct sect_hdr_data *cached_data = NULL;
|
|
const ElfW (Phdr) *phdr_info = info->dlpi_phdr;
|
|
const ElfW (Ehdr) *ehdr_info =
|
|
(const ElfW (Ehdr) *) (info->dlpi_addr + info->dlpi_phdr[0].p_vaddr
|
|
- info->dlpi_phdr[0].p_offset);
|
|
|
|
|
|
/* Get the name of the main executable. This may or may not include
|
|
arguments passed to the program. Find the first space, assume it
|
|
is the start of the argument list, and change it to a '\0'. */
|
|
#ifdef HAVE_GETEXECNAME
|
|
program_invocation_name = getexecname ();
|
|
#endif
|
|
snprintf (program_name, sizeof (program_name), program_invocation_name);
|
|
|
|
/* Check to see if we already have the data for this file. */
|
|
cached_data = search_cached_file_data (info->dlpi_addr);
|
|
|
|
if (cached_data)
|
|
{
|
|
*sect_offset = cached_data->mp_low;
|
|
*sect_len = cached_data->mp_size;
|
|
return;
|
|
}
|
|
|
|
/* Find the first non-escaped space in the program name and make it
|
|
the end of the string. */
|
|
cptr = strchr (program_name, ' ');
|
|
if (cptr != NULL && cptr[-1] != '\\')
|
|
cptr[0] = '\0';
|
|
|
|
if ((phdr_info->p_type == PT_PHDR || phdr_info->p_type == PT_LOAD)
|
|
&& (ehdr_info->e_shoff && ehdr_info->e_shnum))
|
|
{
|
|
int name_len = strlen (sect_name);
|
|
int fd = -1;
|
|
|
|
/* Attempt to open the binary file on disk. */
|
|
if (strlen (info->dlpi_name) == 0)
|
|
{
|
|
/* If the constructor initialization function was put into
|
|
the preinit array, then this function will get called
|
|
while handling preinit array stuff, in which case
|
|
program_invocation_name has not been initialized. In
|
|
that case we can get the filename of the executable from
|
|
"/proc/self/exe". */
|
|
if (strlen (program_name) > 0)
|
|
{
|
|
if (phdr_info->p_type == PT_PHDR)
|
|
fd = open (program_name, O_RDONLY);
|
|
}
|
|
else
|
|
fd = open ("/proc/self/exe", O_RDONLY);
|
|
}
|
|
else
|
|
fd = open (info->dlpi_name, O_RDONLY);
|
|
|
|
if (fd != -1)
|
|
{
|
|
/* Find the section header information in the file. */
|
|
ElfW (Half) strtab_idx = ehdr_info->e_shstrndx;
|
|
ElfW (Shdr) shstrtab;
|
|
off_t shstrtab_offset = ehdr_info->e_shoff +
|
|
(ehdr_info->e_shentsize * strtab_idx);
|
|
size_t bytes_read = ReadFromOffset (fd, &shstrtab, sizeof (shstrtab),
|
|
shstrtab_offset);
|
|
VTV_ASSERT (bytes_read == sizeof (shstrtab));
|
|
|
|
ElfW (Shdr) sect_hdr;
|
|
|
|
/* This code will be needed once we have crated libvtv.so. */
|
|
bool is_libvtv = false;
|
|
|
|
/*
|
|
if (strstr (info->dlpi_name, "libvtv.so"))
|
|
is_libvtv = true;
|
|
*/
|
|
|
|
/* Loop through all the section headers, looking for one whose
|
|
name is ".vtable_map_vars". */
|
|
|
|
for (int i = 0; i < ehdr_info->e_shnum && !found; ++i)
|
|
{
|
|
off_t offset = ehdr_info->e_shoff + (ehdr_info->e_shentsize * i);
|
|
|
|
bytes_read = ReadFromOffset (fd, §_hdr, sizeof (sect_hdr),
|
|
offset);
|
|
|
|
VTV_ASSERT (bytes_read == sizeof (sect_hdr));
|
|
|
|
char header_name[64];
|
|
off_t name_offset = shstrtab.sh_offset + sect_hdr.sh_name;
|
|
|
|
bytes_read = ReadFromOffset (fd, &header_name, 64, name_offset);
|
|
|
|
VTV_ASSERT (bytes_read > 0);
|
|
|
|
if (memcmp (header_name, sect_name, name_len) == 0)
|
|
{
|
|
/* We found the section; get its load offset and
|
|
size. */
|
|
*sect_offset = sect_hdr.sh_addr;
|
|
if (!is_libvtv)
|
|
{
|
|
VTV_ASSERT (sect_hdr.sh_size - VTV_PAGE_SIZE >= 0);
|
|
*sect_len = sect_hdr.sh_size - VTV_PAGE_SIZE;
|
|
}
|
|
else
|
|
*sect_len = sect_hdr.sh_size;
|
|
found = true;
|
|
}
|
|
}
|
|
close (fd);
|
|
}
|
|
}
|
|
|
|
if (*sect_offset != 0 && *sect_len != 0)
|
|
{
|
|
/* Calculate the page location in memory, making sure the
|
|
address is page-aligned. */
|
|
ElfW (Addr) start_addr = (const ElfW (Addr)) info->dlpi_addr
|
|
+ *sect_offset;
|
|
*sect_offset = start_addr & ~(VTV_PAGE_SIZE - 1);
|
|
*sect_len = *sect_len - 1;
|
|
|
|
/* Since we got this far, we must not have found these pages in
|
|
the cache, so add them to it. NOTE: We could get here either
|
|
while making everything read-only or while making everything
|
|
read-write. We will only update the cache if we get here on
|
|
a read-write (to make absolutely sure the cache is writable
|
|
-- also the read-write pass should come before the read-only
|
|
pass). */
|
|
if ((mprotect_flags & PROT_WRITE)
|
|
&& num_cache_entries < MAX_ENTRIES)
|
|
{
|
|
vtv_sect_info_cache[num_cache_entries].dlpi_addr = info->dlpi_addr;
|
|
vtv_sect_info_cache[num_cache_entries].mp_low = *sect_offset;
|
|
vtv_sect_info_cache[num_cache_entries].mp_size = *sect_len;
|
|
num_cache_entries++;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#if defined (__CYGWIN__) || defined (__MINGW32__)
|
|
/* This function is used to iterate over all loaded modules and searches
|
|
for a section called ".vtable_map_vars". The only interaction with
|
|
the binary file on disk of the module is to read section names in the
|
|
COFF string table. If the module contains a ".vtable_map_vars" section,
|
|
read section offset and size from the section header of the loaded module.
|
|
Call 'mprotect' on those pages, setting the protection either to
|
|
read-only or read-write, depending on what's in data.
|
|
The calls to change the protection occur in vtv_unprotect_vtable_vars
|
|
and vtv_protect_vtable_vars. */
|
|
|
|
static int
|
|
iterate_modules (void *data)
|
|
{
|
|
int * mprotect_flags = (int *) data;
|
|
off_t map_sect_offset = 0;
|
|
WORD map_sect_len = 0;
|
|
char buffer[1024];
|
|
const char *map_sect_name = VTV_PROTECTED_VARS_SECTION;
|
|
HMODULE hMods[1024];
|
|
HANDLE hProcess;
|
|
DWORD cbNeeded;
|
|
|
|
hProcess = GetCurrentProcess ();
|
|
|
|
if (NULL == hProcess)
|
|
return 0;
|
|
|
|
if (EnumProcessModules (hProcess, hMods, sizeof (hMods), &cbNeeded))
|
|
{
|
|
/* Iterate over all loaded modules. */
|
|
for (unsigned int i = 0; i < (cbNeeded / sizeof (HMODULE)); i++)
|
|
{
|
|
char szModName[MAX_PATH];
|
|
|
|
if (GetModuleFileNameExA (hProcess, hMods[i], szModName,
|
|
sizeof (szModName)))
|
|
{
|
|
map_sect_offset = 0;
|
|
map_sect_len = 0;
|
|
read_section_offset_and_length (szModName,
|
|
(uintptr_t) hMods[i],
|
|
map_sect_name,
|
|
*mprotect_flags,
|
|
&map_sect_offset,
|
|
&map_sect_len);
|
|
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof(buffer),
|
|
" Looking at load module %s to change permissions to %s\n",
|
|
szModName,
|
|
(*mprotect_flags & PROT_WRITE) ? "READ/WRITE" : "READ-ONLY");
|
|
log_memory_protection_data (buffer);
|
|
}
|
|
|
|
/* See if we actually found the section. */
|
|
if (map_sect_offset && map_sect_len)
|
|
{
|
|
unsigned long long start;
|
|
int result;
|
|
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
" (%s): Protecting %p to %p\n",
|
|
szModName,
|
|
(void *) map_sect_offset,
|
|
(void *) (map_sect_offset + map_sect_len));
|
|
log_memory_protection_data (buffer);
|
|
}
|
|
|
|
/* Change the protections on the pages for the section. */
|
|
|
|
start = get_cycle_count ();
|
|
result = mprotect ((void *) map_sect_offset, map_sect_len,
|
|
*mprotect_flags);
|
|
accumulate_cycle_count (&mprotect_cycles, start);
|
|
if (result == -1)
|
|
{
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
"Failed call to mprotect for %s error: ",
|
|
(*mprotect_flags & PROT_WRITE) ?
|
|
"READ/WRITE" : "READ-ONLY");
|
|
log_memory_protection_data (buffer);
|
|
perror(NULL);
|
|
}
|
|
VTV_error();
|
|
}
|
|
else
|
|
{
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
"mprotect'ed range [%p, %p]\n",
|
|
(void *) map_sect_offset,
|
|
(char *) map_sect_offset + map_sect_len);
|
|
log_memory_protection_data (buffer);
|
|
}
|
|
}
|
|
increment_num_calls (&num_calls_to_mprotect);
|
|
num_pages_protected += (map_sect_len + VTV_PAGE_SIZE - 1)
|
|
/ VTV_PAGE_SIZE;
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
CloseHandle(hProcess);
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
/* This is the callback function used by dl_iterate_phdr (which is
|
|
called from vtv_unprotect_vtable_vars and vtv_protect_vtable_vars).
|
|
It attempts to find the binary file on disk for the INFO record
|
|
that dl_iterate_phdr passes in; open the binary file, and read its
|
|
section header information. If the file contains a
|
|
".vtable_map_vars" section, read the section offset and size. Use
|
|
the section offset and size, in conjunction with the data in INFO
|
|
to locate the pages in memory where the section is. Call
|
|
'mprotect' on those pages, setting the protection either to
|
|
read-only or read-write, depending on what's in DATA. */
|
|
|
|
static int
|
|
dl_iterate_phdr_callback (struct dl_phdr_info *info, size_t, void *data)
|
|
{
|
|
int * mprotect_flags = (int *) data;
|
|
off_t map_sect_offset = 0;
|
|
ElfW (Word) map_sect_len = 0;
|
|
char buffer[1024];
|
|
char program_name[1024];
|
|
const char *map_sect_name = VTV_PROTECTED_VARS_SECTION;
|
|
|
|
/* Check to see if this is the record for the Linux Virtual Dynamic
|
|
Shared Object (linux-vdso.so.1), which exists only in memory (and
|
|
therefore cannot be read from disk). */
|
|
|
|
if (strcmp (info->dlpi_name, "linux-vdso.so.1") == 0)
|
|
return 0;
|
|
|
|
if (strlen (info->dlpi_name) == 0
|
|
&& info->dlpi_addr != 0)
|
|
return 0;
|
|
|
|
/* Get the name of the main executable. This may or may not include
|
|
arguments passed to the program. Find the first space, assume it
|
|
is the start of the argument list, and change it to a '\0'. */
|
|
#ifdef HAVE_GETEXECNAME
|
|
program_invocation_name = getexecname ();
|
|
#endif
|
|
snprintf (program_name, sizeof (program_name), program_invocation_name);
|
|
|
|
read_section_offset_and_length (info, map_sect_name, *mprotect_flags,
|
|
&map_sect_offset, &map_sect_len);
|
|
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof(buffer),
|
|
" Looking at load module %s to change permissions to %s\n",
|
|
((strlen (info->dlpi_name) == 0) ? program_name
|
|
: info->dlpi_name),
|
|
(*mprotect_flags & PROT_WRITE) ? "READ/WRITE" : "READ-ONLY");
|
|
log_memory_protection_data (buffer);
|
|
}
|
|
|
|
/* See if we actually found the section. */
|
|
if (map_sect_offset && map_sect_len)
|
|
{
|
|
unsigned long long start;
|
|
int result;
|
|
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
" (%s): Protecting %p to %p\n",
|
|
((strlen (info->dlpi_name) == 0) ? program_name
|
|
: info->dlpi_name),
|
|
(void *) map_sect_offset,
|
|
(void *) (map_sect_offset + map_sect_len));
|
|
log_memory_protection_data (buffer);
|
|
}
|
|
|
|
/* Change the protections on the pages for the section. */
|
|
|
|
start = get_cycle_count ();
|
|
result = mprotect ((void *) map_sect_offset, map_sect_len,
|
|
*mprotect_flags);
|
|
accumulate_cycle_count (&mprotect_cycles, start);
|
|
if (result == -1)
|
|
{
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
"Failed call to mprotect for %s error: ",
|
|
(*mprotect_flags & PROT_WRITE) ?
|
|
"READ/WRITE" : "READ-ONLY");
|
|
log_memory_protection_data (buffer);
|
|
perror(NULL);
|
|
}
|
|
VTV_error();
|
|
}
|
|
else
|
|
{
|
|
if (debug_functions)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
"mprotect'ed range [%p, %p]\n",
|
|
(void *) map_sect_offset,
|
|
(char *) map_sect_offset + map_sect_len);
|
|
log_memory_protection_data (buffer);
|
|
}
|
|
}
|
|
increment_num_calls (&num_calls_to_mprotect);
|
|
num_pages_protected += (map_sect_len + VTV_PAGE_SIZE - 1) / VTV_PAGE_SIZE;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
/* This function explicitly changes the protection (read-only or read-write)
|
|
on the vtv_sect_info_cache, which is used for speeding up look ups in the
|
|
function dl_iterate_phdr_callback. This data structure needs to be
|
|
explicitly made read-write before any calls to dl_iterate_phdr_callback,
|
|
because otherwise it may still be read-only when dl_iterate_phdr_callback
|
|
attempts to write to it.
|
|
|
|
More detailed explanation: dl_iterate_phdr_callback finds all the
|
|
.vtable_map_vars sections in all loaded objects (including the main program)
|
|
and (depending on where it was called from) either makes all the pages in the
|
|
sections read-write or read-only. The vtv_sect_info_cache should be in the
|
|
.vtable_map_vars section for libstdc++.so, which means that normally it would
|
|
be read-only until libstdc++.so is processed by dl_iterate_phdr_callback
|
|
(on the read-write pass), after which it will be writable. But if any loaded
|
|
object gets processed before libstdc++.so, it will attempt to update the
|
|
data cache, which will still be read-only, and cause a seg fault. Hence
|
|
we need a special function, called before dl_iterate_phdr_callback, that
|
|
will make the data cache writable. */
|
|
|
|
static void
|
|
change_protections_on_phdr_cache (int protection_flag)
|
|
{
|
|
char * low_address = (char *) &(vtv_sect_info_cache);
|
|
size_t cache_size = MAX_ENTRIES * sizeof (struct sect_hdr_data);
|
|
|
|
low_address = (char *) ((uintptr_t) low_address & ~(VTV_PAGE_SIZE - 1));
|
|
|
|
if (mprotect ((void *) low_address, cache_size, protection_flag) == -1)
|
|
VTV_error ();
|
|
}
|
|
|
|
/* Unprotect all the vtable map vars and other side data that is used
|
|
to keep the core hash_map data. All of these data have been put
|
|
into relro sections */
|
|
|
|
static void
|
|
vtv_unprotect_vtable_vars (void)
|
|
{
|
|
int mprotect_flags;
|
|
|
|
mprotect_flags = PROT_READ | PROT_WRITE;
|
|
change_protections_on_phdr_cache (mprotect_flags);
|
|
#if defined (__CYGWIN__) || defined (__MINGW32__)
|
|
iterate_modules ((void *) &mprotect_flags);
|
|
#else
|
|
dl_iterate_phdr (dl_iterate_phdr_callback, (void *) &mprotect_flags);
|
|
#endif
|
|
}
|
|
|
|
/* Protect all the vtable map vars and other side data that is used
|
|
to keep the core hash_map data. All of these data have been put
|
|
into relro sections */
|
|
|
|
static void
|
|
vtv_protect_vtable_vars (void)
|
|
{
|
|
int mprotect_flags;
|
|
|
|
mprotect_flags = PROT_READ;
|
|
#if defined (__CYGWIN__) || defined (__MINGW32__)
|
|
iterate_modules ((void *) &mprotect_flags);
|
|
#else
|
|
dl_iterate_phdr (dl_iterate_phdr_callback, (void *) &mprotect_flags);
|
|
#endif
|
|
change_protections_on_phdr_cache (mprotect_flags);
|
|
}
|
|
|
|
#ifndef __GTHREAD_MUTEX_INIT
|
|
static void
|
|
initialize_change_permissions_mutexes ()
|
|
{
|
|
__GTHREAD_MUTEX_INIT_FUNCTION (&change_permissions_lock);
|
|
}
|
|
#endif
|
|
|
|
/* Variables needed for getting the statistics about the hashtable set. */
|
|
#if HASHTABLE_STATS
|
|
_AtomicStatCounter stat_contains = 0;
|
|
_AtomicStatCounter stat_insert = 0;
|
|
_AtomicStatCounter stat_resize = 0;
|
|
_AtomicStatCounter stat_create = 0;
|
|
_AtomicStatCounter stat_probes_in_non_trivial_set = 0;
|
|
_AtomicStatCounter stat_contains_size0 = 0;
|
|
_AtomicStatCounter stat_contains_size1 = 0;
|
|
_AtomicStatCounter stat_contains_size2 = 0;
|
|
_AtomicStatCounter stat_contains_size3 = 0;
|
|
_AtomicStatCounter stat_contains_size4 = 0;
|
|
_AtomicStatCounter stat_contains_size5 = 0;
|
|
_AtomicStatCounter stat_contains_size6 = 0;
|
|
_AtomicStatCounter stat_contains_size7 = 0;
|
|
_AtomicStatCounter stat_contains_size8 = 0;
|
|
_AtomicStatCounter stat_contains_size9 = 0;
|
|
_AtomicStatCounter stat_contains_size10 = 0;
|
|
_AtomicStatCounter stat_contains_size11 = 0;
|
|
_AtomicStatCounter stat_contains_size12 = 0;
|
|
_AtomicStatCounter stat_contains_size13_or_more = 0;
|
|
_AtomicStatCounter stat_contains_sizes = 0;
|
|
_AtomicStatCounter stat_grow_from_size0_to_1 = 0;
|
|
_AtomicStatCounter stat_grow_from_size1_to_2 = 0;
|
|
_AtomicStatCounter stat_double_the_number_of_buckets = 0;
|
|
_AtomicStatCounter stat_insert_found_hash_collision = 0;
|
|
_AtomicStatCounter stat_contains_in_non_trivial_set = 0;
|
|
_AtomicStatCounter stat_insert_key_that_was_already_present = 0;
|
|
#endif
|
|
/* Record statistics about the hash table sets, for debugging. */
|
|
|
|
static void
|
|
log_set_stats (void)
|
|
{
|
|
#if HASHTABLE_STATS
|
|
if (set_log_fd == -1)
|
|
set_log_fd = __vtv_open_log ("vtv_set_stats.log");
|
|
|
|
__vtv_add_to_log (set_log_fd, "---\n%s\n",
|
|
insert_only_hash_tables_stats().c_str());
|
|
#endif
|
|
}
|
|
|
|
/* Change the permissions on all the pages we have allocated for the
|
|
data sets and all the ".vtable_map_var" sections in memory (which
|
|
contain our vtable map variables). PERM indicates whether to make
|
|
the permissions read-only or read-write. */
|
|
|
|
extern "C" /* This is only being applied to __VLTChangePermission*/
|
|
void
|
|
__VLTChangePermission (int perm)
|
|
{
|
|
if (debug_functions)
|
|
{
|
|
if (perm == __VLTP_READ_WRITE)
|
|
fprintf (stdout, "Changing VLT permissions to Read-Write.\n");
|
|
else if (perm == __VLTP_READ_ONLY)
|
|
fprintf (stdout, "Changing VLT permissions to Read-Only.\n");
|
|
|
|
else
|
|
fprintf (stdout, "Unrecognized permissions value: %d\n", perm);
|
|
}
|
|
|
|
#ifndef __GTHREAD_MUTEX_INIT
|
|
static __gthread_once_t mutex_once VTV_PROTECTED_VAR = __GTHREAD_ONCE_INIT;
|
|
|
|
__gthread_once (&mutex_once, initialize_change_permissions_mutexes);
|
|
#endif
|
|
|
|
/* Ordering of these unprotect/protect calls is very important.
|
|
You first need to unprotect all the map vars and side
|
|
structures before you do anything with the core data
|
|
structures (hash_maps) */
|
|
|
|
if (perm == __VLTP_READ_WRITE)
|
|
{
|
|
/* TODO: Need to revisit this code for dlopen. It most probably
|
|
is not unlocking the protected vtable vars after for load
|
|
module that is not the first load module. */
|
|
__gthread_mutex_lock (&change_permissions_lock);
|
|
|
|
vtv_unprotect_vtable_vars ();
|
|
__vtv_malloc_init ();
|
|
__vtv_malloc_unprotect ();
|
|
|
|
}
|
|
else if (perm == __VLTP_READ_ONLY)
|
|
{
|
|
if (debug_hash)
|
|
log_set_stats();
|
|
|
|
__vtv_malloc_protect ();
|
|
vtv_protect_vtable_vars ();
|
|
|
|
__gthread_mutex_unlock (&change_permissions_lock);
|
|
}
|
|
}
|
|
|
|
/* This is the memory allocator used to create the hash table that
|
|
maps from vtable map variable name to the data set that vtable map
|
|
variable should point to. This is part of our vtable map variable
|
|
symbol resolution, which is necessary because the same vtable map
|
|
variable may be created by multiple compilation units and we need a
|
|
method to make sure that all vtable map variables for a particular
|
|
class point to the same data set at runtime. */
|
|
|
|
struct insert_only_hash_map_allocator
|
|
{
|
|
/* N is the number of bytes to allocate. */
|
|
void *
|
|
alloc (size_t n) const
|
|
{
|
|
return __vtv_malloc (n);
|
|
}
|
|
|
|
/* P points to the memory to be deallocated; N is the number of
|
|
bytes to deallocate. */
|
|
void
|
|
dealloc (void *p, size_t) const
|
|
{
|
|
__vtv_free (p);
|
|
}
|
|
};
|
|
|
|
/* Explicitly instantiate this class since this file is compiled with
|
|
-fno-implicit-templates. These are for the hash table that is used
|
|
to do vtable map variable symbol resolution. */
|
|
template class insert_only_hash_map <vtv_set_handle *,
|
|
insert_only_hash_map_allocator >;
|
|
typedef insert_only_hash_map <vtv_set_handle *,
|
|
insert_only_hash_map_allocator > s2s;
|
|
typedef const s2s::key_type vtv_symbol_key;
|
|
|
|
static s2s * vtv_symbol_unification_map VTV_PROTECTED_VAR = NULL;
|
|
|
|
const unsigned long SET_HANDLE_HANDLE_BIT = 0x2;
|
|
|
|
/* In the case where a vtable map variable is the only instance of the
|
|
variable we have seen, it points directly to the set of valid
|
|
vtable pointers. All subsequent instances of the 'same' vtable map
|
|
variable point to the first vtable map variable. This function,
|
|
given a vtable map variable PTR, checks a bit to see whether it's
|
|
pointing directly to the data set or to the first vtable map
|
|
variable. */
|
|
|
|
static inline bool
|
|
is_set_handle_handle (void * ptr)
|
|
{
|
|
return ((uintptr_t) ptr & SET_HANDLE_HANDLE_BIT)
|
|
== SET_HANDLE_HANDLE_BIT;
|
|
}
|
|
|
|
/* Returns the actual pointer value of a vtable map variable, PTR (see
|
|
comments for is_set_handle_handle for more details). */
|
|
|
|
static inline vtv_set_handle *
|
|
ptr_from_set_handle_handle (void * ptr)
|
|
{
|
|
return (vtv_set_handle *) ((uintptr_t) ptr & ~SET_HANDLE_HANDLE_BIT);
|
|
}
|
|
|
|
/* Given a vtable map variable, PTR, this function sets the bit that
|
|
says this is the second (or later) instance of a vtable map
|
|
variable. */
|
|
|
|
static inline vtv_set_handle_handle
|
|
set_handle_handle (vtv_set_handle * ptr)
|
|
{
|
|
return (vtv_set_handle_handle) ((uintptr_t) ptr | SET_HANDLE_HANDLE_BIT);
|
|
}
|
|
|
|
static inline void
|
|
register_set_common (void **set_handle_ptr, size_t num_args,
|
|
void **vtable_ptr_array, bool debug)
|
|
{
|
|
/* Now figure out what pointer to use for the set pointer, for the
|
|
inserts. */
|
|
vtv_set_handle *handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
|
|
if (debug)
|
|
VTV_DEBUG_ASSERT (vtv_symbol_unification_map != NULL);
|
|
|
|
if (!is_set_handle_handle (*set_handle_ptr))
|
|
handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
else
|
|
handle_ptr = ptr_from_set_handle_handle (*set_handle_ptr);
|
|
|
|
/* Now we've got the set and it's initialized, add the vtable
|
|
pointers. */
|
|
for (size_t index = 0; index < num_args; ++index)
|
|
{
|
|
int_vptr vtbl_ptr = (int_vptr) vtable_ptr_array[index];
|
|
vtv_sets::insert (vtbl_ptr, handle_ptr);
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
register_pair_common (void **set_handle_ptr, const void *vtable_ptr,
|
|
const char *set_symbol_name, const char *vtable_name,
|
|
bool debug)
|
|
{
|
|
/* Now we've got the set and it's initialized, add the vtable
|
|
pointer (assuming that it's not NULL...It may be NULL, as we may
|
|
have called this function merely to initialize the set
|
|
pointer). */
|
|
int_vptr vtbl_ptr = (int_vptr) vtable_ptr;
|
|
if (vtbl_ptr)
|
|
{
|
|
vtv_set_handle *handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
if (debug)
|
|
VTV_DEBUG_ASSERT (vtv_symbol_unification_map != NULL);
|
|
if (!is_set_handle_handle (*set_handle_ptr))
|
|
handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
else
|
|
handle_ptr = ptr_from_set_handle_handle (*set_handle_ptr);
|
|
|
|
vtv_sets::insert (vtbl_ptr, handle_ptr);
|
|
}
|
|
|
|
if (debug && debug_init)
|
|
{
|
|
if (init_log_fd == -1)
|
|
init_log_fd = __vtv_open_log("vtv_init.log");
|
|
|
|
__vtv_add_to_log(init_log_fd,
|
|
"Registered %s : %s (%p) 2 level deref = %s\n",
|
|
set_symbol_name, vtable_name, vtbl_ptr,
|
|
is_set_handle_handle(*set_handle_ptr) ? "yes" : "no" );
|
|
}
|
|
}
|
|
|
|
/* This routine initializes a set handle to a vtable set. It makes
|
|
sure that there is only one set handle for a particular set by
|
|
using a map from set name to pointer to set handle. Since there
|
|
will be multiple copies of the pointer to the set handle (one per
|
|
compilation unit that uses it), it makes sure to initialize all the
|
|
pointers to the set handle so that the set handle is unique. To
|
|
make this a little more efficient and avoid a level of indirection
|
|
in some cases, the first pointer to handle for a particular handle
|
|
becomes the handle itself and the other pointers will point to the
|
|
set handle. This is the debug version of this function, so it
|
|
outputs extra debugging messages and logging. SET_HANDLE_PTR is
|
|
the address of the vtable map variable, SET_SYMBOL_KEY is the hash
|
|
table key (containing the name of the map variable and the hash
|
|
value) and SIZE_HINT is a guess for the best initial size for the
|
|
set of vtable pointers that SET_HANDLE_POINTER will point to. */
|
|
|
|
static inline void
|
|
init_set_symbol_debug (void **set_handle_ptr, const void *set_symbol_key,
|
|
size_t size_hint)
|
|
{
|
|
VTV_DEBUG_ASSERT (set_handle_ptr);
|
|
|
|
if (vtv_symbol_unification_map == NULL)
|
|
{
|
|
/* TODO: For now we have chosen 1024, but we need to come up with a
|
|
better initial size for this. */
|
|
vtv_symbol_unification_map = s2s::create (1024);
|
|
VTV_DEBUG_ASSERT(vtv_symbol_unification_map);
|
|
}
|
|
|
|
vtv_set_handle *handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
vtv_symbol_key *symbol_key_ptr = (vtv_symbol_key *) set_symbol_key;
|
|
|
|
const s2s::value_type * map_value_ptr =
|
|
vtv_symbol_unification_map->get (symbol_key_ptr);
|
|
char buffer[200];
|
|
if (map_value_ptr == NULL)
|
|
{
|
|
if (*handle_ptr != NULL)
|
|
{
|
|
snprintf (buffer, sizeof (buffer),
|
|
"*** Found non-NULL local set ptr %p missing for symbol"
|
|
" %.*s",
|
|
*handle_ptr, symbol_key_ptr->n, symbol_key_ptr->bytes);
|
|
__vtv_log_verification_failure (buffer, true);
|
|
VTV_DEBUG_ASSERT (0);
|
|
}
|
|
}
|
|
else if (*handle_ptr != NULL &&
|
|
(handle_ptr != *map_value_ptr &&
|
|
ptr_from_set_handle_handle (*handle_ptr) != *map_value_ptr))
|
|
{
|
|
VTV_DEBUG_ASSERT (*map_value_ptr != NULL);
|
|
snprintf (buffer, sizeof(buffer),
|
|
"*** Found diffence between local set ptr %p and set ptr %p"
|
|
"for symbol %.*s",
|
|
*handle_ptr, *map_value_ptr,
|
|
symbol_key_ptr->n, symbol_key_ptr->bytes);
|
|
__vtv_log_verification_failure (buffer, true);
|
|
VTV_DEBUG_ASSERT (0);
|
|
}
|
|
else if (*handle_ptr == NULL)
|
|
{
|
|
/* Execution should not reach this point. */
|
|
}
|
|
|
|
if (*handle_ptr != NULL)
|
|
{
|
|
if (!is_set_handle_handle (*set_handle_ptr))
|
|
handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
else
|
|
handle_ptr = ptr_from_set_handle_handle (*set_handle_ptr);
|
|
vtv_sets::resize (size_hint, handle_ptr);
|
|
return;
|
|
}
|
|
|
|
VTV_DEBUG_ASSERT (*handle_ptr == NULL);
|
|
if (map_value_ptr != NULL)
|
|
{
|
|
if (*map_value_ptr == handle_ptr)
|
|
vtv_sets::resize (size_hint, *map_value_ptr);
|
|
else
|
|
{
|
|
/* The one level handle to the set already exists. So, we
|
|
are adding one level of indirection here and we will
|
|
store a pointer to the one level handle here. */
|
|
|
|
vtv_set_handle_handle * handle_handle_ptr =
|
|
(vtv_set_handle_handle *)handle_ptr;
|
|
*handle_handle_ptr = set_handle_handle(*map_value_ptr);
|
|
VTV_DEBUG_ASSERT(*handle_handle_ptr != NULL);
|
|
|
|
/* The handle can itself be NULL if the set has only
|
|
been initiazlied with size hint == 1. */
|
|
vtv_sets::resize (size_hint, *map_value_ptr);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* We will create a new set. So, in this case handle_ptr is the
|
|
one level pointer to the set handle. Create copy of map name
|
|
in case the memory where this comes from gets unmapped by
|
|
dlclose. */
|
|
size_t map_key_len = symbol_key_ptr->n + sizeof (vtv_symbol_key);
|
|
void *map_key = __vtv_malloc (map_key_len);
|
|
|
|
memcpy (map_key, symbol_key_ptr, map_key_len);
|
|
|
|
s2s::value_type *value_ptr;
|
|
vtv_symbol_unification_map =
|
|
vtv_symbol_unification_map->find_or_add_key ((vtv_symbol_key *)map_key,
|
|
&value_ptr);
|
|
*value_ptr = handle_ptr;
|
|
|
|
/* TODO: We should verify the return value. */
|
|
vtv_sets::create (size_hint, handle_ptr);
|
|
VTV_DEBUG_ASSERT (size_hint <= 1 || *handle_ptr != NULL);
|
|
}
|
|
|
|
if (debug_init)
|
|
{
|
|
if (init_log_fd == -1)
|
|
init_log_fd = __vtv_open_log ("vtv_init.log");
|
|
|
|
__vtv_add_to_log (init_log_fd,
|
|
"Init handle:%p for symbol:%.*s hash:%u size_hint:%lu"
|
|
"number of symbols:%lu \n",
|
|
set_handle_ptr, symbol_key_ptr->n,
|
|
symbol_key_ptr->bytes, symbol_key_ptr->hash, size_hint,
|
|
vtv_symbol_unification_map->size ());
|
|
}
|
|
}
|
|
|
|
|
|
/* This routine initializes a set handle to a vtable set. It makes
|
|
sure that there is only one set handle for a particular set by
|
|
using a map from set name to pointer to set handle. Since there
|
|
will be multiple copies of the pointer to the set handle (one per
|
|
compilation unit that uses it), it makes sure to initialize all the
|
|
pointers to the set handle so that the set handle is unique. To
|
|
make this a little more efficient and avoid a level of indirection
|
|
in some cases, the first pointer to handle for a particular handle
|
|
becomes the handle itself and the other pointers will point to the
|
|
set handle. This is the debug version of this function, so it
|
|
outputs extra debugging messages and logging. SET_HANDLE_PTR is
|
|
the address of the vtable map variable, SET_SYMBOL_KEY is the hash
|
|
table key (containing the name of the map variable and the hash
|
|
value) and SIZE_HINT is a guess for the best initial size for the
|
|
set of vtable pointers that SET_HANDLE_POINTER will point to. */
|
|
|
|
void
|
|
__VLTRegisterSetDebug (void **set_handle_ptr, const void *set_symbol_key,
|
|
size_t size_hint, size_t num_args,
|
|
void **vtable_ptr_array)
|
|
{
|
|
unsigned long long start = get_cycle_count ();
|
|
increment_num_calls (&num_calls_to_regset);
|
|
|
|
VTV_DEBUG_ASSERT(set_handle_ptr != NULL);
|
|
init_set_symbol_debug (set_handle_ptr, set_symbol_key, size_hint);
|
|
|
|
register_set_common (set_handle_ptr, num_args, vtable_ptr_array, true);
|
|
|
|
accumulate_cycle_count (®set_cycles, start);
|
|
}
|
|
|
|
/* This function takes a the address of a vtable map variable
|
|
(SET_HANDLE_PTR), a VTABLE_PTR to add to the data set, the name of
|
|
the vtable map variable (SET_SYMBOL_NAME) and the name of the
|
|
vtable (VTABLE_NAME) being pointed to. If the vtable map variable
|
|
is NULL it creates a new data set and initializes the variable,
|
|
otherwise it uses our symbol unification to find the right data
|
|
set; in either case it then adds the vtable pointer to the set.
|
|
The other two parameters are used for debugging information. */
|
|
|
|
void
|
|
__VLTRegisterPairDebug (void **set_handle_ptr, const void *set_symbol_key,
|
|
size_t size_hint, const void *vtable_ptr,
|
|
const char *set_symbol_name, const char *vtable_name)
|
|
{
|
|
unsigned long long start = get_cycle_count ();
|
|
increment_num_calls (&num_calls_to_regpair);
|
|
|
|
VTV_DEBUG_ASSERT(set_handle_ptr != NULL);
|
|
init_set_symbol_debug (set_handle_ptr, set_symbol_key, size_hint);
|
|
|
|
register_pair_common (set_handle_ptr, vtable_ptr, set_symbol_name, vtable_name,
|
|
true);
|
|
|
|
accumulate_cycle_count (®pair_cycles, start);
|
|
}
|
|
|
|
|
|
/* This is the debug version of the verification function. It takes
|
|
the address of a vtable map variable (SET_HANDLE_PTR) and a
|
|
VTABLE_PTR to validate, as well as the name of the vtable map
|
|
variable (SET_SYMBOL_NAME) and VTABLE_NAME, which are used for
|
|
debugging messages. It checks to see if VTABLE_PTR is in the set
|
|
pointed to by SET_HANDLE_PTR. If so, it returns VTABLE_PTR,
|
|
otherwise it calls __vtv_verify_fail, which usually logs error
|
|
messages and calls abort. */
|
|
|
|
const void *
|
|
__VLTVerifyVtablePointerDebug (void **set_handle_ptr, const void *vtable_ptr,
|
|
const char *set_symbol_name,
|
|
const char *vtable_name)
|
|
{
|
|
unsigned long long start = get_cycle_count ();
|
|
VTV_DEBUG_ASSERT (set_handle_ptr != NULL && *set_handle_ptr != NULL);
|
|
int_vptr vtbl_ptr = (int_vptr) vtable_ptr;
|
|
|
|
increment_num_calls (&num_calls_to_verify_vtable);
|
|
vtv_set_handle *handle_ptr;
|
|
if (!is_set_handle_handle (*set_handle_ptr))
|
|
handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
else
|
|
handle_ptr = ptr_from_set_handle_handle (*set_handle_ptr);
|
|
|
|
if (vtv_sets::contains (vtbl_ptr, handle_ptr))
|
|
{
|
|
if (debug_verify_vtable)
|
|
{
|
|
if (verify_vtable_log_fd == -1)
|
|
__vtv_open_log ("vtv_verify_vtable.log");
|
|
__vtv_add_to_log (verify_vtable_log_fd,
|
|
"Verified %s %s value = %p\n",
|
|
set_symbol_name, vtable_name, vtable_ptr);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* We failed to find the vtable pointer in the set of valid
|
|
pointers. Log the error data and call the failure
|
|
function. */
|
|
snprintf (debug_log_message, sizeof (debug_log_message),
|
|
"Looking for %s in %s\n", vtable_name, set_symbol_name);
|
|
__vtv_verify_fail_debug (set_handle_ptr, vtable_ptr, debug_log_message);
|
|
|
|
/* Normally __vtv_verify_fail_debug will call abort, so we won't
|
|
execute the return below. If we get this far, the assumption
|
|
is that the programmer has replaced __vtv_verify_fail_debug
|
|
with some kind of secondary verification AND this secondary
|
|
verification succeeded, so the vtable pointer is valid. */
|
|
}
|
|
accumulate_cycle_count (&verify_vtable_cycles, start);
|
|
|
|
return vtable_ptr;
|
|
}
|
|
|
|
/* This routine initializes a set handle to a vtable set. It makes
|
|
sure that there is only one set handle for a particular set by
|
|
using a map from set name to pointer to set handle. Since there
|
|
will be multiple copies of the pointer to the set handle (one per
|
|
compilation unit that uses it), it makes sure to initialize all the
|
|
pointers to the set handle so that the set handle is unique. To
|
|
make this a little more efficient and avoid a level of indirection
|
|
in some cases, the first pointer to handle for a particular handle
|
|
becomes the handle itself and the other pointers will point to the
|
|
set handle. SET_HANDLE_PTR is the address of the vtable map
|
|
variable, SET_SYMBOL_KEY is the hash table key (containing the name
|
|
of the map variable and the hash value) and SIZE_HINT is a guess
|
|
for the best initial size for the set of vtable pointers that
|
|
SET_HANDLE_POINTER will point to.*/
|
|
|
|
static inline void
|
|
init_set_symbol (void **set_handle_ptr, const void *set_symbol_key,
|
|
size_t size_hint)
|
|
{
|
|
vtv_set_handle *handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
|
|
if (*handle_ptr != NULL)
|
|
{
|
|
if (!is_set_handle_handle (*set_handle_ptr))
|
|
handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
else
|
|
handle_ptr = ptr_from_set_handle_handle (*set_handle_ptr);
|
|
vtv_sets::resize (size_hint, handle_ptr);
|
|
return;
|
|
}
|
|
|
|
if (vtv_symbol_unification_map == NULL)
|
|
vtv_symbol_unification_map = s2s::create (1024);
|
|
|
|
vtv_symbol_key *symbol_key_ptr = (vtv_symbol_key *) set_symbol_key;
|
|
const s2s::value_type *map_value_ptr =
|
|
vtv_symbol_unification_map->get (symbol_key_ptr);
|
|
|
|
if (map_value_ptr != NULL)
|
|
{
|
|
if (*map_value_ptr == handle_ptr)
|
|
vtv_sets::resize (size_hint, *map_value_ptr);
|
|
else
|
|
{
|
|
/* The one level handle to the set already exists. So, we
|
|
are adding one level of indirection here and we will
|
|
store a pointer to the one level pointer here. */
|
|
vtv_set_handle_handle *handle_handle_ptr =
|
|
(vtv_set_handle_handle *) handle_ptr;
|
|
*handle_handle_ptr = set_handle_handle (*map_value_ptr);
|
|
vtv_sets::resize (size_hint, *map_value_ptr);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* We will create a new set. So, in this case handle_ptr is the
|
|
one level pointer to the set handle. Create copy of map name
|
|
in case the memory where this comes from gets unmapped by
|
|
dlclose. */
|
|
size_t map_key_len = symbol_key_ptr->n + sizeof (vtv_symbol_key);
|
|
void * map_key = __vtv_malloc (map_key_len);
|
|
memcpy (map_key, symbol_key_ptr, map_key_len);
|
|
|
|
s2s::value_type * value_ptr;
|
|
vtv_symbol_unification_map =
|
|
vtv_symbol_unification_map->find_or_add_key ((vtv_symbol_key *)map_key,
|
|
&value_ptr);
|
|
|
|
*value_ptr = handle_ptr;
|
|
|
|
/* TODO: We should verify the return value. */
|
|
vtv_sets::create (size_hint, handle_ptr);
|
|
}
|
|
}
|
|
|
|
/* This routine initializes a set handle to a vtable set. It makes
|
|
sure that there is only one set handle for a particular set by
|
|
using a map from set name to pointer to set handle. Since there
|
|
will be multiple copies of the pointer to the set handle (one per
|
|
compilation unit that uses it), it makes sure to initialize all the
|
|
pointers to the set handle so that the set handle is unique. To
|
|
make this a little more efficient and avoid a level of indirection
|
|
in some cases, the first pointer to handle for a particular handle
|
|
becomes the handle itself and the other pointers will point to the
|
|
set handle. SET_HANDLE_PTR is the address of the vtable map
|
|
variable, SET_SYMBOL_KEY is the hash table key (containing the name
|
|
of the map variable and the hash value) and SIZE_HINT is a guess
|
|
for the best initial size for the set of vtable pointers that
|
|
SET_HANDLE_POINTER will point to.*/
|
|
|
|
|
|
void
|
|
__VLTRegisterSet (void **set_handle_ptr, const void *set_symbol_key,
|
|
size_t size_hint, size_t num_args, void **vtable_ptr_array)
|
|
{
|
|
unsigned long long start = get_cycle_count ();
|
|
increment_num_calls (&num_calls_to_regset);
|
|
|
|
init_set_symbol (set_handle_ptr, set_symbol_key, size_hint);
|
|
register_set_common (set_handle_ptr, num_args, vtable_ptr_array, false);
|
|
|
|
accumulate_cycle_count (®set_cycles, start);
|
|
}
|
|
|
|
|
|
|
|
/* This function takes a the address of a vtable map variable
|
|
(SET_HANDLE_PTR) and a VTABLE_PTR. If the vtable map variable is
|
|
NULL it creates a new data set and initializes the variable,
|
|
otherwise it uses our symbol unification to find the right data
|
|
set; in either case it then adds the vtable pointer to the set. */
|
|
|
|
void
|
|
__VLTRegisterPair (void **set_handle_ptr, const void *set_symbol_key,
|
|
size_t size_hint, const void *vtable_ptr)
|
|
{
|
|
unsigned long long start = get_cycle_count ();
|
|
increment_num_calls (&num_calls_to_regpair);
|
|
|
|
init_set_symbol (set_handle_ptr, set_symbol_key, size_hint);
|
|
register_pair_common (set_handle_ptr, vtable_ptr, NULL, NULL, false);
|
|
|
|
accumulate_cycle_count (®pair_cycles, start);
|
|
}
|
|
|
|
/* This is the main verification function. It takes the address of a
|
|
vtable map variable (SET_HANDLE_PTR) and a VTABLE_PTR to validate.
|
|
It checks to see if VTABLE_PTR is in the set pointed to by
|
|
SET_HANDLE_PTR. If so, it returns VTABLE_PTR, otherwise it calls
|
|
__vtv_verify_fail, which usually logs error messages and calls
|
|
abort. Since this function gets called VERY frequently, it is
|
|
important for it to be as efficient as possible. */
|
|
|
|
const void *
|
|
__VLTVerifyVtablePointer (void ** set_handle_ptr, const void * vtable_ptr)
|
|
{
|
|
unsigned long long start = get_cycle_count ();
|
|
int_vptr vtbl_ptr = (int_vptr) vtable_ptr;
|
|
|
|
vtv_set_handle *handle_ptr;
|
|
increment_num_calls (&num_calls_to_verify_vtable);
|
|
if (!is_set_handle_handle (*set_handle_ptr))
|
|
handle_ptr = (vtv_set_handle *) set_handle_ptr;
|
|
else
|
|
handle_ptr = ptr_from_set_handle_handle (*set_handle_ptr);
|
|
|
|
if (!vtv_sets::contains (vtbl_ptr, handle_ptr))
|
|
{
|
|
__vtv_verify_fail ((void **) handle_ptr, vtable_ptr);
|
|
/* Normally __vtv_verify_fail will call abort, so we won't
|
|
execute the return below. If we get this far, the assumption
|
|
is that the programmer has replaced __vtv_verify_fail with
|
|
some kind of secondary verification AND this secondary
|
|
verification succeeded, so the vtable pointer is valid. */
|
|
}
|
|
accumulate_cycle_count (&verify_vtable_cycles, start);
|
|
|
|
return vtable_ptr;
|
|
}
|
|
|
|
static int page_count_2 = 0;
|
|
|
|
#if !defined (__CYGWIN__) && !defined (__MINGW32__)
|
|
static int
|
|
dl_iterate_phdr_count_pages (struct dl_phdr_info *info,
|
|
size_t unused __attribute__ ((__unused__)),
|
|
void *data)
|
|
{
|
|
int *mprotect_flags = (int *) data;
|
|
off_t map_sect_offset = 0;
|
|
ElfW (Word) map_sect_len = 0;
|
|
const char *map_sect_name = VTV_PROTECTED_VARS_SECTION;
|
|
|
|
/* Check to see if this is the record for the Linux Virtual Dynamic
|
|
Shared Object (linux-vdso.so.1), which exists only in memory (and
|
|
therefore cannot be read from disk). */
|
|
|
|
if (strcmp (info->dlpi_name, "linux-vdso.so.1") == 0)
|
|
return 0;
|
|
|
|
if (strlen (info->dlpi_name) == 0
|
|
&& info->dlpi_addr != 0)
|
|
return 0;
|
|
|
|
read_section_offset_and_length (info, map_sect_name, *mprotect_flags,
|
|
&map_sect_offset, &map_sect_len);
|
|
|
|
/* See if we actually found the section. */
|
|
if (map_sect_len)
|
|
page_count_2 += (map_sect_len + VTV_PAGE_SIZE - 1) / VTV_PAGE_SIZE;
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static void
|
|
count_all_pages (void)
|
|
{
|
|
int mprotect_flags;
|
|
|
|
mprotect_flags = PROT_READ;
|
|
page_count_2 = 0;
|
|
|
|
#if defined (__CYGWIN__) || defined (__MINGW32__)
|
|
iterate_modules ((void *) &mprotect_flags);
|
|
#else
|
|
dl_iterate_phdr (dl_iterate_phdr_count_pages, (void *) &mprotect_flags);
|
|
#endif
|
|
page_count_2 += __vtv_count_mmapped_pages ();
|
|
}
|
|
|
|
void
|
|
__VLTDumpStats (void)
|
|
{
|
|
int log_fd = __vtv_open_log ("vtv-runtime-stats.log");
|
|
|
|
if (log_fd != -1)
|
|
{
|
|
count_all_pages ();
|
|
__vtv_add_to_log (log_fd,
|
|
"Calls: mprotect (%d) regset (%d) regpair (%d)"
|
|
" verify_vtable (%d)\n",
|
|
num_calls_to_mprotect, num_calls_to_regset,
|
|
num_calls_to_regpair, num_calls_to_verify_vtable);
|
|
__vtv_add_to_log (log_fd,
|
|
"Cycles: mprotect (%lld) regset (%lld) "
|
|
"regpair (%lld) verify_vtable (%lld)\n",
|
|
mprotect_cycles, regset_cycles, regpair_cycles,
|
|
verify_vtable_cycles);
|
|
__vtv_add_to_log (log_fd,
|
|
"Pages protected (1): %d\n", num_pages_protected);
|
|
__vtv_add_to_log (log_fd, "Pages protected (2): %d\n", page_count_2);
|
|
|
|
close (log_fd);
|
|
}
|
|
}
|
|
|
|
/* This function is called from __VLTVerifyVtablePointerDebug; it
|
|
sends as much debugging information as it can to the error log
|
|
file, then calls __vtv_verify_fail. SET_HANDLE_PTR is the pointer
|
|
to the set of valid vtable pointers, VTBL_PTR is the pointer that
|
|
was not found in the set, and DEBUG_MSG is the message to be
|
|
written to the log file before failing. n */
|
|
|
|
void
|
|
__vtv_verify_fail_debug (void **set_handle_ptr, const void *vtbl_ptr,
|
|
const char *debug_msg)
|
|
{
|
|
__vtv_log_verification_failure (debug_msg, false);
|
|
|
|
/* Call the public interface in case it has been overwritten by
|
|
user. */
|
|
__vtv_verify_fail (set_handle_ptr, vtbl_ptr);
|
|
|
|
__vtv_log_verification_failure ("Returned from __vtv_verify_fail."
|
|
" Secondary verification succeeded.\n", false);
|
|
}
|
|
|
|
/* This function calls __fortify_fail with a FAILURE_MSG and then
|
|
calls abort. */
|
|
|
|
void
|
|
__vtv_really_fail (const char *failure_msg)
|
|
{
|
|
__fortify_fail (failure_msg);
|
|
|
|
/* We should never get this far; __fortify_fail calls __libc_message
|
|
which prints out a back trace and a memory dump and then is
|
|
supposed to call abort, but let's play it safe anyway and call abort
|
|
ourselves. */
|
|
abort ();
|
|
}
|
|
|
|
/* This function takes an error MSG, a vtable map variable
|
|
(DATA_SET_PTR) and a vtable pointer (VTBL_PTR). It is called when
|
|
an attempt to verify VTBL_PTR with the set pointed to by
|
|
DATA_SET_PTR failed. It outputs a failure message with the
|
|
addresses involved, and calls __vtv_really_fail. */
|
|
|
|
static void
|
|
vtv_fail (const char *msg, void **data_set_ptr, const void *vtbl_ptr)
|
|
{
|
|
char buffer[128];
|
|
int buf_len;
|
|
const char *format_str =
|
|
"*** Unable to verify vtable pointer (%p) in set (%p) *** \n";
|
|
|
|
snprintf (buffer, sizeof (buffer), format_str, vtbl_ptr,
|
|
is_set_handle_handle(*data_set_ptr) ?
|
|
ptr_from_set_handle_handle (*data_set_ptr) :
|
|
*data_set_ptr);
|
|
buf_len = strlen (buffer);
|
|
/* Send this to to stderr. */
|
|
write (2, buffer, buf_len);
|
|
|
|
#ifndef VTV_NO_ABORT
|
|
__vtv_really_fail (msg);
|
|
#endif
|
|
}
|
|
|
|
/* Send information about what we were trying to do when verification
|
|
failed to the error log, then call vtv_fail. This function can be
|
|
overwritten/replaced by the user, to implement a secondary
|
|
verification function instead. DATA_SET_PTR is the vtable map
|
|
variable used for the failed verification, and VTBL_PTR is the
|
|
vtable pointer that was not found in the set. */
|
|
|
|
void
|
|
__vtv_verify_fail (void **data_set_ptr, const void *vtbl_ptr)
|
|
{
|
|
char log_msg[256];
|
|
snprintf (log_msg, sizeof (log_msg), "Looking for vtable %p in set %p.\n",
|
|
vtbl_ptr,
|
|
is_set_handle_handle (*data_set_ptr) ?
|
|
ptr_from_set_handle_handle (*data_set_ptr) :
|
|
*data_set_ptr);
|
|
__vtv_log_verification_failure (log_msg, false);
|
|
|
|
const char *format_str =
|
|
"*** Unable to verify vtable pointer (%p) in set (%p) *** \n";
|
|
snprintf (log_msg, sizeof (log_msg), format_str, vtbl_ptr, *data_set_ptr);
|
|
__vtv_log_verification_failure (log_msg, false);
|
|
__vtv_log_verification_failure (" Backtrace: \n", true);
|
|
|
|
const char *fail_msg = "Potential vtable pointer corruption detected!!\n";
|
|
vtv_fail (fail_msg, data_set_ptr, vtbl_ptr);
|
|
}
|